【作者】 张静；

【导师】 薛林宝； 朱为民；

【作者基本信息】 扬州大学 ， 蔬菜学， 2003， 硕士

【摘要】 为研究番茄苗期低温下生理生化特性的变化，本试验以耐寒性较强的品种1386、1481和耐寒性较弱的品种010为试材，分析测定了番茄幼苗在6、10、15和25℃的不同温度处理下POD、SOD活性；MDA、叶绿素、游离脯氨酸、自由水、束缚水含量；观察了细胞超微结构的变化，结果表明： 不同的低温胁迫下，番茄生长受影响的程度不同。15℃下植株受影响程度较小，短期胁迫后，可以恢复生长，10℃次之，而6℃下植株受伤害程度最重。 低温胁迫下，番茄叶片叶绿素含量降低，下降幅度随胁迫程度的加强而增加，耐性强的品种下降幅度小。POD和SOD活性在低温胁迫的初期有所降低，以后在低温的诱导下增加，在胁迫时间的两周左右酶活性达到最大。随胁迫程度的加强，POD活性增加的速度和幅度也增加，耐性强的品种POD活性增加量多；10℃胁迫下，能诱导出SOD活性的最大值，耐性强的品种SOD活性增加的速度快，幅度也大。叶绿素含量和POD活性在品种间和处理间差异均达到极显著水平。 MDA和游离脯氨酸含量均随着低温胁迫时间的延长而快速增加，随胁迫程度的增强而增加；耐性强的品种脯氨酸含量增加的快且多，而其MDA含量却增加的慢且少；自由水含量的降低幅度和束缚水含量的增加幅度均随着胁迫程度的增强而加强，耐性强的品种自由水含量降低幅度大，束缚水含量增加幅度也大，冷敏感品种则相反。MDA含量变化在品种间和处理间差异均达到极显著水平。 低温损伤了叶绿体的超微结构，叶绿体部分膜解体破裂，类囊体片层结构排列紊乱，变形或扭曲，细胞内有较大的淀粉粒和大量嗜锇颗粒的积累。 低温下番茄叶片的叶绿素含量、POD活性、MDA含量、自由水和束缚水含量可作为番茄耐低温性鉴定较好的生理生化指标。更多还原

【Abstract】 In order to investigate the physiological and biochemical changes of tomato seedling under chill stress, this experiment tested the materials of tomato chill-tolerant cultivars 1386,1481 and chill-sensitive cultivar 010 the activities of POD and SOD, the contents of chlorophyll, MDA, proline, free water and bound water ,the change of ultrastructure under different temperatures of 6 , 10 , 15 and 25 for two weeks or more. The results were shown as follows:The growth of tomato seedling was affected differently under different chill stresses.The degree of chilling effect under 15 stress was the slightest among these three chill stresses, and after a short period of chill stress ,the seedling can continue to grow, and that under 6 stress was the heaviest.The content of chlorophyll in the leaves of tomato gradually decreased under chill stress, the degree of decline was according to the intensity of chill stress, but that of chill- tolerant cultivars relatively decreased less than that of chill-sensitive one. The activities of POD and SOD lessened at the early stage of chill stress, then were induced to increase, and reached the maximum around two weeks later. The speed and the degree of POD activity increase was according to the intensity of chill stress, the POD activity of chill-tolerant cultivars increased more than that of chill-sensitive one.When under chill stress of 10 , the activity of SOD was induced to the maximum, and that of the chill-tolerant cultivars increased more and faster than that of chill-sensitive one. The variations of chlorophyll content and POD activity had significant difference between different cultivars and treatments.The contents of MDA and proline increased greatly and fast with the stress time,whose degree increased with the intensity of chill stress. The proline content of chill-tolerant cultivars increased more and faster than that of chill-sensitive one, which was in opposition to the content of MDA. The content of free water decreased under chill stress, whereas that of bound water increased. The decline degree of free water increased with the intensity of chill stress, so did the increasing degree of the bound water. The content of free water in chill-tolerant cultivars decreased more, and whose bound water content also increased more, these in the chill-sensitive cultivars variated reversely. The variation of MDA content had significant difference between different cultivars and treatments.The structure of chloroplast was partly destroyed under chill stress.The membrane of chloroplast partly disjointed ,and the structure of it arrayed disorderly and twisted, there were numerous and large starch grains, and quite amount of osm iophilic granules in the cell.When under chill stress, the activity of POD and the contents of chlorophyll, MDA, free water and bound water in the leaves of tomato could be taken as good physiological and biochemical index for testing chilling-tolerance in tomato.更多还原