Effect of 2,4-D pre-treatment on quality during ripening of on-tree longan fruit Yunfen Liu, Lingyan Liao, Feilong Yin, Boyang Guan, Hongmei Pu, Chao Kang and Liang Shuai E3S Web Conf., 251 (2021) 02031 Published online: 15 April 2021 DOI: 10.1051/e3sconf/202125102031