根际低氧对不同抗性猕猴桃幼苗生长和内源激素的影响

Effects of Root-zone Hypoxia Stress on Growth and Endogenous Hormones in Young Kiwifruit Seedlings with Different Resistant Ability

采用水培通氮低氧胁迫法,研究猕猴桃幼苗生长量及叶、根内源激素脱落酸(ABA)、赤霉素(GA3)、吲哚乙酸(IAA)和玉米素核苷(ZR)对低氧胁迫的响应。结果表明:低氧胁迫下猕猴桃幼苗生长受到抑制,植株鲜、干样质量均低于对照,美味猕猴桃生长受影响相对较小;低氧胁迫下美味猕猴桃和中华猕猴桃叶内ABA分别较对照增加289.2%和412.9%,根内ABA含量分别增加188.5%和177.4%;叶内IAA含量先升高后下降,6d达峰值时美味猕猴桃和中华猕猴桃分别比对照增加87.3%和61.4%,根内IAA含量变化与叶类似,4d达峰值时分别比对照增加90.4%和59.6%;叶和根内GA3和ZR含量随胁迫时间延长而降低,低氧胁迫8d时,美味猕猴桃和中华猕猴桃幼苗叶内GA3分别比对照降低56.5%和79.0%;根内降低33.1%和55.1%,叶内ZR分别对比照降低70.5%和86.1%,根内降低46.9%和71.3%;低氧胁迫下,猕猴桃幼苗根和叶内IAA/ABA、ZR/ABA、GA3/ABA比值均呈现下降趋势。

Young kiwifruit seedlings （Actinidia deliciosa and A. chinensis） were planted in nutrient solutions aerated with nitrogen. Under root-zone hypoxia stress, the growth and response of endogenous hormones abscisic acid （ABA） , indole-acetic acid （IAA） , zeatin riboside （ZR）, gibberellins （GA3） in kiwifruit seedlings were studied. The results showed that the fresh and dry weight of seedlings treated under hypoxia were less than those of control. Effects of hypoxia stress on A. deliciosa were much slighter than on A. chinensis, which made A. deliciosa perform a better resistance. The ABA contents in A. deliciosa, A. chinensis leaves and roots were enhanced obviously, namely raised by 289.2%, 412.9%, 188.5%, 177.4%, respectively. The IAA contents in A. deliciosa, A. chinensis leaves were raised to the maximum on the 6th day, then reduced but still higher than those of control, namely raised by 87.3%, 61.4%, respectively. Same tendencies happened in the roots of both species, but the peak appeared on the 4th day and differed from that of the leaves. The IAA contents in roots of A. deliciosa, A. chinensis were increased by 90. 4%, 59. 6% , respectively. The GA3 contents in A. deliciosa, A. chinensis leaves were decreased by 56. 5%, 79.0% correspondingly. The ZR contents were decreased by 70.5%, 86. 1% correspondingly. The GA3 contents in A. deliciosa, A. chinensis in roots were lessened by 33.1%, 55.1% correspondingly. The ZR contents were lessened by 46. 9%, 71.3% correspondingly. The ratios of IAA/ABA, ZR/ABA, GA3/ABA were also studied and the results of them decreased, which showed that kiwifruit seedlings were obviously inhibited from growing under hypoxia and the resistant ability had an intimate relationship with endogenous hormones.