3个紫薇品种形态和生理特性对干旱胁迫的响应

Response of Morphology and Physiological Characteristics of Three Lagerstroemia indica Cultivars to Drought Stress

【目的】探明干旱胁迫对紫薇品种形态特征和生理特性的影响,为鉴选耐旱紫薇品种提供参考依据。【方法】以睡美人、莎拉的最爱、纳齐兹3个紫薇典型品种为材料,采用持续干旱和梯度干旱(盆苗浇水量100%;浇水量75%,轻度干旱;浇水量50%,中度干旱;浇水量25%,重度干旱;浇水量0%,极度干旱)胁迫法进行处理,通过测定植株形态、盆苗日失水量、叶片含水量、复水成活率和叶绿素荧光等指标变化,对3个紫薇品种的耐旱性开展综合分析。【结果】持续干旱试验中,紫薇植株形态评分依次为睡美人>莎拉的最爱>纳齐兹;平均盆苗日失水量/水盘日蒸发量比值依次为睡美人<莎拉的最爱<纳齐兹;睡美人、莎拉的最爱复水成活率均为80%,纳齐兹为60%。梯度干旱试验中,紫薇品种植株形态得分、叶片含水量、最大荧光(F_(m))、最大光化学效率(F_(v)/F_(m))均随干旱程度的加深而降低,初始荧光(F_(0))则随之增大,各指标变化幅度3个紫薇品种间表现为睡美人<莎拉的最爱<纳齐兹;睡美人盆苗浇水量0%处理、莎拉的最爱盆苗浇水量0%和25%处理、纳齐兹盆苗浇水量25%和50%处理下快速叶绿素荧光诱导曲线(OJIP曲线)在300μs出现显著峰值(K-band),说明干旱造成PSII供体侧的放氧复合体(OEC)受损。使用隶属函数法对3个紫薇品种的复水成活率、盆苗日失水量/水盘日蒸发量、植株形态、叶片含水量、PSⅡ初始荧光、PSⅡ最大荧光、PSⅡ最大光化学效率7个测量指标进行综合评价,分值依次为睡美人(0.934)>莎拉的最爱(0.366)>纳齐兹(0.116)。【结论】3个紫薇品种的耐旱能力依次为睡美人>莎拉的最爱>纳齐兹。睡美人、莎拉的最爱适合在节水园林中应用。

【Objective】The effects of drought stress on the morphological and physiological characteristics of Lagerstroemia indica cultivars were studied,which provided reference for selecting drought-resistant L.indica cultivars.【Method】L.indica‘Acoma’,L.indica‘Sarah’s Favorite’and L.indica‘Natchez’were treated by continuous drought stress and different gradient watering amounts drought stress(watering potted seedlings with 100%;watering potted seedlings with 75%,mild drought;watering potted seedlings with 50%,medium drought;watering potted seedlings with 25%,severe drought;watering potted seedlings with 0%,extreme drought),and then their resistance to drought were analyzed through determining the index variation in plant shape,daily water loss of potted seedlings,water content of leaves,survival rate after rehydration and chlorophyll fluorescence.【Result】In the continuous drought test,the morphological performance of plants showed as‘Acoma’>‘Sarah’s Favorite’>‘Natchez’.Average daily water loss of pot seedling/daily evaporation of water tray was‘Acoma’<‘Sarah’s Favorite’<‘Natchez’.The survival rates after rehydration of‘Acoma’and‘Sarah’s Favorite’were 80%and that of‘Natchez’was 60%.In the gradient drought test,the plant morphological score,leaf water content,F_(m) and F_(v)/F_(m) of cultivars decreased with the deepening of drought,and F_(0) increased.The change ranges were‘Acoma’<‘Sarah’s Favorite’<‘Natchez’.The OJIP curve of‘Acoma’(treated with 0%water),‘Sarah’s Favorite’(treated with 0%and 25%water),‘Natchez’(treated with 25%and 50%)appeared significant peak value(K-band)at 300μs,indicating that drought caused damage to the oxygen-evolving complex(OEC)on the donor side of PSII.According to membership function,the survival rate after rehydration,daily water loss of potted seedlings/daily evaporation of water tray,plant shape,water content in leaves,F_(0),F_(m) and F_(v)/F_(m) showed as‘Acoma’(0.934)>‘Sarah’s Favorite’(0.366)>‘Natchez’(0.116).【Conclusion】The drought resistance of the three cultivars is‘Acoma’>‘Sarah’s Favorite’>‘Natchez’.‘Acoma’and‘Sarah’s Favorite’are suitable for application in water-saving gardens.