Arabicum RCN

Di dalam buku Teknik Adenium Spektakuler, RCN memiliki karakteristik sebagai berikut:

1. Akar

Pada umumnya karakter akar RCN sama dengan arabicum dataran rendah yaitu caudex/ batang tinggi. Namun hal ini hanya didasarkan pada RCN dewasa yang ditanam dipot. Cabang tumbuh merumpun lurus dan meninggi. Tidak berkelok kelok seperti arabicum dataran rendah. Spasi perantingan sangat rapat dan kecil kecil.

2. Daun

Daun mengkilap seperti obesum, berukuran kecil, 2-5 cm, berbentuk bulat telur, dan seringkali agak mengatup seperti mangkok. Seringkali bagian pinggir daun berwarna keputihan yang ditafsirkan sebagian orang sebagai varigata. Kenyataannya, bila kebutuhan semua unsur hara terpenuhi, warna menjadi hijau segar.

3. Bunga

Sosok, ukuran, dan bentuk mirip arabicum dataran tinggi dan rendah. Hanya saja ia berbunga jauh lebih banyak karena rantingnya amat rimbun. Saking lebat bunganya, ia dijuluki queen of thousand flowers.

ULAT ADENIUM

ULAT ADENIUM

Salah satu hama yang menyerang adenium adalah ulat atau larva kupu-kupu. Meskipun hama ini tidak langsung mematikan tanaman, namun karena tingkat serangannya yg lebih sering serta tingkat kerusakan yang tinggi, hama ini harus diwaspadai dengan seksama.

Ulat adenium berasal dari larva ngengat, dimana ngengat adalah keluarga dekat kupu-kupu (Lepidoptera). Ngengat merupakan serangga yang tergolong ke dalam ordo Lepidoptera, atau 'serangga bersayap sisik' (lepis, sisik dan pteron, sayap).
Metamorfose ngengat bertipe sempurna (Holometabola) yang perkembangannya melalui stadia : telur ---> larva ---> kepompong ---> dewasa. Larva bertipe polipoda , memiliki baik kaki thoracal maupun abdominal, sedang pupanya bertipe obtekta. Melalui sebuah evolusi, larva ngengat akhirnya mampu beradaptasi dengan memangsa adenium yg banyak mengandung racun (toksin). Racun adenium ini terdapat pada diseluruh bagian tanaman. Bahan racun tersebut diantaranya :

• Digitalis glikosid (kardiak glikosid)
• ekugin
• cardenolides somalin
• hongheloside A
• 16-acetylstrospeside
• honghelin
• Oleandrigenin beta-gentiobiosyl-beta-D-thevetoside
• Neridienone A dan 16,17 - dihydroneridienone
• dihydroifflaionic acid
• flavonol, 3-O-methylkaempferol
• flavonol 3,3′ - bis(O-methyl) quercetin

TELUR
Telur ngengat berwarna hijau kekuningan, soliter, bulat, berukuran 0,75--1,00 mm, diletakkan pada permukaan daun bagian bawah. Stadia telur 4--6 hari. Telur ini diletakkan satu persatu dan bukan berkelompok pada satu daun.

ULAT / LARVA
Pada stadium larva, ulat terdiri dari 6 instar. Instar pertama panjangnya sekitar 1,2 – 1,5 mm, instar kedua sampai instar terakhir antara 1,5 – 19 mm. Setelah instar terakhir ulat merayap atau menjatuhkan diri ke tanah untuk berkepompong. Ulat lebih aktif pada malam hari. Stadium larva berlangsung selama 8 – 10 hari.
Larva yang masih kecil merusak daun dengan meninggalkan sisa-sisa epidermis bagian atas/transparan dan tinggal tulang-tulang daun saja dengan menggunakan mulut bertype menggigit. Larva instar lanjut merusak tulang daun bunga bahkan pucuk muda dan kadang-kadang menyerang buah. Biasanya larva berada di permukaan bawah daun memakan daun demi daun hingga dapat menyebabkan tanaman gundul karena daun. Serangan berat umumnya terjadi pada musim hujan. Larva mempunyai warna yang bervariasi. Ulat yang baru menetas berwarna hijau muda dan hidup sendiri-sendiri. Beberapa hari kemudian tergantung ketersediaan makanan, panjang ulat sekitar 5 cm.

PUPA
Setelah ulat berumur +/- 2 minggu akan mencapai panjang 6-7 cm selanjutnya akan berhenti makan dan turun ke dalam media atau bawah pot. Ulat berkepompong dalam tanah atau dibawah tumpukan daun kering dan dibawah pot, membentuk pupa tanpa rumah pupa (kokon) berwarna coklat kemerahan dengan panjang sekitar 5cm. Setelah pupa berumur 2-3 minggu (tergantung cuaca),maka pupa akan berubah menjadi ngengat.

NGENGAT
Pada stadium ngengat ini, biasanya bukan merupakan hama. Warna ngengat sangat tergantung warna ulat. Ulat yang berwarna hijau, akan berubah menjadi ngengat hijau, sedangkan ulat merah akan berubah menjadi ngengat coklat Ngengat ini berbulu halus, jantan mempunyai antena berumbai sirip seperti daun kelapa, betina mempunyai antena seperti cambuk tanpa sirip. Sayap ngengat terdiri dari dua pasang, membranus dan tertutup oleh sisik-sisik yang berwarna-warni. Pada kepala dijumpai adanya alat mulut seranga bertipe pengisap.
Ngengat ini umumnya hidup dengan mengisap madu bunga (nektar/ sari kembang). Beberapa ngengat type lain juga lebih menyukai cairan yang diisap dari buah-buahan yang jatuh di tanah dan membusuk serta tanah basah
Perbedaan utama antara kupu-kupu dan ngengat terletak pada waktu aktifitasnya. Jika kupu-kupu aktif pada siang hari (diurnal), maka ngengat aktif pada malam hari (nocturnal). Pada malam hari ngengat dapat terbang sejauh 5 kilometer. Ngengat ini terbang berdasarkan receptor cahaya pada malam hari.

gb. ngengat Coklat

FISIOLOGI TUMBUHAN

Fisiologi Tumbuhan meliputi :

AKAR
Akar adalah bagian pokok di samping batang dan daun bagi tumbuhan yang tubuhnya telah merupakan kormus.

Sifat-sifat akar:

• Merupakan bagian tumbuhan yang biasanya terdapat di dalam tanah, dengan arah tumbuh ke pusat bumi (geotrop) atau menuju ke air (hidrotrop), meninggalkan udara dan cahaya.
• Tidak berbuku-buku, jadi juga tidak beruas dan tidak mendukung daun-daun atau sisik-sisik maupun bagian-bagian lainya.
• Warna tidak hijau, biasanya keputih-putihan atau kekuning-kuningan.
• Tumbuh terus pada ujungnya, tetapi umumnya pertumbuhannya masih kalah pesat jika dibandingkan dengan bagian permukaan tanah.
• Bentuk ujungnya seringkali meruncing, hingga lebih mudah untuk menembus tanah.
  

Fungsi akar bagi tumbuhan:

• memperkuat berdirinya tumbuhan.
• untuk menyerap air dan zat-zat makanan yang terlarut di dalam air tersebut dari dalam tanah.
• mengangkut air dan zat-zat makanan yang sudah diserap ke tempat-tempat pada tubuh tumbuhan yang memerlukan.
• kadang-kadang sebagai tempat untuk penimbunan makanan.

Jenis akar :
Secara umum, ada dua jenis akar yaitu

• Akar serabut. Akar ini umumnya terdapat pada tumbuhan monokotil. Walaupun terkadang, tumbuhan dikotil juga memilikinya (dengan catatan, tumbuhan dikotil tersebut dikembangbiakkan dengan cara cangkok, atau stek). Fungsi utama akar serabut adalah untuk memperkokoh berdirinya tumbuhan.
• Akar tunggang. Akar ini umumnya terdapat pada tumbuhan dikotil. Fungsi utamanya adalah untuk menyimpan makanan.

