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以番茄“寿信98”为试材,设置4个土壤水分处理,土壤水分为田间持水量的70%~80%为正常灌溉(CK)、60%~70%为轻度胁迫、50%~60%为中度胁迫、40%~50%为重度胁迫,系统测定水分胁迫对设施番茄结果期植株叶片衰老特性和根系活力的影响。结果表明:番茄叶片细胞色素含量随胁迫程度的加重先升高后降低,轻度胁迫下细胞色素含量显著高于其它处理;随水分胁迫时间延长番茄叶绿素a、叶绿素b和类胡萝卜素含量均呈下降趋势。叶片组织的超氧化物歧化酶(SOD)、过氧化物酶(POD)活性随水分胁迫时间延长均呈先增加后减少的趋势,不同土壤水分处理下,番茄叶片SOD和POD活性均表现为重度胁迫>中度胁迫>轻度胁迫>CK,且2种抗氧化酶活性均在果实膨大期达到最大值。在果实膨大期,轻度胁迫、中度胁迫、重度胁迫下SOD活性分别是CK的1.00、1.82、1.68倍,而POD活性分别是CK的1.81、2.37、2.91倍。轻度胁迫显著增加番茄根系活力,而其它水分处理下番茄根系活力较CK均有不同程度的降低,成熟期轻度胁迫、中度胁迫、重度胁迫下番茄根系活力分别是CK处理的102.08%、90.62%、80.56%。因此,轻度水分胁迫有利于细胞色素合成和根系活力的提高,增加了设施番茄对水分逆境的耐受力,减缓植株的衰老进程。
With tomato Shouxin98 as the test material, four soil moisture treatments were set up. The soil water content was 70% ~ 80% of the field water capacity for normal irrigation (CK), 60% ~ 70% ~ 60% for medium stress and 40% ~ 50% for severe stress. The effects of water stress on leaf senescence and root activity of tomato plants were measured systematically. The results showed that the cytochrome content of tomato leaves increased first and then decreased with the increase of stress degree, and the cytochrome content of the tomato leaves under light stress was significantly higher than that of other treatments. The content of chlorophyll a and chlorophyll b and carotenoid in tomato leaves increased with water stress prolonging Downtrend. The activities of superoxide dismutase (SOD) and peroxidase (POD) in leaves increased firstly and then decreased with the prolongation of water stress. Under different soil moisture treatments, the activity of SOD and POD in tomato leaves showed severe Stress> moderate stress> mild stress> CK, and the activities of the two antioxidant enzymes reached the maximum during the fruit enlargement period. The activity of superoxide dismutase was 1.00, 1.82 and 1.68 times of that of CK, while the activity of POD was 1.81, 2.37 and 2.91 times of that of CK respectively in the period of fruit enlargement, mild stress, moderate stress and severe stress. Mild stress significantly increased the root activity of tomato, while the root activity of tomato under other water treatments decreased to some extent than that of CK. Mild and moderate stress during ripening, the root vigor of tomato under severe stress were 102.08% of CK, 90.62%, 80.56%. Therefore, mild water stress is conducive to the increase of cytochrome synthesis and root activity, increased tolerance of plant tomato to water stress and slowed the process of plant senescence.