Supplementation of natural light duration promotes accumulation of sugar and anthocyanins in apple (Malus domestica Borkh.) fruit

Zhuoxin Mei, Zhiqiang Li, Xia Lu, Shuhui Zhang, Wenjun Liu, Qi Zou, Lei Yu, Hongcheng Fang, Zongying Zhang, Zhiquan Mao, Xuesen Chen, Nan Wang