Modifikasi akar

• Akar napas. Akar naik ke atas tanah, khususnya ke atas air seperti pada genera Mangrove (Avicennia, Soneratia).
• Akar gantung. Akar sepenuhnya berada di atas tanah. Akar gantung terdapat pada tumbuhan epifit Anggrek.
• Akar banir. Akar ini banyak terdapat pada tumbuhan jenis tropik.
• Akar penghisap. Akar ini terdapat pada tumbuhan jenis parasit seperti benalu.

DAUN
Daun merupakan salah satu organ tumbuhan yang tumbuh dari batang, umumnya berwarna hijau dan terutama berfungsi sebagai penangkap energi dari cahaya matahari melalui fotosintesis. Daun merupakan organ terpenting bagi tumbuhan dalam melangsungkan hidupnya karena tumbuhan adalah organisme autotrof obligat, ia harus memasok kebutuhan energinya sendiri melalui konversi energi cahaya menjadi energi kimia.

Bentuk daun sangat beragam, namun biasanya berupa helaian, bisa tipis atau tebal. Gambaran dua dimensi daun digunakan sebagai pembeda bagi bentuk-bentuk daun. Bentuk dasar daun membulat, dengan variasi cuping menjari atau menjadi elips dan memanjang. Bentuk ekstremnya bisa meruncing panjang.

Daun juga bisa bermodifikasi menjadi duri (misalnya pada kaktus), dan berakibat daun kehilangan fungsinya sebagai organ fotosintetik. Daun tumbuhan sukulen atau xerofit juga dapat mengalami peralihan fungsi menjadi organ penyimpan air.

Warna hijau pada daun berasal dari kandungan klorofil pada daun. Klorofil adalah senyawa pigmen yang berperan dalam menyeleksi panjang gelombang cahaya yang energinya diambil dalam fotosintesis. Sebenarnya daun juga memiliki pigmen lain, misalnya karoten (berwarna jingga), xantofil (berwarna kuning), dan antosianin (berwarna merah, biru, atau ungu, tergantung derajat keasaman). Daun tua kehilangan klorofil sehingga warnanya berubah menjadi kuning atau merah (dapat dilihat dengan jelas pada daun yang gugur).

Fungsi daun

• Tempat terjadinya fotosintesis. Pada tumbuhan dikotil, terjadinya fotosintesis di jaringan parenkim palisade. sedangkan pada tumbuhan monokotil, fotosintesisi terjadi pada jaringan spons
• Sebagai organ pernapasan. Di daun terdapat stomata yang befungsi sebagai organ respirasi (lihat keterangan di bawah pada Anatomi Daun).
• Tempat terjadinya transpirasi.
• Tempat terjadinya gutasi.
• Alat perkembangbiakkan vegetatif.
  Misalnya pada tanaman cocor bebek (tunas daun).
  

Anatomi Daun

• Epidermis terbagi atas epidermis atas dan epidermis bawah. Epidermis berfungsi melindungi jaringan di bawahnya.
• Jaringan palisade atau jaringan tiang adalah jaringan yang berfungsi sebagai tempat terjadinya fotosintesis
• Jaringan spons atau jaringan bunga karang yang berongga. Jaringan ini berfungsi sebagai tempat menyimpan cadangan makanan. Berkas pembuluh angkut yang terdiri dari xilem atau pembuluh kayu dan floem atau pembuluh tapis. Xilem berfungsi untuk mengangkut air dan garam-garaman yang diserap akar dari dalam tanah ke daun (untuk digunakan sebagai bahan fotosintesis). Sedangkan floem berfungsi untuk mengangkut hasil fotosintesis ke seluruh tubuh tumbuhan.
• Stoma (jamak: stomata) berfungsi sebagai organ respirasi. Stoma mengambil CO2 dari udara untuk dijadikan bahan fotosintesis. Kemudian stoma akan mengeluarkan O2 sebagai hasil fotosintesis. Stoma ibarat hidung kita dimana stoma mengambil CO2 dari udara dan mengeluarkan O2, sedangkan hidung mengambil O2 dan mengeluarkan CO2. Stoma terletak di epidermis bawah. Selain stoma, tumbuhan tingkat tinggi juga bernafas melalui lentisel yang terletak pada batang.

ENDOSPERMA
Dalam botani, adalah bagian dari biji tumbuhan berbunga (Angiospermae) yang merupakan hasil dari pembuahan berganda selain embrio. Endosperma dapat dikatakan sebagai "saudara kembar" embrio karena selalu terbentuk bersama namun, berbeda dengan embrio yang diploid, endosperma adalah triploid.
Endosperma dapat dilihat dengan jelas pada biji-bijian tertentu, seperti padi, jagung, apokat, serta jarak. Fungsinya yang paling utama adalah sebagai penyedia cadangan energi bagi embrio dalam proses perkecambahan. Karena itu, protein penyusunnya adalah albumin, protein yang larut dalam air. Karena fungsinya ini, pada endosperma seringkali terkandung karbohidrat dan lemak. Walaupun demikian, endosperma tidak selalu ditemukan pada biji-biji yang masak. Pada suku kacang-kacangan (Fabaceae) serta sawi-sawian (Brassicaceae) misalnya endosperma tidak ditemukan karena menyusut (rudimenter) dalam perkembangan biji.

FITOKROM

Fitokrom adalah reseptor cahaya, suatu pigmen yang digunakan oleh tumbuhan untuk mencerap (mendeteksi) cahaya. Sebagai sensor, ia terangsang oleh cahaya merah dan infra merah[1] Infra merah bukanlah bagian dari cahaya tampak oleh mata manusia namun memiliki panjang gelombang yang lebih besar daripada merah.
Fitokrom ditemukan pada semua tumbuhan. Molekul yang serupa juga ditemukan pada bakteri. Tumbuhan menggunakan fitokrom untuk mengatur beberapa aspek fisiologi adaptasi terhadap lingkungan, seperti fotoperiodisme (pengaturan saat berbunga pada tumbuhan), perkecambahan, pemanjangan dan pertumbuhan kecambah (khususnya pada dikotil), morfologi daun, pemanjangan ruas batang, serta pembuatan (sintesis) klorofil.
Secara struktur kimia, bagian sensor fitokrom adalah suatu kromofor dari kelompok bilin (jadi disebut fitokromobilin), yang masih sekeluarga dengan klorofil atau hemoglobin (kesemuanya memiliki kerangka heme). Kromofor ini dilindungi atau diikat oleh apoprotein, yang juga berpengaruh terhadap kinerja bagian sensor. Kromofor dan apoprotein inilah yang bersama-sama disebut sebagai fitokrom.

