LUTHER BURBANK 



ther fact that young vegetation, such as the buds 

 of trees in the spring, is very generally red in color, 

 the subsequent greenness being due to the devel- 

 opment of chlorophyll granules. 



Just why the chlorophyll granule is green is 

 of course only matter for conjecture. But it is obvi- 

 ous that this is the ideal color for this purpose, 

 otherwise it would not have been so universally 

 adopted. 



The presumption is that the plant finds it desir- 

 able to utilize the short rays of the upper part of 

 the spectrum and the long rays of the lower part — 

 those that stimulate chemical action chiefly, and 

 those that are the greatest conveyors of heat, re- 

 spectively — and that the intermediate rays pro- 

 ducing the color green are not needed, hence are 

 reflected or transmitted without influencing the 

 plant. 



A possible clew to the reason for this is found 

 in the supposition that the plant needs the short 

 light waves to enable it to carry out its chemical 

 function of transforming water and carbon into 

 sugar, and that this process is facilitated by hav- 

 ing the tissues warmed by the long waves of the 

 lower end of the spectrum. 



It has been calculated that the sun beating on 

 a leaf would raise its temperature to a point that 

 would destroy the protoplasm and kill the leaf 



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