【作者】 冉秀芝；

【导师】 吴文彬；

【作者基本信息】 西南农业大学 ， 生物化学与分子生物学， 2003， 硕士

【摘要】 与暖季型草坪草相比较，冷季型草坪草的绿期长、质地柔软、色泽嫩绿、外貌美观，因而深受人们喜爱。本文以巴润、诺德，塞博、凌志、猎狗和鳄鱼等6种冷季型草坪草(分属三属，四类)为材料，研究了它们的抗热抗旱生理生化机理。试验结果表明： (1)在干旱胁迫条件下，不同草坪草的抗旱性差异显著(1％的显著水平)，各自的抗旱机理也有所不同。在供试的6个草坪草品种中，抗旱性最强的为草地早熟禾中的诺德，最弱的是粗茎早熟禾的塞博。在四类草坪草种中，草地早熟禾类的抗旱性最强，高羊茅类的抗旱性较弱，而抗旱性最差的为粗茎早熟禾类。对于同属于早熟禾属的巴润、诺德和塞博，其抗旱性差异也很显著。各品种的抗旱机理也有所不同，具有较高的绿叶率和较大的膜保护酶活性及较强的抗氧化能力，同时具有相对较低的质膜透性和较少的MDA含量的品种(诺德)的抗旱性最强。 (2)在干旱胁迫条件下，供试的6个冷季型草坪草品种的绿叶率和叶绿素含量随处理时间的延长都逐渐下降，质膜透性则呈上升趋势，MDA含量也逐渐增大；三种膜保护酶活性都是先上升后下降，但6个品种的SOD、POD和CAT活性达到最高值的时间不同，多数品种的SOD、POD活性在处理6d后达最大值，少数品种的SOD活性在4d或8d后达最大；6个品种的CAT活性都在2d后达最高，以后随胁迫时间的延长其活性都逐渐下降，到处理的10d时，甚至低于对照。 (3)在42℃高温胁迫下，6种冷季型草坪草的绿叶率持续下降，叶绿素含量也呈下降趋势；细胞膜透性和MDA含量呈持续上升趋势；脯氨酸含量和POD活性先明显上升，分别于2d和4～6d达最大值，然后逐渐下降；而SOD活性在处理时间内则几乎持续增加，除猎狗的CAT活性呈持续下降的趋势外，其它5个品种的CAT活性在胁迫初期逐步下降，2d后有所回升，然后又下降，巴润和诺德两个品种在回升时超出对照。 (4)各草坪草的抗热性有差别(1％的显著水平)，其抗热机理也有所不同。在供试的6个草坪草品种中，抗热性最强的为草地早熟禾中的诺德，最弱的是多年生黑麦 冷季型草坪草杭热抗旱生理生化机理研究革（鳄鱼〔层越急的oA含量虽首 然 nL P0仇、C地捞物技｝联摘调M鳄鱼的MDA含量比诺德低，但其三种酶活性却较低，Pro含量也较低。 卜）草坪草抗逆性与抗氧化能力婊关系。在6种冷季型草坪草品种中，抗旱性和抗氧化能力最强的都是诺德，而塞博的抗旱性和抗氧化能力都最差。在42C高温胁迫下，6种冷季型草坪草品种中，诺德的抗热性和抗氧化能力都最强，而鳄鱼的却与之相反。因此，在逆境胁迫时，草坪植物的抗逆性与抗氧化能力基本一致。 （6）高温和干旱胁迫下，草坪草的某些生理生化指标的变化趋势基本一致，如绿叶率、叶绿素含量都呈下降趋势，细胞膜透性和MDA含量都呈上升趋势，POD活性都先上升后下降。而革坪草的Pro含量、SOD和CAT活性在高温与干旱胁迫时的变化趋势不一样：在干旱胁迫下Pro的含量呈持续上升的趋势，而在高温胁迫下却是先上升后下降的趋势；SOD活性在于旱胁迫下呈先升后降的趋势，而在高温胁迫下几乎是持续上升；CAT活性在干旱胁迫下先上升后下降，而在高温胁迫下却先下降后回升，然后又下降。这说明高温与干旱这两种不利环境因子对草坪草的影响有相似之处，草坪草的抗热机理与抗旱机理有一定的联系，同时又存在一定的差异。 （7）早熟禾（诺得）的抗热抗旱的综合指标都为最高，粗茎早熟禾（塞博）的抗旱综合指标最低，抗热指标较低；多年生黑麦草（鳄鱼）的抗热性综合指标最低，其抗旱指标偏低。因此，初步确定，在供试的6种草坪草中，草地早熟禾（诺德）在高温伏旱地区（如重庆等）具有较强的越夏能力，可能是一种较适宜于这些地区引种栽培的冷季型草坪革草种；而粗茎早熟禾（塞博）和多年生黑麦革（摸鱼）引种到这些地区则会出现越夏困难的问题。更多还原

