Effects of exogenous abscisic acid on foliar anthocyanin accumulation and drought tolerance in purple rice

Abstract

AbstractThe effects of drought and exogenous ABA on foliar anthocyanin accumulation and its role in drought tolerance were studied in two purple rice cultivars GS. No. 00621 and GS. No. 21427. The seedlings were grown for 14 days and separated into four groups including control (well-watered), drought (withholding water), ABA (foliar sprayed with 20 mg L−1 ABA and well-watered), ABA and drought (foliar sprayed with 20 mg L−1 ABA and withholding water). Drought was imposed by withholding water for 7 days. The results showed that drought significantly reduced root and shoot growth in GS. No. 00621, while had little effect on GS. No. 21427. Drought stress also induced anthocyanin overaccumulation in GS. No. 21427, whereas its content was reduced in GS. No. 00621. Exogenous ABA had no effect on anthocyanin in both wellwatered and drought conditions in both cultivars. Higher anthocyanin in GS. No. 21427 was coincided with higher DPPH scavenging ability, antioxidant enzyme activities as well as higher relative water content. It is, therefore, concluded that drought-induced anthocyanin overaccumulation may be different between purple rice cultivars and anthocyanin is beneficial for the response to drought stress by protecting plant antioxidant mechanism. Unlike anthocyanin in plant reproductive organs, exogenous ABA has no effect on foliar anthocyanin accumulation in purple rice. It is possible that anthocyanin accumulation in leaf and reproductive organs may be regulated differently or triggered by different mechanisms.