Morphological, Chemical and Environmental Factors Affecting Leaf Rolling in Rice During Water Stress

The effects of morphological, chemical and environmental factors were found to have profound impact on leaf rolling in rice during water stress. Morphological variations such as the existence of “ridged” and “smooth” portions in the leaf blade, length of leaf, angle of leaf attachment, specific leaf weight and the chronology of leaf production were all found to cause variability in leaf rolling. The “ridged” portion of leaf rolled first followed the “smooth” one as the water potential of the former was less by 0.48 MPa than the latter at rolling score 5. Similarly, the water potential of “apical-half portion of the leaf blade was less by 0.41 MPa in comparison to the “basal-half portion. The process of leaf rolling and unrolling was reversible. Length of leaf was positively (r=0.969), wheareas leaf angle (r=-0.887) and the specific leaf weight (r=-0.955) were negatively correlated with leaf rolling. In other words, longer the leaf the quicker was its rolling and conversely, the wider the angle of leaf attachment with the culm and the higher the specific leaf weight, the less was the rolling of leaves. Altering the path of water transport and its distribution through several cuts and incisions made on leaf blades did not materially change the leaf rolling behaviour during field moisture stress. Exogenous leaf feeding with abscisic acid and sucrose delayed the rolling of excised leaves. Light hastened the process of leaf rolling whereas dark regime had opposite effect.