Variations of cuticular wax in mulberry trees and their effects on gas exchange and post-harvest water loss

Abstract

Though mulberry (Morus alba) tree shows great adaptations to various climate conditions, their leaf water status and photosynthesis are sensitive to climate changes. In the current study, seven widely planted mulberry cultivars in Chongqing, Southwest China, were selected to analyze leaf cuticular wax characteristics, gas exchange index, post-harvest leaf water status and their relationships, aiming to provide new theory in screening high resistant mulberry cultivars. Mulberry trees formed rounded cap-type idioblasts on the adaxial leaf surface. Film-like waxes and granule-type wax crystals covered leaf surfaces, varying in crystal density among cultivars. The stomatal aperture on the abaxial surface of cultivars with high wax amount was smaller than that of cultivars with low wax amount. The amount of total wax was negatively correlated with the net photosynthetic rate (P N ), transpiration rate (E) and stomatal conductance (g s ) and positively correlated with the moisture retention capacity. It suggested that both cuticular wax and stomatal factor might be involved in regulating water loss in mulberry leaves under field conditions. The variability in moisture retention capacity and cuticular wax characteristics might be important in evaluating and screening mulberry cultivars for increasing silk quality and silkworm productivity.

Molecular and Evolutionary Mechanisms of Cuticular Wax for Plant Drought Tolerance

“…It was found that cuticular wax content increases by 20–28% in cucumber ( Cucumis sativus L.), bean ( Phaseolus vulgaris L.), and barley ( Hordeum vulgare L.) when plants are exposed to UV-B light (Steinmüller and Tevini, 1985). It was reported that increasing gas exchange rate for in vitro grown carnation plants leads to thicker epidermal wax (Majada et al, 2001), and larger amount of wax covering the leaf surface affect rate of gas exchange in mulberry ( Morus alba ) (Yu et al, 2015) and canola ( Brassica napus ) (Ni et al, 2014). However, the regulatory mechanism of changes of cuticular wax induced by high UV-B radiation and its link to gas exchange and plant performance needs further study.…”

Residual transpiration as a component of salinity stress tolerance mechanism: a case study for barley

“…However, the correlation between residual transpiration and the thickness of cuticle and/or amount of total cuticular waxes is still not clear-cut. Some researchers found that the total amount of cuticular waxes and cuticular thickness are negatively correlated with residual transpiration in different plants [ 16 – 19 ]. However, some authors reported no correlation between residual transpiration and waxes [ 2 , 20 , 21 ].…”

Changes in foliar epicuticular wax and photosynthesis metabolism in evergreen woody species under different soil water availability

“…The low stomata frequency on the adaxial side and exclusively present on the main vein suggests C. flexuosa is functionally hypoestomatic (Torrecilla et al 2008). This low stomata number on this face would be leaf protection against excessive water loss and intense radiation during the driest months of the year (Ni et al 2015). In fact, the absence of pores along adaxial cuticle would allow the homogenous wax layer formation; therefore, a barrier with greater resistance to water flow.…”