Penemuan
Penelitian rintisan terhadap pengaruh cahaya merah dan merah jauh terhadap pertumbuhan tumbuhan antara 1940-1960 dilakukan oleh Sterling Hendricks dan Harry Borthwick dari Pusat Penelitian Pertanian Beltsville di Maryland, dengan menggunakan spektrograf dari bahan-bahan sisa Perang Dunia Kedua. Dari hasilnya diketahui bahwa cahaya merah memacu perkecambahan dan memicu tanggap untuk pembungaan. Lebih lanjut, cahaya merah jauh berpengaruh sebaliknya terhadap pengaruh cahaya merah. Penelitian lanjutan menunjukkan bahwa bagian yang peka terhadap rangsang cahaya ini berada di daun.
Baru pada tahun 1959 Warren Butler, ahli biofisika, dan Harold Siegemman, ahli biokimia, berhasil mengidentifikasi pigmen yang bertanggung jawab untuk gejala ini menggunakan teknik spektrofotometri. Butler menamakan pigmen itu sebagai fitokrom (secara harafiah berarti "zat warna tumbuhan").
Diperlukan waktu 23 tahun sebelum Peter Quail dan Clark Lagarias melaporkan pemurnian kimiawi fitokrom dari tumbuhan (1983). Selanjutnya, perhatian diarahkan pada struktur dan aspek genetika molekularnya. Sekuens gen fitokrom pertama kali diumumkan pada tahun 1985 oleh Howard Hershey and Peter Quail. Berturut-turut dilaporkan bahwa terdapat bermacam-macam tipe fitokrom, yang dikendalikan oleh gen-gen yang berbeda. Kapri, misalnya, hingga sekarang diketahui memiliki paling sedikit dua tipe, Arabidopsis thaliana memiliki lima gen fitokrom, sementara padi hanya tiga. Jagung memiliki enam gen. Perbedaan-perbedaan itu semua terletak pada bagian apoprotein, sementara senyawa sensor cahayanya tetap sama: fitokromobilin.
Pada tahun 1996 diketahui adanya gen (disebut Cph1) dari bakteri biru hijau Synechocystis yang agak memiliki kemiripan sekuens dengan gen-gen fitokrom dari tumbuhan. Jon Hughes dari Berlin dan Clark Lagarias dari Universitas California di Davis secara berturut-turut melaporkan bahwa gen ini mengkode "fitokrom", dalam pengertian sebagai kromoprotein yang sensitif terhadap perubahan rangsang cahaya merah/merah jauh. Dari penelitian terhadap Cph1 selanjutnya orang mengetahui bagaimana mekanisme kerja fitokrom. Penggunaan Cph1 lebih ekonomis karena bakteri biru hijau relatif mudah dikerjakan di laboratorium daripada tumbuhan, dan juga lebih produktif. Dalam perkembangan selanjutnya, gen-gen fitokrom ditemukan pula pada prokariot Deinococcus radiodurans dan Agrobacterium tumefaciens. Peran biologi fitokrom pada Synechocystis dan Agrobacterium belum diketahui, sementara bagi Deinococcus fitokrom mengatur produksi pigmen pelindung dari cahaya.
Pada tahun 2005 tim dari laboratorium Vierstra berhasil membuat model tiga dimensi fitokrom dari bakteri Deinococcus. Bentuk protein fitokrom sangat tidak lazim karena memiliki simpul ("knot").

Catatan kaki
Dalam konteks fitokrom, infra merah sering kali disebut "merah jauh" atau far-red.
Kriptokrom, reseptor cahaya biru
Fototropin, reseptor cahaya ultraungu

FOTORESPIRASI
Fotorespirasi adalah sejenis respirasi pada tumbuhan yang dibangkitkan oleh penerimaan cahaya yang diterima oleh daun. Diketahui pula bahwa kebutuhan energi dan ketersediaan oksigen dalam sel juga mempengaruhi fotorespirasi. Walaupun menyerupai respirasi (pernafasan) biasa, yaitu proses oksidasi yang melibatkan oksigen, mekanisme respirasi karena rangsangan cahaya ini agak berbeda dan dianggap sebagai proses fisiologi tersendiri.
Proses
Proses yang disebut juga "asimilasi cahaya oksidatif" ini terjadi pada sel-sel mesofil daun dan diketahui merupakan gejala umum pada tumbuhan C3, seperti kedelai dan padi. Lebih jauh, proses ini hanya terjadi pada stroma dari kloroplas, dan didukung oleh peroksisom dan mitokondria.
Secara biokimia, proses fotorespirasi merupakan cabang dari jalur glikolat. Enzim utama yang terlibat adalah enzim yang sama dalam proses reaksi gelap fotosintesis, Rubisco (ribulosa-bifosfat karboksilase-oksigenase). Rubisco memiliki dua sisi aktif: sisi karboksilase yang aktif pada fotosintesis dan sisi oksigenase yang aktif pada fotorespirasi. Kedua proses yang terjadi pada stroma ini juga memerlukan substrat yang sama, ribulosa bifosfat (RuBP), dan juga dipengaruhi secara positif oleh konsentrasi ion Magnesium dan derajat keasaman (pH) sel. Dengan demikian fotorespirasi menjadi pesaing bagi fotosintesis, suatu kondisi yang tidak disukai kalangan pertanian, karena mengurangi akumulasi energi.
Jika kadar CO2 dalam sel rendah (misalnya karena meningkatnya penyinaran dan suhu sehingga laju produksi oksigen sangat tinggi dan stomata menutup), RuBP akan dipecah oleh Rubisco menjadi P-glikolat dan P-gliserat (dengan melibatkan satu molekul air menjadi glikolat dan P-OH). P-gliserat (P dibaca "fosfo") akan didefosforilasi oleh ADP sehingga membentuk ATP. P-glikolat memasuki proses agak rumit menuju peroksisoma, lalu mitokondria, lalu kembali ke peroksisoma untuk diubah menjadi serin, lalu gliserat. Gliserat masuk kembali ke kloroplas untuk diproses secara normal oleh siklus Calvin menjadi gliseraldehid-3-fosfat (G3P).
Kegunaan
Peran fotorespirasi diperdebatkan namun semua kalangan sepakat bahwa fotorespirasi merupakan penyia-nyiaan energi. Dari sisi evolusi, proses ini dianggap sebagai sisa-sisa ciri masa lampau (relik). Atmosfer pada masa lampau mengandung oksigen pada kadar yang rendah, sehingga fotorespirasi tidak terjadi seintensif seperti masa kini. Fotorespirasi dianggap bermanfaat karena menyediakan CO2 dan NH3 bebas untuk diasimilasi ulang, sehingga dianggap sebagai mekanisme daur ulang (efisiensi). Pendapat lain menyatakan bahwa fotorespirasi tidak memiliki fungsi fisiologis apa pun, baik sebagai penyedia asam amino tertentu (serin dan glisin) maupun sebagai pelindung klorofil dari perombakan karena fotooksidasi.Karena tidak efisien, sejumlah tumbuhan mengembangkan mekanisme untuk mencegah fotorespirasi. Untuk menekan fotorespirasi, tumbuhan C4 mengembangkan strategi ruang dengan memisahkan jaringan yang melakukan reaksi terang (sel mesofil) dan reaksi gelap (sel selubung pembuluh, atau bundle sheath). Sel-sel mesofil tumbuhan C4 tidak memiliki Rubisco. Strategi yang diambil tumbuhan CAM bersifat waktu (temporal), yaitu memisahkan waktu untuk reaksi terang (pada saat penyinaran penuh) dan reaksi gelap (di malam hari).

GETAH

Getah adalah istilah umum untuk menyebut cairan kental yang keluar dari tubuh, baik tumbuhan maupun hewan. Namun demikian, penggunaan getah pada hewan terbatas, yaitu untuk menyebut cairan limfa (getah bening).
Pada tumbuhan, getah adalah segala sesuatu yang bersifat cair dan kental yang keluar dari batang atau daun yang terluka. Dengan demikian tidak dibedakan apakah cairan itu merupakan cairan nutrisi dari pembuluh tapis, lateks, atau resin. Lateks dan resin merupakan cairan yang dihasilkan dari pembuluh khusus. Bagi tumbuhan fungsinya adalah sebagai alat pertahanan diri.
Lateks dihasilkan oleh banyak tumbuhan anggota bangsa Malpighiales (misalnya suku Apocynaceae dan Euphorbiaceae). Resin, hars, atau cairan damar merupakan cairan kental dan agak transparan yang mengeras bila terkena udara. Resin dihasilkan oleh banyak anggota bangsa Pinales serta sejumlah anggota Dipterocarpaceae dan Burseraceae.

