干旱胁迫对木麻黄蒸腾作用和渗透调节的影响

EFFECT OF DROUGHT STRESS ON TRANSPIRATION AND OSMOTIC ADJUSTMENT OF CASUARINA SPECIES

在温室条件下控制不同土壤干旱梯度,研究4种木麻黄在水分逆境下蒸腾作用和气孔调节的变化,并应用 PV 技术研究了参试树种的水分参数。结果表明,木麻黄的蒸腾速率和气孔阻力具有明显的日变化规律,在干旱胁迫下蒸腾速率逐步降低,气孔阻力增大。当水势下降到某一临界时,因气孔关闭使气孔阻力急剧增大,蒸腾速率降至最低水平。木麻黄的气孔调节为反馈式反应。在干旱胁迫下木麻黄具有保持一定细胞膨压的能力,且细胞膨压与弹性模量随树种而异。

Based on the condition controlling soil water potential in the green house,the transpiration and sto- matal response were tested,and the water parameters of Casuarina species were studied using Pressure-Vol- tune technique under the adeverse circumstance of water stress.The results showed that Casuarina species ex- amined had clearly daily variation in transpiration and stomatal resistance.The transpiration rate droped gradu- ally and stomatal resistance increased under the condition of drought stress.When water potential droped to some critical level,stomatal increased sharply and the transpiration rate decreased to lowest level because of stomatal closing.The pattern of stomatal regulation of Casuarinas species is feedback manner.All tree species examined have some ability of maitaining turgot under the condition of drought stress.Moreover,the turgor and bulk modulus of elasticity vary with Casuarina species.