杂交水稻

为研究激动素（kinetin,KT）引发对盐胁迫下杂交水稻种子萌发、幼苗生长及生理特性的影响，以杂交水稻品种民两优丝苗为材料，采用40 mmol/L的NaCl溶液模拟盐胁迫，设置1、50、100、150、200 mmol/L共5个激动素浓度，进行种子引发处理。测定并分析了种子发芽指标、幼苗生长指标、叶片叶绿素含量，以及幼苗叶片和根系中的抗氧化酶活性、丙二醛（MDA）含量、可溶性糖和可溶性蛋白含量等。结果表明，盐胁迫下，杂交水稻种子萌发和幼苗生长受到抑制。与无盐胁迫且未经激动素引发处理（CK1）相比，盐胁迫但未经激动素引发处理（CK2）种子的发芽率、发芽势、发芽指数和活力指数分别显著降低6.25%、12.54%、17.03%和30.77%；幼苗的芽长、根长、芽鲜重、根鲜重、芽干物质重和根干物质重分别降低26.39%、29.67%、36.48%、36.72%、26.92%和13.64%；叶片总叶绿素含量显著降低28.05%。与CK2处理相比，50 mmol/L激动素引发处理的效果较好，能显著提高种子发芽率、发芽势、发芽指数、活力指数等发芽指标，促进幼苗及根系生长，显著增加叶片叶绿素a、叶绿素b和总叶绿素含量，提升叶片和根系中超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）活性，显著提高可溶性蛋白含量，并显著降低丙二醛（MDA）含量。综上，50 mmol/L的激动素引发可通过促进种子萌发、幼苗生长、叶绿素合成，增强抗氧化能力，调节渗透平衡等途径，有效提高杂交水稻幼苗的耐盐性。

This study investigated the effects of kinetin(KT) priming on seed germination, seedling growth and their physiological characteristics of hybrid rice under salt stress. The salt stress of the hybrid rice variety Minliangyou Simiao was simulated with 40 mmol/L NaCl solutions. Rice seeds were primed with KT solutions at five concentrations: 1, 50, 100, 150, and 200 mmol/L. Seed germination indices, seedling growth parameters, leaf chlorophyll content, as well as antioxidant enzyme activities, malondialdehyde(MDA) content, and soluble sugar and soluble protein levels in leaves and roots of seedlings were determined. The results showed that salt stress inhibited seed germination and seedling growth of hybrid rice. Compared with the treatment without salt stress and without KT priming(CK1), the treatment with salt stress but without KT priming(CK2) markedly decreased the seed germination rate, germination energy, germination index, and vigor index by 6.25%, 12.54%, 17.03%, and 30.77%, respectively. In addition, salt stress reduced the seedling shoot length, root length, shoot fresh weight, root fresh weight, shoot dry weight, and root dry weight by 26.39%, 29.67%, 36.48%, 36.72%, 26.92%, and 13.64%, respectively, and markedly decreased the total chlorophyll content in leaves by 28.05%. Compared with CK2, priming with 50 mmol/L KT exhibited relatively pronounced ameliorative effects. It significantly improved the seed germination rate, germination energy, germination index, and vigor index, promoted seedling and root growth, significantly increased the levels of chlorophyll a, chlorophyll b, and total chlorophyll in leaves, enhanced the activities of superoxide dismutase(SOD), peroxidase(POD), and catalase(CAT) in both leaves and roots, significantly improved soluble protein level, and markedly reduced MDA content. In conclusion, priming with an 50 mmol/L of KT can effectively enhance salt tolerance of hybrid rice seedlings by promoting seed germination, seedling growth, and chlorophyll synthesis, as well as by strengthening the antioxidant ability and regulating osmotic balance.