【作者】 王红玲；

【导师】 阿不来提； 齐曼；

【作者基本信息】 新疆农业大学 ， 草业科学， 2003， 硕士

【摘要】 狗牙根（Cynodon dactylon）是暖季型草坪草中得分最高、应用最广泛、研究最深入的草种。我国西北地区气候较寒冷而且盐碱地面积较大，因而狗牙根的利用受到极大的限制。新农一号狗牙根和喀什狗牙根是新疆农业大学草业工程系研究人员经过十几年的引种驯化、筛选培育而成的优良草坪草新品种，也是发现的暖季型草坪草中最抗寒的品种之一。同时新农一号狗牙根在盐碱较重地段（以硫酸盐为主的盐渍化土壤，全盐含量3.86mS/cm）播种种植后长势良好。本文以新农一号狗牙根、喀什狗牙根、托克逊狗牙根、普通狗牙根和矮生天堂草为材料，采用农作物和牧草种质资源鉴定上广泛运用的生理生化指标，对Na2SO4盐胁迫下狗牙根的耐盐性及其生理变化过程进行研究，结果如下：1 种子发芽试验表明，盐胁迫下Na2SO4极显著抑制了狗牙根种子发芽率，盐溶液浓度与发芽率呈极显著负相关性。变温条件极显著提高了狗牙根盐胁迫下的发芽率，种子耐盐性大小为普通狗牙根＞托克逊狗牙根＞喀什狗牙根＞新农一号狗牙根。2 细胞膜伤害率可作为衡量狗牙根耐盐能力强弱的有效生理指标之一。Na2SO4盐胁迫下，矮生天堂草细胞膜伤害率升高幅度大，膜透性增加快，电解质外渗率高，抗盐性较弱；新农一号狗牙根、 喀什狗牙根和托克逊狗牙根则相反，抗盐性较强。3 Na2SO4盐胁迫下，供试狗牙根体内丙二醛（MDA）含量上升，膜脂过氧化产物增多。MDA含量与膜脂过氧化程度有一定的正相关性，MDA含量越高，膜脂过氧化程度越重，抗盐性越弱。4 Na2SO4盐胁迫下，供试狗牙根体内脯氨酸(Pro)含量增加，且与细胞膜伤害率呈显著正相关性。Pro累积量越大，抗盐性越弱，反之则越强。因而矮生天堂草抗盐性弱于新农一号狗牙根、喀什狗牙根和托克逊狗牙根。5硝酸还原酶活性（NRA）与细胞膜伤害率呈显著负相关性。Na2SO4盐胁迫下，供试狗牙根体内NRA下降，新农一号狗牙根下降速率大于其它三种狗牙根，体内积累有毒氮化物少，因而受害最轻，抗盐性最强。6 Na2SO4盐胁迫下，叶绿素(Chl)含量降低，但Chla/b升高，表明狗牙根在以Na2SO4为主的较重盐碱地上可通过提高Chla/b比值促进光合作用，降低盐分对其生长的抑制。Chl含量的大小可作为狗牙根抗盐性判断的参考指标。7 K+/Na+比与狗牙根抗盐性有一定的相关性。盐胁迫下，K+/Na+比呈下降趋势，抗盐性较强的新农一号狗牙根和喀什狗牙根以及托克逊狗牙根下降速率慢，抗盐性较弱的矮生天堂草下降速率快。<WP=7>8 Na2SO4盐胁迫下，新农一号狗牙根、喀什狗牙根和托克逊狗牙根具有较强的从土壤中选择吸收K+的能力，因而抗盐性较强，矮生天堂草则相对较弱。9 盐碱生境下，新农一号狗牙根和喀什狗牙根较强的选择吸收K+的能力，从而维持体内较高水平的K+含量是其能在较重盐碱地上良好生长的原因之一。10 综合各项测试指标，认为细胞膜伤害率、丙二醛、脯氨酸、硝酸还原酶活性、钾钠吸收选择性系数可作为狗牙根抗盐性强弱的重要指标，叶绿素为参考指标。细胞膜伤害率越低，丙二醛含量越少，脯氨酸累积量越低，硝酸还原酶活性下降速率越快，钾钠吸收选择性系数越大，则狗牙根抗盐性就越强。更多还原

