有机物对苹果叶片脯氨酸和水分利用效率的影响

以盆栽3年生红富士苹果（Malus domestica Borkh cv.Rehd. Fuji）做试材，研究了土壤控水和自然失水过程中，甜菜碱（Bet）、β-氨基丁酸（β-ABA）和壳聚糖（OC）以及自然干旱（ND）对叶片水分利用效率（WUE）和脯氨酸含量的影响。结果表明，在土壤相对含水率（RWC）70%～80%时，β-ABA和OC处理后第2天叶片脯氨酸含量升高、第10天叶片WUE升高。在自然失水过程中，预先Bet、β-ABA和OC的叶片脯氨酸含量明显升高。自然失水第5天（RWC=50%～60%），经自然干旱（ND）预处理的植株，叶片WUE最高，其次是经Bet预处理的，再次是OC；自然失水第10天（RWC=25%～35%），叶片WUE普遍下降，但经Bet、β-ABA和OC预处理的明显高于对照。综合比较显示，Bet、β-ABA、OC和ND预处理都能不同程度地诱导苹果叶片积累脯氨酸，并可有效延缓严重干旱胁迫引起的叶片WUE下降，其中甜菜碱效果最好，其次是β-氨基丁酸。

Effects of organics on proline content and water use efficiency in apple leaves

Three-years-old apple trees (Malus domestica Borkh c.v.Rehd Fuji) were used as materials in this experiment. It was studied that the effect of Betaine (Bet), β- aminobutyric acid (β-ABA), Oligo-Chitosan (OC) and natural drought (ND) on leaf proline accumulation and water use efficiency (WUE) under controlling water treatments and natural water-losing of soil. The results show that β-ABA and OC increase proline content in secourd day with treatment and increas WUE on tenth day under RWC 70%～80%. The treatments of Bet, β-ABA, OC and ND all increase the content of proline in leaves during water-losing of soil. On fifth day of water-losing (RWC=50%～60%), leaf WUE is the highest in the plant treated by ND, in that by Bet secondly and OC thirdly. On tenth day of water-losing (RWC=50%～60%), leaf WUE decreas generally; the WUE of leaf pre-treated by Bet, β-ABA and OC all are higher than that by control significantly. Those results suggest that the pretreatments of Bet, β-ABA , OC and ND all can induce the accumulation of proline in a certain degree and resist the decrease of leaf WUE under severe water stress, in which effect of Bet is best and β-ABA secondly. Betaine can increase effectively the drought resistance and leaf WUE of apple tree.