Responses of Flue-cured Tobacco Seedlings with Humic Acid Fertilized to Low Temperature Stress

• KUANG Ziyang, 
• QIN Ling, 
• JIN Jianghua, 
• ZHANG Sai, 
• LI Xu, 
• HUANG Jie, 
• XIA Bing, 
• DENG Xiaohua