不同基质的水分亏缺对大花蕙兰生理生化特性的影响

Effects of Different Media Water Deficiency on Physiologyof Cymbidium hybridum

测定了大花蕙兰(Cymbidiumhybridum)在不同基质及基质含水量下的基质含水量(MWC)、叶片含水量(LWC)、叶水势(LWP)气孔导度、蒸腾速率、叶绿素含量,以及SOD、CAT、POD活性,MDA和PRO含量及叶片相对透性。结果表明,水藓(SP)基质的保水力高于花生壳掺沙(VPH∶VS=1∶1)基质。SP基质临界水分是基质相对含水量的15.86%～12.32%,PH/S基质临界水分16.42%～12.29%,叶片含水量的阈值为87.41%～80.31%。气孔对水分亏缺反应的水势阈值是-0.70-1.35MPa。叶绿素含量对水分亏缺的反应不敏感,叶绿素的变化滞后于水势和叶片含水量。叶片外渗液相对电导率值在水分亏缺处理的后期急剧增加。SOD、CAT、POD活性和MDA及PRO含量变化与水分亏缺之间的变化复杂不宜作水分亏缺的指标。叶片含水量、叶水势可作为大花蕙兰水分亏缺的指标。

Change of water physiology of Cymbidium hybridum growth in different media and its moisture condition were studied.And the media water content(MWC),leaves water content(LWC) and water potential(WP),as well as stoma conductance(SC),transpiration rate(TR),chlorophyll content(CC) of leaves and superoxide dismitase(SOD) catalase activities(CAT),peroxidase(POD),relative permeability(RP) were tested.The results showed that Sphagnum(SP) medium had a higher water holding capacity than peanut hull mixed with sand.The critical MWC were about 15.86%~12.32% in SP media,and 16.42%~12.29% in PH/Smedia.The critical LWC was about 87.41%~80.31%.The change of CC slowly response to water deficiency,for which,changed more slowly than that of WP and LWC.The RP increased rapidly during the end of the water treatment.The change of the activities of SOD,CAT,POD,and the content of MDA and PRO were so complicated that could not be the practical index of water deficiency.The LWC and LWP were the practical parameter to determine water deficiency of Cymbidium hybridum.