EFEK PEG 6000 TERHADAP PERKECAMBAHAN BIJI Vanda tricolor Lindl. DAN PERTUMBUHAN PLANTLET VANDA HIBRIDA (Vanda limbata Blume X Vanda tricolor Lindl.) SECARA IN VITRO

SEKAR PELANGI MANIK PUTRI, Dr.rer. nat. Ari Indrianto, S.U.

2014 | Skripsi | BIOLOGI

Bibit tanaman anggrek hasil perbanyakan secara in vitro belum berkembang sempurna untuk beradaptasi dengan kondisi lingkungan luar, sehingga bibit anggrek rentan terhadap kekeringan apabila dikeluarkan dari botol dan ditanam secara in vivo. Dibutuhkan upaya untuk meningkatkan ketahanan bibit anggrek terhadap kekeringan, salah satunya dengan mengadaptasikan tanaman pada medium dengan perlakuan cekaman kekeringan. Polietilen glikol (PEG) merupakan senyawa dengan berat molekul tinggi yang dapat menghambat absorbsi air dalam jaringan tumbuhan. Tujuan dari penelitian ini untuk mengetahui perkembangan embrio Vanda tricolor Lindl. dan pertumbuhan plantlet Vanda hibrida (Vanda limbata Blume X Vanda tricolor Lindl.) secara in vitro pada perlakuan PEG 6000 berbagai konsentrasi. Biji V. tricolor dan plantlet Vanda hibrida (V. limbata Blume X V. tricolor Lindl.) digunakan sebagai eksplan pada penelitian ini. Eksplan ditanam pada medium 2 lapis, medium padat VW+ekstrak air kelapa+pisang raja+kentang di bagian bawah serta larutan PEG 6000 konsentrasi 0%; 5%; 15%; 35%; dan 45% di bagian atas, masing-masing perlakuan dibuat 3 ulangan. Pengamatan dilakukan selama 12 minggu. Perlakuan PEG menghambat perkembangan embrio V. tricolor pada fase awal pembengkakan embrio. Perlakuan 15% dan 35% PEG 6000 dapat meningkatkan persentase perkembangan embrio fase 3 (embrio berwarna putih, tidak terdapat testa). Perlakuan PEG 6000 tidak berpengaruh nyata terhadap morfologi daun dibandingkan kontrol tetapi efektif menurunkan panjang akar. Perlakuan PEG 6000 pada konsentrasi 15%-45% dapat meningkatkan indeks stomata dan ukuran sel epidermis plantlet Vanda hibrida (V. limbata Blume X V. tricolor Lindl.), serta meningkatkan ukuran stomata pada konsentrasi 5%-35%. Perlakuan PEG 6000 konsentrasi 35% mengakibatkan bibit anggrek Vanda hibrida lebih toleran terhadap cekaman kekeringan. Kata kunci: Vanda tricolor Lindl., Vanda limbata Blume, PEG 6000, Cekaman kekeringan.

In vitro orchid plantlets have high risk of damages caused by drought after growth in open condition. An effort to increase the orchid plantlets resistance to drought stress is strongly needed, such as by adapting the orchid plantlets on medium with drought stress treatments. Polyethylene glycol (PEG) is a high molecular weight compound that can bind water molecules to inhibit water penetrations in plant tissues. The objectives of this research were to determine the development of the Vanda tricolor Lindl. embryos and to determine the Vanda hybrid plantlets (V. limbata Blume X V. tricolor Lindl.) growth in vitro with various concentrations of PEG 6000. V. tricolor seeds and Vanda hybrid (V. limbata Blume X V. tricolor Lindl.) seedling were used as explants. Explants were cultured on 2 layers medium. First layer was composed of VW medium with coconut water extract, banana extract, and potatoes extract and covered by PEG 6000 solution with concentration variations of 0%; 5%; 15%; 35%; and 45% at the medium surface, Observation was performed for 12 weeks. PEG treatments inhibited embryonic development that occurs on V. tricolor at the early phase of embryo swelling. The 15% and 35% PEG 6000 treatment was able to increase the percentage of the third phase of embryo development (white colored embryo and no testa). PEG 6000 treatments did not significantly affect the leaf morphology compared to control, but effectively affected the root growth. PEG 6000 treatments with concentration of 15-45% increase stomatal index and epidermal cell size of plantlet Vanda hybrid. PEG 6000 treatments with concentration of 5-35% increased stomatal cell size of plantlet Vanda hybrid. PEG 6000 treatments with a concentration of 35% affectively increased drought tolerant of plantlet Vanda hybrid. Keyword: Vanda tricolor Lindl., Vanda limbata Blume, PEG 6000, Drought stress.

Kata Kunci : Vanda tricolor Lindl., Vanda limbata Blume, PEG 6000, cekaman kekeringan