138 



FUNDAMENTALS OF FRUIT PRODUCTION 



From the data available it is impossible to say how much of the nitrogen of 

 the trunk is stored and how much is a permanent part of its tissues. Hence any 

 attempt to calculate the amount taken up yearly from the soil would be guess- 

 work. However, it is interesting that in a 30-year old tree, two-thirds as much 

 nitrogen goes into the crop as falls with the leaves and the amount used for new 

 growth is insignificant in comparison. 



Similar relationships hold for fruits other than the apple as Table 22 shows. 



Table 



-Pounds of Nitrogen in Parts of a Full Grown Tree'^" 



Apple 



Peach 



Pear 



Plum Quince 



Fruit or fruit pulp 



Stones 



Stems 



Leaves 



New growth 



0.09 



0.09 

 0.01 



The data presented in Table 23 show the nitrogen contents of various fruits. 



Table 23 



Almonds 



Apricots 1 . 94 



Apples 1 . 05 



Bananas 0.97 



Cherries 2.29 



Chestnuts 6.40 



Figs 2.38 



Grapes 1.26 



Pounds of Nitrogen in 1,000 Pounds of Fresh Fruit^^ 



7.01 Lemons 1.51 



Olives 5.60 



Oranges 1 . 83 



Peaches 1.20 



Pears 0.90 



French primes 1 . 82 



Plums 1.81 



Walnuts 5.41 



PHOSPHORUS 



It has been pointed out that the nitrates absorbed by the roots 

 probably are carried to the leaves and there elaborated into organic nitro- 

 gen-containing compounds. Though there is no direct evidence to show 

 where the elaboration of inorganic phosphates to organic phosphorus- 

 containing compounds takes place, the remarkable similiarity that exists 

 between the variations in nitrogen and in phosphorus content of practi- 

 cally all tissues, suggests that phosphorus, like nitrogen, is elaborated for 

 the most part in the leaf. 



Synthesis of Phosphorus-containing Organic Compounds. — The 

 amount of phosphorus assimilated is stated to be closely related to the 

 amount of illumination ^^^ the plant receives and appears to be connected 

 with photosynthetic activity. Red and yellow light have been found 

 more effective than blue or violet in promoting phosphorus assimilation. ^^^ 



Wherever phosphorus is found in organic combination it exists as 

 phosphate. Thus it occurs in nucleic acids, nucleins and nucleo-proteins 



