CHAPTER VIII. FRUITS 

 I. HORTICULTURAL AND BOTANICAL FRUITS 



Material. — Green ears of corn or wheat, fresh pods of beans, young 

 fruits of apple, grape, tomato, melon, buckeye, chestnut, or pecan. A 

 young fruiting stem of squash, gourd, or tomato. 



Appliances. — Coloring fluid, glasses of water, a piece of cardboard, 

 tin-foil, vaseline. 



Experiment 87. Where do the food substances contained in 

 FRUITS COME FROM ? — Apply your food tests to the pulp of a young apple, 

 squash, bean pod, chestnut, buckeye, or a "green" ear of corn or wheat, 

 and see what it contains. Te.st the stem and roots of a plant of the same 

 kind in the same way. Do you find the same foods in them? Where 

 is the food stored? 



Experiment 88. Through what parts of the stem and fruit do 



WATER AND NOURISHMENT TRAVEL TO THE SEED ? — Cut a yOUUg Squash 



or cucumber from the vine, leaving stem enough to insert by its cut end 

 in a glass of eosin solution. Leave for two or three days, then make a 

 vertical section through the stem and fruit. What course has the liquid 

 followed ? Can you trace some of it into each seed ? Do you see now a 

 use for the seed stalk and the rhaphe ? 



Experiment 89. Does the surface of fruits give off water by 

 TRANSPIRATION ? — Try Exp. 39, using in place of leaves a young squash, 

 eggplant, or a bunch of grapes, and after a day or two notice whether 

 any moisture has been given off. If the fruit skin gives off moisture, 

 it is natural to expect that it would be provided with stomata, like other 

 transpiring organs. To find out whether this is so, place a thin piece of 

 the outer epidermis of a grape, tomato, plum, or apple under the micro- 

 scope. Do you find stomata on any of them ? Do you see anything else ? 

 Try the skin of an apple, and compare the corky dots you find there with 

 those on the bark of a young dicotyl stem (118) and decide what they are. 



Experiment 90. Will fruits ripen well in the absence of light 

 AND AIR ? — Envelop a number of immature fruits in bags of dark cloth 

 or paper so that no light can reach them. Keep a number of others well 

 coated with oil or vaseline, and watch. Do the fruits so treated mature 

 as quickly or develop as fully as those of the same kind left untreated ? 



250 



