干旱胁迫对鼓节竹生理生化的影响

Effect of Drought Stress on Physiological and Biochemical Responses of Bambusa tuldoides‘Swolleninternode’

以1年生鼓节竹分株苗为材料,采用盆栽试验,分别设置对照组、轻度干旱胁迫、中度干旱胁迫和重度干旱胁迫等4个土壤水分梯度,分析鼓节竹在人工模拟干旱胁迫下的各项生理生化指标的变化。结果表明:鼓节竹叶片在干旱胁迫过程中出现了失水、黄化、长斑及脱落等现象,在轻度和中度干旱胁迫下表现出较强的抗旱性,而对持续的重度干旱胁迫则不具有耐受性。随胁迫时间和程度的增加,叶片丙二醛、脯氨酸、可溶性糖及可溶性蛋白含量均显著上升,而过氧化物酶和超氧化物歧化酶的活性则呈先升后降的趋势。叶片光合色素在干旱胁迫过程中总体呈下降的趋势。当土壤含水量持续为8.8%~11.0%的环境下,鼓节竹会生长不良甚至枯死,而在土壤含水量大于17.6%时,鼓节竹生长状态相对较好。因此,鼓节竹在干旱胁迫条件下,通过增加渗透调节物质、增强叶片酶活性、增强光合作用等一系列反应来提高自身对干旱环境的适应性。

One-year-old ramets Bambusa tuldoides‘Swolleninternode’were used as materials to simulate drought stress artificially in four different soil water gradients:control group(CK),light drought stress(LD),moderate drought stress(MD)and severe drought stress(SD),to explore the physiological response mechanism of B.tuldoides‘Swolleninternode’under drought stress.During drought stress,the leaves of B.tuldoides‘Swolleninternode’suffered from water loss,shrinkage,yellowing,long spots and abscission.B.tuldoides‘Swolleninternode’showed strong drought resistance under light and moderate drought stress,but had no tolerance to persistent severe drought stress.With the increase of stress time and degree,the content of malondialdehyde,proline,soluble sugar and soluble protein in leaves increased significantly,while the activity of catalase,peroxidase and superoxide dismutase showed a trend of first increasing and then decreasing.The photosynthetic pigments in leaves of B.tuldoides‘Swolleninternode’showed a downward trend during drought stress.When the water content of soil is 8.8%-11.0%,the growth of B.tuldoides‘Swolleninternode’will be poor,even the leaves and bamboo poles will die.The growth of B.tuldoides‘Swolleninternode’is better in the environment with soil water content higher than 17.6%.Therefore,under drought stress,B.tuldoides‘Swolleninternode’improves its adaptability to drought environment by increasing osmotic regulation substances,enhancing enzyme activity in leaves,enhancing photosynthesis and other reactions.