Protein Sequences and Expression Profiles of 4 B-box Zinc Finger Genes and Functions of PeBZF 4 from Phyllostachys edulis Expression of Zinc Finger Protein Gene in Populus alba×P.berolinensis in the Infection Process by Cytospora chrysosperma Cloning and Primary Functional Analysis of a Zinc Finger Protein Gene of BoBZF from Bambusa oldhamii