Response of balanites aegyptiaca (L.) Del. seedlings from varied geographical source to imposed drought stress

Abstract

Seedlings of Balanites aegyptiaca (Hegleig) from eight geographical sources were exposed to a multiple series of drought cycles to test the effect of drought conditioning on seedlings survival. Three successive cycles were imposed to a four-month old seedlings. At the end of the cycles, water was withheld from both stressed and well-watered seedlings and mortality was counted for one month. Water stress significantly reduced seedlings mortality, suggesting that stress conditioning enhanced adaptive traits for drought tolerance. There is observed relationship between drought tolerance and original soil type of the sources. Seedlings exhibit highest mortality were from clay provenances, while those having the least were from sandy clay loam. Seedlings mortality was positively correlated with leaf area, leaf weight and specific leaf weight, and negatively correlated with specific leaf area, indicating that leaf traits are the most adaptive characters for drought tolerance for this species. The study showed that Hegleig tree is a drought tolerant species with significant differences among provenances. Selection of Id Elfrissan provenance for drought prone sites and Ed Dinder source in relatively favourable sites with clay soil, may enhance first year survival of this species.