[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 ap...[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.展开更多
文摘[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.
