Studi Anatomi Organ dan Perkembangan Bunga Tanaman Jarak Pagar (Jatropha curcas L.)

Abstract

Jatropha curcas L. is a monoecious plant, which produces male and female flowers in a single plant. J. curcas plant produces hermaphrodite flowers called andromonoecious plant. Based on its morphology, andromonoecious and monoecious plants have many differences such as branch amount, gap between joint branch, type of flower, and amount of fruit. The knowledge of anatomy structures J. curcas was lacked. Necessary to do some research in anatomical structure of the organ and flower development of monoecious and andromonoecious J.curcas plants. The observation of anatomical structure of organ and flower development was conducted by undergoing microscopical observation. The results showed that root and stem of andromonoecious and monoecious J. curcas plants had the same anatomical structures. The abaxial surface of the leaf had more stomata than the adaxial surface. The thickness of andromonoecious J. curcas leaf was thinner than that of monoecious due to the size of upper epidermis, palisade parenchyma, and spongy parenchyma of andromonoecious J. curcas. The structure differences of hermaphrodite flower and male flower could be distinguished by looking at its smaller bud phase, medium bud phase, at one day before anthesis, and anthesis phase. Pollen grains in hermaphrodite and male flowers were formed in the smaller bud phase and pollen grains had matured at one day before anthesis. Ovaries in hermaphrodite flowers were formed during the medium bud phase and their ovules could be seen at one day before anthesis. The embryo sac was seen by the presence of polar nucleate that has not through fertilization, during anthesis phase on hermaphrodite flower.

Jarak pagar (Jatropha curcas L.) merupakan tanaman monoecious yang menghasilkan bunga jantan dan bunga betina dalam satu tanaman. Tanaman J. curcas yang menghasilkan bunga hermaprodit disebut sebagai tanaman andromonoecious. Berdasarkan morfologinya, tanaman andromonoecious dan monoecious memiliki perbedaan pada jumlah cabang, jarak antar buku batang, tipe bunga dan jumlah buah. Struktur anatomi J. curcas belum banyak dipelajari. Penelitian mengenai struktur anatomi organ dan perkembangan bunga tanaman J. curcas monoecious dan andromonoecious perlu dilakukan. Pengamatan struktur anatomi organ dan perkembangan bunga dilakukan dengan membuat sediaan mikroskopis. Hasil menunjukkan bahwa akar dan batang J. curcas andromonoecious dan monoecious memiliki struktur anatomi yang sama. Daun pada sisi abaksial memiliki stomata lebih banyak dibandingkan sisi adaksialnya. Tebal daun andromonoecious lebih tipis dari pada daun monoecious karena daun andromonoecious memiliki ukuran epidermis atas, parenkima palisade, parenkima bunga karang yang lebih tipis. Struktur anatomi bunga hermaprodit dan bunga jantan dapat dibedakan dari fase kuncup kecil, kuncup sedang, 1 hari sebelum anthesis (bunga mekar), dan anthesis. Polen pada bunga hermaprodit dan bunga jantan telah terbentuk pada fase kuncup kecil dan telah dewasa pada fase 1 hari sebelum anthesis. Ovari pada bunga hermaprodit telah terbentuk pada fase kuncup sedang dan ovul dapat dilihat pada fase 1 hari sebelum anthesis. Saat bunga hermaprodit anthesis, kantong embrio telah terlihat dengan adanya inti polar yang belum mengalami fertilisasi.