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以“金粉2号”(‘Jinfen 2’)番茄为试材,设计3个土壤水分胁迫处理,即轻度(T1)、中度(T2)、重度(T3),以正常灌溉为对照(CK),于2014年4月25日至5月30日测定了叶片保护酶活性及植株形态指标,以研究土壤水分胁迫对番茄苗期植株形态指标和叶片保护性酶活性的影响。结果表明:随水分胁迫时间增加,叶片的超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性和丙二醛(MDA)含量均有不同程度增加,同期内SOD、POD、CAT活性呈现CK>T1>T2>T3趋势,MDA含量则表现为T3>T2>T1>CK,且不同处理间存在显著差异。水分胁迫下,苗期后期番茄株高、茎粗、叶片数和叶面积指数均有不同程度的减小,尤其是重度胁迫T3处理减幅最大,分别仅为CK的61.0%、56.3%、60.1%和48.3%;轻度水分胁迫能显著促进根系的生长,T1处理的根系总表面积和根尖数比CK高34.5%和38.5%,而T2根系较于CK的优势随时间逐渐减弱,T3后期根系总长度、总表面积、平均直径和根尖数分别仅为CK的30.2%、34.5%、61.5%和32.7%;研究表明水分胁迫会抑制苗期番茄地上部分的生长,但是轻度胁迫能显著促进根系生长。短期的中度胁迫有利于根系生长,但随胁迫时间延长,这种促进作用逐渐减弱甚至转变为抑制作用。而在重度胁迫下,番茄根系则受到明显的抑制。
Three soil water stress treatments, light (T1), moderate (T2) and severe (T3), were designed with the experiment of ’Jinfen 2’ (CK), the activities of protective enzymes and plant morphology were measured from April 25 to May 30, 2014 to study the effects of soil water stress on plant morphology and protective enzyme activities in tomato seedling. The results showed that the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and malondialdehyde (MDA) increased with the increase of water stress time, During the same period, the activities of SOD, POD and CAT showed the trend of CK> T1> T2> T3. The content of MDA showed T3> T2> T1> CK, and there were significant differences among different treatments. Under water stress, plant height, stem diameter, leaf number and leaf area index decreased to different extents in late stage of seedling stage, especially in severe stress T3 treatment, which were only 61.0%, 56.3% and 60.1 % And 48.3%, respectively. The mild water stress could significantly promote the growth of root system. The total surface area and root tip number of root in T1 treatment were 34.5% and 38.5% higher than CK, while the advantages of T2 root system over CK gradually weakened with time. The total root length, total surface area, average diameter and root tip number were only 30.2%, 34.5%, 61.5% and 32.7% of the CK, respectively. The results showed that water stress inhibited the growth of tomato shoots at seedling stage, but mild stress could significantly Promote root growth. Moderate short-term stress is conducive to root growth, but with the prolonged stress, this promoting effect gradually weakened or even changed to inhibitory effect. Under severe stress, tomato root system was significantly inhibited.