Morpho - anatomical modifications of leaf in sugarcane hybrids under normal and water deficit conditions

Abstract

Drought is the most important deleterious abiotic stress factor largely affecting sugarcane productivity. It is reported that among the different morphological organs, leaf is the most adaptable organ in response to water stress. In the present study five sugarcane hybrids viz., SRH-13-69, SSH-14-453, SRH-15-602, SRH-15-749 and SSH-14-356 ( resistance to red rot ) were evaluated for variation in morpho-anatomical characteristics of leaf under normal and water stress ( moderate drought with 40-50 % of irrigation at GGP ) to explain drought tolerance based on modification in internal structures. SSH-14-453, SRH-15- 602 and SSH-14-356 were identified as drought resistant based on leaf morphology and cane yield. Further these hybrids were evaluated for quantitative anatomy of water-stressed leaves. Water stress had led to increased leaf cuticle ( prevents excess water evaporation ) thickness and also observed that lower epidermal cuticle was significantly thickened in resistant clones. Bulliform cell area was largely reduced and this obviously resulted in leaf curling ( morphological adaptation ) to reduce plant injuries under stress. The higher relative change of 35.8 % of bulliform cell area was observed in SSH-14-453 between normal and stress condition. Mesophyll cells were deformed to increase cell gaps as an important adaptation to reduce the metabolic cost in resistant clones. Area of vascular bundle and xylem vessels was significantly increased by above 20.0 % in SSH-14-453 and SRH-15-602 under drought and lignification around vascular bundle was also observed. This study indicates that significant modifications occur in leaf anatomy during drought and hence it is suggested for evaluation of leaf morpho-anatomical adaptations in selection of clones for drought tolerance