传递细胞/ Transfer cells Ingrowth of cell wall; important role in transferring dissolved substances between adjacent cells Sieve element ) Wall ingrowth 2.5m Transverse section of a portion of the phloem from a small vein of a Senecio leaf, arrows indicating wall ingrowth传递细胞/Transfer cells Ingrowth of cell wall; important role in transferring dissolved substances between adjacent cells Transverse section of a portion of the phloem from a small vein of a Senecio leaf, arrows indicating wall ingrowth. Sieve element Wall ingrowth