ABSTRACT

The present study aimed to evaluate the implication of silicon nutrition on activating physiological 
mechanisms for thermal adjustment and growth of cowpea plants under water restriction. Thus, two 
cowpea genotypes (Xiquexique and Novaera) were grown in plastic posts in a greenhouse and subjected 
to three levels of water stress (control, moderate and severe stress) and two silicon (Si) levels (0 - without 
and 2.0 mmol/L - with Si). In general, the growth data revealed that Xiquexique plants are more tolerant 
to drought than the Novaera genotype. However, under moderate drought, Si-treated Novaera plants 
displayed elevated values of leaf area (LF), shoot dry mass (SDM), root dry mass (RDM) and total dry 
mass (TDM) compared to those from treatments without Si. The superior performance of moderately 
drought-stressed Novaera plants under Si supplementation was attributed to restricted control of leaf 
temperature under water stress. Our findings show that silicon counteracts the harmful effects of drought 
by promoting thermal adjustment and increasing water stress tolerance in cowpea plants.