Klorofil adalah kelompok pigmen fotosintesis yang terdapat dalam tumbuhan, menyerap cahaya merah, biru dan ungu, serta merefleksikan cahaya hijau yang menyebabkan tumbuhan memperoleh ciri warnanya. Terdapat dalam kloroplas dan memanfaatkan cahaya yang diserap sebagai energi untuk reaksi-reaksi cahaya dalam proses fotosintesis.
Klorofil A merupakan salah satu bentuk klorofil yang terdapat pada semua tumbuhan autotrof. Klorofil B terdapat pada ganggang hijau chlorophyta dan tumbuhan darat. Klorofil C terdapat pada ganggang coklat Phaeophyta serta diatome Bacillariophyta. Klorofil d terdapat pada ganggang merah Rhadophyta.
Kromofor (chromophore) adalah bagian dari pigmen yang paling sensitif terhadap rangsangan cahaya. Kromofor berfungsi sebagai antena, alat penangkap gelombang elektromagnetik pada panjang gelombang tertentu. Suatu panjang gelombang spektrum tertentu dapat merangsang perubahan struktur molekul kromofor karena molekul itu "tereksitasi". Perubahan struktur ini mengakibatkan pelepasan energi/elektron. Energi atau elektron yang terlepas ini lalu ditangkap oleh sistem pembawa signal (signaling) yang pada akhirnya memicu dihasilkannya sejumlah enzim bagi suatu proses biokimia tertentu.
Pada tumbuhan, kromofor selalu merupakan molekul dengan kerangka heme, seperti pada fitokrom dan klorofil.

RUBISCO
Ribulosa-1,5-bisfosfat karboksilase-oksigenase, disingkat Rubisco (dari nama bahasa Inggrisnya), adalah enzim raksasa yang berperan sangat penting dalam reaksi gelap fotosintesis tumbuhan. Enzim inilah yang menggabungkan molekul ribulosa-1,5-bisfosfat (RuBP, kadang-kadang disebut RuDP) yang memiliki tiga atom C dengan karbondioksida menjadi atom dengan enam C, untuk kemudian diproses lebih lanjut menjadi glukosa, molekul penyimpan energi aktif utama pada tumbuhan.
Enzim ini sangat banyak dikandung oleh sel-sel daun dan merupakan salah satu protein yang paling banyak dihasilkan di dunia.
Rubisco merupakan enzim dengan empat gugus polipeptida besar yang mirip dan empat gugus polipeptida kecil yang juga mirip satu sama lain. Ia memiliki dua sisi aktif yang saling bersaing untuk dua reaksi yang bertolak belakang. Sisi karboksilase, yang berfungsi pada fotosintesis, dan sisi oksigenase, yang bertanggung jawab dalam fotorespirasi. Kedua reaksi ini memerlukan RuBP sebagai substratnya.Dilihat dari komposisi asam amino penyusunnya, Rubisco sangatlah konservatif, dalam arti tidak banyak mengalami perubahan dalam urutan asam amino ataupun basa N dari gen-gen pengkodenya. Gen-gen Rubisco berlokasi di plastida.

Disunting dari :

http://id.wikipedia.org/wiki/Akar

Teknik Penyemaian Adenium

Teknik Penyemaian Adenium

Adenium merupakan tanaman hias yang mudah tumbuh. Pada kedua ujung biji terdapat bulu yang mampu membawa biji tersebut terbang jauh dan dapat tumbuh dengan mudah. Jika ingin mendulang sukses dalam menyemai benih adenium, kuncinya adalah penggunaan media yang steril dan berkualitas baik. Jika dalam tahap awal memulai anda tidak yakin pada media yg digunakan, sebelumnya sterilkan dulu dengan cara mengukus dan menyemprotkan fungisida serta menjemurnya.

Berikut ini langkah-langkah dalam menyemai adenium :
1. Rendam biji dalam air hangat (suam kuku) sekitar 10 menit.

2. Siapkan media dalam pot dengan komposisi sekam bakar dan cocopeat dengan perbandingan 1 : 1.
3. Isi pot dengan ¾ media saja.
4. Letakkan biji-biji dengan posisi horizontal (terbaring) dengan jaraj antar biji 1 cm.
5. Taburkan media secara merata dengan ketebalan sekitar ½ - 1 cm.
6. Taruh ditempat teduh yang terhalang dari sinar matahari dan hujan, lakukan spray air setiap hari atau tergantung kondisi media agar kelembaban terjaga.
7. Dalam waktu 4-6 hari biji akan mulai tumbuh.
8. Setelah seedling berdaun 4-6 daun pindahkan ke dalam pot/polybag individu serta tambahkan media yang telah dicampur pupuk kandang dengan perbandingan 1:1. Usahakan tanaman tetap terlindung dari hujan dan panas secara langsung kurang lebih 2 minggu. Selepas itu tanaman dapat diletakkan apda areal trebuka dengan intensitas cahaya matahari penuh minimal 8 jam per hari.
9. Tambahkan pupuk yang banyak mengandung unsure N (nitrogen) tinggi untuk menjamin pertumbuhan vegetatif. Pupuk kimia yang terbaik untuk tanaman adenium adalah yang berujud cair.
10. Jika anda menggunakan kompos, gunakan daun kering bamboo, petai cina, atau cacahan pakis yang banyak mengandung unsur nitrogen tinggi, namun harap berhati-hati dengan daya rekat air pada media kompos tersebut.

Selamat mecoba

Zaidaflora

The Genus Adenium In Cultivation

THE GENUS ADENIUM IN CULTIVATION
PART 1: A.OBESUM AND A.MULTIFLORUM
MARK A.DIMMITT § AND CHUCK HANSON §§
§ Arizona-Sonora Desert Museum, §§ Arid Lands Greenhouses
© No reproduction without consent of the authors

