Abstract: Changes in root vigor, hydraulic conductance,and leaf chlorophyll content under nutritional stress were measured and compared in different hydroponic trial treatments of half-Hoagland nutrition (CK) and half-Hoagland nutrition without nitrogen (-N),phosphorus (-P) and potassium (-K) of referenced Astragalus membranaceus seedlings.When compared with full nutrient (CK) treatment,root vigor,root absorption surface area,root hydraulic conductance and leaf chlorophyll content significantly decrease in treatments without N,P and K elements along with significant difference in root/shoot ratio (R/T) between both the control and element-deficit treatments.Specially,both-N and -P treatments most significantly affect root hydraulic conductance.