Belowground resprouting potential and nutrient acquisition traits of three perennial grasses during the short dry season in Kenya

Abstract

Survival of perennial grasses between wet seasons depends on the maintenance of belowground buds and root systems. Belowground bud and root traits were evaluated in three perennial grasses (Pennisetum mezianum (Leeke), Digitaria macroblephara (Hack. ex Schinz) Paoli, and Themeda triandra (Forssk.) in semi-arid Kenyan rangelands during the short dry season. Bud number remained stablae while bud size declined for all three grass species during the study period. Non-structural carbohydrates in roots and percent root dry matter had increased in all three species by the end of the dry season. Pennisetum mezianum had more buds, larger bud sizes, larger average root diameter, lower specific root length (SRL), lower root tissue density (RTD), and the least amount of non-structural carbohydrate (NSC) content when compared to the other two species. Perennial grasses preserved their resprouting capacity during the short dry season through both their stable bud numbers and increasing availability of carbohydrates for resprouting. Further research should be conducted on more range grass species over multiple seasons to better understand how their belowground traits enable the persistence of these species during dry seasons and long-term drought.