Mekanisme Sitologi Kemunduran Viabilitas Serbuk Sari dan Potensinya dalam Produksi Benih Paria (Momordica charantia L.)

Abstract

Pengelolaan serbuk sari memiliki peran penting dalam produksi benih hibrida Cucurbitaceae, dengan tantangan utama pada viabilitas serbuk sari yang menurun dengan cepat. Tujuan dari penelitian ini adalah untuk mendapatkan informasi periode reseptif stigma paria, mempelajari daya simpan dan mekanisme penurunan viabilitas serbuk sari paria selama penyimpanan dan untuk mengetahui potensi serbuk sari paria yang disimpan untuk produksi benih. Penelitian dilaksanakan di Kampus Institut Pertanian Bogor (IPB), Dramaga Bogor, pada bulan September 2018 hingga Juni 2021. Pengamatan ultrastruktur sel dilakukan di laboratorium TEM dan Histologi, Lembaga Eijkman, Jakarta. Periode reseptif stigma diamati secara visual dan berdasarkan fruit set dan seed set dari waktu penyerbukan berbeda (pukul 07.00; 09.00; 11.00; 13.00; dan 15.00). Serbuk sari paria dipanen pada saat bunga mekar kemudian disimpan dalam deep freezer kisaran suhu (-24) hingga (-18) ºC. Pengamatan viabilitas serbuk sari dilakukan pada serbuk sari segar, 0, 2, 4, 6, 8, 10, dan 12 minggu setelah simpan (MSS), sedangkan ultrastruktur serbuk sari pada serbuk sari segar, 4, 8, dan 12 MSS. Serbuk sari yang disimpan juga digunakan untuk penyerbukan di lapangan, kemudian diamati produksi dan mutu benih yang dihasilkan. Hasil penelitian menunjukkan bahwa periode reseptif stigma paria aksesi No 9 (Balitsa) terjadi antara pukul 07.00-11.00. Penyimpanan serbuk sari dalam deep freezer kisaran suhu (-24) hingga (-18) ºC hanya dapat mencegah penurunan viabilitas sampai 4 minggu. Penurunan viabilitas disebabkan oleh degenerasi dinding sel (exine) dan membran mitokondria yang mulai terlihat pada 4 MSS. Exine, membran luar dan dalam mitokondra mengalami degenerasi total pada 12 MSS. Serbuk sari paria yang telah disimpan dalam deep freezer kisaran suhu (-24) hingga (-18) ºC sampai dengan 2 minggu efektif untuk produksi benih bermutu.

Pollen management has an essential role in hybrid seed production of Cucurbitaceae, with a significant challenge on the rapid decline of pollen viability. The aims of the research were to obtain information on the bitter gourd stigma receptive period, to study the mechanism of pollen deterioration of bitter gourd during storage, and to investigate if stored pollen is as effective as fresh pollen for seed production. The research was carried out at Dramaga Campus of IPB University from September 2018 to June 2021. Cell ultrastructure observations were carried out at the TEM and Histology Laboratory, Eijkman Institute, Jakarta. The stigma receptive period was observed visually and based on fruit set and seed set from a different pollination time (07.00; 09.00; 11.00; 13.00; and 15.00 h). Bitter gourd pollen was harvested at anthesis and then stored in the deep freezer at a temperature around (-24) to (-18) ºC. Observation on viability was done on fresh pollen, 0, 2, 4, 6, 8, 10, and 12 weeks after storage (WAS), while pollen ultrastructure was on fresh pollen, 4, 8, and 12 WAS. The stored pollen was also used for pollination in the field. Seed production as well as seed quality were observed. The result showed that the stigma receptive period for bitter gourd accession No 9 (Balitsa) occurred between 07.00-11.00 h. Pollen stored in a deep freezer (ranged (-24) to (-18) ºC) would inhibit the declining viability for up to 4 weeks. The declining pollen viability was due to degeneration of pollen cell walls (exine) and mitochondria membrane started at 4 WAS. Exine, mitochondrial outer and inner membranes totally degenerated at 12 WAS. Bitter gourd pollen stored in a deep freezer (ranged (-24) to (-18) ºC) for up to 2 weeks was as effective as fresh pollen for the production of quality seed.