Abstract:Jasmonic acid and its derivative such as methyl jasmonate (Me-Ja) belong to ubiquitous cyclopentanane compounds that are claimed to represent a new type of regulator for plant groWth and development. Its physiological activities were similar to those of abscisic acid (ABA). A biological role of Me-Ja was suggested to substitute ABA in the developmental regulation of seeds under desiccation. So we wish to test the idea that it might be involved in seed germination. After peanut seeds germinating in the Me-Ja solution (0.01 -5 mmol/L or 0.001 - 100 umol/L) for 7 days in the dark (28 ±1℃), the germination percentage could hardly be decreased, but the growth of hypocotyl and radicle were much slower in high Me-Ja concentration than that in water. The activities of amylase and endopeptidase in cotyledons were inhibited partially by high concentration of Me-Ja, and promoted by low concentration. But the lipase activity was strongly inhibited in all Me-Ja treatments. The degradation of starch and salt soluble protein were inhibited partially by high Me-Ja concentration, while arachin and lipid degradation were inhibited partially at all Me-Ja concentrations. Our previous experiment showed that the inhibition of peanut seed germination by ABA was mainly via the depression of endopeptidase activity, while in present study, the decrease of germination by Me-Ja was probably due to the inhibition of lipase activity and lipid degradation. It is suggested that there is an essential difference between ABA and Me-Ja in inhibiting the gerdrination of peanut seeds.
