ABSTRACT Water stress problems including drought stress and flooding are the most important factors limiting in citrus growth, development and production. The main purpose of this study was to investigate the effects of putrescine on reducing negative effect of flooding of Carrizo Citrange (Citrus sinensis Osb. × Poncirus trifoliata Raf.) and Volkameriana (Citrus volkameriana) rootstocks under flooding condition. Three concentrations of putrescine [0.0, 1.0 and 2.0% (w/v)] were sprayed on all the leaves of two mentioned rootstocks in a factorial experiment in a completely randomized design under flooding and field capacity conditions. In comparison to the field capacity condition, growth vegetative indicators, RWC, SPAD unit, stomatal conductance (gs), chlorophyll a and b content, chlorophyll fluorescence yield (Fv/Fm), and CO2 assimilation rate (AcO2) decreased in the flooded seedlings whereas intercellular CO2 concentration (Ci), SOD, and CAT antioxidant enzymes activities increased. Putrescine foliar application particularly in 2 mM concentration, resulted in a decrease in the intercellular CO2 concentration and an increase in the other study values. Overall, putrescine could help seedlings against flooding stress through increasing growth, improving physiological statuses, and reducing oxidative damages.

中文翻译：

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洪水胁迫下腐胺对 Carrizo Citrange 和 Volkameriana 砧木生理、形态和生化性状的影响

摘要 干旱胁迫和洪水等水分胁迫问题是限制柑橘生长、发育和生产的最重要因素。本研究的主要目的是研究腐胺对减少水淹条件下 Carrizo Citrange (Citrus sinensis Osb. × Poncirus trifoliata Raf.) 和 Volkameriana (Citrus volkameriana) 砧木的水淹负面影响的影响。在完全随机设计的析因试验中，在洪水和田间持水量条件下，将三种浓度的腐胺 [0.0、1.0 和 2.0% (w/v)] 喷洒在两个提到的砧木的所有叶子上。与田间持水量条件相比，生长营养指标、RWC、SPAD单位、气孔导度（gs）、叶绿素a和b含量、叶绿素荧光产量（Fv/Fm）、和 CO2 同化率 (AcO2) 在淹水幼苗中降低，而细胞间 CO2 浓度 (Ci)、SOD 和 CAT 抗氧化酶活性增加。叶面喷施腐胺，特别是 2 mM 浓度，导致细胞间 CO2 浓度降低和其他研究值增加。总的来说，腐胺可以通过促进生长、改善生理状态和减少氧化损伤来帮助幼苗抵抗洪水胁迫。