Nitrogen and Growth Stage Influence Epicuticular Wax Composition on Rice Leaf and Sheath

Epicuticular wax plays an important part in protecting plant aerial organs from biotic and abiotic stresses. Nitrogen is the key limiting nutrient for crops and influences metabolite synthesis. However, how nitrogen influences wax composition on rice leaf and sheath at different growth stages has not been systematically examined. In this study, a total of 19 wax compounds in rice leaf and sheath were detected by using gas chromatography–mass spectrometry. Permutational multivariate analysis of variance (PermANOVA) indicated a significant influence of both nitrogen and growth stage on rice leaf and sheath wax composition. Nitrogen influenced wax composition on leaf and sheath mainly at 70 and 110 d, while the growth stage significantly influenced wax composition under all nitrogen levels. Our study provides the first report that rice wax composition changes with nitrogen and growth stage. This may support exploring nitrogen application and the associated ecological effects.