YampolskY: Study of OU palni. 161 



The larger fjraniiles in tlie cytoplasm, a commoii phenomenon in the 

 cells dcscribed above, caii hardly liave the sif^iiificaiice ascribed to them 

 by several iiivestij^ators who claim for them zymogeiiic properties, since 

 in later stages, although endosperm digestion is in full swing, thèse large 

 granules hâve disappeared. 



There is no évidence of starch grains in thèse cells at this stage. 

 Active nuclear and cell division go on and the plane of division of the 

 cell is always in the long axis of the cell. Simultaneously with active 

 sécrétion and absorbtioii thèse cells multiply. Much has been ascribed to 

 the nucleiis as that part of the cell around which the activities center. 

 We hâve évidence however, that the cells in diverse stages of karyokenesis 

 still carry on ail the functions of sécrétion, digestion and assimilation. In 

 stages of préparation for nuclear division, for chromosomal séparation 

 and distribution, as one can see from Figure 112, there is apparently no 

 diminution in the activitity of the cytoplasm. In the epidermal cells 

 sécrétion undoubtedly goes on, and in the meristematic cells, even in the 

 ones where the chromosomes are seen in polar view of the equatorial 

 plate, and the equatorial plate, the cytoplasm and its starch grains do not 

 differ from the cytoplasm in the resting condition. 



The cells of the next two layers, the meristematic cells in contrast 

 with the outer layer of cells, show a much lighter staining cytoplasm. 

 This is immediately apparent when one examines a préparation even with 

 a low magnification. The inner cells differ form the outer cells also in 

 size, in form, and in the présence of starch grains. It is interesting to 

 note in thèse three layers — the absence of starch grains in the outermost 

 layer, the présence of many small starch grains in the second layer and 

 the présence of many large starch grains in the third layer. 



As the haustorium continues to grow the cells of the epidermis become 

 smaller, the cytoplasm less dense and the cells, beside carrying the function 

 of secreting enzymes for endosperm digestion, begin also to store up 

 countless numbers of minute starch grains. The dots within the cells of 

 the outermost layer shown in Figure 140, Plate XVII, show their relative 

 distribution. In Figure 142, which shows a row of those cells, they are 

 seen as small circles and in Figure 143 they are seen in greater magnifi- 

 cation. 



The présence of starch grains in the outer layer of the haustorium of 

 Elaeis is interesting in view of the absence of starch grains in this layer 

 in Plwenix as described by SACHS and by REED. In contrasting the two 

 cells, the one shown in Figure 112, Plate, XIII, with that of Figure 143, 

 Plate XVII, the modifications that hâve taken place are most significant. 

 The cell shown in Figure 143 was drawn from a stage where only half 

 of the endosperm had been absorbed so that there could be no question 

 of loss of function having taken place. Simultaneously with the sécrétion 

 of enzymes thèse cells carry on the synthetic process of starch formation. 



