ROLE OF LEAF MICRO-STRUCTURAL AND TOPOGRAPHICAL TRAITS IN ECOLOGICAL SUCCESS OF SOME ARID ZONE GRASSES

Water deficit influences the phenotypic appearance of leaf hairs and stomata which plays a critical role in adaptability of plants growing in such habitats. Four grass species Aristida adscensionis, Cenchrus ciliaris, Desmostachya bipinnata and Heteropogon contortus were collected along with soil sample from six moisture deficit areas. Soil attributes including soil pH, ECe, moisture content, saturation percentage, organic matter, P, Na+, K+, Ca2+, Mg2+, Cl, NH4-N, NO3-N were recorded. Leaf topographical traits such as density and area of adaxial hairs, and microstructural traits including adaxial and adaxial stomatal density and area measured. Moisture deficit affected morpho-anatomical traits such as growth traits and development of leaf hair and stomata. Populations from hyper-arid regions relied particularly upon smaller leaf area, decreased fresh to dry biomass ratio for both root and shoot tissue, and, longer roots to extract water from soil deeper layers. Among leaf micro-structural traits, more stomata were found to be oriented on leaf abaxial as compared to the adaxial surface in hyper-arid populations of all grasses. Adaxial leaf surface covered with long hairs possibly helped survive in these environments by decreasing leaf transpirational losses in most of the species under study.

Automated summary

The study revealed that water deficit affects the expression of leaf hairs and stomata in plants, especially in species growing in arid regions, where the microstructural and growth traits of leaves are significantly influenced.