【作者】 韩瑞宏；

【导师】 毛凯； 杨春华；

【作者基本信息】 四川农业大学 ， 草业科学， 2003， 硕士

【摘要】 本试验以四川野生雅安假俭草(Eremochloa ophiruoides)为研究材料，通过盆栽和水培试验，从干旱胁迫对植株外部形态的影响和生理指标的改变进行研究，旨在为选育抗旱性强的野生假俭草资源及其开发和利用提供理论依据。试验结果表明： 1．盆栽试验中，对形态指标的测定表明：在一定的干旱胁迫下，假俭草仍在生长，生长前期与对照相差不大，但随胁迫时间的延长，地上部分叶片较对照变短，变窄。胁迫15天有少部分叶片发生对折，干旱胁迫25天土壤含水量为1.02％时，叶长为7.04cm，叶宽为4.40mm，分别比对照少0.78cm和0.52mm。根系的变化主要表现为根系增深，数目增多。胁迫15天根系长度为16.30cm，比对照多1.1cm。根系数目为16条，比对照多3条。假俭草形态上的变化有助于它对干旱的适应。试验表明，控水后假俭草各处理间叶长、叶宽、根长变化差异显著(P＜0.05)。 生理指标的测定表明：干旱胁迫下假俭草植株体内叶绿素发生降解。控水的第0天叶绿素含量为1.304mg／g.FW，控水的第20天含量为0.84mg／g.FW。可溶性糖含量、相对电导率、丙二醛含量随胁迫有增高的趋势，并在控水的第20天增加幅度突然加大，以上三项生理指标在控水第20天较控水第15天的增加率分别为30.71％、101.31％、37.71％，三者变化有相似性。根系活力在控水的最初阶段表现为上升，随控水时间的延长根系活力逐渐下降。控水的第0天，根系活力为60.08ugTPF／g.h，控水的第10天根系活力上升到156.34ugTPF／g.h，到控水的第25天根系活力下降至16.99ugTPF／g.h。 分别在控水5天、10天、15天对假俭草复水，复水后假俭草得以很快恢复，并继续生长；在干旱胁迫20天土壤含水量为5.79％时进行复水，大部分植株可恢复至正常状态，少部分死亡；干旱胁迫25天土壤含水量为1.02％时复水，绝大部分假俭草植株不能恢复生长，大部分植株死亡。 2．通过PEG(聚乙二醇)模拟干旱胁迫，以水为对照，PEG的浓度分别为5％、10％、20％，胁迫24小时和48小时后进行观测。试验结果表明：PEG胁迫下，假俭草地上部形态及生理指标的变化趋势与盆栽试验一致，地下部则表现为根系颜色的加深和部分根系萎缩。浓度为5％、10％的PEG胁迫24小时，根系活力有所提高，其根系活力分别比对照高出11.7％和18.9％，浓度为20％的PEG胁迫24小时根系活力下降。而各浓度的PEG溶液胁迫48小时，根系活力均表现为下降。 3．盆栽和PEG水培试验表明，假俭草适应干旱的途径既包括耐旱性又包括避旱性。 4．控水条件下，丙二醛、叶绿素和相对电导率三项生理指标与土壤含水量具较大的相关性，且盆栽与水培试验均表明三项生理指标之间也存在较大的相关性，能很好的反映假俭草的抗旱性。同时它们的测定方法简便易行。因此在选择假俭草抗旱性的测定指标时，可考虑丙二醛、叶绿素和相对电导率作为检测指标。更多还原

【Abstract】 Ya’an centipedegrass cultivated in the pot or in the water was used as material to study its drought resistance in this experhnent.The changes of the plants’ morphologies and physiologies were studied under drought-stress. The purpose of this experiment is to find theoretical foundation for centipedegrass’exploitation and use. The result showed:l.In pot culture experiment centipedegrass still grew at certain drought-stress.There was not much difference between control and treatment in the frist growing period. Along with the process of water-stress the length and width of treatment became shorter and narrower than control. On the fifteenth day of drought-stress a small part of leaves became foldable. The length of leaf was 7.04 cm and width of leaf was 4.40cm on the fifteenth day of drought-stress when the content of soil water was 1.02%. The length of leaves decreased 0.78cm and the width of leaves decreased 0.52mm compared with control on the fifteenth day. The length of root became longer than control and the number of root increased under drought-stress. On the fifteenth day of drought-stress the length of root was 16.30cm and the number of root was 16.The length of roots increased l.lcm and the number of roots increased 3 compared than control. The experiment showed the length and width of the leaves and the length and number of the roots changed obviously (PO.05).The result of physiologies showed: Under drought-stress chlorophyll decomposed. On the zero day the content of chlorophyll was 1.304 mg/g.FW . On the twentieth day the content of chlorophyll was0.84mg/g.FW.On the twentieth day the content of soluble carbohydrate relative electric conductivity and MDA increased and the content of these three physiologies increased sharply. The increase extent of this three physiologies were 30.71?cK 101.31?<K 37.71%.They had the same trend. In the first drought-stress period root vigor increased .On the zero day the root vigor was 60.08ugTPF/g.h .On the tenth day of drought-stress the root vigor was 156.34ugTPF/g.h.On the twenty-fifth day the root vigor was 16.99 ugTPF/g.h.After being stressed for Sdays lOdays and ISdays respectively, centipedegrass could resume quickly and continue to grow when it was rewatered. Most centipedegrasses could resume and become normal after being rewatered on the twentieth day when the content of soil water was 5.79% and only a small part of centipedegrasses could not resume and died. Most centipedegrass could not resume and died after being rewatered when the content of soil water was 1.02% on the twenty-fifth day.2.PEG was used to induce drought-stress in this experiment.Water was used for control. The consistency of PEG are 5%, 10%> 20% and the material was stressed for 24 hour and 48hour. Both morphologies and physiologies of the part of centipedegrass which grew above soil had the same trend compared with pot culture experiment. The color of root became darker than control after and some roots withered after being stressed. Root vigor was increased after being stressed by PEG(5% and 10%) for 24 hour. The increase extent was 11.7% and 18.9% compared with control.Root vigor decreased after being stressed by PEG(20%) for 24 hour and all consistencies for 48 hour.3.Both pot culture and water culture showed the mechanism of drought resistance of centipedegrass are drought tolerance and drought escape.4. Since the operations of the experiment for MDA chlorophyll and relative electric conductivity are easy and these three indexes have significant correlation to the content of soil water in pot culture and these three indexes have significant correlation in twos both in pot culture and water culture they can be used for drought resistance indexes.更多还原