Adenium is a genus of spectacular succulents from tropical Africa and ArabiA.The species range from shrublets with subterranean or above-ground caudexes to small trees with swollen trunks and stems to 15 feet tall. Their striking forms are further enhanced by some of the showiest flowers of all succulents, often borne in masses over a long season. Last but not least, they adapt readily to container culture in the warmer parts of the world (Dimmitt and Hanson, in press).
Some authors recognize only one species in the genus, Adenium obesum (Rowley, undated); others split it into six or more (Plaizier, 1980). Each taxon, whether recognized as a species or variety, is a distinct entity from a horticultural viewpoint, exhibiting a unique combination of plant habit, growth cycle, flower form, and blooming season. We regard most of the taxa as species, based on easily recognized forms in cultivation which seem to overlap little or not at all in nature.
Despite their beauty and ease of culture, adeniums are not nearly as popular as one might expect. Perhaps they simply haven't received the exposure they deserve. This series of articles will describe the nine recognized taxa plus several selected clones and hybrids from a horticultural perspective.
Adenium obesum (Desert Rose)
Adenium obesum (A.obesum var. obesum Roem. & Schult.) (Figs. 1, 2) even as narrowly defined here is a highly variable taxon in growth and flowering habits. It occurs nearly all the way across Africa in a broad band south of the Sahara, from Senegal to Sudan and Kenya (Plaizier, 1980; Rowley, undated). Most plants in cultivation are of unknown origin, so it is not known how much of the natural variation of this wide-ranging taxon is represented. The few documented plants known to the authors are from southeastern Kenya, except for A.o. var. coetanum (='Singapore'), which is reportedly from Arabia (Albert Chan, pers. comm.).
Adenium obesum is a shrubby plant. The thickened stems taper gradually upwards and may be rigid and upright or, less commonly, rather weak and spreading. Young plants have a small, ovoid caudex, and old specimens in habitat have large caudexes. Mature plants in cultivation, however, usually lack a distinct one (Fig. 5).
Therefore this species is not, strictly speaking, a caudiciform in cultivation. (See Rowley, 1987 for an excellent definition.) The leaves range from narrow-linear to quite broad (but never as broad as those of A.multiflorum), and from bright, shiny green to light, dull green.
Adenium obesum is potentially semi-evergreen: if kept warm and well watered, plants will grow and often flower through the winter. Under such conditions they undergo only a brief leaf-drop and dormancy, usually a few weeks in spring or early summer. They can also endure a drought or cold-induced dormancy of several months, which is the normal condition in nature.
The flowers (Fig. 2) are pale pink to deep red on the petal margins, always fading to near white toward the throat. The throat (floral tube) is white, sometimes with faint red nectar guides. The anther appendages are long, equaling or exceeding the throat. Flower size averages about 6-7 cm (2 inches) in diameter, but this is quite variable among clones.
Flowering habit is extremely variable and is influenced by both cultural and genetic factors. When grown under ideal conditions of ample heat and water, some clones flower for two to four months; some clones are nearly everblooming. Most plants slow their growth and stop flowering when temperatures exceed about 100 degrees F, which occurs from about mid June to early August in Tucson (Dimmitt and Hanson, in press).
Seed-grown plants are typically vigorous and can be flowered in as little as 8 to 12 months. Cutting-grown plants are equally vigorous; their roots become greatly enlarged in a couple of years and can be exposed when the plant is repotted to make a more interesting specimen. After several years the stems also will have thickened such that cuttings are indistinguishable from seed-grown plants. This is by far the commonest taxon of the genus in cultivation.
Adenium multiflorum (Sabi Star)
Adenium multiflorum [A.obesum var. multifiorum (Klotsch) Codd] (Figs. 3, 4) is very different from A.obesum both horticulturally and geographically. It occurs on the east side of southern Africa, in Mozambique and the countries bordering it on the west and south. Neither Plaizier (1980) nor Rowley (undated) show any geographic overlap with A.obesum on their distribution maps, though Rowley says that intergrades occur. (They easily cross in cultivation.)
In nature the plants are tall, multiple-stemmed shrubs (Plaizier, 1980). In cultivation they are always thick, sturdy, and upright. As in A.obesum, there is no distinct caudex in mature cultivated plants, but they have very enlarged stems and roots. Seedlings have a prominent, ovoid caudex for the first several years. The leaves are large and very broad.
In distinct contrast with A.obesum, this species has an obligatory long winter dormancy. Regardless of growing conditions, the leaves fall in autumn; growth will not resume for at least four months, longer in cool or dry conditions.
Adenium multiflorum flowers profusely for two to four months in winter while leafless, never at other times. The petals are white with sharply defined red edges (Fig. 4). There are always 15 prominent red nectar guides in the white throat (three per petal). The anther appendages equal or exceed the throat. Flowers average about 6-7 cm (2 1/2 inches) in diameter, and the petals are more pointed than those of A.obesum.
Adenium multiflorum grow vigorously from seed, but mature at a larger size than plants of A.obesum. Plants rarely flower until they are 4 to 5 years old. Cuttings of A.muitiflorum develop thick roots and stems and make good specimens after a few years. This taxon is in cultivation but is a distant second to A.obesum in availability, probably because of its slower growth and shorter blooming season.
Fig.1. A four-year-old cutting of Adenium obesum 'Red Everblooomer'. This clone is more upright than many plants of this taxon and has unusually dark flowers.
Fig.3. An eleven-year-old seed-grown plant of Adenium multiflorum. The profusion of flowers on a leafless plant is typical of this taxon. Note the absence of a caudex on this mature specimen.

Fig.2. Flower of Adenium obesum 'Red Everbloomer'. Note that the petal color fades toward the unmarked throat. (Nectar guides are sometimes present.)
Fig.5. Close-up of the base of a 12-year-old Adenium obesum, showing the absence of a distinct caudex. The plant is in a24-inch pot and is 6 feet tall.
Fig.4. Flowers of Adenium multiflorum. The distict red edge, narrow petals, and prominent nectar guides (stripes) in the throat are diagnostic.



PART 2: A.SWAZICUM, A.BOEHMIANUM AND A.OLEIFOLIUM
MARK A. DIMMITT § AND CHUCK HANSON §§
§ Arizona-Sonora Desert Museum, §§ Arid Lands Greenhouses
© No reproduction without consent of the authors
Adenium is a genus of spectacular succulents from tropical Africa and Arabia. They range from shrublets with subterranean or above-ground caudexes to small trees with succulent stems to 15 feet tall. Their striking forms are further enhanced by some of the most beautiful flowers of all succulents, often borne in masses over a long season. Last but not least, they adapt readily to container culture in the warmer parts of the world (Dimmitt and Hanson, in press).
Adenium swazicum
Adenium swazicum [A.boehmianum Schinz var. swazicum (Stapf) Rowl.] (Figs. 6-8) occurs on the east coast of southern Africa, in Swaziland and adjacent parts of South Africa and Mozambique (Plaizier, 1980). It is a shrubby species, lower growing and more spreading than A.obesum or A.multiflorum (Dimmitt and Hanson, 1991). The stems of most clones are weak (decumbent), spreading horizontally or even drooping over a pot (Fig. 8). Mature plants have massive roots and thick stems, but a caudex is evident only in young ones. Cuttings develop the same characteristics in a few years. The long, narrow leaves are lighter green than in most adeniums, widest near the tips, and the margins are usually slightly crisped (wavy). In full sun the leaves tend to be folded upward along the midrib. Like A.obesum it is nearly evergreen if kept warm and watered, or can be forced into a long winter dormancy. Under warm greenhouse or tropical conditions growth ceases in autumn, but the leaves fall gradually throughout the winter; new growth begins early in spring.
Adenium swazicum usually flowers for a few months in late summer and fall. Some clones, however, are in almost continuous bloom, experiencing only a few weeks of rest in late winter. The broad-petaled flowers are uniform in color from the petal margins to the edge of the darker, unmarked throat and average 6-7 cm (2.5 inches) in diameter. The color is typically medium pink, but is deep purple in some clones (Fig. 8). Plaizier (1980) says that the flowers may be crimson or white, but such plants do not seem to be in cultivation. The anther appendages are short and hidden deep in the floral tube. Adenium swazicum is fairly easily found in cultivation, and is easy to grow.
Adenium boehmianum
Adenium boehmianum (A.boehmianum var. boehmianum) is quite different from A.swazicum in a number of traits. It is an upright, profusely-branched shrub 10 eight feet tall in nature (Plaizier, 1980), where it is always found in rocks (Chuck Hanson, pers. obs.). Its leaves are the largest in the genus, several inches long and broad, widest near the tip. The plant has a very short (summer) growing season. It is in leaf only about three months a year, and this cannot be extended by cultural conditions. The caudex is poorly developed. It occurs in Namibia and Angola, on the other side of the continent from A.swazicum.
The flowers are very similar to those of A.swazicum, though usually smaller, less than five cm (two inches) in diameter. They are produced for only a few weeks while the plant is in active growth.
Adenium boehmianum is only occasionally offered in cultivation, probably because of its short growing season and consequent slow growth.
Adenium oleifolium
Adenium oleifolium Stapf (=Adenium lugardii N.E.Br.) occurs in the interior of southem Africa, in the Kalahari Desert of southern Botswana, South Africa, and eastern Namibia. It is a small, slow-growing species with a subterranean caudex rarely more than a foot in diameter (and this only with great age). Both roots and stems rise toward the surface; the above-ground stems are not thickened noticeably and are seldom as much as two feet tall (Plaizier, 1980). The leaves are very long and narrow with nearly parallel sides, but do not tend to fold upwards along the midrib as do those of Adenium swazicum.
The flowers are small, about 2-5 cm (1 inch) in diameter with a wide floral tube. The petals are pink and the tube white or gold with faint nectar guides. Plaizier (1980) describes the corollas as, "bright scarlet or red to pink," but we have seen only pink in cultivation. Plants bloom for a couple of months in summer. Pollinated follicles often take more than a year to mature; the seeds are much larger than those of other Adenium. Adenium oleifolium is only occasionally offered in the trade. It is easy to grow, but is quite slow to become a specimen.
Fig.6. Adenium swazicum 'Perpetual Pink', a twelve-year old seed-grown plant in a twenty-four inch pot. This clone has more upright stems than is typical of the species. It also has a very long blooming season. Note the absence of caudex.
Fig.8. Adenium swazicum 'Boyce Thompson'. This clone has the weak stems typical of the species, but the flowers are an unusually deep color. This is a three-year old graft onto a seedling of the same species.

