3种护坡灌木对干旱胁迫的生理响应

齐泰高速公路位于松嫩平原干旱、半干旱地区，耐旱护坡植物的选择对防止公路边坡水土流失，增强路基稳定性及公路周边生态恢复具有重要意义。以紫穗槐(Amorpha fruticosa)、柽柳(Tamarix chinensis)和小叶锦鸡儿(Caragana microphylla)2年龄灌木为试验材料，采用干旱棚控水法，对灌木进行5个水分梯度处理(对照、轻度胁迫、中度胁迫、重度胁迫、极重度胁迫)21 d后，测定灌木叶片的电导率、叶绿素(Chl)总量、超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量、可溶性糖(SS)含量以及脯氨酸(Pro)含量，探讨3种植物的抗干旱能力。结果表明，随着干旱胁迫的加剧，3种灌木叶片的Pro含量、膜质透性(RPP)呈上升趋势；叶片的Chl总量、SOD活性呈先上升后下降的趋势。紫穗槐和小叶锦鸡儿的叶片MDA含量和SS含量呈先上升后下降的趋势，柽柳叶片MDA和SS含量呈上升趋势。通过隶属度函数得出3种灌木对干旱胁迫适应程度由高至低为紫穗槐>小叶锦鸡儿>柽柳。紫穗槐适宜种植在轻度干旱和极重度干旱边坡，柽柳适宜种植在中度干旱边坡，小叶锦鸡儿适宜种植在重度干旱边坡。

Physiological responses of three kinds of slope protection shrubs to drought stress

Qitai Highway is located in the arid and semi arid areas of Songnen Plain. Selection of drought tolerant plants applied to slope eco engineering has great significance in preventing the highway slope from soil erosion, enhancing the stability of the roadbed and ecological restoration of highway surroundings. In this study, two year old seedlings of Amorpha fruticosa, Tamarix chinensis and Caragana microphylla were taken as test materials, which were individually treated with five moisture gradients (control, mild stress, moderate stress, severe stress and extremely severe stress). After 21 days, the conductivity、total chlorophyll content, activity of SOD, content of MDA, soluble sugar content and proline content of the seedlings leaves were determined to investigate the drought resistant abilities of these three kinds of seedlings. The results showed that with the prolonged drought, proline content and membrane permeability of three kinds of seedlings presented a rising trend. Total chlorophyll content and SOD activity of three kinds of seedlings increased in the beginning and then decreased. content of MDA and soluble sugar content in the leaves of A.fruticosa and C.microphylla increased first and then decreased. Content of MDA and soluble sugar content in the leaves of T. chinensis were in an upward trend. Through subordinate function analysis on 6 physical signs, the order of drought resistant abilities of three kinds of seedlings was: A.fruticosa>C.microphylla>T.chinensis, and the difference was not obvious. The results showed that three species were all suitable as Qitai Highway slope protection plant. A.fruticosa was suitable planted in mild drought and very severe drought slope, T.chinensis was suitable planted in moderate stress drought slope and C.microphylla was suitable for planted in severe drought slope.