不同浓度PEG胁迫对甘草幼苗光合特性的影响

EFFECTS OF DIFFERENT CONCENTRATIONS OF PEG-6000 STRESS ON PHOTOSYNTHETIC CHARACTERISTICS OF Glycyrrhiza YOUNG SEEDLINGS

研究甘草光合作用对阐明甘草抗旱机制以及合理利用甘草资源具有重要意义。本研究以甘草幼苗为试,采用不同浓度PEG模拟干旱胁迫处理,观测甘草叶片光合相关指标变化,结果显示:5%、10%PEG胁迫下,甘草叶片净光合速率、蒸腾速率、气孔导度、胞间CO2、叶绿素含量、RuBPase活性均表现出早期高于对照,后期达到与对照相当水平,表明适度干旱胁迫能促进甘草光合作用;15%PEG胁迫下,上述指标呈先升高后下降的变化趋势,且净光合速率与胞间CO2表现出高度一致性,认为气孔因素是影响净光合速率的限制因子;20%、25%PEG胁迫下,早期净光合速率虽有所提高,但后期迅速下降,同时叶绿素含量、RuBPase活性显著下降,胞间CO2升高,表明此时叶片光合器官已明显受损,非气孔因素成为净光合速率下降的主要限制因子。

Studying the photosynthesis characteristics of Glycyrrhiza isimportant for clarifying the drought-stress mechanism of Glycyrrhiza and rational utilization of Glycyrrhiza resources.In this study,Glycyrrhiza seedlings were used as experimental materials,and different concentrations of PEG-6000 were used to simulate drought-stress treatment,and observation the change of indexes in photosynthesis related of Glycyrrhiza leaves,the conclusion is:the PEG-6000 stress in 5%,10%,the net photosynthetic rate of Glycyrrhiza leaves,transpiration rate,stomatal conductance,intercellular CO2, chlorophyll content,RuBPase activity both showed the early stage higher than the contrast,and the late stage reached the same level of the contrast,indicating that moderate drought stress can promote the photosynthesis of Glycyrrhiza;the PEG-6000 stress in 15%,the tendency of above indexes are increasing first and then decreasing,the net photosynthetic rate and intercellular CO2 show high consistency,it is consider that the stomatal factor is the limiting divisor affecting the net photosynthetic rate;the PEG-6000 stress in 20%,25% the net photosynthetic rate improve in the early stage,but decreasing rapidly in the late stage,at the same time,the chlorophyll content,RuBPase activity significant reduction,and intercellular CO2 increase,it indicates that the photosynthetic organs of the leaves have been significantly damaged at this time,Non-stomatal factors are the main limiting divisor for the decreasing of the net photosynthetic rate.