外源一氧化氮供体对渗透胁迫下小麦种子萌发和水解酶活性的影响

采用含水量测定和种子吸胀实验,发现一氧化氮(nitric oxide,NO)供体硝普钠(sodium nitroprusside,SNP)促进小麦种子在渗透胁迫下萌发的效应是通过提高种子的吸胀能力实现的;SNP还能明显诱导胁迫下种子淀粉酶同工酶Ⅰ活性的上升,加速淀粉胚乳的液化或溶解,而对酯酶影响不大.此外,在无胁迫条件下的小麦种子萌发早期(12 h),SNP处理可以显著诱导葡萄糖、果糖和蔗糖含量的上升;采用外源糖和SNP,结合NO清除剂处理小麦种子,观察到葡萄糖、果糖和蔗糖都参与萌发早期NO信号对小麦种子淀粉酶同工酶Ⅰ的激活.

Effects of Exogenous Nitric Oxide Donor on Germination and Activities of Hydrolytic Enzymes in Wheat Seed Under Osmotic Stress

Results in this paper showed that theeffect of nitric oxide (NO) donor, sodium nitro-prusside (SNP), which could promote the ger-mination of wheat seeds under osmotic stress,was through enhancing imbibition using watercontent determination and imbibition analysis ofwheat seed (Fig.1). SNP could also enhanceamylase isozyme I activities (Fig.2A), acceler-ate the liquefaction of endosperms (Fig.2C),while have no effect on esterase (Fig.2B).Moreover, SNP could strongly increase thesugars, such as the fructose, glucose and sucrosecontents in wheat seeds during early germina-tion (12 h) under normal conditions (Fig.3A).When the seeds were treated with SNP with orwithout PTIO, an NO scavenger, and different exogenous sugars, i.e. fructose, glucose andsucrose, it was found that these sugars mightactivate amylase isozyme I activity mediated bythe signal molecule NO to start the early stageof germination (12 h, Fig.3B, C).