4o Elementary Plant Physiology. 



showing the awakening growth of the spore and the various 

 stages leading to the formation of the green prothallus. 



33. Germination of pollen cells. Add one gram of 

 gelatine and four or five grams of cane sugar to fifty cubic cen- 

 timeters distilled water. Warm until a homogeneous solution is 

 obtained. Place a drop of this solution on a glass slip, and when 

 cold add a number of pollen cells from bursting anthers of Nar- 

 cissus, Fritillaria, Lathyrus, or Hyacinthus. Cover with a thin 

 glass slip, and set in a small moist chamber kept at the tem- 

 perature of a living-room. Examine eight or ten hours later 

 and on the following day. Make a series of drawings showing 

 the development and growth of the tubes sent out by the ger- 

 minating cells as seen under a magnification of 400 diameters. 

 (See "Practical Plant Physiology," p. 61.) 



34. Germination of grains of corn. Soak a number 

 of grains of Indian corn (Zea Mays] in water for twenty-four 

 hours, then imbed in a box containing moist sawdust, and keep 

 at a temperature of 16 to 20 C. for several days, to observe 

 the process of awakening growth. Reserve a few of the seeds 

 for dissection. Cut one of the grains in halves longitudinally 

 through the shortest diameter of the seed. Note the embryo, 

 which has been split in two parts, lying in the depression on 

 one side of the apical portion of the grain. A conspicuous 

 organ of absorption, the scutellum, lies in contact with the 

 starchy portion, or endosperm. Measure the young root seen to 

 be pointed toward the small end of the grain, and the plumule 

 extending in the opposite direction. Repeat the dissection 

 two days later, with a grain taken from the germmator. Con- 

 tinue the dissections daily, noting the development of the shoot 

 and root, and the action of the scutellum. Write out a de- 

 scription of the growth shown in sprouting. When the shoot 

 has attained a length of 3 to 6 cm., make a longitudinal sec- 

 tion through the entire plant. Note the origin of other roots 

 besides those arising from the extreme lower end of the stem. 



