ABSTRAKPentingnya penyimpanan biji telah dikenal manusia semenjak manusia mulai mendomestikasi tumbuhan. Telah diketahui bentuk hubungan antara kadar air dan viabilitas pada biji utuh dan potongan biji yang mengandung embrio Artocarpus heterophyllus Lam. Viabilitas diukur dengan nilai daya hantar listrik (DHL atau konduktivitas). Setiap 1,5 jam sekali dilakukan pengamatan terhadap kadar air biji dan nilai DHL yang dilakukan sampai waktu pengeringan 6 jam melalui 3 macam metode pengeringan (silica gel, matahari, dan oven suhu 40°C).Hasil uji statistik menunjukkan terdapat perbedaan nyata antara kadar air awal biji utuh dan kadar air awal dan potongan biji yang mengandung embrio. Dari ketiga metode pengeringan, silica gel mengeringkan material paling cepat, diikuti pengeringan dengan matahari, dan oven. Bentuk potongan biji yang mengandung embrio lebih cepat mengering daripada biji utuh. Kerentanan biji Artocarpus heterophyllus Lam. terhadap pengeringan memperlihatkan bentuk model regresi yang berbeda antara biji utuh dan potongan biji yang mengandung embrio. Kadar air diduga melalui perhitungan berat kering. Diperoleh hasil bahwa bentuk hubungan yang terjadi pads biji utuh adalah sesuai dengan model Y = 1339,544 - 22,1332X dengan koefisien determinasi sebesar 0,978, sedangkan pada potongan biji yang mengandung embrio adalah mengikuti model Y=965,575 - 14,772X dengan koefisien determinasi sebesar 0,948. Ada pun X adalah peubah kadar air (peubah bebas) dengan Y sebagai peubah viabilitas dengan nilai DHL (peubah).Biji nangka mampu bertahan pada suhu 14°C dengan viabilitas 100% dalam kondisi kadar air tanpa pengeringan dan kadar air 50% selama dua bulan atau lebih. Walau pun demikian kadar air kondisi tanpa pengeringan masih tetap mampu bertahan pada suhu 26°C selama dua bulan. Kadar air awal biji berpengaruh nyata dalam menentukan viabilitas biji selama disimpan.

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ABSTRACT

Seed is the most convenient part of the plant to store and have been known to survive for many weeks. The basic principles of a seed bank are to collect, conserve and provide or exchange germplasm. Seed can be deposited for different periods - short, mid, and long term for different purposes. The longevity of seed is considerable.

Seed can be classified into two groups, orthodox and recalcitrant. Many of seed of tropical tree is recalcitrant. Because many tree species in tropic have the economic value, so study of recalcitrant seed is needed. The aim of this study was to find out the relationship between the seed moisture content decreased with the viability decreased. Therefore, the results can be used as a basic information for the further research.

The research was conducted on two kind of material, the excised embryo and whole seed. Each of those materials was desiccated with three kind of desiccation methods - silica gel, sun, and oven_ The viability is known by a conductivity value.

The effect of desiccation on storability of recalcitrant seed of Artocarpus heterophyllus was studied. As the seed moisture of A. heterophyllus decreased, viability decreased while conductivity value increased. The excised embryo could be desiccated more rapidly rather than whole seed. The silica gel seem to be efective method for seed drying than that of the sun and the oven.

Whole seeds were stored in sealed thin plastic container. Seed with seed coat could germinate on 26°C in one month. In sealed container there were no significantly different of moisture content during eight weeks storage or more. Seed without desiccation is best for maintaining their viability especially at 14°C in sealed container.