8342937126

Pertanika 14 (1). 1-6(1991)

Changes in Germination, Respiration Ratę and Leachate Conductivity

during Storage of Hevea Seeds

M.N. NORMAH¹ and H.F. CHIN

Agronomy Department, Faculty ofAgńculture UniwerńtiPertanian Malaysia 43400 UPM, Serdang, SelangorDarulEhsan, Malaysia

Key words: Hevea; storage; changes.

ABSTRAK

Biji benih Hevea telah disimpan terpedap dałam suhu 10, 22 dan 27°C. Selepas setiap bulan penyimpanan, pertukaran dałamperatuspercambahan, kadar respirasi dan konduktiviti lułuhlarutan diukur. Didapati dengan penambahan masa, penyimpanan ber laku penurunan dałam peratus percambahan, ketinggian beral keńnganak benih, kadar respirasi serta penambahan konduktiviti lułuhlarutan. Kehilangan integriti membran dicadangkan sebagaipunca kerosakan biji semasapenyimpanan.

ABSTRACT

Hevea seeds were stored imbibed at the temperatures of 10, 22 and 27°C. After e ach month of storage, changes in percentagegermination, respiration ratę and leachate conducliuity were obserued. There was a decrease in percentage germination, seedling height, seedlingdry weight, respiration ratę and an increasein leachate conductńńty asduration ofstorage increased. Loss of membranę integrity was suggested as one of the causes of deteńoration ofseeds during storage.

INTRODUCTION

Rubber (Hevea brasiliensisMuell. - Arg.) seeds are considered to be recalcitrant in naturę. Roberts (1973) classiffied recalcitrantseedsasthosewhose viability tends to decrease with a decrease in moisture content below some relatively high value, between 12 and 31 %. Hevea$eeds are killed by dehydration, high temperaturę orfree/ing (Chin etal. 1981). At present no method is availabie for the storage of Hevea seeds beyond ayear. Storage of Heveaseeds mixed with moist sawdust in perforated polythene bagsat 7°Ccan mantain viability up to four months (Ang 1976). Treatment with polyethylene glycol 1500 was found to improve the storage lifeof seeds uptosbc months with 25% germination (Sakhibun 1981).

Other than thestudiescarriedoutbyChin etal. (1981), Hor (1984) and Berjak et al. (1984), very little work has been done to study changes that occur in recalcitrant seeds during deterioration. Seed deterioration has been defined as irreversible changes that reduce survival capacity and lead to lossofvigour and germinability (Anderson 1973). It has been postulated that as the seed deteriorates, various functions of the seed are impaired in a definite sequence (Delouche 1969; Heydecker 1972). Thus,deterioration is not confined to any one cellular function, but is manifested in avariety ofways with any one beingsufficient to impede germination (Bewleyand Black 1982).

According to Delouche (1969), delayed seed germination is one of the earliest physiological signs of deterioration. It occurs well ahead of decreased germination and has been used to index deterioration in a wide rangę of seeds including corn (Grabę 1965), sorghum and soybean (Teng 1977). Retardation of seedling growth was ob-served in a wide rangę of deteriorating seeds including broad beans, peas and barley (Abdalla and Roberts 1969),snap beans (Tooleetai 1957),and corn (Grabę 1965; Woodstock and Feeley 1965).

The decline in respiratory ratę has also been reported for various seeds under different condi-tions of deterioration. These include natural age-

1

Present address: Department of Botany, Faculty of Life Sciences, Universiti Kebangsaan Malaysia, 436(X) Bangi. Selangor Darni Ehsan, Malaysia.