Effects of shading intensities on the yield and contents of anthocyanin and soluble sugar in tubers of purple sweet potato

Abstract

AbstractLight intensity is an important factor affecting crop yield and quality. Studies on the effect of light intensity on the synthesis and accumulation of anthocyanin and soluble sugar in purple sweet potato tubers (Ipomea batatas L.) have rarely been documented. In this experiment, the effects of different shading intensities (no shading [L0], 20% shading [L1], 40% shading [L2], 60% shading [L3], and 80% shading [L4]) on the agronomic traits, fresh tuber yield, anthocyanin, and soluble sugar contents of purple sweet potatoes were investigated. Results showed that the fresh tuber yield was not decreased, and the accumulation of anthocyanin and soluble sugars in the tubers was increased under L1 compared to L0; however, these parameters were significantly decreased from L2 to L4 treatments. Further analysis showed that anthocyanin synthase (ANS) may be the restriction enzyme for anthocyanin synthesis in purple sweet potato tubers, and either excessive or insufficient light intensity decreased ANS activity. Results suggested that purple sweet potatoes might be planted in intercropping system with a little insufficient light intensity in tropical areas. However, the mechanisms underlying the effects of shading intensities on the yield and contents of anthocyanin and soluble sugar in tubers of purple sweet potato will be addressed in the future.