| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1991: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1990: ¥1,600,000 (Direct Cost: ¥1,600,000)
|
|---|
| Research Abstract |
The effects of day length on the dynamism of gibberellins(GAs)during germination and early growth of Pharbitis nil were studied. Four hundreds of cotyledons of P. nil cultivated at 25 C under contineous light(CL)or 8h light-16h dark(8L-16D)condition for 10 days were harvested. and their petioles were dipped in a solution of 2OmM EDTA(pH 7.5)and moved into distiled water to collect phloem exudates. This solution containing phloem exudates was submijected to the conventioan solvent fractionation to afford an acidic ethyl acetate soluble(AE)fraction. The residual cotyledons were hanogenized in 80% acetone and subjected to the solvent fractionation to give an AE fraction. Each AF fraction was dissolved in a small volume of methanol and subjected to prepurification using cartridges containing Sepralyte DEA. The eluates v'ith methanol containing 0.1% acetic acid from the DEA cartridge was then purifed by HPLC using a column of Senshu Pak NMe2 eluted with methanol containing 0.05% acetic acid
… More
in reethanol. The eluates from the column wi#, 'collected in a fraction every minute. Aliquots of each fraction were analyzed by either radiaimmunaassay or ELISA using antibodies specific for GA3-methyl ester. GA20-methyl ester. or GA24. These experiments showed that GA1, GA20, and GA19 were major GAs in phloem exudates of P. nil. Then, radioactive GA19, GA20, and GAI were administrated an the surface of cotyledons scrapted with sandpaper(600 meshes), and the effect of 1 light condition on their translocation was studied. GAI was translocated into hypocatyls within 5 min after administration, and rapistly converted GA8 and GA8 glucoside. However, the translocation of GAI administrated into cotyledon was hardly translocated to epicotyls under any light condition. GA20 was translocated to hypocotyls within 50 min, and it was accelerated by dark treatmtent. GA20 translocated to hypocotyls was converted to GA29 and GA29-glucoside. After 50 min, GA20 was noticed in epicotyls and converted to GAl there. While the translocation of GA20 from cotyledons to hypocotyls was accelerated under dark condition, the movement to epicotyls was accelerated by CL. The pattern of the translocation of GA19 was quite similar to that of GA20, but the conversion of GA19 to other GAs such as GA20, GAI, and GA29 was undetectable. These result showed that GAI produced in cotyledons was translocated to hypocotyls, converted into inactive GAs, and hardly translocated to epicotyl which contains growing points. On the other hand, GA19 and GA20, which are precursors of biologically active GA1, are translocated from cotyledons to epicotyls and converted to GA1. Less
|
