SEEDS AND SEEDLINGS in 



The parts of the seedling. Root up a bean plant on which the char- 

 acteristic bean leaves begin to appear plainly and sketch it, labeling the 

 following parts: (a) cotyledons, (5) plumule, now expanding into what? 



(c) stem, (d) taproot, (e) secondary roots. 



Soak several lima beans overnight. Open one, remove one cotyledon, 

 and make a diagram to show (a) seed coat, (b) micropyle, (c) chalaza, 



(d) hilum, (e) cotyledon, (/) hypocotyl (how is it related to the micropyle ?), 

 (g) plumule. What constitutes the embryo ? 



Study the pine seed, the castor bean, soaked kernels of corn, pumpkin, 

 and pea; diagram each (enlarged) to show the parts. There are two seed 

 coats present in some of these (testa and tegmen). The material packed 

 around the embryo in the corn is called " endosperm." Keep in mind what 

 you have seen in the growing seedlings as you try to interpret what you see 

 in the seed. How does the sunflower plantlet get rid of its seed coats? 

 Describe the method here. See and sketch the special device of the pump- 

 kin plant for tearing off the seed coats. 



7. Plant food in seed. Put a little starch into a test tube, fill the latter 

 one-quarter full of water and shake it. Add a drop of chloride of zinc 

 solution; note the color. This is a characteristic test for starch. Cut the 

 coat from a dry corn kernel and scrape, testing the scrapings with iodine 

 in the same way. State your conclusion. 



8. Take the "meat" out of a Brazil nut, cut it in half, stick one-half on 

 a knife blade or hatpin and light the cut surface. How long will it burn ? 

 Lay the other half, cut face down, on a piece of paper. These experiments 

 show what ? Put a pea on the end of a hatpin and hold in a flame to burn 

 it. Notice the odor. It smells like what ? 



9. As soon as bean plants are up far enough cut one cotyledon from one, 

 two from the second, and leave the third with both cotyledons on. Keep a 

 record of the rate of growth. Thus: 



At the end of ten days No. i is inches high and its largest 



leaf is inches long. No. 2 is inches high and its 



largest leaf is long. No. 3 is inches high and its 



largest leaf is. long. 



From these last experiments what do you conclude? State your 

 conclusions. What use does man make of the facts you have just 

 stated ? 



Read up on the structure of a grain of wheat and diagram it here to 

 show where the chief food substances are located in the grain. Do the 

 same for a kernel of corn. 



The process of food manufacture in the plant, after the supply stored 

 in the seed is exhausted, is made plain by the following experiments : 



