用CO₂激光(20.1 mW/mm2)辐照小麦种子3 min,待幼苗长至二叶一心时,用质量浓度为100 g/L的聚乙二醇6000(PEG6000)胁迫其幼苗,并通过添加过氧化氢酶(catalase,CAT;H2O2清除剂)、抗坏血酸(ascorbate,AsA;H2O2清除剂)和二苯基碘(diphenylene iodonium,DPI;NADPH氧化酶抑制剂),研究过氧化氢在CO₂激光预处理提高小麦耐旱性中的作用。结果表明,激光预处理可使干旱胁迫的小麦幼苗丙二醛(malondialdehyde,MDA)含量显著降低(p<0.05),而超氧化物歧化酶(superoxide dismutase,SOD)、过氧化物酶(peroxidase,POD)和CAT活性、叶绿素a、叶绿素b、类胡萝卜素含量和株高、根长和根干重却显著增加(p<0.05)。而经过适当剂量激光辐照干旱胁迫小麦幼苗再加外源CAT(L+P+C),AsA(L+P+A)或DPI(L+P+D)处理能有效逆转激光对干旱胁迫小麦幼苗的防护作用。从而说明激光预处理主要通过诱导内源H2O2产生而对植物在生理生化水平上起到一定的防护作用,且H2O2的形成与NADPH氧化酶途径有关。

The objective of this study is to test whether hydrogen peroxide (H2O2) is involved in laser pretreatment induced drought tolerance in wheat seedlings due to its nature as a second messenger in stress responses. Plant is treated with 3 min CO2 laser pretreatment, laser pretreatment in combination with catalase (CAT), ascorbate (AsA) or diphenylene iodonium (DPI) and their effects on the lipid peroxidation, the activities of antioxidant enzymes and the concentration of photosynthesis pigment and seedlings growth and development were compared. The results show that 3 min laser pretreatment can enhance drought tolerance in wheat seedlings by decreasing the concentration of malondialdehyde (MDA) and increasing the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and the concentration of chlorophyll a, chlorophyll b, carotenoid and plant height, root length and root dry weight. But the promotive effect of laser pretreatment induced drought tolerance in wheat seedling is effectively reversed by the addition of CAT, AsA or DPI. The results suggest that H2O2 is involved in laser pretreatment induced drought tolerance in wheat seedlings and laser induced protective effect is likely related to NADPH oxidase-dependent H2O2 production.