Differential Occurrence of Cuticular Wax and Its Role in Leaf Physiological Mechanisms of Three Edible Aroids of Northeast India

Abstract

The localization of cuticular wax (CW) on the leaf epidermis and its interaction with the physiological mechanisms of three edible aroids, Alocasia, Colocasia, and Xanthosoma, were assessed. CW in the leaf tissues was visualized using scanning electron microscopy, which was higher in Colocasia (10.61 mg·dm−2) and Xanthosoma (11.36 mg·dm−2) than in Alocasia (1.36 mg·dm−2). Colocasia CW exhibited superhydrophobic properties with a higher static contact angle (CA) (>150°) than Xanthosoma (99.0°) and Alocasia (128.7°). The higher CW in Colocasia and Xanthosoma resulted in better leaf chlorophyll stability, moisture retention ability, and cellular membrane integrity compared to Alocasia. CW acted as a protecting barrier against deleterious solar radiation in terms of sun protection factor (SPF). The glossy appearance of wax crystals in the Alocasia leaf cuticles resulted in higher SPF. Overall, Colocasia CW highly influenced the qualitative and protective mechanisms of the leaf. Our study sheds light on the pivotal role of CW in the physiological properties of aroid leaves, which would be useful for the selection of wax-rich plants for augmenting future breeding strategies. The information would also be useful for further exploration of the industrial potential of superhydrophobic wax crystals obtained from edible aroids.

Keywords

• aroid leaves
• cuticular wax
• chlorophyll stability
• hydrophobicity
• physiological mechanisms
• sun protection factor