以北板蓝根(Isatis tinctoria)为研究对象, 于2018年在河西走廊中部干旱绿洲开展水分控制试验, 设轻、中、重度亏水及充分供水4个控水水平, 通过大田试验探究膜下滴灌条件下亏缺灌溉对板蓝根叶片生理指标、灌水量及产量的影响, 为河西地区板蓝根灌溉策略的制定提供理论依据。结果表明, 板蓝根叶片净光合速率(P_n)、蒸腾速率(T_r)和气孔导度(G_s)因营养和肉质根生长期受到亏缺灌溉影响而显著下降, 降幅随亏水程度的加剧而增大, 轻度亏水处理对叶片光合能力的影响不显著, 且在复水之后存在一定的补偿响应; 轻度亏水处理的产量与对照(8 348.91 kg·hm^-2)相比无显著差异, 而其它处理的产量均有不同程度的下降; 灌水量与产量的拟合关系呈二次抛物线, 即产量不随灌水量的增加而升高。因此, 综合分析表明膜下滴灌调亏降低了板蓝根叶片的光合能力, 而营养生长期轻度亏缺灌溉可以节水并提高产量和灌溉效率。

Taking the Isatis tinctoria as research crop, the field water control experiment was carried out in an arid oasis of the middle of the Hexi Corridor in 2018, and deficit levels included slight, moderate, severe water deficit (WD) and suitable irrigation, the influences of WD on physiological parameters, irrigation volume, yield and quality of Isatis tinctoria were studied with drip irrigation and plastic mulch, which would provide the theoretical basis for the establishment of irrigation management strategy of I. tinctoria in Hexi area. The results showed that WD treatment during the vegetative and fleshy root growth stages reduced the leaf photosynthetic rate (P_n), transpiration rate (T_r), and stomatal conductance (G_s), and with the higher degree of WD, the greater the decrease. Slight WD treatment had no significant effects on leaf photosynthetic capacity, and yield as compared with control, but the rest of treatment led to varying degrees of decrease in leaf photosynthetic capacity and yield. Fitting the relationship between the irrigation amount and the yield showed a quadratic parabola, which demonstrated that the yield did not enhance along with the increase of the irrigation amount. In conclusion, under-mulched drip irrigation WD reduces photosynthetic capacity of I. tinctoria leaves, while slight WD irrigation applied during the vegetative growth period saves irrigation water and improves yield and irrigation water use efficiency.