284 FINE-STRUCTURE OF PROTOPLASMIC DERIVATIVES 



III 



Fig. 140. Elongating cells iii Arena coleoptilcs {c-e electron micrographs), a) Elongating 



parenchyma cell, 200:1; b) elongating epidermal cell, 630:1; c) face and edge of a 



parenchyma cell, 8000: i; d) tip of an elongating parenchyma cell, 8000: i ; e) tip of an 



elongating epidermal cell, 8000: i (from Muhlethaler, 1950b). 



