【作者】 刘洋；

【导师】 常智慧；

【作者基本信息】 北京林业大学 ， 草学， 2015， 硕士

【摘要】 为研究细胞分裂素(CK)和氮素(N)的共同作用对匍匐翦股颖(Agrostis stolonifera)抗旱反应和机制的影响,本试验从匍匐翦股颖的生理反应入手,进一步从抗氧化代谢角度研究CK和N提高匍匐翦股颖抗旱性的机制。试验以匍匐翦股颖品种’PennA-4’为研究材料,采用完全随机区组设计,共设置3种CK浓度：0(CK0)、10μM(CK10)、 100 μM(CK100);2种N浓度：2.5 kg N ha-1(低氮)、7.5 kg N ha-1(高氮)。在充分浇水和干旱处理两种水分条件下研究CK和N对匍匐翦股颖抗旱性的影响及其抗氧化生理机制。研究结果表明：1.充分浇水条件下,CK100+高氮处理能够显著改善匍匐翦股颖的品质和草坪质量。2.干旱条件下,CK10和CK100处理均显著提高了匍匐翦股颖的坪观质量、叶绿素含量和叶片相对含水量,并延迟了叶片萎蔫时间；与低氮水平相比,高氮水平下两种浓度的CK处理对匍匐翦股颖坪观质量、叶绿素含量和叶片相对含水量的提升效果更加明显。3.干旱胁迫下,匍匐翦股颖细胞内活性氧(ROS)大量积累,导致膜脂过氧化,丙二醛(MDA)含量增加,电解质大量外渗；CK10和CK100处理均降低了细胞内活性氧水平,减轻了膜系统受破坏程度,使其叶片MDA含量减少,电导率(EL)降低；高氮水平下,CK处理试验效果更加明显。4.干旱胁迫下,匍匐翦股颖抗氧化酶(SOD、APX、CAT、POD)活性整体呈下降的趋势,但经过CK10和CK100处理的匍匐翦股颖的4种抗氧化酶活性均显著高于对照；高氮处理SOD、APX、CAT和POD活性比低氮处理分别增强7.6%、17.7%、5.8%和13.0%。5.干旱条件下,CK100处理均显著增强了4种抗氧化酶同工酶的活性；高氮处理和低氮处理相比,高氮处理显著增强了匍匐翦股颖CAT和POD同工酶的活性,但不同氮肥水平下,SOD和APX同工酶活性之间的差异不显著。6.干旱胁迫使匍匐翦股颖硝酸还原酶活性下降,根系活力和根系重量降低；不同浓度CK处理之间的硝酸还原酶活性、根系活力和根系重量均呈现出显著性差异；高氮处理减缓了匍匐翦股颖硝酸还原酶的下降趋势,降低了其根系活力和根系重量。综上所述,施用细胞分裂素能够显著增强匍匐翦股颖在干旱条件下的抗氧化代谢,从而提高匍匐翦股颖的抗旱性；高氮水平下细胞分裂素的增强效果显著优于低氮水平。本研究中“CK100+高氮”是提升匍匐翦股颖抗旱能力的最佳组合。更多还原

【Abstract】 To research effects of cytokinin and nitrogen on drought resistance reactions and mechanisms of creeping bentgrass(Agrostis stolonifera), the study investigated impact of cytokinin and nitrogen on growth and metabolic activities in drought stressed creeping bentgrass. Creeping bentgrass of ’PennA-4’ treated with three rates of CK (trans-zeatin riboside,0,10 and 100 μM, designated by CK0,10, and 100) and two nitrogen rates (2.5 and 7.5 kg N ha-1 every 15 days, designated by low and high N) in a complete factorial arrangement was grown under two soil moisture regimes:well-watered and drought stress. The results showed that:1. Under well watered condition, CK100+ high N treatment enhanced turfgrass quality of creeping bentgrass.2. Under drought stress regime, CK10 and CK100 improved turfgrass quality, chlorophyll content and leaf relative water content of creeping bentgrass, delayed the leaf wilting. During the drought period, high N treated grass showed higher turfgrass quality, chlorophyll content and leaf relative water content than low N treated grass.3. Drough stressed creeping bentgrass had higher levels of ROS, MDA and electrolyte leakage relative to well watered creeping bentgrass. Exogenous CK reduced ROS, MDA and electrolyte leakage of creeping bentgrass under moisture stress, specially in high N condition.4. Drought stress led to significant decline in the activities of SOD, APX, CAT and POD, but both CK10 and CK100 treatments showed the positive effects to maintain the enzyme activities. In addition, high N treatment enhanced the activities of SOD, APX, CAT and POD by 7.6%,17.7%,5.8% and 13.0%, respectively, relative to low N treatment.5. Under moisture stress, SOD, APX, CAT and POD isozymes in the grass treated with CK 100 showed stronger stain intensity than the grass treated with CKO. And high N plants exhibited a stronger intensity of CAT and POD isoforms than low N plants.6. Drought stress led to significant reduction in nitrate reductase activity, root mass and root viability of creeping bentgrass relative to well watered condition. But exogenous CK enhanced the nitrate reductase activity, root mass and root viability of creeping bentgrass under drought stress. Moreover, high N treatment improved nitrate reductase activity, reduced root mass and root viability of creeping bentgrass under drought stress.Our results demonstrated the beneficial impacts of CK and N on physiological reactions, especially antioxidant metabolism, and CK at 100 uM plus high N rate may be the best application combination to improve drought stress resistance of creeping bentgrass.更多还原