34 LABORATORY AND FIELD EXERCISES 



f. Drawings of cells characteristic of each root zone. 



(1) Select a small group of about three cells from each 



zone of the root, and outline each cell group on 

 the same scale as that shown in Fig. 11. 



(2) Fill in the details of cytoplasmic and nuclear struc- 



ture in a group of cells of the rootcap, meristem, 

 and elongating and permanent zones. Indicate 

 clearly the growth of vacuoles and the origin of 

 the cytoplasmic sac incident to growth. See 

 Fig. 11 for the proportionate size and form of 

 cells in the main zones of the root. 



3. Elongation. Read the discussion in the text on the method 



of elongation of the root by cell division and growth. 

 Summarize the facts relating to the cellular growth of 

 the root in length. 



4. Structure and growth of buds. 



a. Structure of buds. Review the parts of the bud of the 



lilac as seen from the exterior. Cut median vertical 

 long sections of buds and study the cut surface with 

 a hand lens. 



(1) Determine the parts of the bud and their relation 

 to each other. Is there an apical meristem as in 

 roots? Observe the relation of leaves to nodes 

 and internodes. If prepared slides are available, 

 observe the cellular structure of the above por- 

 tions of a bud. Make an accurate drawing of a 

 long section of a bud and compare it with that 

 of roots. See Figs. 37 and 40 of the text. 



b. G-rowth of buds. Observe buds which are expanding 



in growth. (Preserved material may be used if fresh 

 is not available.) What is the general method of 

 elongation ? Is the elongating zone in buds a con- 

 tinuous product of the meristem, as in the root ? Is 



