Study on the free-radical production and stress signal transduction of jasmonates and abscissic acid

干旱胁迫对'Shiranui'树[（Citrus unshiu Marc.？（柑橘）？柑橘布兰科]、黄原胶、脱落酸（阿坝）、菜豆酸（PA）、双甘酸（DPA）、表双甘酸（epi-DPA）和茉莉酸类化合物。使用各自的氘标记内标物对其进行定量。黄嘌呤，阿坝，DPA浓度在纸浆中的干旱胁迫的树木被发现高于那些良好的浇水的树木在整个发展。黄毒素的浓度，但是，低于阿坝。这些结果可能意味着从黄嘌呤到阿坝的快速周转。此外，阿坝浓度较高的干旱胁迫的树木比浇水良好的树木，虽然PA和DPA水平之间的干旱胁迫和浇水良好的树木不清楚。DPA被发现是在果肉，皮肤，和叶的初级代谢产物。在干旱胁迫下，果肉、果皮和叶片中茉莉酸（JA）和脱落酸（阿坝）的含量均较高。然而，随着收获的临近，果肉中的JA水平下降。干旱胁迫树的纸浆中的蔗糖浓度高于那些充分浇水的树。阿坝和茉莉酸的应用诱导叶片气孔关闭。阿坝对气孔关闭的影响强于茉莉酸。研究了几种热带水果的抗氧化活性和抗氧化剂。总酚和抗坏血酸作为抗氧化剂进行了分析。果实清除超氧阴离子和DPPH自由基的IC 50值一般与总酚含量有关。二氢茉莉酸正丙酯（PDJ）处理降低了冷害。总的来说，超氧阴离子和DPPH自由基清除活性的IC 50值也与冷害程度有关。这些结果表明茉莉酸酯，抗坏血酸和多酚之间的联系。

Drought stress was applied to ‘Shiranui' trees [(Citrus unshiu Marc.? Citrus unshiu Osbeck)? Citrus reticulata Blanco], and xanthoxin, abscisic acid (ABA), phaseic acid (PA), dihydrophaseic acid (DPA), epi-dihydrophaseic acid (epi-DPA), and jasmonates were monitored in fruit and leaf. They were quantified using the respective deuterium-labeled internal standards. Xanthoxin, ABA, and DPA concentrations in the pulp of the drought-stressed trees were found to be higher than those of the well-watered trees throughout development. Xanthoxin concentrations, however, were lower than those of ABA. These results may imply a rapid turnover from xanthoxin to ABA. In addition, ABA concentrations in the leaf were higher in drought-stressed trees than the well-watered trees, although PA and DPA levels between the drought-stressed and well-watered trees were not clear. DPA was found to be the primary metabolite in the pulp, skin, and leaf. Both jasmonic acid (JA) and ABA concentrations in the pulp, skin, and leaf showed high values in the drought-stressed trees. However, JA levels in the pulp decreased as the harvest approached. Sucrose concentrations in the pulp of the drought-stressed trees were higher than those of the well-watered trees. ABA and jasmonate applications induced stomatal closure in leaf. The effect of ABA on stomatal closure was stronger than that of jasmonate.Antioxidant activities and antioxidants of some tropical fruits were investigated. Total phenolics and ascorbic acid were analyzed as antioxidants. IC 50 values of superoxide and 1-diphenyl-2-picrylhydrazyl (DPPH)-radical scavenging activity in fruit are generally linked with total phenolics. n-Propyl dihydrojasmonate (PDJ) treatment decreased chilling injury. In general, IC 50 values of superoxide and DPPH radical scavenging activity were also associated with the degree of chilling injury. These results suggest the connections among jasmonates, ascorbic acid, and polyphenolics.