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【目的】研究干旱胁迫对甘蔗苗期根系保护酶系统及相关指标的影响,探讨甘蔗苗期根系对干旱胁迫的应答机制。【方法】以新台糖22号为材料,在甘蔗苗期进行土壤自然干旱胁迫,测定甘蔗根系保护酶系统及质膜过氧化产物相关指标的变化,并进行相关性分析。【结果】随着干旱胁迫程度的加强,根系中可溶性蛋白质、丙二醛(MDA)、过氧化氢(H2O2)含量逐渐增加,细胞膜脂过氧化保护酶系统的酶活性均呈先升后降的趋势,干旱胁迫处理15d后SOD和POD活性达到峰值然后降低,CAT活性于11d到达峰值后下降。甘蔗苗期根系保护酶活性与膜脂过氧化作用呈显著或极显著正相关。【结论】甘蔗根系保护酶系统的干旱胁迫响应机制为:轻度干旱与中度干旱时表现为积极应对,重度干旱时则为被动忍耐。根系保护酶系统与甘蔗抗旱性的关系密切。
【Objective】 The objective of this study was to investigate the effects of drought stress on the protective enzyme system and its related indexes in roots of sugarcane at seedling stage and to explore the mechanism of root response to drought stress in sugarcane seedlings. 【Method】 With Xintai22 as material, the natural drought stress in sugarcane seedling stage was carried out to determine the change of protective enzyme system and plasma membrane peroxidation related indicators in root system of sugarcane. The correlation analysis was carried out. 【Result】 With the increase of drought stress, the content of soluble protein, malondialdehyde (MDA) and hydrogen peroxide (H2O2) in roots gradually increased, and the activities of cell membrane lipid peroxidation protective enzymes increased first and then decreased After 15 days of treatment, the activities of SOD and POD reached the peak and then decreased, and the CAT activity decreased after reaching the peak on the 11th day. Sugarcane seedlings root protection enzyme activity and membrane lipid peroxidation was significant or very significant positive correlation. 【Conclusion】 The response mechanism of drought stress in the protective enzyme system of sugarcane root system is positive response in mild drought and moderate drought, and passive tolerance in severe drought. The root protection enzyme system is closely related to the drought resistance of sugarcane.