盐胁迫下ABA对水稻萌芽期及孕穗期生长、生理代谢的影响

Effects of ABA on Growth and Physiological Metabolism of Rice at Germinating Stage and Booting Stage under Salt Stress

为探讨盐胁迫下脱落酸(ABA)浸种的最适浓度及其对水稻孕穗期生长和生理代谢的影响,本试验以前期筛选出的耐盐水稻品种FL478和盐敏感型品种万胜A为材料,研究了盐胁迫下不同浓度(2.5、5.0、7.5、10.0 mg/L)ABA浸种对水稻萌芽期根长和芽长以及用ABA最适浓度浸种后对孕穗期生理特性的影响。结果表明,2.5和5.0 mg/L ABA浸种均能有效增加盐胁迫下水稻萌芽期的根长和芽长,其中5.0 mg/L ABA显著增加了FL478根长及万胜A的芽长,因此5.0 mg/L ABA为最佳浸种浓度。盐胁迫降低了2个水稻品种孕穗期的叶片相对含水量、叶绿素a、叶绿素b、总叶绿素等光合色素含量,增强了叶片的超氧化物气化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)、抗坏血酸过氧化氢酶(APX)等保护酶活性;经5.0 mg/L ABA浸种处理后,提高了孕穗期叶片相对含水量、光合色素和可溶性蛋白含量,显著提高了FL478的POD、CAT活性以及万胜A的APX活性,并降低了2个水稻品种的MDA含量。因此,在盐胁迫下,5.0mg/L ABA浸种能有效促进水稻萌芽期的生长及改善孕穗期的生理特性。

In order to study the optimal seed-soaking concentration of abscisic acid(ABA) and its effects on the growth and physiological metabolism of rice at booting stage under salt stress, FL478, a salt-tolerant rice cultivar and Wansheng A, a salt-sensitive rice cultivar, identified in the previous experiment, were used as the materials to figure out the effects of different seed-soaking concentrations(2.5, 5.0, 7.5, 10.0 mg/L) of ABA on the length of root and shoot of rice at the germinating stage and the effects of the optimum seed-soaking concentration of ABA on the physiological characteristics of rice at the booting stage. The results showed that 2.5 and 5.0 mg/L ABA increased the root and shoot length at the germination stage under salt stress, particularly 5.0 mg/L ABA significantly increased the root length in FL478 as well as the shoot length in Wansheng A. Therefore, 5.0 mg/L ABA was the optimum concentration for seed soaking. Salt stress reduced the relative water content, the content of chlorophyll a, chlorophyll b and total chlorophyll of two rice cultivars, while the activities of protective enzymes such as superoxide dismutase(SOD), catalase(CAT),peroxidase(POD), ascorbate peroxidase(APX) in leaf were enhanced. After soaking seeds with 5.0 mg/L ABA, the relative water content, photosynthetic pigments and soluble protein content in leaf were increased at the booting stage,the POD and CAT activity of FL478 and the APX activity of Wansheng A were significantly increased,, and the MDA content was decreased in two rice cultivars. It is indicated that soaking seeds with 5.0 mg/L ABA could effectively improve the growth at the germinating stage and the physiological characteristics of rice at booting stage under the salt stress conditions.