protophloem
n. [植]原生韧皮部
例句
- Mature or almost mature protophloem sieve element. 质膜已发生局部解体。
- It consists of the PROTOPHLOEM (formed first) and METAPHLOEM. 由原生韧皮部（最早形成的）和后生韧皮部组成。
- Portion of a protophloem sieve element at the stage of maturation. 另外可见到电子致密的多膜复合体（箭）。
- Protophloem The first-formed PRIMARY PHLOEM, differentiated from the procambium in the region just behind the meristem. 原生韧皮部：最早形成的初生韧皮部，由位于分生组织中的原形成层分化而来。
- A protophloem sieve element at an early stage of maturation,showing a nucleus at the onset of degeneration. 注意高尔基体发生某些变化，显示解体的迹象。
- The PROTOPHLOEM and METAPHLOEM are primary tissues and derived from the procambium，while the secondary phloem is formed from the VASCULAR CAMBIUM. 苯丙氨酸是苯化合物以及像箭毒和吗啡等生物碱的前体。