逐渐干旱对牡丹实生苗某些生理指标的影响

Effects of Gradual Drought on Physiological Indexs of Seedling in Paeonia suffruticosa

以牡丹实生苗凤丹为试材,研究了逐渐干旱对牡丹实生苗叶绿素含量、光合特性、过氧化氢酶(CAT)活性等生理指标的变化。结果显示:随着干旱胁迫的加剧,牡丹实生苗叶绿素含量呈先升后降趋势。轻度干旱时叶绿素含量达到最大值,比干旱胁迫前上升18.6%;重度干旱时达到最小值,比干旱胁迫前下降了51.2%。净光合速率、胞间CO2浓度、气孔导度均逐渐下降,重度干旱时都达到最小值,分别比干旱胁迫前下降了88.0%、89.4%、78.6%。蒸腾速率呈现先升后降的趋势,中度干旱达到最大值,然后逐渐减小,重度干旱时降到最小值,比干旱胁迫前下降了50%,表明牡丹实生苗的光合作用受到一定程度抑制。CAT活性变化在根与叶中表现不同。叶片CAT活性随干旱程度的加剧先升高后降低,但整体来说,干旱胁迫下叶片中CAT活性均比干旱胁迫前有所提高,从而一定程度上提高了牡丹实生苗的抗旱性。根中CAT活性呈逐渐降低趋势,需要进一步研究。复水后各指标都有所回升,但均未达到干旱前水平。

The seedlings,Paeonia suffruticosa Feng Dan were used as material to study the changes of physiological indexs,such as chlorophyll content,photosynthesis,CAT activity.The result indicated that chlorophyll content increased first,then decreased with the intensification of draught.In contrast to non-drought,chlorophyll content maximized increasing by 18.6% under slight drought and minimized decreasing by 51.2% under severe drought.Pn,Ci and Gs were all declining and at the lowest volume under severe drought,going down by 88.0%,89.4%,78.6% compared to non-drought respectively.Trincreaced then decreaced under moderate drought and it droped by 50% under severe drought conpared to non-drought.The changes showed that photosynthesis of seedlings was restrained to some degree.CAT activiity had different changes in roots and leaves,and in leaves,it rose then droped with the intensification of draught.On the whole CAT activity increased under drought stress compared to non-drought.CAT activity decreased gradually in roots.All indexs rebounded,but could not reach the lever of non-drought after watering.