Physiological Responses of Three Melastomaceae Species to Drought Stress
This study aimed to explore the response and adaptability of different Melastomaceae under different drought stresses and reveal the drought resistance mechanism.In order to explore the response and adaptability of Melastomaceae species under different drought stresses,in this study,Melastoma penicillatum,Medinilla ar-boricola and Diplectria barbata were selected to evaluate drought resistance from osmotic adjustment sub-stances,antioxidant enzyme system,photosynthetic capacity and root morphological structure.The results showed that:(1)Drought stress significantly inhibited the morphological growth of three species of Melastom-aceae.Under the influence of drought stress,the root length,root volume and root surface area of Melastoma penicillatum and Medinilla arboricola were increased first and then decreased,while the root volume of Diplec-tria barb ata was increased first and then decreased,and other root indicators were decreased continuously.(2)With the intensification of drought stress,the net photosynthetic rate(Pn),stomatal conductance(GS),intercel-lular CO2 concentration(Ci),transpiration rate(Tr)and water use efficiency(WUE)of the three species of Melastomaceae decreased,while the contents of proline,soluble sugar and soluble protein continued to in-crease,while the activities of SOD and POD increased first and then decreased.(3)The principal component analysis showed that three principal components were extracted from 15 indicators,and the drought resistance of three species of Melastomaceae was comprehensively analyzed by using three principal components.The results showed that the drought resistance of Medinilla arboricola was the strongest,followed by the Melastoma penicil-latum,and the Diplectria barbatawas the most sensitive to water loss.
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