Peningkatan Perkecambahan Benih Andaliman (Zanthoxylum acanthopodium DC.) Melalui Penentuan Umur Panen, Sortasi, dan Pematahan Dormansi

Abstract

endemic to North Sumatra. Farmers still use wild seeds in propagating andaliman plants, because the seeds are difficult to germinate. Low germination and long germination may be due to dormancy. The cause of andaliman seed dormancy is unclear, so the effort to release the seed dormancy still showed low results. Low germination might also be caused by many seeds without embryos (empty seeds) and low seed viability. The research aimed to describe the development of andaliman seeds to physiological maturity and determine the physiological maturity of the andaliman seeds; determine the causes of low andaliman seed germination; determine the causes of andaliman seed dormancy; get a sorting technique and breaking of andaliman seed dormancy which results in high germination. The general aim was to increase the seed germination of andaliman (Zanthoxylum acanthopodium DC.). The research consisted of four stages. The study used the flower, fruit, and seed of Simanuk accession plants in the Dairi Regency at 2o50’32.5" North Latitude, 98o24'45.4" East Longitude, at an altitude of 1300 m above sea level. The first stage, Andaliman Seed Phenology, consisting of three sub-parts, namely (a). Flower and Development of Andaliman Fruit; (b) Development of Andaliman Seeds to Physiologically Mature and Andaliman Seed Germination; (c) Sorting Andaliman Seeds and Andaliman Seed Anatomy. The dry weight of seeds increased up to 24-25 weeks after anthesis and did not increase significantly between the ages of 26-29 weeks after anthesis. The physiological mature age of andaliman seeds was achieved at the age of 28 week after anthesis, that was characterized by red exocarp, shiny black seed coat, seed moisture content of 17.26%, seed dry weight of 0.0068 g, seed dry weight percentage 82.74%, and percentage of seed germination 53.75%. The low of andaliman seed germination was caused that most of the seeds did not have embryo (empty seeds/wrinkled seeds), also the psresence of non-viable embryos due to immature or aging and deterioration. Sorting andaliman seeds with 15% sugar solution and sorting with water increased percentage of germination (60.0% and 57.5% respectively) and increased growth speed (1.153%/etmal and 1.172%/etmal respectively). The possibility to obtain filled and viable seeds was higher in sorting with a 15% sugar solution. The second stage, Effect of Andaliman Fruit Extract on Seed Germination; and the third stage, Scarification and Imbibition Test of Andaliman Seeds. Andaliman seed dormancy was caused by several dormancy mechanisms, namely the hardness and thickness of seed coat, the presence of lignin on the seed coat, and germination inhibitor, terpenoid, in the seed coat and embryo. Germination inhibitor from terpenoid compounds was identified as geraniol and geranyl acetate. The fourth stage, Breaking of Andaliman Seed Dormancy. Andaliman seed dormancy release method was heated into a 46oC oven for 30 minutes and then the seeds soaked in gibberellin 500 ppm for 10 hours that gave the highest germination percentage, 82.22%, with the fastest germination time of 58.20 days, with the highest growth rate, 1.517%/etmal; each difference in germination of 23.33%, time of germination 8.17 days, growth rate of 0.58%/etmal compared to treatment without breaking dormancy. The breaking technique of seed dormancy that can accelerate germination significantly had not been found in this study. The results show that, the age of seed harvesting 28 weeks after anthesis, sorting with 15% sugar solution or water, and combination of broken dormancy seeds were heated in an oven 46oC for 30 minutes and then the seeds soaked in gibberellin 500 ppm for 10 hours, could improve seed germination.

