为了探讨施用保水剂对干旱胁迫下大麦幼苗生长及光合特性的影响，给保水剂在大麦抗旱栽培中的应用提供理论依据。采用盆栽法通过测定在不同干旱胁迫下大麦幼苗根长、茎长、叶片相对含水量、叶片光合参数、叶绿素含量等指标，结果表明，在同等水分条件下，施用保水剂可增加大麦幼苗根长、茎长及叶片相对含水量，显著增加大麦幼苗叶片的净光合速率、气孔导度、胞间CO₂浓度、蒸腾速率，说明保水剂可以通过保持大麦叶片较高的光合特性来增强其碳同化能力，进而促进大麦幼苗的生长。且施用保水剂后大麦幼苗叶绿素含量得到显著提高，从而减小了干旱胁迫对植株带来的损害，延缓植株衰老。施用保水剂可以较好地促进干旱胁迫下大麦幼苗的生长发育。

In this study, the physiological basis for the application of water-retaining agent to improve the drought resistance of barley seedlings under different drought stresses was investigated by measuring root length, stem length, leaves relative water content, leaf photosynthetic parameters and chlorophyll content using the pot method. The results showed that water-retaining agent could effectively enhance root length, stem length and relative leaf water content of barley seedlings under drought stress. Application of water-retaining agent could increase the carbon assimilation capacity of barley seedlings by enhancing net photosynthetic rate, stomatal conductance, intercellular CO₂ concentration and transpiration rate, and maintaining high photosynthetic characteristics of leaves, thus promoting the growth of forage barley seedlings. Application of water-retaining agent could significantly increase the chlorophyll content of barley seedlings, reduce the damage caused by drought stress and delay plant senescence. Thus, Application of water-retaining agent could better promote the growth and development of barley seedlings under drought conditions.

S512.3

国家自然基金(31760358、 32260535)；国家大麦青稞产业体系 (CARS-05-01A-08)；甘肃省农业科学院中青年基金项目(2021GAAS38)。