干旱胁迫对鸭茅幼苗根系生长及光合特性的影响

以不同耐旱型鸭茅品种(系)“01998”(敏感型)和“宝兴”(耐旱型)为试材,采用盆栽控水试验方法,研究土壤干旱胁迫对鸭茅幼苗根系生长、生理特性及叶片光合作用的影响,探讨不同品种耐旱机制的差异.结果表明：干旱胁迫下,不同耐旱型鸭茅幼苗的根系活力和根系数量均呈先上升后下降的趋势,当土壤相对含水量降到30%时,根系活力和根数显著增加并达到最大值；干旱胁迫降低了两个品种鸭茅叶片的相对含水量、叶绿素含量、净光合速率、叶片蒸腾速率、气孔导度,提高了电导率和胞间CO₂浓度.干旱胁迫降低了两个品种鸭茅的单株叶面积,品种“01998”的地下及地上生物量下降,而“宝兴”无显著变化.

Effects of drought stress on the root growth and photosynthetic characters of Dactylis glomerata seedlings.

Taking the drought sensitive Dactylis glomerata line “01998” and drought tolerant cultivar “Baoxing” as test materials, a pot experiment was conducted to study the effects of drought stress on the seedlings root growth, physiological characteristics, and leaf photosynthesis, aimed to approach the differences in the drought tolerance mechanism of different D. glomerata lines (cultivars). Under drought stress, the root vitality and root number of “01998” and “Baoxing” presented a trend of increased first and decreased then. When the soil relative moisture content decreased to 30%, the root vitality and root number of “01998” and “Baoxing” increased significantly and reached the maximum. Drought stress decreased the relative water content, leaf chlorophyll content, net photosynthesis, transpiration, and stomatal conductance, but increased the electric conductivity and intercellular CO2 concentration of “01998” and “Baoxing”. Under drought stress, the leaf area per plant of both “01998” and “Baoxing” decreased, and the underground and aboveground plant biomass of “01998” decreased while that of “Baoxing” had less change.