知识贝壳
知识贝壳
所属栏目：英汉烟草科技
Even within the same plant,leaves from different stalk positionsshow a definite pattern of chemical distribution. For example,total nitrogen and nicotine contents increase with higher stalk position,but reducing sugars are higher in the middle position as ......（本文共 1427 字 ） [阅读本文] >>