Tanaman andaliman (Zanthoxylum acanthopodium DC.) merupakan tanaman rempah liar lokal endemik di Sumatera Utara. Petani masih menggunakan bibit liar dalam perbanyakan tanaman andaliman, karena bijinya sulit berkecambah. Daya kecambah yang rendah dan lamanya berkecambah diduga disebabkan adanya dormansi. Penyebab dormansi benih andaliman belum jelas, sehingga usaha memecahkan dormansi benihnya masih menunjukkan hasil yang rendah. Daya kecambah yang rendah kemungkinan juga disebabkan banyaknya biji tanpa embrio (biji kosong/biji keriput) dan biji tidak viabel. Penelitian bertujuan menggambarkan perkembangan benih hingga matang fisiologis dan menentukan umur matang fisiologis benih andaliman; menentukan penyebab rendahnya daya kecambah benih andaliman; menentukan penyebab dormansi benih andaliman; mendapatkan teknik sortasi dan pematahan dormansi benih yang menghasilkan daya kecambah yang besar. Tujuan umum penelitian meningkatkan daya kecambah benih andaliman (Zanthoxylum acanthopodium DC.). Penelitian terdiri atas empat tahap. Penelitian menggunakan bunga, buah, dan benih dari tanaman aksesi Simanuk di Kabupaten Dairi berada pada 2o50'32,5” Lintang Utara, 98o24'45,4” Bujur Timur, pada ketinggian 1300 m di atas permukaan laut. Penelitian tahap pertama, yakni Fenologi Benih Andaliman, terdiri atas tiga sub bagian, yaitu (a). Bunga dan Perkembangan Buah Andaliman; (b) Perkembangan Benih Andaliman Hingga Matang Fisiologis dan Daya Kecambah Benih Andaliman Saat Matang Fisiologi; (c) Sortasi Benih Andaliman dan Struktur Benih Andaliman. Hasil penelitian menunjukkan bobot kering benih terus meningkat hingga 24-25 minggu setelah antesis dan tidak meningkat lagi secara signifikan pada kisaran umur 26-29 minggu setelah antesis. Umur matang fisiologis benih andaliman dicapai pada umur benih 28 minggu setelah antesis, dengan ciri: wama eksokarp merah, kulit biji hitam mengkilap, kadar air benih 17,26%, bobot kering benih 0,0068 g, persentase bobot kering benih mencapai 82,74%, dan daya kecambah sebesar 53,75%. Daya kecambah benih andaliman rendah disebabkan sebagian besar biji tidak memiliki embrio (biji kosong/biji keriput), juga adanya biji tidak viabel akibat belum matang ataupun mengalami penuaan dan kerusakan (deteriorasi). Sortasi benih andaliman dengan larutan gula 15% dan sortasi dengan air meningkatkan daya kecambah (masingmasing 60,0% dan 57,5%) dan meningkatkan kecepatan tumbuh (masing-masing 1,153 %/etmal dan 1,172 %/etmal). Kepastian untuk mendapatkan benih yang bernas dan viabel lebih besar pada sortasi dengan larutan gula. Penelitian tahap kedua, yakni Pengaruh Ekstrak Buah Andaliman terhadap Perkecambahan Benih; dan penelitian tahap ketiga, yakni Uji Skarifikasi dan Imbibisi Benih Andaliman. Benih andaliman dorman disebabkan oleh beberapa mekanisme dormansi, yaitu kekerasan dan ketebalan kulit biji, adanya lignin pada kulit biji, dan zat penghambat perkecambahan, terpenoid, pada kulit biji dan embrio. Jenis senyawa terpenoid yang teridentifikasi adalah geraniol dan geranil asetat. Penelitian tahap keempat, yakni Pematahan Dormansi Benih Andaliman. Berdasarkan pada hasil penelitian didapatkan kombinasi metode pematahan dormansi benih andaliman dipanaskan dalam oven 46oC selama 30 menit dan selanjutnya benih direndam dalam giberelin 500 ppm selama 10 jam memberi daya kecambah tertinggi, yakni sebesar 82,22 %, dengan umur berkecambah tercepat 58,20 hari, dengan kecepatan tumbuh tertinggi, yakni 1,517 %/etmal; masing-masing selisih daya kecambah 23,33%, umur berkecambah 8,17 hari, kecepatan tumbuh 0,58 %/etmal dibanding dengan perlakuan tanpa pematahan dormansi. Teknik pematahan dormansi yang dapat mempercepat perkecambahan secara nyata belum ditemukan dalam penelitian ini. Hasil penelitian menunjukkan bahwa umur panen benih 28 minggu setelah antesis, sortasi dengan larutan gula 15% atau air, dan kombinasi pematahan dormansi benih dipanaskan dalam oven 46oC selama 30 menit dan selanjutnya benih direndam dalam giberelin 500 ppm selama 10 jam, dapat meningkatkan daya kecambah benih andaliman.