单词metaxylem
n.: 【植】后生木质部网络: 次生木质部；晚成木质部
【植物;植物学】后生木质部
复数：metaxylems
The xylem of the root is tetrarch, lateral root initiate the in metaxylem radiating angle opposite to pericycle cell.
根木质部为四原型，侧根发生于木质部放射角所对的中柱鞘细胞；