干旱胁迫对乌鲁木齐市常用绿化灌木光合生理特性的影响

以4年生乌鲁木齐市城市绿化常用5种灌木为试材,设置停灌5 d、10 d及复水3个处理,以正常灌溉为对照.测定其土壤含水量、气体交换参数和叶绿素含量等指标,研究干旱胁迫条件下5种灌木的光合特性,为耐旱园林植物的筛选提供理论依据.结果表明:随着停灌时间的延长,停灌5 d和停灌10 d处理的土壤含水量不断下降,且在第5 d至...

Effects of Drought Stress on Photosynthetic and Physiological Characteristics of Commonly used Green Shrubs in Urumqi

In this study,5 kinds of 4-year-old shrubs commonly used in urban afforestation in Urumqi were used as test materials,and three treatments,including stop irrigation for 5 d,10 d and rewatering,were set and normal irrigation was used as contrast treatment(CK).Soil water content,gas exchange parameters and chlorophyll content were measured and photosynthetic characteristics of five kinds of shrubs under drought stress were studied to provide theoretical basis for selection of drought-tolerant garden plants.The results showed that with the extension of irrigation stop time,the soil water content of the treatment of stop irrigation for 5d and 10d decreased continuously,and was significantly lower than the normal irrigation level from the 5^th day to the 10^th day,and the soil water content recovered after rehydration treatment.After 10 days of drought stress,the photosynthetic rates of Amygdalus triloba,Prunus x cistena,Syringa oblata,Ligustrum obtusifolium and Ulmus pumila decreased by 51.33%,71.92%,13.12%,71.45%and 83.78%,respectively,compared with CK.The photosynthetic rate of five garden plants was restored to some extent by rehydration treatment,among which,the photosynthetic rate of Amygdalus triloba and Syringa oblate returned to the level of normal irrigation.Drought stress significantly reduced the stomatal conductance of five garden plants,especially at the 10th day of drought stress,the lowest value was 0.02 mol/(m²·s),0.06 mol/(m²·s),0.08 mol/(m²·s),0.03 mol/(m²·s)and 0.03 mol/(m²·s),respectively.However,rehydration did not restore stomatal conductance of shrubs.The concentrations of intercellular CO² of Prunus×cistena,Syringa oblate,Ligustrum obtusifolium and ulmus pumila remained relatively unchanged,while that of Amygdalus triloba increased significantly after 10 days of drought stress,and decreased significantly after rehydration treatment.Similarly,the transpiration rate of five shrubs decreased to the lowest point after 10 days of drought stress,and decreased by 86.95%,61.15%,19.51%,77.43%and 81.64%compared with the control,respectively.After rehydration treatment,that of Amygdalus triloba and Syringa oblate returned to normal irrigation level.Except for the chlorophyll a/b of Amygdalus triloba,the chlorophyll and carotenoid contents of the 5 kinds of shrubs were relatively unchanged.Comprehensive analysis of the changes of chlorophyll content and photosynthetic parameters of the 5 kinds of shrubs under drought stress and re-watering showed that the comprehensive drought resistance ability of Syringa oblata and Amygdalus triloba was stronger.The two kinds of shrubs are very suitable for landscaping plants in arid cities like Urumqi with long winters,hot summers and lack of water.