摘要
During long term storage at 25℃ in the dark,a large number of cell content were transferred from the senescing scape to the developing cloves,and the transfer from the basal part of scape was earlier than that from the apical part in the excised garlic scape ( Allium sativum var Taichang).Levels of H 2O 2 decreased in the cloves and significantly increased up to 10 folds and then declined quickly in the scape.Levels of H 2O 2 were enhanced early in the basal part of scape.In the treatment of GA 3 at the cloves,levels of H 2O 2 were strongly enhanced in the cloves and inhibited in the scape,coinciding with the distinct inhibition of cell content tansfer.The results indicated that H 2O 2 may be involved in cell content redistribution and its regulation.3-Amino-1,2,4-triazole (AT) is a specific inhibitor of catalase.Effects of AT on cell content redistribution and levels of H 2O 2 were almost similar to those of GA 3,It further proved the above concept.According to the changes of H 2O 2 leves and activities of peroxidase and catalase in the cloves and in the scape,we suggest that the accumulation of H 2O 2 in the scape was transducted from the cloves,and the decline of H 2O 2 level in the scape with GA 3 or AT at the cloves was mainly through the inhibition of H 2O 2 synthesis in the cloves.
植物生长发育过程中经常发生新老器官更替和细胞内含物的再分配、再利用。Lepold提出新生器官向衰老器官传递某种信息 ,动员后者细胞内含物向前者再分配。但是该信息的化学本质迄今仍不清楚。大蒜 (Alliumsativum)的离体蒜苔是研究细胞内含物再分配的良好材料。细胞内含物大量从苔茎向珠蒜中再分配 ,结果珠蒜显著膨大而苔茎衰老死亡。蔡可等发现赤霉素 (GA3)处理可有效抑制细胞内含物再分配。我们此前的研究发现GA3处理苔茎基部可显著改变珠蒜和苔茎H2 O2 代谢。本研究中我们分别用GA3和 3-氨基 - 1 ,2 ,4-三唑 (AT)H2 O2 清除酶catalase的专一性抑制剂处理珠蒜 ,结果发现GA3和AT均可有效抑制离体蒜苔细胞内含物再分配 (Fig .1 )。根据浓度不同 ,H2 O2 可以诱导细胞产生保护性反应或凋亡。细胞内含物再分配过程中 ,珠蒜H2 O2 浓度显著下降后保持于低水平 ,相反苔茎H2 O2 浓度极显著升高 1 0倍以上 ,而且细胞内含物转移早的苔茎下部H2 O2 峰值出现也早 (Fig .2 )。GA3或AT处理珠蒜 ,珠蒜H2 O2 浓度显著提高而苔茎H2 O2 浓度保持稳定的低水平或峰值显著推迟 (Fig .2 )。可见苔茎高浓度的H2 O2 诱导了苔茎细胞凋亡并把细胞内含物转移给珠蒜。已知约 2 %的呼吸耗氧生成H2 O2 。珠蒜呼吸速率显著高于苔茎
基金
TheprojectwassupportedbytheScienceFoundationofJiangsuProvince
