Some leaves on main limbs and subsequent main limbs of younger Nizisseiki pear trees trained by Momozawa-training type are thick, narrow and twisted and the shoots can't grow at serious time of abnormal leaves, but bigin to grow again at light serious time.
To find the causes of the appearance of the abnormal leaves, we analysed quantitatively N, P, K, Ca and reducing sugar content of the apex parts of shoots 7 times from April 30th to July 20th and analysed next year NH_3-N, protein-N and total sugar content in leaves which gathered on July 1st.
1, Water content in the current shoots of 4 years old trees is higher than that of 20 years old trees, but both water contents in leaves are scarcely differents.
2, N content in the current shoots of 4 years old trees is little higher than that of 20 years old trees, until the appearance of abnormal leaves, but N content in the leaves of the former is remarkably higher than that of the latter and the difference of the two decreases after appearance of abnormal leaves.
3, P content in the current shoots of 4 years old trees is little higher than that of 20 years old trees just before the apperance of abnormal leaves.
P content in leaves of the former is little higher than that of the latter from the appearance period of it till the recovery period.
4, K content in the current shoots of 4 years old trees is lower than that of 20 years old trees about early in May, but is higher than the latter just before the appearance of it and becomes afterward lower than that of the latter again.
K content in leaves of 4 years old trees is lower than that of 20 years old trees from April 30th till the appearance of abnormal leaves and the difference of the two becomes little after appearance of it. K content in leaves of 4 years old trees is rather higher than that of 20 years old trees after the recovery time.
5, Ca content in the currant shoots of 4 years old trees is little higher than that of 20 years old trees, but Ca content in leaves of the former is lower than that of the latter from the appearance time of abnormal leaves to the recovery time.
6, The total N content in the abnormal leaves on July Ist is higher than the normal leaves, and both protein-N and NH_3-N contents in the former are higher than the latter and especially NH_3-N content in the former is twice or 4 times as much as that of the latter. The total sugar content in abnormal leaves is remarkably lower than that of normal leaves.