It is an agricultural unified examination subject.

4 14 plant physiology and biochemistry

It is an agricultural unified examination subject. It's two textbooks.

Biochemistry is a self-proposition

It is a professional biochemistry, which is more difficult than 4 14 biochemistry.

Reference book:

Biochemistry (3rd Edition) (Volume I and Volume II) edited by Wang Jingyan, Higher Education Press.

Whether it will affect admission depends on your tutor's research direction.

I have an agricultural outline. Write to me if you like.

Wish you success!