高羊茅叶片表皮蜡质含量与其抗旱性的关系

Epidermis Wax Content and Drought Resistance among Different Tall Fescue (Festuca arundinacea Schreb.) Varieties

以14个高羊茅品种为试验材料,在田间试验中对干旱高温胁迫下的叶片表皮蜡质含量、净光合速率、蒸腾速率、气孔导度、胞间CO2浓度等生理指标测定分析。结果表明,干热胁迫下高羊茅品种间的叶片表皮蜡质含量和水分利用效率均存在极显著差异(P<0.01);叶片蜡质含量与综合抗旱性和水分利用效率的等级相关系数分别为0.78(P<0.01)和0.68(P<0.01);蜡质含量越高的品种,其叶片气孔导度和胞间CO2浓度越低,水分利用效率越高,但所有品种的水分利用效率绝对值都较低。研究发现,在干热胁迫时,高羊茅叶片表皮蜡质可通过对气孔导度的调节来减少气孔蒸腾,提高水分利用效率,最终提高其抗旱性;表皮蜡质含量可以作为高羊茅品种抗旱性鉴定的一个新指标。

14 varieties of tall fescue in field as the experiment material, epidermis wax content, net photosynthesis rate, transpiration rate, stomatal conductance and intercellular CO2 concentration of leaves were mensurated under drought and high temperature conditions. The difference of epidermis wax content or the water use efficiency of leaves was very significant in different tall fescue varieties （P〈0.01）. Spearman＇s rank correlation coefficient of epidermis wax content and drought resistance or water use efficiency was 0. 78（P〈0. 01） or 0. 68（P〈0. 01） ,respectively. The higher epidermis wax content of leaf was,the lower stomatal conductance was,and the lower intercellular CO2 concentration was and the higher water use efficiency was,but the water use efficiency of all varieties was low. The results showed that epidermis wax content of leaf can decrease stomatal transpiration, increase water use efficiency, consequently enhance drought resistance by adjusting stomatal conductance mechanism under drought and heat stresses, and epidermis wax content of leaf can be a new index for identifying drought resistance of tall fescue varieties.