【Abstract】 Bermudagrass was a turfgrass which was used widely, studied deeply among warm-season turfgrasses. But due to the colder climate and saline soil spreading widely in northwest China, the utilization of Bermudagrass was greatly limited. New varieties "Xinnong No.1 Bermudagrass" and "Kashi Bermudagrass", which were cultivated by the researchers of Xinjiang Agricultural University through ten years’ study, were one of the highest cold-resistant warm-season turfgrasses, furthermore they could grow well in heavy saltnized soil which mainly contains of Na2SO4 （total salinity：3.86mS/cm）.Study on the salt-resistant capacity and physiological changes process of Xinnong No.1 Bermudagrass, Kashi Bermudagrass, Tuokexun Bermudagrass(Bermudagrass line), Tifdwarf and common Bermudagrass under salt stress of Na2SO4 was made through the physiological and biochemical indexes ,which were generally used in crop and herbage appraisal. The results were：1 Seed germination experiment shown, under salt stress of Na2SO4, seed germination rate of Bermudagrass was reduced significantly, and the concentration of salt solution was negative correlation with seed germination rate. Seed germination rate could be increased significantly by the condition of changed temperature, and the order of salt-resistance was Common Bermudagrass＞Tuokexun Bermudagrass＞Kashi Bermudagrass＞Xinnong No.1 Bermudagrass.2 Membrane injury rate was one of physiological indexes that could effectively measure salt-resistant ability of Bermudagrass. Under salt stress of Na2SO4, the extent of membrane injury rate was greater in Tifdwarf than in others, so it had lower salt-resistance.3 The MDA content in Bermudagrass was increased with the salt stress, and it had certain positive correlation with over-oxidation degree of cytoplasm membrane. The more MDA content was, the more critical degree of cytoplasm membrane was oxidized, the worse salt-resistant ability of Bermudagrass was.4 Under salt stress of Na2SO4, Pro content of Bermudagrass was increased ,and was positive correlation with membrane injury rate. The more accumulation of Pro content was, the lower salt-resistance of Bermudagrass was. So the salt-resistant capacity of Tifdwarf was lowest among the Bermudagrass.5 NRA was negative correlation significantly with membrane injury rate. NRA in all Bermudagrass emerged the descending trend, and high-speed falling of NRA in Xinnong No.1 Bermudagrass was helpful to prevent accumulation of toxic nitrogenous compounds, so it possessed higher salt-resistance.6 Chl content was reduced with the increasing salt concentration, but Chla/b was increased, as show Bermudagrass could decrease the restraint of growth by raising Chla/b. Chla/b can be used as a referential index to measure salt-resistance of Bermudagrass.7 K+/Na+ had some correlation with salt-resistance of Bermudagrass. K+/Na+ indicated the declining tendency due to the decreasing of salt concentration, and Xinnong No.1<WP=9>Bermudagrass、Kashi Bermudagrass、Tuokexun Bermudagrass had low-speed falling, so they had higher salt-resistance.8 Under salt stress of Na2SO4, Xinnong No.1 Bermudagrass、Kashi Bermudagrass、Tuokexun Bermudagrass possessed higher capacity of absorption selectivity of K+ and Na+ from the soil, so they had rather salt-resistance.9 The capacity of absorption selectivity of K+ and Na+ from the soil was one of reasons they could grow well in heavy saline-alkali habitat.10 By summarizing all indexes, membrane injury rate, MDA, Pro, NRA and SK+、Na+absorption could be utilized as important indexes to measure the salt-resistance of Bermudagrass.更多还原