Biomass partition, leaf gas exchange and water relations of alfalfa and milkvetch seedlings in response to soil drying

This study compared physiological and growth responses to water stress of two legume species during the seedling stage. Potted alfalfa ( Medicago sativa L. cv. Algonquin) and milkvetch ( Astragalus adsurgens Pall. cv. Pengyang earlymaturing vetch) seedlings were grown under well-watered [soil water content (SWC) maintained at 14.92% daily] or water-stressed conditions (drying) for 15 days. Net photosynthetic rate ( P N ), transpiration rate ( E ) and stomatal conductance ( g s ) of both species decreased parabolically. When SWC decreased to 7.2% and 10.3%, g s values for alfalfa and milkvetch were significantly different from those of the respective well-watered plants ( p