外源甜菜碱对干旱胁迫下平邑甜茶叶片生理效应的影响

为探索苹果对干旱的生理反应、抗旱机制及甜菜碱对其抗旱性的影响，以苹果砧木平邑甜茶为试材，通过砂培试验，研究了叶面喷施不同浓度甜菜碱(GB，5~40 mmol/L)对干旱胁迫下平邑甜茶生理效应的影响。结果表明，干旱胁迫下，叶面喷施低浓度的甜菜碱(5~20 mmol/L)有效缓解了叶绿素含量的下降，提高了叶片的光合能力；降低了叶片超氧自由基(O2?-)的积累，降低了叶片的相对电导率和膜脂过氧化水平，提高了平邑甜茶的抗干旱能力，其中以甜菜碱10.0 mmol/L的保护效果最好，这种保护作用可能与它能够增加叶片的脯氨酸含量、可溶性糖含量，提高叶片的水分状况和叶片中抗氧化酶活性、减轻活性氧的积累，缓解水分胁迫对膜的破坏作用有关。而喷施高浓度甜菜碱(40 mmol/L)则没有此种保护效果。

Effect of Exogenous Glycinebetaine on Physiological Indicators of Malus hupehensis Leaves Under Drought Stress

Abstract: To explore the physiological changes of apple to drought, the drought resistance mechanism and the effects of exogenous glycinebetaine on apple drought resistance, apple root stock (Malus hupehensis) seedlings were used to study the effects of foliar-applied glycinebetaine (GB, 5-40 mmol/L) under drought stress condition. The results showed that CO2 assimilation rate, and stomatal conductance increased at low GB concentrations (5-20 mmol/L) but decreased significantly at high GB concentrations (40 mmol/L). Leaf relative water content and anti-oxidative enzyme activitie (SOD) increased at low GB concentrations but decreased at high GB concentrations under drought stress. Foliar-applied low GB concentrations increased the proline content and soluble sugar accumulation and decreased the MDA content and cell membrane permeability in Malus hupehensis leaves, increased its drought resistance, the effect of 10 mmol/L GB concentration was the best.