【作者】 赵会颖；

【导师】 江海东；

【作者基本信息】 南京农业大学 ， 作物栽培学与耕作学， 2008， 硕士

【摘要】 高羊茅是目前我国应用最广泛的冷季型草坪草之一。由于其适宜的地上部生长温度是15-24℃,根系为10-18℃,因此在我国长江流域气候过渡地带夏季高温伏旱季节普遍存在着难以越夏的问题.夏季氮肥的缺失更加重了草坪色泽的枯黄,草坪质量的降低.本试验以“猎狗5”(Festuca arundznacea Schreb.var.Huntdog5)为材料,以外源抗氧化剂抗坏血酸为调节物质,采用人工控温的方式研究氮肥和抗坏血酸协同作用对高羊茅耐热性的影响及其调控机理,并试验出二者适宜的配比方案,以期能为提高高羊茅草坪草的耐热性、缓解高温对草坪的伤害、提高草坪质量提供理论依据和技术支持。试验结果表明:1.在40/35℃(昼/夜各12h)高温胁迫下,不同浓度抗坏血酸喷施处理高羊茅草坪的结果表明:高温胁迫下,对照处理叶片含水量、绿叶比和生物量下降迅速;经抗坏血酸处理后,喷施浓度为20mmol/L较10mmol/L或30mmol/L处理更能提高单蘖重、绿叶比,并且生长良好,叶片具有较高的叶绿素、类胡萝卜素含量,也有利于增强抗氧化酶(SOD、POD、CAT)的活性,增加抗坏血酸、谷胱甘肽含量,降低丙二醛和脯氨酸含量,提高草坪耐热性。抗坏血酸喷施浓度为30mmol/L时叶片会出现灼伤的斑点,降低草坪生长质量。2.高温胁迫下,10mmol/L单纯高氮处理加重胁迫伤害,表现为单株干重下降,分蘖死亡,含水量和绿叶比及色素含量下降,并且大部分植株在8天后死亡,表明高温高氮双重胁迫加剧了细胞的新陈代谢速度,加重植株的死亡。喷施20mmol/LAsA一次后的植株显著提高了叶绿素、类胡萝卜素和可溶性蛋白质含量,增强了抗氧化酶(SOD、CAT、POD)的活性,显著降低了脯氨酸和丙二醛含量,进而增加了植株含水量、单蘖干重、绿叶比例和单株分蘖数,有利于增强高羊茅耐热性和延缓植株衰老,使其安全越夏。3.经过短期高温(40/32℃)胁迫后,恢复生长一段时间,在5mmol/L氮素水平下再喷施20mmol/L抗坏血酸一次,植株恢复效果最好,此处理比N0和N10处理下具有较高的生物量、绿叶比(%)、植株含水量和根系活力,较强的抗氧化酶活性,可溶性蛋白质、游离氨基酸及可溶性糖含量也较高,表明此处理能够有效的清除活性氧,降低膜脂过氧化水平,提高草坪草耐热性和生长质量。4.在N5水平下,喷施抗坏血酸处理与对照相比,1次/1周,1次/2周,1次/3周,三个喷施频率都能延长植林在高温胁迫下的生存时间,增加生物量,单株分蘖数,绿叶比例,存活率,以及叶绿素含量和可溶性蛋白质含量,提高抗氧化酶活性,降低丙二醛含量等。其中以1次/1周的抗坏血酸喷施频率在增加草坪色泽,提升草坪质量上效果最好,其次是喷施频率为1次/2周效果较好.更多还原

【Abstract】 Tall fescue is one of the most widely used cold-season turf grasses in China at present. The optimum growth temperature of tall fescue of shoot is 15-24℃and of root is 10-18℃. So it is difficult to survive heat and drought stress in summer in the transition zone in the Yangtze River area. The leaf of tall fescue turned yellow and turf quality decreased for nitrogen deficiency in summer. The experiment studied the effects and the regulation mechanism of nitrogen and ascorbic acid synergies on tall fescue so as to obtain appropriate application method of AsA and the appropriate combination of N and ASA for improving heat resistance of tall fescue turf grass. The results showed that:1. Under the heat stress of 40/35℃(day / night 12 h, respectively), water content, the ratio of green leaves and biomass of tall fescue declined rapidly. It showedplants’ heat resistance was poor. After the application of ascorbic acid, the tiller weight and the ratio of green leaves improved. Treatment of sprayed with the 20mmol/L AsA were relatively better than of 10mmol/L and 30mmol/L. It improved the chlorophyll and carotenoid contents and the antioxidant enzymes (SOD, POD, CAT) activity and improved the AsA and GSH content, reduced the MDA and proline production and also improved the lawn heat resistance. And the concentration of 30mmol/L resulted in poisoning, burning spot on leaves and reducing the turf quality.2. Under heat stress, high nitrogen treatment aggravated stress injury. As a result, the plant dry weight decreased, tiller died, moisture content, green leaf number and pigment content decreased, and most plants died after eight days stress of heat and high N. It showed that high-temperature High-nitrogen double aggravated the stress of the metabolic rate, when in anti-oxidation system can not remove toxic substances at the plant caused the deaths. The treatment applied with AsA significantly increased the contents of chlorophyll and carotenoid, the activity of SOD, CAT and POD, soluble protein content, while decreased the contents of proline and MDA. AsA treatment also increased the water content, dry weight, green leaf ratio and tillers. Thus it improved the heat tolerance, postponed the senescence of tall fescue plants, which helped tall fescue to oversummer safely.3. During the resumption of growth, AsA can ease the injury of on the tall fescue after short-term high temperature under 5mmol/L of nitrogen level application. Tall fescue of 5mmol/L nitrogen treatment has a higher biomass, the ratio of green leaves (%), water content and plant root activity, strong antioxidant activity, soluble protein, free amino acid and soluble sugar content than of 0mmol/L and 10mmol/L of nitrogen level application. It showed that ascorbic acid and nitrogen coordination can remove reactive oxygen species effectively, and reduce the lipid peroxidation, improved the lawn heat resistance and the turf quality.4. compared with no spraying AsA, treatments of spraying frequency of 1 time / 1week, 1/2 weeks and 1/3 weeks of ascorbic acid with 5 mmol/L N level, all improved the biomass, tiller number, the ratio of green leaves and the survival rate of the plant, also improved the plant pigment content, activity, soluble protein content, such as lower membrane permeability. And the best treatment was spraying, then was 1/2 weeks spraying.更多还原