Correlation between plant morphological traits and water potential exhibits drought avoidance in Chrysopogon zizanioides

Abstract

Plant acclimation to drought involves morphological changes such as leaf shrinkage and root elongation. We sought correlations between drought acclimated plant morphological traits and water potential of leaf (${\psi }_L$) and root (${\psi }_R$), which are limitedly available. Leaves and roots of Chrysopogon zizanioides L. (vetiver) grown for different periods (3, 4 and 5 months) in biochar amended sandy soil were sampled at a soil water potential (${\psi }_S$) representing drought condition. Morphological traits including leaf area, root diameter and root length were determined to correlate with ${\psi }_L$ and ${\psi }_R$. Leaf area and root length increased with increasing growth period, but root diameter remained largely constant. Leaf area and ${\psi }_L$ was positively and linearly correlated. Root diameter and root length displayed a contrasting response with ${\psi }_R$; lower ${\psi }_R$ was measured in larger root diameters and shorter root lengths. Vetiver grass avoided the drought stress by increasing their root length, which will benefit the use of this species for soil bioengineering. The proliferation of roots to deeper soil depths could stabilise soil sliding and at the same time survive under drought conditions.