Effect of drought and ABA on growth, photosynthesis and antioxidant system of Cotinus coggygria seedlings under two different light conditions

▶Drought treatment significantly reduced net photosynthesis rate (A) and transpiration (E), but increased chlorophyll a (chla), carbon isotope (δ13C), endogenous abscisic acid (ABA), malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents, and guaiacol peroxidase (POD) and catalase (CAT) activities. ▶ There was an apparent alleviation of drought effects by shade, as indicated by the lower relative growth rate, and chlorophyll, MDA and H2O2 contents, and increases in indoleacetic acid (IAA) and reduced glutathione (GSH) contents. ▶ The exogenous ABA application under shade induced protective effects on drought-stressed seedlings, as visible in MDA, A, stomatal conductance (gs), E, δ13C, ABA and IAA values. ▶ Our results suggest that seedlings of Cotinus coggygria are more sensitive to drought under full-light than under shade.