高羊茅对高温的生理生态响应

分析了昼/夜38℃/30℃高温下2种高羊茅草坪草(凌志和交战Ⅱ)与狗牙根叶片的相对含水量、叶绿素含量、细胞膜脂过氧化、抗氧化系统以及光合作用等生理生态指标的变化.结果表明:随高温时间的延长,2种高羊茅的相对含水量、叶绿素含量、净光合速率和最大光能转化效率均呈降低趋势,而且凌志高羊茅的平均降幅小于交战Ⅱ高羊茅.经过9d的高温处理,凌志高羊茅叶片超氧化物歧化酶、过氧化物酶和过氧化氢酶的平均活性比交战Ⅱ高羊茅分别高19.7%、17.9%和17.7%,而凌志和交战Ⅱ高羊茅的净光合速率分别下降了60.7%和81.9%.与交战Ⅱ高羊茅相比,凌志高羊茅具有更高的光化学转换功能,有利于减轻高温对光合器官的损伤,使其保持较高的净光合速率.在整个高温处理过程中,狗牙根的各项生理生态指标随时间变化的差异不显著.狗牙根、凌志高羊茅和交战Ⅱ高羊茅对高温胁迫的适应能力由强到弱.

Ecophysiological responses of Festuca arundinacea to high temperature stress

The measurement of leaf relative water content (RWC), chlorophyll content, cell membrane lipid peroxidation, anti-oxidative system, and photosynthesis of two F. arundinacea cultivars (Barlexas and Crossfire II) and Cynodon dactylon under high temperature (38 degrees C / 30 degrees C, day/ night) showed that with the increasing time of exposure to high temperature, the leaf RWC, chlorophyll content, net photosynthetic rate (P(n)) and photochemical efficiency (F(v)/F(m)) of two F. arundinacea cultivars had a decreasing trend, and the average decrement was smaller for Barlexas than for Crossfire II. After exposed to high temperature for 9 days, the average activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in Barlexas leaves were 19.7%, 17.9% and 17.7% higher than those in Crossfire II leaves, and the P(n) of Barlexas and Crossfire II was decreased by 60.7% and 81.9%, respectively. Under high temperature, the F(v)/F(m) of Barlexas leaves was higher than that of Crossfire II leaves, which could be helpful to mitigate the damage of high temperature to the photosynthetic apparatus of Barlexas. No significant change was observed for each test physiological parameter of C. dactylon leaves with the increase of exposure time under high temperature. The adaptation ability to high temperature was in the order of C. dactylon > Barlexas > Crossfire II.