Maize leaf rolling and its response to drying soil and evaporative demand

Abstract

Leaf rolling is an adaptive mechanism associated with water deficiencies; however, the23 physiological processes and environmental factors contributing to leaf rolling are not fully24 understood. The objective of this study was to examine (i) a possible relationship between25 the degree of leaf rolling and soil water content, and (ii) the possible influence of vapor26 pressure deficit on the degree of leaf rolling. Leaf rolling was measured on maize plants27 grown in pots and subjected to various soil drying and atmospheric vapor pressure deficit28 (VPD) treatments. The experimental results indicated that (i) high VPD by itself does not29 readily induce leaf rolling, and (ii) leaf rolling was observed in proportion to the extent of30 soil drying. The values of the fraction of transpirable soil water thresholds for the decline31 in normalized transpiration rate and for the initiation of plant leaf rolling were sensitive to32 environmental conditions (VPD and temperature). With soil drying, leaf rolling was33 initiated slightly after the initiation of decrease in transpiration rate.