Endang Murniati

Pengaruh Antioksidan sebagai Perlakuan Invigorasi Benih Sebelum Simpan terhadap Daya Simpan Benih Bunga Matahari (Helianthus annuus L.)

Oilly seeds, such as those of sunflower ( Helianthus annuus L.), have short storability (3-4 months in room condition) due to oxidative stress during storage. The objective of this research was to determine whether prestorage seed invigoration by antioxidants, could improve storability of sunflower seeds. The research was performed using fresh harvested seeds. Prestorage seed invigorations were conducted by matriconditioning with water or antioxidants solution i.e. 4.17% curcumin or 100 and 150 ppm ascorbic acid. The seeds were stored for four months at room condition (28-29 °C and 62-79% relative humidity). Observations were conducted monthly. Experiment was arranged in split plot design. The result showed that all prestorage seed invigoration treatments were not effective to enhance storability of sunflower seeds compared to control. Inefficiency exogenous antioxidants was probably due to highly endogenous antioxidants activity during storage. This was indicated by the slow deterioration rate of control seeds, or due to high concentration of curcumin which was actually potential to enhance storability of sunflower seeds. It is suggested that presowing treatment and midstorage treatment will enhance storability of sunflower seeds.

Effects of Antioxidants as Prestorage Seed Invigoration Treatments on Storability of Sunflower (Helianthus annuus L.) Seeds

A number of abiotic stress responsive genes have been identified from various plant species through reverse genetic strategy. A group of genes are involved in plant responses to stress; they are activated by diverse stress conditions and through different mechanisms. One single gene can be induced by several different stress factors; on the other hand, a number of genes can be up-regulated by a single factor. In Physcomitrella patens, through Northern hybridization, the transcript level of the gene GFDD4-I was detected to be markedly increased by ABA, dehydration and cold, but not by salinity and osmotic stress. In Arabidopsis thaliana, a homologous gene to GFDD4-1 namely At2g47770, was confirmed to fulfill similar function as in P. patens: it is inducible by various abiotic stress treatments, i.e. ABA, dehydration, salinity, and cold. Inducible genes in response to abiotic stress factors may be responsible for plant tolerance to those factors.

PENGARUH KAPUR TOHOR UNTUK EKSTRAKSI BENIH TERHADAP VlABILITAS BEIH MANGGIS (Garcinia mangostana L

The objectives of this experiment were to evaluate the possibility of using quick lime for extraction of mangosteen seed and the effects on its viability; The experiment was done in Seed Science and Technology Laboratory, Greenhouse, Bogor Agriculture University from November 1997 until February 1998. The materials were taken from smallholder plantation in Jasinga, Bogor. The treatments were arranged factorial in a group randomized block design with two factors. The first factor was 6 levels of quick lime concentration (K) : 0 g/l, 10 g/l, 15 g/l, 20 g/l, 25 g/l, 30 g/l and the second factor was 4 levels of soak periods: 0 minute, 10 minutes, 20 minutes, 30 minutes. The experiments had 24 treatments combination with 4 replicates so there were 72 experiment units. The data show that seed extraction using quick lime gave statistically significant different results compared with seed extraction without using quick lime and so the soak periods compared with no soak. Interaction between 20 g/l quick lime concentration and 30 minutes soak period gave the best seed emergence (96 %). 20 g/l quick lime concentration save higher vigour than other concentration as measured from its speed of germination, spontaneous growth, and root length. The soak periods increased seed moisture content 30 minutes soak period resulted higher viability and vigour than other soak periods as measured from its normal seed dry weigh, spontaneous growth, epycotyl length and root length.