Fig.7. Adenium swazicum 'Perpetual Pink'. The flowers of this species are of a uniform color on the petal blades and have dark throats.
Fig.9. Adenium oleifolium. This eight-year-old plant has not outgrown a six-inch pot.
Fig.10. Adenium boehmianum in cultivation at the Huntington Botanic Gardens



PART 3: A.SOMALENSE
MARK A. DIMMITT § AND CHUCK HANSON §§
§ Arizona-Sonora Desert Museum, §§ Arid Lands Greenhouses
© No reproduction without consent of the authors
Adenium is a genus of spectacular succulents from tropical Africa and Arabia. They range from shrublets with subterranean or above-ground caudexes to small trees with succulent stems to 15 feet tall. Their striking forms are further enhanced by some of the most beautiful flowers of all succulents, often bome in masses over a long season. Moreover, they adapt readily to container culture in the warmer parts of the world. This installment describes two very different taxa from Somalia and adjacent countries.
Adenium somalense
Adenium somalense Baif. f. occurs from Somalia south through the Rift Valley into Kenya and Tanzania (Rowley, 1983). The leaves arc 5 to 10cm long by 18 to 25 mm wide (2-4" by 0.75- 1"), bright green and usually with white veins. In habitat the most conspicuous form is the nominate variety somalense, a small tree to 15 feet tall with a very wide-based, distinctly conical caudex (Fig.11). The flowering branches are very thin and spreading to pendent. These giant-caudiciform populations occur in Somalia and northwestern Kenya. In most of Kenya they are shrubby with smaller caudexes, apparently from intergrading with A.obesum, which occurs on the coastal side of that country.
The flower is smaller than that of A.obesum, usually less than 5 cm (2") in diameter with narrower, pointed petals and prominent nectar guides that may extend slightly beyond the pubescent throat onto the petals (Fig.15). The flower color varies from pink to deep red, and, as in A. obesum, the color fades toward the throat. The flowering period of cultivated plants is usually from autumn through early summer but is considerably influenced by culture.
Adenium somalense is available in cultivation and easy to grow. Nearly all the plants are of the shrubby, presumed intergrade with A.obesum. This species has an obligate dormancy, usually beginning in November or December in Tucson. Plants do not releaf until flowering is past its peak in late spring.
In 1991 Dimmitt obtained seeds from an arborescent population in northwestem Kenya. The plants are extremely vigorous; seedlings produced mostly unbranched stems to six feet tall in a single growth spurt lasting 18 months. During the second and third growing seasons the plants scarcely increased in height, but the trunks thickcned substantially and grew numerous thin, ascending to horizontal flowering branches (Fig.13).
Adenium somalense var. crispum
Adenium somalense var. crispum Chiov. is dramatically different from the nominate (first-described, i.e., the arborescent) variety and its intergrades with A.obesum. The plants are dwarfs with napiform (turnip-shaped) subterranean caudexes (Fig.14). The relatively thin roots originate almost exclusively from the top of the caudex, whjch is just below the soil surface, very unlike the arborescent form's thick, succulent roots that radiate from the base of the broad, above-ground caudex. The few above-ground stems are erect to ascending, scarcely succulent, and rarely more than a foot tall (Fig.18). The leaves are narrowly linear, usually strongly crisped (wavy-margined), and prominently white-veined.
The flowers of variety crispum are also distinctive (Fig.16). Compared to the arborescent variety, they have larger throats and smaller, narrower, white to pinkish petals. The margins of the squarish petals are often curled downward (quilled). The pink to red nectar guides in the throat may extend halfway to the tips of the petals, giving the flowers a distinctly striped aspect. In some plants the petals are solid red (Fig.17). Flowering in cultivation is sporadic; it seems to be most profuse during winter dormancy but may extend well into summer. Seedlings can flower in less than two years when only 6 inches tall.
This variety occurs in the same area as A.somalense somalense but apparently does not intergrade with it (Gerald Barad and Seymour Linden, pers. comm.). John Lavranos (pers. comm.) considers tbe two to belong to the same taxon. The variety crispum grows slowly in cultivation; it takes about five years to produce a specimen with its characteristic, though still small, caudex. The caudex can be exposed above the potting medium to create charismatic bonsai-like treelets (the base can produce roots in cultivation).
Acknowledgements
We express our gratitude to Gerald Barad and Myron Kimnach for lending us photos for this article.
Fig.6. Adenium swazicum 'Perpetual Pink', a twelve-year old seed-grown plant in a twenty-four inch pot. This clone has more upright stems than is typical of the species. It also has a very long blooming season. Note the absence of caudex.
Fig.8. Adenium swazicum 'Boyce Thompson'. This clone has the weak stems typical of the species, but the flowers are an unusually deep color. This is a three-year old graft onto a seedling of the same species.

Fig.7. Adenium swazicum 'Perpetual Pink'. The flowers of this species are of a uniform color on the petal blades and have dark throats.
Fig.9. Adenium oleifolium. This eight-year-old plant has not outgrown a six-inch pot.
Fig.10. Adenium boehmianum in cultivation at the Huntington Botanic Gardens


Adenium arabicum
Adenium arabicum Balf. f. occurs along the southern and western margin of the Arabian peninsula. The plants are caudiciform in the more arid habitats and treelike in wetter ones. The Saudi form may produce an erect trunk to four meters (12 feet) tall (Vincett, 1984). Higher in the mountains the trunk is reduced to a massive caudex (Collenette, 1985). The leaves are generally larger than those of A.obesum, tend to be pubescent, and have very rounded tips. Populations in southern Yemen (Figs.19 and 21) are characterized by short, broad caudexes and the largest leaves in the genus-up to 20cm long and 12 cm wide (8 x 4.5", larger than those of A.boehmianum, which was erroneously reported to have the largest leaves in Dimmitt and Hanson, 1992). The caudex can attain a meter in diameter (Collenette, 1985; Miller and Morris, 1988).
In cultivation this species has a definite winter dormancy and seems to leaf out several weeks after A.obesum cultivated under the same conditions. The Saudi form retains leaves year round but still grows only during the hot season. Plants begin flowering at the end of dormancy in late winter and continue into early summer. The Saudi form has a major flush in spring but flowers sporadically all year. The flowers vary in size and pubescence. Those of the Saudi form are about 4cm (1.5") in diameter. The form from southern Yemen has flowers up to 8.5 cm (3") with very prominent pubescence in the throat (Fig.20). The petals are bright pink with some fading toward the white throat, which has usually one nectar guide per petal. The follicles (at least of the Yemeni form) are much larger than those of A.obesum and dark mahogany in color; the seeds are correspondingly large.
Both the Yemeni and Saudi forms of this species have only recently become readily available. They seem to be as easy to grow as the other taxa. The common cultivar sold as A.obesum 'Singapore' may be a Yemeni A.arabicum (see the next installment).
Adenium socotranum
Adenium socotranum Vierh.(Fig.22) is endemic to the island of Socotra in the Indian Ocean south of the Arabian peninsula. It is the giant of the genus, forming a conical trunk/caudex several metres tall and up to 2.4 m (eight feet) in diameter (Balfour, 1888; Rowley, 1983). It resembles a miniature baobab. The stems of the single clone available to us are strongly vertical and distinctly striated, a unique character in the genus. The leaves are about 12 cm (4.7") long, are widest (4 cm, 1.6") near the tip, and are dark green with a white midrib and light major veins. Balfour described the flowers as bright pink and twice the size of those of "mainland A.multiflorum" (he considered the Socotran population to be of this species), which would make them 10-13 cm (4-5") in diameter.
This magnificent species is virtually unknown in cultivation, so its performance cannot be described with confidence. The six-foot tall specimen in Hanson's collection is in leaf only during the summer months, leafing out even later than A.boehmianum. It has not flowered in seven years, although it did once when Frank Horwood owned it. A specimen at the Huntington Botanical Gardens has also not flowered to date. The only other cultivated specimen known to us is in the collection of the Botanical Research Institute, Pretoria, South Africa (Myron Kimnach, written comm.).
Summary
This completes the series on the natural taxa, articles on Adenium cultivars and hybrids will follow soon. This account is not complete, nor are our opinions unassailable. Cultivated material is typically derived from very small samples, often from a single fruit or collected plant, so our descr single fruit or collected plant, so our descriptions may not be representative of the wild populations or even of cultivated material in other countries. We hope to stimulate others to share their knowledge and interpretations of this spectacular genus and to fill in the gaps. For example, it is obvious that the genus is comprised of several taxa with differing horticultural needs, but are these taxa forms, varieties, or full species? What is the extent of natural variability and how much do different taxa overlap? Where different phenotypes (recognizable forms) grow together, how common are intergrades? Do the different forms have different pollinators? And perhaps most urgent: would someone please conduct a seed collecting expedition to Socotra!
Acknowledgements
We express our gratitude to John Lavranos and Gerald Barad for lending us their photos for publication. They are among a tiny group of botanists who have visited some of the nearly inaccessible areas where adeniums grow.

