Variation Trend of Chemical Components in Main Vein of Procured Tobacco

• Jihui LIU, 
• Hui GAO, 
• Yuzhen WANG, 
• Zhanyong GAO, 
• Xianguo WANG, 
• Chuan HE, 
• Jiefei QIU, 
• Yong YANG, 
• Hui WANG