【作者】 于景金；

【导师】 陈丽华； Ming Xu； Bingru Huang；

【作者基本信息】 北京林业大学 ， 生态环境工程， 2012， 博士

【摘要】 高羊茅(Festuca arundinacea)是一种世界性分布的冷季型多年生羊茅属牧草兼草坪草,在中国主要分布于华北、华中、中南和西南地区,适宜于寒冷潮湿和温暖潮湿的过渡带生长,广泛应用于学校、公园、运动场和高尔夫球场等绿地建设。高羊茅属于丛生型,分蘖性强,须根发达,入土深,具有广泛的适应性,抗逆性强,耐酸、耐瘠薄,抗病性强,其耐寒和耐热能力都很强,同时也是最耐践踏的草坪草,夏季不休眠,而且建坪速度较快,是长江流域能够保持四季常绿的草坪草种。因此,本文以高羊茅(cv. Rembrandt)为研究对象,(1)研究高浓度CO2如何缓解过渡性干旱对高羊茅生理指标的影响,包括光合作用、呼吸作用、电解质渗漏率、光化学效率、羧化速率和电子传输速率及气孔导度；(2)确定高浓度CO2如何缓解5℃增温对高羊茅生理指标的影响；(3)明确高浓度CO2及高温和干旱三者的交互作用对高羊茅生理指标的影响,并探究其机理；(4)研究在热胁迫条件下(10℃增温)高羊茅对高浓度CO2的生理响应,并探究其机理。(5)研究在高浓度CO2条件下,非过渡性干旱及复水处理对高羊茅各项生理指标的影响。本文在第三章以当前人们普遍关注的气候变化为研究背景,以冷季型草坪草高羊茅为实验材料,研究了高羊茅应对温度升高5℃和逐步干旱做出的生理生化响应,并发现了高浓度CO2对植物应对不利气候条件所发挥的缓解性作用,包括通过降低气孔导度来减少蒸腾作用,降低土壤和叶片水平的水分损失来提高光合作用、抑制呼吸作用；同时,提高光化学效率,降低电解质渗漏率。此外,高浓度CO2可以显著降低气孔对光合作用的限制,该作用不受温度升高及过渡性干旱的影响。连续的夏季高温是影响冷季型草坪草的一个重要的非生物因素,为了探索在CO2浓度升高的条件下,冷季型草坪草如何应对长期的热胁迫环境,本文在第四章对此进行了详细阐述。结果表明,热胁迫严重影响了高羊茅材料的正常生长代谢,包括降低了光合速率,胞间CO2浓度,气孔导度,水分利用效率,坪观质量,生长率,比叶面积,电子传递速率,Rubisco (?)舌性及细胞膜的稳定性,而CO2浓度升高则对各项生理生化指标均表现出正效应,再次证明了高浓度CO2在高羊茅应对热胁迫过程中所起到的保护性作用。夏季高温通常伴随少雨或无雨,使草坪草受到干旱的不利影响,本文在第五章就高浓度CO2下高羊茅如何应对干旱胁迫及胁迫结束后进行复水处理所做出的响应进行了阐述。完全停止浇水造成高羊茅材料的土壤含水量,叶片相对含水量,光合速率,气孔导度,蒸腾速率及Rubisco (?)舌性和激活比率的急剧下降,经过复水处理后,土壤含水量,叶片相对含水量,光合速率,气孔导度和蒸腾速率逐步恢复到干旱处理前的水平,但Rubisco活性和激活比率仍然比干旱处理10天的值显著下降,说明Rubisco活性及Rubisco催化酶由于干旱而造成了不可逆的破坏性影响。总之,高浓度CO2能够极大地减轻高温和干旱胁迫对高羊茅各项生理生化指标的不利影响,提高了植物的耐热及耐旱性,有利于植物更好的应对未来全球气候变化。更多还原

【Abstract】 Tall fescue (Festuca arundinacea) is a cool-season trufgrass and forage grass which widely distributes all over the world. Tall fescue adapts transitional zones between cool-wet and warm-wet areas and is extensively used in schools, parks, sports ground and golf courses, et ac. Tall fescue is a bunch type grass established from seeds, with strong tiller, developed fibrils, powerful resistant to heat, disease, cold, drought, acid, barren and trample. It could make early, dense and fast growing lawns with lower maintenance so that it is one of the more welcome turfgrass. Taking tall fescue as target material, we (1) studied how elevated CO2 alleviated the effects of transitional drought on physiological indexes; (2) elaborated the alleviation of CO2 enrichment on physiological indexes in response to elevated temperature (5℃above normal temperature); (3) discussed the interactive effects of elevated CO2, elevated temperature and drought on physiological indexes; (4) studied the responses of physiological and biochemical indexes to elevated CO2 under heat stressed conditions to look for mechanisms from protein and metabolism levels; (5) studied the effects of non-transitional drought and rewartering treatment on all indexes under elevated CO2 conditions.Taking tall fescue as material, the physiological and biochemical responses to elevated temperature and transitional drought in conditions of CO2 enrichment were studied under climate change scenario in chapter 3. Results showed that elevated CO2 mitigated the adverse effects of elevated temperature and drought in tall fescue, including decreased stomatal conductance, SWC, and RWC, but increase photochemical efficiency and electrolyte leakage to reduce water loss and protect cellular integrity to improve photosynthesis and decrease respiration. Additionally, elevated CO2 could significantly decrease stomatal limitation to photosynthesis and this effect was not affected by temperature elevation and transitional drought.Successive high temperature in summer is one of the pretty important abiotic factors affecting cool-season turfgrass growth. Chapter 4 would elaborate how cool-season turfgrass responds to long term heat-stressed environment under elevated CO2. Results indicated that heat stress seriously affected the normal growth and metabolism, including decreases in A, Ci, gs, WUE. TQ, Gr, SLA, Jmax, cellular stability, Rubisco activity and activation state, while elevated CO2 suppressed their decreases. Results showed the protective effects of elevated CO2 on tall fescue under heat stress.High temperature always accompanying with little precipitation in summer impose negative effects on turfgrass. Chapter 5 elaborated how tall fescue response to drought stress and rewartering under elevated CO2 concentration.100% drought stress induced the rapid decreases in SWC, RWC, A, gs, Tr, Rubisco activity and activity state. SWC, RWC, A, gs and Tr recovered to 0 d (without treatments) after rewartering for one week, but Rubisco activity and activity state still had significantly lower values than those of 10 d of drought treatment indicating that server drought caused irreversible injury to Rubisco activity and Rubisco activase.In conclusion, elevated CO2 could significantly mitigate the adverse effects of temperature and drought stresses on physiological and biochemical indexes in tall fescue. The alleviation effects of elevated CO2 could improve heat and drought tolerance which is better for responding to global climate change.更多还原