【Abstract】 Contrasting with the warm-season turfgrasses, the cool-season turfgrasses are more and more welcomed for their long-green periods, soft-qualities, brilliant-colors, and their good-lookings. The special climate characters ie high temperature and drought stress handicap the growth of the cool-season turfgrasses which would be inclined for cool and warm climate. Physiological and biochemical mechanisms of 6 different cool-season turfgrass cultivars( Baron, Node, Sabre, Barlexas, Houndog and Alligator ) under heat stress and drought stress were systemicaliy studied, green leaves were numbered, chlorophyll contents (including Chla and Chlb ),and electrolyte leakage(EL) ,contents of the lipid peroxidation product-malondialdehye (MDA), contents of proline(Pro),and activities of 3 major antioxidant enzymes ie superoxide dismutase(SOD), catalase(CAT), and peroxidase(POD) in fresh leaves were determined every other day during 20%-PEG drought stress or 42 heat stress, and the relationships between the antioxidation abilities and heat or drought-resistance were preliminarily studied. The main results and conclusions were as follows.(1) Among the 6 cool-season turfgrass cultivars, different cultivars held different drought-resistance and their own physiological and biochemical mechanisms during the drought stress. Poa pratemis L. cv(Node) was the most resistant to drought stress, while Poa trivialis L. was weakest, and Festuca arundinacea Schreb was more resistant than Lolium prenne L. . Poa pralemis L. and Poa trivialis L. both belonging to the same genera had obviouse drought-resistances, the physiological and biochemical mechanisms of them were also different: more green leaves, more content of Pro, more activities of SOD, POD, CAT, and less content of MDA, or less leakage of electrolytes from cells occurred in Poa pratensi.s L. which had more resistance than Poa trivialis L. .(2) Green leaves, chlorophyll content decreased constantly, whereas EL, content of MDA and Pro increased constantly under drought stress in the 6 different cool-season turfgrass cultivars; The activities of SOD, POD and CAT firstly increased slowly thendecreased under the drought stress in the 6 cool-season turfgrass cultivate: in most of the 6 cool-season turfgrass cultivars, the activities of SOD, POD reached maximum values in 6d, while others’ activities of SOD reached the highest level in 4d or 8d; the activities of CAT reached the highest content in 2d then decreased constantly with the drought stress progressing, and down lower than the levels in 0d.(3) Green leaves, chlorophyll content decreased constantly, whereas EL, content of MDA increased constantly under heat stress in the 6 different cool-season turfgrass cultivars; and the content of Pro and the activities of POD firstly increased slowly then decreased under the heat stress, and reached their maximum values in 2d and 4-6d during heat stress respectively; the other two antioxidant enzymes ie SOD, CAT changed in difference respectively the activities of SOD increased constantly in all of the 6 cool-season turfgrass cultivars while in one of the 6 cultivars the activity of CAT decreased constantly but in other 5 of the 6 cool-season turfgrass cultivars the activity of CAT firstly decreased then increased and declined again at last, in both cultivars of Poa pratensis ,L, grew up above the control condition.(4) Among the 6 cool-season turfgrass cultivars, different cultivars held different heat-resistance and their own physiological and biochemical mechanisms during the heat stress. Poa pratensis L. cv(Node) was the.most resistant to drought stress, while Lolium prenne L. was weakest. Although the content of MDA was more in Poa pratensis L. cv(Node) than in Lolium prenne L. , it held the most or secondly most activities of the 3 antioxidant enzymes in all of the 6 cultivars and had.the secondly most content of Pro while Lolium prenne L. held the lest content of Pro and the:.lest activities of the 3 antioxidant enzymes. As for the Poa pratensis L, cv(Baron) and the F更多还原