持续干旱下杜鹃花类菌根真菌对桃叶杜鹃内源激素的影响

以桃叶杜鹃为材料,采用播种法接种2株杜鹃花类菌根(ericoid mycorrhizas,ERM)菌株培育桃叶杜鹃菌根苗,研究在持续干旱下ERM菌株对桃叶杜鹃内源激素生长素(indole-3-acetic acid,IAA)、脱落酸(abscisic acid,ABA)、赤霉素(Gibberellin A3,GA3)和玉米素核苷(trans-Zeatin-riboside,ZR)的影响.结果表明:接种ERM菌株显著增加了桃叶杜鹃在正常水分及持续干旱条件下IAA,ABA,GA3,ZR的质量比.持续干旱下,桃叶杜鹃IAA和GA3的质量比呈升高降低变化,接种ERM菌株桃叶杜鹃IAA和GA3的质量比呈升高变化在重度胁迫时达到最大值;ABA的质量比呈升高变化,当田间持水量低于30%时接种ERM菌株桃叶杜鹃ABA的质量比急剧上升并维持在较高水平;ZR的质量比变化不一,对照组和TY29根系ZR的质量比呈降低升高变化,TY35根系ZR的质量比呈降低变化.持续干旱下,桃叶杜鹃IAA/ABA,ZR/ABA,(IAA+ZR+GA3)/ABA比值呈下降变化,其中ZR/ABA比值急剧下降,接菌处理显著低于对照组.试验表明:ERM菌株能有效增加桃叶杜鹃内源激素IAA,ABA,GA3和ZR的质量比,增加干旱胁迫下的内源激素调节及协作能力,增强桃叶杜鹃的抗旱能力.

Influences of ERM Strain on Endogenous Hormones of Rhododendron annae Franch in Continuous Drought

Two strains of ERM (ericoid mycorrhiza) were inoculated at sowing to cultivate the rhizome of Rhododendron annae to study their effects on indole-3-acetic acid (IAA), abscisic acid (ABA), gibberellin A3 (GA3) and trans-zeatin-riboside (ZR) in R.annae under continuous drought.Inoculation of ERM significantly increased IAA, ABA, GA3 and ZR contents in R.annae plants under conditions of normal water and continuous drought.The content of IAA and GA3 in R.annae increased first and then decreased in continuous drought.In ERM inoculation treatment IAA and GA3 contents of R.annae increased and reached the maximum at severe stress.When the field water holding capacity was less than 30%, ABA content increased sharply and was maintained at a fairly high level.ZR content varied:the ZR content increased in the control group and TY29 root, and decreased in TY35 root.The ratios of IAA/ABA, ZR/ABA and (IAA + ZR + GA3)/ABA decreased, and the ratio of ZR/ABA decreased sharply.They were significantly lower in inoculation treatments than in the control group.The above results showed that ERM strains could enhance the contents of IAA, ABA, GA3 and ZR in R.annae to increase the ability of regulation and cooperation of its endogenous hormones under drought stress and improve the drought resistance of the plant.