环状加厚：原生木质部导管和管胞的内层环状増厚。
Annular thickening rings of thickening laid down on the inner wall of protoxylem vessels and tracheids.
可在原生木质部和初始后生木质部的管胞和导管中见到。
It is found in protoxylem and first metaxylem tracheids and vessels.
在茎原生木质部和次生木质部的形成过程中可以看到这种类型的分化。
Basipetal differentiation is seen in the formation of proto-and metaxylem in the stem.
伸向子叶的子叶迹，直接由原生木质部极外面的一群薄壁组织细胞分化形成。
The extending cotyledon traces differentiate directly from the parenchymatous cells which locate on the outside of the poles of primary xylem.
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.
单中柱：原生中柱的一种类型，是由韧皮部、中柱鞘和内皮层包围着内方的木质部构成的实心中柱。
Haplostele a type of protostele having a solid strand of stele with the xylem on the inside encircled by phloem pericycle and endodermis.
单中柱：原生中柱的一种类型，是由韧皮部、中柱鞘和内皮层包围着内方的木质部构成的实心中柱。
Haplostele a type of protostele having a solid strand of stele with the xylem on the inside encircled by phloem pericycle and endodermis.
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