油桃花芽破眠过程中H_2O_2代谢与Ca^(2+)转运的关系

Relationships between H_2O_2 metabolism and Ca^(2+) transport in dormancy-breaking process of nectarine floral buds

利用化学测定法分析高温、单氰胺和TDZ 3种破眠处理对"曙光"油桃休眠花芽H2O2代谢的主要影响,利用非损伤微测技术检测H2O2对休眠芽Ca2+转运的影响,研究H2O2在芽休眠解除过程中的调控作用.结果表明:在深休眠时期,高温和单氰胺处理均能诱导芽内H2O2含量升高和过氧化氢酶(CAT)活性降低,并具有显著的破眠作用;TDZ对H2O2含量及CAT、过氧化物酶(POD)活性影响不大,破眠效果较差.休眠花芽原基组织钙通道活跃,对外源Ca2+呈吸收状态.外源H2O2可诱导休眠花芽原基组织Ca2+转运发生变化,低浓度H2O2降低Ca2+吸收速率,高浓度H2O2使组织对Ca2+的转运由吸收转变为释放.这表明休眠芽内H2O2信号和Ca2+信号相关联,通过诱导H2O2积累调控Ca2+信号可能在高温和单氰胺打破休眠的信号转导过程中起重要作用.

In order to explore regulatory function of H2O2 in bud dormancy release, main effects of three dormancy-breaking treatments （ high temperature, hydrogen cyanamide and TDZ） on H2 O2 metabolism were determined, and impacts of H2O2 on Ca〉 transport were tested using non-invasive micro-test technique. The results showed that both high temperature and hydrogen cyanamide induced H2O2 accumulation and CAT inhibition were efficient in breaking dormancy during deep dormancy period. However, TDZ showed little impacts on H2 O2 metabolism and was much less effective in breaking dormancy. Dormant floral primordium was absorbing state to exogenous Ca2＋ due to active calcium channels. The Ca2＋ transport could be changed by exogenous H2O2. H2O2 of low concentration reduced the absorption rate of Ca2＋, and at high concentration, it changed the Ca〉 transport direction from absorption to release. The results indicated that H2 O2 signals were related with Ca2＋ signals in dormant buds. Ca2＋ signal regulated by H2O2 accumulation might be important in the dormancy-breaking signal transduction process induced by high temperature and hydrogen cyanamide.