水分胁迫下4种观赏草的生理特性

Morphological and physiological responses of four ornamental grasses under drought stress

以观赏植物细叶芒(Miscanthus sinensis)、狼尾草(Pennisetum alopecuroides)、拂子茅(Calamagrostis epigeios)和披针叶苔草(Carex lanceolata)为试验材料,探究水分胁迫对这4种观赏草的生理特性。采用盆栽控水法,设置正常供水和水分胁迫两种处理,测定水分胁迫下4种观赏草的枯叶率、叶片相对含水量(relative water content,RWC)、相对电导率(relative electrical conductivity,REC)、游离脯氨酸(free proline,Pro)、可溶性蛋白、超氧化物歧化酶(SOD)活性的变化。结果表明:随着水分胁迫时间的延长,4种观赏草的枯叶率、脯氨酸含量与相对电导率均呈上升趋势;叶片相对含水量逐渐下降;超氧化物歧化酶活性和可溶性蛋白含量均呈现出先上升后下降的变化。细叶芒、披针叶苔草的枯叶率和REC的上升幅度均低于狼尾草和拂子茅,并且细叶芒、披针叶苔草RWC较狼尾草和拂子茅下降慢(共4种观赏草),SOD和可溶性蛋白含量均高于狼尾草和拂子茅。根据隶属函数对各项指标进行综合评价,细叶芒的抗逆性最强,在长期水分胁迫环境下能够保持较高的叶片含水量,生长状况良好;其次是披针叶苔草;狼尾草在4种供试草种中抗旱性最差。因此,探究4种观赏草生理生化方面对水分胁迫的响应特征,为揭示其对干旱环境的适应策略提供了参考依据。

In this study,we examined the physiological characteristics of the ornamental plants Miscanthus sinensis,Pennisetum alopecuroides,Calamagrostis epigeios,and Carex lanceolata in response to drought stress.Using the potted water control method,two treatments of normal and deficient water supply were set up to determine the changes in withered leaf rate,relative water content,relative electrical conductivity,free proline and soluble protein contents,and superoxide dismutase activity of the four ornamental grasses under drought stress.The results showed that with the prolongation of drought stress,there were increases in the dry leaf rate,proline content,and relative conductivity of all four ornamental grasses,whereas the relative water content of leaves gradually decreased,and the activity of superoxide dismutase and the content of soluble protein initially increased and then decreased.The rate of leaf withering,relative electrical conductivity,and changes in relative water content of Erigeron tenuifolia and C.lanceolata were lower than those of P.alopecuroides and Brucea gracilis,whereas the superoxide dismutase activity and soluble protein content were higher than those of P.alopecuroides and B.gracilis.According to the membership function,comprehensive evaluation of each index showed that the drought resistance of Elsholtzia tenuifolia was the strongest and that this species could maintain high leaf water content and grows well under long-term drought stress,followed by C.lanceolata and P.alopecuroides,which had the worst drought resistance among the four tested grass species.Therefore,our data,obtained from an examination of the physiological and biochemical characteristics of four ornamental grasses in response to drought stress,provide a reference source for adaptation strategies in drought-prone environments.