Physiological response of three native garden ground cover plant seedlings to increasing drought stress
To develop and utilize three native garden ground cover plants (Distylium buxifolium,Ternstroemia gymnanthera,and Syzygium grijsii),a water controlling experiment was conducted to measure the physiological responses of soil water conditions to differing soil water contents:suitable soil moisture (field moisture capacity of 75％-80％),mild drought (55％-60％),medium drought (40％-45％),and severe drought (30％-35％).A subordinate function method was used to rank drought-resistance.Results showed that as drought stress increased,the content of leaf relative water and chlorophyll for the three plants decreased rapidly,but membrane permeability and malondialdehyde (MDA) content increased rapidly.The content of free proline,soluble sugar,and soluble protein increased with free proline playing a key role in resisting drought stress.With an increase in drought stress,the superoxide dismutase (SOD),peroxidase (POD),and catalase (CAT) activity of D.buxifolium increased;however,T.gymnanthera and S.grijsii only increased with suitable soil moisture to medium drought conditions,and decreased with severe drought.The subordinate function method ranking drought-resistance was D.buxifolium ＞ T.gymnanthera ＞ S.grijsii.Thus,D.buxifolium could conduct physiological regulation by antioxidant enzyme systems;whereas T.gymnanthera and S.grijsii reached a tolerable limit where the ability to scavenge oxygen free radicals decreased rapidly.
botanynative garden ground cover plantdrought stressphysiological responsessubordinate function method
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