290 



Mineral Nutrition of Plants 



TABLE V 



Average Leaf Number, Leaf Color, Leaf Size, and Shoot Length of Representa- 

 tive One- Year-Old Terminal Growths from Two Mcintosh Apple Orchards 

 Under Differential Nitrogen Fertilization in 1948 



alcohol extracts of leaf disks. Leaf size is easily and accurately deter- 

 mined by measurement of length and width and by reference to con- 

 version tables previously prepared. These measurements may be rated 

 on the basis of reference groupings like those in Table VI. 



Terminal growth of shoots and development of leaves in number 

 and size are determined to a considerable extent by the food reserves 

 in the tree at the beginning of the growing season. Leaf color, on the 

 other hand, reflects more closely the nitrogen supply in the tree at the 

 time of observation. Thus, evidence of the effects of food reserve and 

 of the current nitrogen supply may be obtained from these four 



TABLE VI 

 Tentative Growth Standards for New York Mcintosh Apple Shoots and Leaves 