Fig.19. Adenium arabicum, shrubby form in northen Yemen. Photo: Gerald Barad
Fig.20. Adenium arabicum, flower of Yemeni form in cultivation. Photo: Gerald Barad
Fig.21. A hillside in northern Yemen richly populated with Adenium arabicum Photo: Gerald Barad
Fig.22. Adenium socotranum, Socotra, with Dracaena cinnabari. This magnificent adenium is virtually unknown in cultivation. Photo: John Lavranos.


PART 5: SUPERIOR CULTIVARS
MARK A. DIMMITT §
§ Arizona-Sonora Desert Museum
© No reproduction without consent of the author
As would be expected in a genus that ranges from southern Arabia to southern Africa, Adenium exhibits a great deal of natural variation among and within the taxa. Stems vary from sturdy and erect to thin and decumbent, forming plants from a few decimeters to several meters tall. Flower size and form vary from round disks of broad, overlapping petals to star-shaped ones with petals that are narrow, pointed, and even curled (quilled). Flower color ranges from white through pink to deep purple and crimson; some are bicolored. Duration of bloom varies among taxa and between clones within a taxon from as little as a few weeks to nearly year-round. Variability among taxa has been described in parts one through four of this series; this article details some of the infrataxon variations.
Despite all this variation, very little effort has been expended at selecting or breeding superior horticultural forms until recently. Most adeniums are still offered with no data as to their geographical or horticultural origin. Furthermore, 'Singapore' is the only named clone that is well-known in the trade. A distinctive form of A.obesum from near Mombasa is also offered. During the past decade, interest in adeniums has been growing, and several breeders in the USA, India, Australia, and Kenya are actively selecting superior variations.
Several variables can be selected toward the goal of better adeniums for the horticultural trade. Which ones are most important depends on the breeder: flowering season, flower color, flower size and abundance, flower shape, plant form, growth rate, temperature tolerance, and disease resistance.
Superior Selections Within Taxa
Adenium arabicum 'Singapore' (also known as A.obesum var. coetanum) was until 1993 the only well-known, named cultivar. According to Professor Holttum it was introduced in 1933 (Frank Horwood, written comm.). Its most distinguishing characteristic is its abundance of very large flowers (Fig.23). The deep pink flowers are up to 10 cm (over 4 in.) in diameter, twice the average size. Grown warm and watered all year, it flowers up to 10 months per year, far longer than most clones. If given a dry winter rest, it breaks dormancy with a massive bloom (see Rowley, 1987, p.184).
'Singapore' seems to be a selection of A.arabicum. Its characteristics fit those of the Yemeni A.arabicum more than those of typical A.obesum: large flowers of bright pink fading toward the throat, faint nectar-guides, large though not gigantic leaves, and a tendency to form a caudex. However, the throat is glabrous, not hairy. Nursery people in Singapore claim that the original plant was imported there from Arabia (Albert Chan, written comm.).
Adenium obesum 'Mombasa' was introduced from seed collected from a plant near that town on the Kenyan coast. It is distinguished by its small stature and profuse basal branching at an early age. It also forms a caudex, unlike most other A.obesum's in cultivation.
Adenium obesum 'Red Everbloomer' bears 7 cm (2 3/4 in.) round, bright red flowers for 7 to 11 months a year. In some years a large plant has been in continuous bloom for twelve months. This clone has a sturdy, upright branching habit, and cuttings form swollen stems and roots quickly. See Dimmitt and Hanson (1991) for photos.
'Red Everbloomer' was selected from a grex of second-generation seedlings grown by me in 1978. It has not been marketed because it has a significant flaw: much of the year the flowers are deformed and poorly colored. However, I continue to maintain it because it is a superb pollen and seed-parent that transmits its vigor, long blooming season and deep flower color to its off- spring. (Many adenium plants seem to be either male- or female-sterile, while others like 'Singapore' seldom transmit their superior traits to their offspring.) 'Red Everbloomer' is a parent of most of my hybrids.
Adenium obesum (unnamed white-flowered cultivars) are known with pure white flowers (Fig.24). Several clones have been selected by growers in Kenya, Singapore, and the United States. Plants should be available soon.
Adenium obesum (or A.arabicum) 'Fritz Dederer' is distinctive in forming a thick, corky white bark, even on small branches. It could be useful in breeding more sunburn-resistant plants. Unfortunately it has been infertile to date.
Adenium swazicum 'Perpetual Pink' is superior to the species in several characteristics. The growth form is much more sturdy than is typical of the species. Its branches are ascending and thicker than any other clone the author has seen. The flowers are of excellent, round form and much larger than average, 9.5 cm (3.7 in.) in diameter (see Dimmitt and Hanson, 1992, for photos). They are also borne nearly year-round (8 to 12 months) on mature plants, compared to a few months for most clones.
'Perpetual Pink' produces copious viable pollen and is the parent of several clones of the cultivar group Arizona (Adenium obesum X Adenium swazicum, to be described in the next installment of this series). It is a nearly infertile seed-parent.
Adenium swazicum 'Boyce Thompson' is typical of the species in growth habit: weak-stemmed, nearly pendent when grown on its own roots (see Dimmitt and Hanson, 1992, for photo). It is outstanding for its flowers, which are deep purple (Fig.25). This clone was found in the collection of the Boyce Thompson Southwestern Arboretum in Superior, Arizona; its geographic origin is unknown. The flowering season is better than average, up to 7 months a year.
'Boyce Thompson' produces copious viable pollen and is also a fertile seed parent. It contributes intense flower-color to its hybrid offspring but usually not its weak stems.
To my knowledge there are no named cultivars of any other species to date, though the need exists. For example, plants sold as A.somalense vary from squatty shrubs to tall trees with massive trunks. These growth habits are more genetically than culturally determined and should be identified so collectors know what they are buying.
Breeders in India and Florida are growing thousands of adeniums in fields, and many out-standing variants have appeared. There is a seedling from Florida with velvety, blackish-red flowers. Several forms with very ruffled petals have been selected in India. Many hybrids have also been produced in recent years and will be described in future installments.
Fig.23. Flower of Adenium 'Singapore' (right) with an average Adenium obesum flower beside it for size comparison.
Fig.24. Tom Grumbley's clone of white-flowered A.obesum
Fig.25. Deep purple flower of Adenium swazicum 'Boyce Thompson

