It is found in protoxylem and first metaxylem tracheids and vessels.
可在原生木质部和初始后生木质部的管胞和导管中见到。
Protoxylem the PRIMARY xylem elements that are formed from the procambium first.
初生木质部的成分，最早由原形成层形成。
Annular thickening rings of thickening laid down on the inner wall of protoxylem vessels and tracheids.
环状加厚：原生木质部导管和管胞的内层环状増厚。
The degree of lignification varies from slight in protoxylem to heavy in sclerenchyma and some xylem vessels, but values of 25-30% lignin and 50% cellulose are average.
不同部位的木质化的程度不同，原生木质部中只有轻微的加厚，而在厚壁组织和一些木质部导管中则进一步加厚，平均含25%-30%的木质素和50%的纤维素。
The degree of lignification varies from slight in protoxylem to heavy in sclerenchyma and some xylem vessels, but values of 25-30% lignin and 50% cellulose are average.
不同部位的木质化的程度不同，原生木质部中只有轻微的加厚，而在厚壁组织和一些木质部导管中则进一步加厚，平均含25%-30%的木质素和50%的纤维素。
应用推荐