5种屋顶绿化常绿植物的耐热性研究

高温是影响植物生长发育的限制因素，为研究常绿木本植物对高温的抵御能力，以金叶女贞、金边黄杨、南天竹、海桐、红叶石楠为试验材料进行高温胁迫处理，采用Logistic方程拟合得到高温半致死温度（LT₅₀），结合测定细胞质膜透性（EC）、叶绿素含量（chl）、脯氨酸（Pro）含量生理生化指标，运用隶属函数值法综合评价其耐热性。结果表明:1）5种常绿灌木的高温半致死温度由高到低依次为:金边黄杨（62.62℃）、海桐（62.43℃）、金叶女贞（61.10℃）、红叶石楠（58.20℃）、南天竹（58.09℃）。2）5种常绿灌木的耐热性综合排序为:海桐＞金边黄杨＞红叶石楠＞金叶女贞＞南天竹。总体而言，这5种常绿灌木具有较好的耐热性，均可作为我国西北地区屋顶绿化的潜在植物资源加以应用。

Heat Tolerance of Five Evergreen Plants for Roof Greening

High temperature is a limiting factor affecting plant growth and development.In order to get the resistance of evergreen woody plants to high temperature,five ever green shrubs were selected as the materials for high temperature stress test,i.e.,Ligustrum×vicaryi,Buxus megistophylla,Nandina domestica,Pittosporum tobira,and Photinia×fraseri.The logistic equation was used to fit the semi-lethal temperature (LT₅₀) of the plants tested.Relative physiological and biochemical indictors were measured,such as cytoplasmic membrane permeability (EC),chlorophyll content (chl),proline (Pro) content.The membership function method was adopted to comprehensively evaluate the capabilities of heat resistance of the plants tested.The results showed that 1) the values of LT₅₀ were in the order of B.megistophylla>P.tobira>L.×vicaryi>P.× fraseri>N.domestica,with the corresponding numbers of 62.62,62.43,61.10,58.20,and 58.09℃.2) After comprehensive assessment,the order of heat resistance of the 5 evergreen shrubs was P.tobira>B.megistophylla>P.× fraseri >L.×vicaryi >N.domestica.In general,these five evergreen shrubs have good heat tolerance and can be used as potential plant resources for roof greening in northwest China.