Use of Breathing 



it is the loore rapidly does breathing occur. It goes 

 on night and day, and rises with every increase in 

 temperature until the heat is too great for the plant 

 to sustain. By it the plant obtains the energy 

 stored up in its food, and is thus enabled to perform 

 all its other functions. Without it aU activities cease, 

 and after a time death ensues. It becomes active 

 with the moistening of the seed ; it finally ceases 

 only with the death of the plant. Any interference 

 with free breathing results in lowered efficiency 

 and in iU-health. 



~" The part of the plant most likely to suffer in 

 cultivation is that which is underground. Few 

 cultivated plants are able to obtain sufficient oxygen 

 from water, and the soil cannot, when saturated with 

 water, hold enough air to supply these parts, and it 

 is upon this fact that the value of good drainage 

 depends ; and to the interference with root-breathing, 

 the evil practices of over-watering and of standing 

 plants for long periods in saucers of water owe their 

 bad results. The breathing of the stem and leaves 

 is, as a rule, only likely to be interfered with when 

 something is deposited on the leaves which tends to 

 choke the openings through which the gases pass. 



Before passing to a brief consideration of the 

 special functions of the various parts of the plant, 

 the part temperature plays in plant life may be 

 alluded to. The performance of every function of a 

 plant is more or less dependent upon temperature, 



5 



