1978 Volume 46 Issue 4 Pages 449-456
The relationship between the levels of nutrients and the various degrees of the disordered fruit of Nijisseiki pear, were studied by chemical analysis of the fruits. The results obtained are as follows:
1) Phosphorus content increased while total nitrogen and calcium contents tended to decrease as the disease progressed. It seemed that this physiological disorder became apparent when calcium content fell to a level of 0.047% or less, based on dry weight.
2) The amounts of total sugars, reducing sugars and fructose in affected fruits were lower while the amounts of glucose and starch were higher than those in normal fruits. In particular, fructose content showed a remarkable change proportionally with the degrees of disorder, but glucose content increased only slightly.
3) A significant positive correlation was observed between total nitrogen content, and total sugars, and reducing sugars or fructose contents, between calcium content, and total sugars or fructose contents, whereas a significant negative correlation was found between total nitrogen content, and glucose or starch contents, between calcium and starch contents. No correlation was found between calcium and glucose contents.
4) From the results of principal component analysis and multiple regression analysis, it is concluded that the degree of ‘yuzuhada’ disorder is characterized by a decrease in calcium absorption accompanied by changes in sugar composition in affected fruit. In particular, fructose content is remarkably lower for affected fruits than for normal ones.
