Fig. 1

Map showing the locations in Guangdong Province where the leaf and soil samples were collected. a Shaoguan. b Qingyuan. c Heyuan. d Zhaoqing. e Huizhou. f Yunfu. g Dongguan. h Jiangmen. i Yangjiang
Map showing the locations in Guangdong Province where the leaf and soil samples were collected. a Shaoguan. b Qingyuan. c Heyuan. d Zhaoqing. e Huizhou. f Yunfu. g Dongguan. h Jiangmen. i Yangjiang