EXPERIMENTS AND PRACTICAL WORK 55 



deposit shows that the soil contains mineral matter that 

 may be dissolved. 



(b) Hoots absorb Matter in Solution. Take up a small 

 plant carefully and put its roots into a vessel of water 

 coloured with red ink; after four hours' exposure to 

 sunlight, examine and note that the red ink has travelled 

 into the veins of the leaves; pull a portion of the bark 

 down and cut the stem across, observing that the ink 

 has travelled up the woody portion only. 



(c) Boots cannot absorb Particles in Suspension. Repeat 

 the foregoing experiment, colouring the solution with 

 carmine instead of red ink. In this case no colouring 

 matter will be absorbed, as the red of the carmine is due 

 to the small particles that are in suspension and not in 

 solution. 



Expt. 78. Plants get rid of the Surplus of Water by- 

 Evaporation through their Leaves. 



(</) Collection of Water evaporated from a Quango Tree. 

 On the morning of a sunn} 7 day insert a bunch of leaves 

 of a guango tree in a wide-mouthed bottle; tie the bottle 

 to the branch and tightly plug the bottle with a piece 

 of cloth or cotton wool. Examine in the afternoon and 

 pour out the water collected. 



(b) Collection of Water evaporated from a Cashew Tree. 

 Try the same experiment on a cashew tree, the small 

 leaflets of which are specially adapted to growth in a 

 dry district, and note that less water will be collected. 



(c) Plants unable to secure a Sufficient Supply of Water 

 will wilt. Examine the soil in which a growing plant is 

 wilting; note if it is dry or wet. 



(d) Leaves possess Small Openings (Stomata). Put a leaf 

 from any tree (e.g. sour-sop, orange) into hot water that 

 has only just ceased boiling, and note the air bubbles 

 due to the heated air escaping through the stomata. 

 The bubbles are chiefly on the under sides. 



