换锦花和中国石蒜对干旱胁迫的生理响应

Physiological Response of Lycoris sprengeri and Lycoris chinensis to Drought Stress

以2种春出叶石蒜属植物中国石蒜和换锦花为材料,通过盆栽控水试验,以适宜水分（最大持水量的75％～80％）为对照,设置干旱胁迫（最大持水量的35％～40％）处理,研究干旱胁迫对其幼苗生理生化指标的影响,以明确2种植物的耐旱特性.结果显示：（1）换锦花和中国石蒜幼苗叶片相对含水量（RWC）和叶绿素a、b含量均随着干旱胁迫时间的延长而降低.（2）换锦花可溶性糖含量和脯氨酸含量均随着干旱时间的延长表现出持续增加的趋势,而中国石蒜则表现出先升高后降低的趋势.（3）换锦花和中国石蒜幼苗叶片TBARS含量和相对电导率总体上呈增大趋势,并在干旱末期达到最大值;超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）活性均呈现出先上升后下降趋势.（4）换锦花和中国石蒜幼苗叶片净光合速率（Pn）、胞内二氧化碳浓度（Ci）和蒸腾速率（Tr）随着干旱胁迫时间延长均有不同程度下降.研究表明,在土壤干旱胁迫条件下,换锦花和中国石蒜幼苗叶片在水分生理、光合特性、渗透调节物质和抗氧化酶活性等方面表现出一定的差异,其中换锦花较中国石蒜表现出较强的耐旱性,且具有明显的优势.

An experiment was conducted to find out the effects of drought stress on morpho-physlologmai characters and antioxidant responses in two spring-sprout Lycoris species（L, sprengeri and L. chinensis）. Seedlings were transferred into plastic pots filled with loamy soil and then subjected to a limiting level of water regimes（35 %--40 % of field capacity）. The results showed that：（1）Drought stress caused a significant reduction in leaf relative water content（RWC） and chlorophyll content in both species. （2）There was sustained increase in soluble sugar content, proline accumulation under drought stress conditions in L. sprengeri,while they increased at first, and then decreased in L. chinensis. （3）As the drought stress pro- ceeding,the relative electric conductivity and levels of thiobarbituric acid reactive substances（TBARS） were increasing, and the highest levels were observed at the end of the drought stress. Moreover, the variation trend in superoxide dismutase（SOD）, guaiacol peroxidase （POD）, and catalase（CAT） activities increased at first and then decreased in both species. （4）It was also observed that the net photosynthesis （Pn） ,intercellular CO2 concentration？ and transpiration rate（Tr） decreased upon drought treatments. These results indicated that drought sensitivities actually differ between L. sprengeri and L. chinensis. L. sreneri was with higher water conservation, ohotosynthetic production, osmatic adjustment substances,and antioxidant enzymes,thus was more tolerant to drought stress.