Effects of Abscisic Acid on Drought Resistance in Apple Rootstock Malus baccata Seedlings

脱落酸对苹果砧木幼苗抗旱性的影响（英文）

[Objective] Abscisic acid （ABA）, a plant endogenous hormone, plays an important role in plant responses to adverse environments. This study was to explore the effects of exogenous ABA on the drought resistmlce of apple rootstocks under simulated drought condition induced by polyethylene glycol （PEG）. [Method] Apple （Malus baccata） seedlings were employed as test material. There were five treatments （T1-5） designed as ABA application rates at 0 （T1）, 25 （T2）, 50 （T3）, 75 （T4） and 100 （T5） μmol/L in the hydroponic experiments. The changes of the relative leaf water content （RLWC）, root activity, malondialdehyde （MDA） content, proline （Pro） content, superoxide dismutase （SOD） activity and peroxidase （POD） activity were assayed under PEG stress. All indices were analyzed by principal component analysis （PCA） to evaluate the optimal ABA concentration alleviating drought stress. [Result] The different concentration of ABA could increase Pro content and antioxidant enzyme activities, relieve the descent of RLWC and decrease MDA content. Low levels of ABA increased root activity, whereas the high concentrations （T3-T5） inhibited it. Statistical analysis based on the PCA indicated that the cumulative contribution rate of the first two principal components was raised to 96.457%, and the PCA in the T2 scored the highest. [Conclusion] The exogenous ABA could decrease the damage caused by drought stress to Malus baccata seedlings and enhance the ability of drought tolerance by increasing osmolyte content, anti- oxidative enzyme activity and reducing the level of membrane lipid peroxidation. The optimal concentration of ABA was 25 μmol/L.

[目的 ]脱落酸(ABA)是一种植物内源激素,在应对不利环境的反应中起着重要作用。试验旨在研究外源ABA对聚乙二醇(PEG)诱导的模拟干旱条件下的苹果抗旱性的影响。[方法 ]以‘山定子’(Malus baccata Borkh.)幼苗为材料,采用水培的方法设置了5个ABA浓度,分别为0(T1)、25(T2)、50(T3)、75(T4)和100(T5)μmol/L,研究了干旱胁迫下山定子相对叶片含水量(RLWC),根系活力,脯氨酸(Pro)含量,丙二醛(MDA)含量,超氧化物歧化酶(SOD)活性和过氧化物酶(POD)活性的变化规律。并利用主成分分析(PCA)综合评估了ABA的最适浓度。[结果 ]不同浓度的ABA均能提高Pro含量和抗氧化酶活性,缓解RLWC下降,降低MDA含量。低浓度的ABA增加根系活力,而高浓度(T3～T5)则抑制了根系活力。PCA显示:第一、二主成分的累积方差贡献率达到96.457%,T2处理的PCA得分最高。[结论 ]外源ABA通过提高渗透调节物质含量和抗氧化酶活性、降低膜脂过氧化水平而减轻了干旱胁迫对山定子幼苗的伤害、增强其抗旱能力。ABA的最适浓度是25μmol/L。