干旱胁迫对马占相思幼苗生长及生理特性的影响OA

To investigate the tolerance of Acacia mangium to drought stress,a pot drought experiment was conducted.The growth indicators(plant height),antioxidant enzymes[superoxide dismutase(SOD),catalase(CAT),peroxidase(POD)],malondialdehyde(MDA)content,osmotic regulatory substances[proline(Pro),soluble sugar(SS),soluble protein(SP)],photosynthetic parameters[photosynthetic rate(Pn),transpiration rate(Tr),intercellular CO2 concentration(Ci),stomatal conductance(Gs)],and chlorophyll content of Acacia mangium seedlings under different degrees of water stress(drought stress for 7,14,21,and 28 days)were measured.Correlation analysis and principal component analysis were used to analyze the main influencing factors of its drought resistance.The results showed that as the degree of drought stress increased,the increase in plant height of Acacia mangium gradually decreased,while the activities of SOD,the contents of MDA,SS,Ci and chlorophyll all showed a trend of first decreasing and then increasing.The activities of POD and photosynthetic parameter indicators(except Ci)all showed a decreasing trend,while the contents of Pro,SS and SP all showed an increasing trend.Correlation and principal component analysis indicated that Pro,chlorophyll b(Chlb)and SP could be used as the main indicators for evaluating the drought resistance of Acacia mangium,while SOD and plant height could be used as auxiliary indicators.In conclusion,moderate drought can promote the accumulation of osmotic adjustment substances and the enhancement of antioxidant enzyme activity in Acacia mangium.