CLIMATE AND PLANT GROWTH. 



55 



Furthermore, the curve representing these percentages bears an 

 intimate agreement with both of the temperature summation curves. 

 This increased conservatism in the use of water in wheat leaves may, 

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— — ' Temperature cttoi/e 4-0" 



— Water requirements- per mm. L eafL enqth ( Wheat) 



P/7ys/o/oqica/ Temperature Efficiency 



— — — Water requirements permm.LeafLer?qfh(Brome-qrass) 



Fig. 30. — Water requirements per unit (1 mm.) of leaf length of brome grass and wheat. 



in a way, account for the high yielding qualities of wheat, other 

 conditions remaining the same, in regions where the summers are 

 relatively cool. 



