种子引发对水分胁迫下水稻发芽及幼苗生理性状的影响

不同基因型稻种经水引发及聚乙二醇(PEG)渗透胁迫引发处理均能降低稻种丙二醛(MDA)含量，促进可溶性总糖(SS)降解，加快稻种内部糖代谢进程，提高相溶性溶质脯氨酸(Pro)及可溶性蛋白质(SP)含量，也有利于提高苯丙氨酸解氨酶(PAL)、超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性，引发效果较明显。且适度PEG引发稻种的效果明显好于水引发，杂交籼稻在PEG浓度为20%的条件下引发效果最优，而常规粳型水稻在PEG浓度为10%~15%的引发条件下效果较好，但超出最高PEG引发浓度的阈值，会对稻种产生危害，影响其正常萌发。引发处理后的稻种对不同程度水分胁迫程度的响应表明，适当强度的引发处理利于激发稻种物质代谢、利于各水稻品种的萌发、幼苗形态指标及保护性酶等生理指标的显著提高，而严重的水分胁迫均不利于稻种萌发；表明引发处理虽能提高水分胁迫条件下种子活力，但稻种激发自身对外界萌发环境的协调能力有限，且不同品种间存在明显差异，籼稻优于粳稻。

Effects of Seed Priming on Germination and Seedling Growth of Rice under Water Stress

Seeds of four different rice genotypes, Gangyou 527, Yangdao 6, Zhonghan 3 and Nongken 57, were treated with two priming method, H₂O and different concentrations of polyethylene glycol (PEG). Nonprimed or primed seeds were germinated under different water stress. The contents of proline, soluble protein (SP), total soluble sugars (SS), malonicdialdehyde (MDA), phenylalanine ammonia lyase (PAL), superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) in seeds or stressed seedlings, and seed germination and rice seedling characteristics were determined. The results showed that significantly higher levels of proline and SP and lower levels of SS and the content of MDA in primed seeds were observed as compared with control (nonprimed seeds). Priming accelerated the process of glucose metabolism, improved the activities of PAL, SOD, CAT and POD in stressed different genotypic rice seeds, moreover, priming effects was relatively significant. Rice seeds could be initiated significantly better by the priming of proper PEG concentration than hydropriming. The results showed that the best priming conditions was 20% PEG for hybrid indica rice seeds, and 10%–15% PEG for conventional japonica rice seeds. Normal germination of rice seeds it was inhibited when PEG content was beyond the threshold. Response of hydroprimed seeds or PEG primed seeds on seedlings growth of different genotypic rice under different water stresses. Showed that the proper water stress could activate material metabolism, promote rice seeds germination, and significantly increase kinds of physiological index of seedlings in different genotypes of rice, such as morphological index and protective enzymes after the treatment of proper PEG content, But it went against and serious water stress to inhibited germination..It showed that although seed priming treatment could improve activity of rice seedlings, the coordination ability to external germinating environment by self-regulation was limited. It also indicated that indica rice had greater PEG tolerance than conventional japonica rice, but better priming effects were observed in hybrid indica rice.