盐胁迫条件下杂交水稻种子发芽特性和幼苗耐盐生理基础

 两个杂交稻组合汕优10号和两优培九种子分别放在H2O、50 mmol/L、100 mmol/L和150 mmol/L的NaCl溶液中于30℃下发芽，测定种子发芽性能和淀粉酶活性及幼苗保护酶活性、丙二醛（MDA）含量和脯氨酸、可溶性糖、果糖和蔗糖等相容性溶质含量。结果表明，盐胁迫条件下杂交水稻种子平均发芽时间延长，发芽指数降低，但发芽势和发芽率变化不明显。盐胁迫后明显降低两优培九种子α，β-淀粉酶活性，而汕优10号中， 除在50 mmol/L NaCl溶液中α-淀粉酶活性高于对照（H2O）外，其余处理均降低了α，β-淀粉酶活性。不同盐胁迫程度下杂交水稻幼苗超氧物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶(CAT)活性和丙二醛含量及脯氨酸、可溶性糖、果糖和蔗糖等相容性溶质含量变化有差异，但未见规律性趋势。杂交水稻幼苗相对含水量和耐盐比率随着盐胁迫程度加深而明显下降。试验还表明，盐胁迫条件下杂交水稻组合汕优10号种子发芽性能比两优培九好，淀粉酶和保护酶活性、相容性溶质含量和相对含水量及耐盐指数和耐盐比率也均高于两优培九，说明汕优10号幼苗耐盐性强于两优培九。

ermination Characteristics of Seeds under Salt Stress and Physiological Basis of Salt-Tolerance of Seedlings in Hybrid Rice

Seeds of two hybrid rice combinations, Shanyou 10 and Liangyoupeijiu, were germinated in H₂O, 50 mmol/L, 100 mmol/L or 150 mmol/L NaCl solutions at 30℃, germination performance, activities of α,β-amylase and content of malondialdehyde(MDA) and compatible solutes, proline, total soluble sugar, fructose and sucrose were determined. Results showed that germination index were significantly reduced and mean germination time were prolonged significantly under salt stress. Except that activities of α-amylase in Shanyou 10 seeds were increased under 50 mmol/L NaCl concentration, activities of α,β-amylase were decreased under salt stress as compared with the control (H₂O). Activities of protective enzymes, superoxide dismutase(SOD), peroxidase(POD) and catalase(CAT), and content of MDA and compatible solutes, proline, total soluble sugar, fructose and sucrose, differ at different concentrations of NaCl solutions, but their regular trends were not found. Relative water content and tolerance ratio of hybrid rice seedlings were decreased with gradient enhancement of NaCl concentrations. It also indicated that Shanyou 10 had better germination performance than Liangyoupeijiu. Activities of α,β-amylase, protective enzymes, SOD, POD and CAT, and content of MDA and compatible solutes, proline, total soluble sugar, fructose and sucrose, in Shanyou 10 were significantly greater than those in Liangyoupeijiu. It suggested that Shanyou 10 had better salt tolerance of seedlings than that of Liangyoupeijiu.