干旱胁迫对不同木薯苗期生理特性及气孔形态的影响

Effects of Drought Stress on Physiological Characteristics and Stomatal Morphology of Different Cassava Seedlings

【目的】为探究干旱胁迫下木薯苗期光合特性及生理响应,比较木薯品种间耐旱性。【方法】选择5个木薯品种为试验材料,采用盆栽试验,设置正常供水(CK)和重度干旱胁迫(D)处理,研究干旱胁迫及复水后木薯苗期光合、渗透调节物质、膜脂过氧化物含量、抗氧化酶活性等生理指标以及气孔形态的变化。【结果】①干旱胁迫后各品种木薯的净光合速率、气孔导度、胞间CO_(2)浓度和蒸腾速率与对照相比均降低;②干旱胁迫后,木薯叶片中的可溶性糖和脯氨酸积累,同时超氧化物歧化酶和过氧化氢酶活性显著升高,丙二醛含量均有不同程度的升高,复水后上述指标都有所降低或恢复到对照水平;③相较于其他品种,干旱胁迫后1-3-4的气孔密度增大,开度明显减小。【结论】干旱胁迫下木薯通过改变自身的渗透调节能力、酶促抗氧化活力以及叶片保水能力来抵抗干旱,其中木薯品种1-3-4的光合性能、生理特性和抗旱能力优于其他品种,并且在恢复水分供应后能迅速恢复植物生长势,从而表现出较强抗旱能力。

【Objective】To investigate the photosynthetic characteristics and physiological responses of cassava seedlings under drought stress,and to compare the drought tolerance among cassava varieties.【Method】Five cassava varieties were selected as experimental materials.Pot experiments were con⁃ducted,with normal water supply(CK)and severe drought stress(D)treatments were set up to study the changes in physiological indicators such as photosynthesis,osmotic regulators,membrane lipid per⁃oxide content,antioxidant enzyme activity,and stomatal morphology of cassava seedlings during drought stress and rehydration.【Result】①After drought stress,the net photosynthetic rate,stomatal conduc⁃tance,intercellular CO2 concentration,and transpiration rate of each variety of each cassava variety de⁃creased compared with the control.②After drought stress,the soluble sugars and proline accumulate in cassava leaves,while the activities of superoxide dismutase and catalase increase significantly,and the content of malondialdehyde increases to varying degrees.After rehydration,the above indicators decrease or return to the control level.③Compared to other varieties,the stomatal density of 1-3-4 increased and the opening significantly decreased after drought stress.【Conclusion】It can be concluded that under drought stress,cassava can resist drought by changing its own osmotic regulation ability,enzymatic anti⁃oxidant activity,and leaf water retention ability.In summary,cassava variety 1-3-4 have better photo⁃synthetic performance,physiological characteristics,and drought resistance than other varieties,and can quickly restore plant growth after restoring water supply,thus demonstrating strong drought resistance.