深山含笑和杜英幼苗对干旱-复水的生理生态响应

Eco-physiological Responses to Drought and Rewatering of Michlia maudiae and Elaeocarpus decipiens Seedlings

摘要:

为了解不同树种对干旱胁迫的生理响应机制和旱后恢复能力，对具有园林和生态价值的深山含笑(Michlia maudiae)和杜英(Elaeocarpus decipiens)幼苗采用盆栽方法进行干旱复水实验，测定2树种在干旱和复水过程中的气体交换参数、叶片水分状况、超氧化物歧化酶(SOD)活性和渗透调节物质等生理指标。结果表明，在干旱胁迫下，杜英幼苗的叶片水势和光合参数较深山含笑下降的更快，仅6 d就比对照下降了99.1%。复水前深山含笑和杜英幼苗叶片中SOD活性分别为对照的36.1%和33.4%；2树种幼苗叶片中脯氨酸含量分别是对照的2.1和5.5倍；但杜英幼苗可溶性糖含量与对照无显著差异。复水7 d后，深山含笑幼苗的净光合速率、气孔导度和蒸腾速率仍未恢复至对照水平，而杜英幼苗已完全恢复。2树种复水后的SOD活性和渗透调节物质都逐渐恢复至对照组水平。因此，深山含笑和杜英幼苗对干旱胁迫的响应及旱后恢复能力存在差异，其中杜英对干旱更为敏感但复水后的恢复能力强于深山含笑。这从植物生理学的角度阐明了深山含笑和杜英对干旱-复水的生理响应机制，可为苗木栽培管理、园林绿化和树种筛选等实践提供参考依据。

Abstract:

To understand the physiological response mechanisms and post-drought recovery capabilities of different tree species to drought stress, a pot experiment was conducted on the seedlings of Michelia maudiae and Elaeocarpus decipiens, which have both ornamental and ecological values. Gas exchange parameters, leaf water status, superoxide dismutase (SOD) activity, and osmotic adjustment substances were measured during the drought and rewatering processes. The results showed that under drought stress, the leaf water potential and photosynthetic parameters of E. decipiens seedlings decreased more rapidly than those of M. maudiae, with a 99.1% decrease compared to the control after only 6 days. Before rewatering, the SOD activity in the leaves of M. maudiae and E. decipiens seedlings was 36.1% and 33.4% of the control, respectively; the proline content in the leaves of the two tree species was 2.1 and 5.5 times that of the control, respectively; however, the soluble sugar content of E. decipiens seedlings was not significantly different from that of the control. Seven days after rewatering, the net photosynthetic rate, stomatal conductance, and transpiration rate of M. maudiae seedlings did not yet recover to the control level, while those of E. decipiens seedlings fully recovered. The SOD activity and osmotic adjustment substances of the two tree species gradually returned to the control level after rewatering. Therefore, there are differences in the response to drought stress and post-drought recovery capabilities between M. maudiae and E. decipiens seedlings. Elaeocarpus decipiens is more sensitive to drought but has a stronger recovery ability after rewatering than M. maudiae. This study clarifies the physiological response mechanisms of M. maudiae and E. decipiens to drought and rewatering from the perspective of plant physiology, providing a reference basis for practical applications such as seedling cultivation management, landscaping, and tree species selection.