5-ALA浸种对干旱胁迫下紫花苜蓿种子萌发特性的影响

Effect of 5-ALA on seed germination of alfalfa under drought stress

摘要:

为了探究干旱胁迫下5-氨基乙酰丙酸(5-ALA)溶液浸种对紫花苜蓿的调控作用,以紫花苜蓿品种中苜1号(Medicago sativa cv.Zhongmu No.1,ZM)和阿尔冈金(Medicago sativa cv.Algonguin,AG)为供试材料,了解不同浓度(0,5,10,25,50,75,100 mg/L)5-ALA溶液浸种对15% PEG-6000模拟干旱胁迫的条件下种子萌发特性的影响,试验采用随机区组设计。结果表明:当5-ALA浓度为10 mg/L时,AG的发芽率最大,为91.0%,而当浓度为50 mg/L时,ZM的发芽率和发芽势均最大,分别为98.0%和79.5%。当5-ALA浓度为50 mg/L时,AG和ZM的根重均达到最大值,分别为6.8 mg和7.5 mg;当5-ALA浓度为5 mg/L时,AG和ZM的芽重最大,分别为11.4和10.5 mg,表明高浓度5-ALA溶液浸种促进幼苗根系生长而抑制芽的生长。综合评价认为,干旱胁迫下随着5-ALA浓度的增加,紫花苜蓿缓解干旱胁迫的能力呈先增强后减弱的趋势;当5-ALA浓度为25 mg/L时,隶属函数综合评价得分最高(0.27),表明5-ALA为25 mg/L时缓解干旱胁迫的效果最佳。

Abstract:

This study aimed to explore the effects of various 5-ALA concentrations (0,5,10,25,50,75,100 mg/L) on seed germination of two alfalfa cultivars (Medicago sativa cv.Zhongmu No.1,ZM) and (Medicago sativa cv.Algonguin,AG) under 15% PEG-6000 induced drought stress.The experiment was arranged in a randomized complete block design.AG had a maximum germination rate of 91% at 10 mg/L of 5-ALA;while ZM had both the maximum germination rate (98%) and germination energy (80%) at 50 mg/L of 5-ALA.The maximum root weight of both AG and ZM (6.8 mg and 7.5 mg,respectively) was observed at 50 mg/L of 5-ALA;while the maximum shoot weight was found at 5 mg/L of 5-ALA for both AG and ZM (11.4 mg and 10.5 mg,respectively).5-ALA at high concentration promoted root growth but inhibited shoot growth.The comprehensive evaluation index showed that 5-ALA at lower concentrations alleviated drought stress followed by the reduced effects along the increased concentration,with the optimum effects achieved at 25 mg/L of 5-ALA in alfalfa.