Effects of soil water deficit on seedlings of different Medicago falcata L. populations

Abstract

Medicago falcata L. survives in desiccation conditions and is used to provide the genetic material for improved drought survival of this otherwise productive forage species (crosses referred to as M. media). Seedlings were grown in one of three soil water contents (80, 50 and 25% of field capacity) to compare physiological and morphological response under soil water stress. After eight weeks, populations differed in drought responses, and populations from Russia displayed superior characteristics such as more survival than others; maintaining stomatal more open, high water use efficiency (WUEi) and photosynthesis rate; less leakage of electrolytes from the plasma membrane, large leaf area, more crown buds, big crown diameter, high root length and relative root length, and an approximately 1.5 fold root: shoot ratio than others, etc. We recommended that the Russian M. falcate L. populations with excellent drought tolerance are suitable to grow in arid and semi-arid regions in China, and also a potential selection for breeding new drought tolerant forage. Key words: Medicago falcata L., soil water deficit, photosynthesis, water use efficiency, leaf area, survival, biomass allocation.