PART 6: SELECTED HYBRIDS
MARK A. DIMMITT §
§ Arizona-Sonora Desert Museum
© No reproduction without consent of the author


The purpose of hybridizing plants is to combine desirable characteristics from different individuals to produce superior forms, with the definition of "superior" being mostly the breeder's opinion. My goals for adeniums are a sturdy growth-form with a large caudex or trunk, vigor manifested as fast growth and disease resistance, such intense flower colors as blood-red and sharply contrasting red/white picotees, and a long blooming season. Significant progress has been realized in only three generations.
Adenium Arizona
Adenium Arizona Group is the name I have given to a cultivar group of hybrids created by crossing Adenium obesum and Adenium swazicum.
The F1 progeny show a pattern:
The plants exhibit hybrid vigor with fast growth, prolific flowering, and high resistance to root-rot. The last trait is apparently inherited from A.swazicum, which tolerates heavy, wet soils (Peckover, 1995).
The stems are usually much sturdier than the floppy stems of Adenium swazicum. Neither parent species is distinctly caudiciform (at least among the plants in my collection) nor are the offspring. They do rapidly develop swollen roots and stems, however.
The leaves are intermediate between those of the parents.
Like the parents, hybrids lack an obligatory seasonal dormancy, tending to grow and flower continuously if kept warm and well-watered.
Flower coloration resembles that of Adenium swazicum in being solid or fading only slightly toward the dark throat. The anther appendages are intermediate in length.
In short, this cultivar group tends to inherit the best qualities of both parents and exhibits hybrid vigor. When superior parents are used, the results are spectacular. Adenium obesum 'Red Ever-bloomer' has been used in all of my released Arizona crosses to date because of its upright stems, good red flower-color, and long blooming season.
Adenium swazicum 'Perpetual Pink' contributes sturdy stems, large flower size, long blooming season, and flower color from pale pink to deep raspberry red. When the deep purple A.swazicum 'Boyce Thompson' is used, the most noticeable difference is darker flower color ranging to blood- red. See Dimmitt and Hanson (1992) and Dimmitt for photographs of these plants.
Adenium 'Endless Sunset': Young plants have weak stems but become arborescent if grown hard and pruned until maturity. Flowers are 7.4 cm (2.9 inches) in diameter, solid deep pink. This clone is everblooming-it never stops flowering if grown under tropical conditions. At 15 years of age the trunk of the original seedling has dramatically thickened to halfway up its 2.1-meter (seven-foot) height. Cuttings grow vigorously and form massive roots quickly; stems thicken nicely in their third year. The parentage is A.obesum 'Red Everbloomer' X A.swazicum 'Perpetual Pink'.
Adenium 'Crimson Star': Stems are very sturdy and erect to ascending. Flowers are large (8.6 cm, 3.4 inches), solid, deep blood-red (Fig.26), and are borne nearly year round (Table 1). The plants often take only a month's rest in early spring, then resume growth and flowering. The parents are A.obesum 'Red Everbloomer' and A.swazicum 'Boyce Thompson'. This is the best adenium clone I have seen to date. In addition to the above qualities, cuttings root readily, grow rapidly, and begin to flower in four-inch pots. Roots and stems of cuttings thicken dramatically in the first year. Well-branched, nearly caudiciform shrubs or treelets four feet tall and wide can be produced in as little as three years (Fig.27). Plants continue flowering well through cool weather and almost never rot. It's only negative is that it is a very reluctant breeder, though it has parented a few offspring.
Adenium 'Red Ribbons': Stems are thin and weak, tending to droop under the weight of the large leaves unless pruned or grown in windy conditions that strengthen branches. Flowers are very large (10.9 cm, 4.3 inches), deep red with only slight fading toward center. The petals hang down like ribbons. The flowers are borne up to eleven months a year. It has the same parentage as 'Crimson Star'.
Adenium 'Volcanic Sunset': Stems are very sturdy and erect, with crowded leaves due to short internodes. Flowers are large (9.4 cm, 3.7 inches), deep red, fading slightly toward the throat. It blooms almost 12 months a year, usually profusely except during hottest weather. It has the same parents as 'Crimson Star'.
Adenium 'Asha': This is an Arizona back-crossed to A.obesum. It was created by Dr. Ashish Hansoti of Bombay, India, and named after his mother. Its outstanding characteristic is its huge, bright pink flowers. At 11.4cm (4.5 inches) across they surpass those of the previous champion, A.arabicum 'Singapore' (=A.obesum coetanum, Fig.28). The flowers are of good form, being very round in outline, and usually face upward or outward. It is nearly everblooming, taking only a few weeks' rest during the hottest part of summer. If temperatures remain below 100F (38C), it can bloom 12 months a year. Its thick, very fast-growing, yet weak, stems soon droop to the ground. Grafting onto a sturdier rootstock greatly improves the form, but frequent hard pruning is still needed to maintain an upright plant. It is an inferior parent: offspring so far have had disappointing flowers.
Other Hybrids
Adenium 'Crimson Picotee': (crosses between A.obesum and A.multiflorum tend to have large, evergreen leaves and very thick, sturdy stems. The flowers are like those of A. multiflorum but with a broad rather than narrow red border on the white petals. The clone 'Crimson Picotee' has moderate-sized (7.0 cm, 2.75 inches), ruffled flowers with a fairly distinct, broad border of blood-red (Fig.29). It blooms intermittently up to 8 months a year but never profusely. The parentage is A.obesum 'Red Everbloomer' by a mediocre clone of A.multiflorum; better plants of this grex are undoubtedly possible. It is a fertile breeder in both directions and tends to produce very robust offspring. None have yet flowered.
Continuing Selection
The horticultural potential of the genus Adenium has only begun to be developed. The best cultivars to date are shrubby succulents with long blooming seasons. Their flowers are richly colored in pink to red and bicolored red-white. Look forward to these further potentials:
Plants with massive caudexes and brilliant, year-round flowers. Crossing the arborescent species with one of the existing superior-flowered cultivars should produce such plants. Unfortunately, my first two crosses between A.cf.somalense (a shrubby form) and 'Crimson Star' produced plants with nearly year-round dormancy and deformed flowers. Hopefully the solution is using other clones for parents.
Plants more tolerant of cool conditions. Adenium swazicum tends to transmit this trait to its offspring.
Plants with large, striped and spotted flowers. Those of A. somalense crispum are beautiful at close range; imagine such coloring on a four-inch flower.
Other flower colors. The yellow throat of A.oleifolium might be expanded onto the petals. The red flower pigment can be expected to mutate to blue one of these days, as it has in many other red-flowered species. I once had an A.obesum with blue petal margins, but it died.
Variegated foliage. Well, some people like it; I think such plants look sick and should be destroyed. Someone else will have to select these.
Double flowers. See the first paragraph about what constitutes' "superior." I think most double flowers are ugly. Compare the misshapen abominations created in other plants such as gloxinia and hibiscus with the elegant symmetry of their single-flowered ancestors. (I'll acknowledge that some double roses have superb forms, but they are the products of more than a century of intensive selection.)
Fig.26. Flower of Adenium 'Crimson Star' (bottom) with parents A.obesum 'Red Everbloomer' and A.swazicum 'Boyce Thompson' (top)
Fig.27. Four-year-pld cutting of 'Crimson Star' in a 24-inch pot. Even faster growth is possible.
Fig.28. Flowers of Adenium 'Asha'. The topmost flower is one of 'Singapore', the previous size-champion
Fig.29. Flowers on a young plant of Adenium ' Crimson Picotee'. Flower size and sharp coloration decline in larger plants.