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(c) Cover the upper and under surface of a part of a leaf with a 



piece of cork and place in sunlight. Next day remove cork 

 and test leaves for starch. 



(d) Give a reason why the upper surface of leaves is always 



turned to the light. Note shape and arrangement of leaves 

 with relation to sunlight. 



GROWTH OF PLANTS. 



1. Growth of Roots. 



(a) Germination. 



Soak peas, beans, corn, squash, pumpkin, etc., for twelve 

 hours; place between folds of paper or cloth; keep moist and 

 warm. 



(b) Pumpkin. 



When radicle or first root is a quarter of an inch in length; 

 beginning with the tip, mark off sections one-sixteenth of an 

 inch in length. Keep moist and warm. Determine the 

 growing part of root. 



2. Growth of Stem. 



Embryo develops into root, stems and leaves. Nodes are enlarge- 

 ments at the juncture of the leaves with the stem; internodes, spaces 

 on stem between successive nodes. 



(a) Use a bean or corn seedling. Mark off several internodes into 

 sections one-sixteenth of an inch apart. Note region of 

 greatest elongation. Compare growth of root and stem. 



IRRITABILITY. 



1. Influence of Earth on Direction of Growth. 



(a) Pin germinating peas, beans, or squash seeds marked off as 



above, on a large cork in such a position that one may be 

 horizontal, one in a normal position, one in inverted posi- 

 tion. Keep moist and warm. What changes do you ob- 

 serve? What is the region of greatest activity. 



(b) Remove tip of roots of other seedlings and place on corks as 



above. Contrast the two experiments. 



(c) Turn pot containing germinating seedlings over on the side. 



Note effect. 



2. Influence of Light. 



(a) Plant seeds in dark, shade and light. 



(b) 'Subject seedlings to one sided illumination. 



(c) Put growing seedlings in a dark chamber with small opening. 



