@article{oai:soar-ir.repo.nii.ac.jp:00010907, author = {熊代, 克己}, issue = {4}, journal = {信州大学農学部紀要}, month = {Dec}, note = {1. In the Ina district of Nagano Prefecture, Nijisseiki pear trees usually develop abnormal leaves (so-called Ijoyo) when their terminal shoots are left to grow vigorously about two years afetr planting without being cut back in Momozawa's training system. Once the abnormal leaves develop, they also appear successively in the following years. The growth and yield of the disordered trees are considerably reduced. The disorder develops also in the other districts when Nijisseikj pear trees are grown in the same training system. The purpose of this experiment is to study the symptoms, processes or causes of development, and treatments or control measures of the disorder. 2. The abnormal leaves are glabrous, narrow, thick and brittle, showing a mosaic mottling. They have one or two more cell layers than the normals, namely, one or two more epidermis-like layers in the light green part and one more palisade layer in the dark green part, though their conductive tissues and number of chromosomes are normal. The distribution of abnormal leaves on a disordered shoot is limited to a range of from the middle to the upper parts, and several normal leaves exist on the basal part. The disordered shoots are somewhat stunted and of faint russet stripes. The fruits which bear on them are inferior in the transverse growth, the skin of which partially lacking dots and often having irregular stripes on the surface though the dessert quality of which being generally normal. 3. The longer the shoot growth more than 115 cm on an average, the higher the percentage of disordered shoots which sprout newly in the following year. The location of buds which would develop the disordered shoots in the following year is restricted to the top of the vigorous shoots. Therefore, it is recommended for the growers to cut back the vigorous shoots at their tops during the dormant period. 4. In any variety other than Nijisseiki, none of abnormal leaves develop even when the shoots grow vigorously under Momozawa's training system. The development of the disorder in the Nijisseiki pear trees has no connection with an individuality of mother tree of scions, or with a variety of stocks and interstocks. 5. Even when the sap of abnormal leaves is inoculated to normal leaves of the same variety or other species, none of abnormal symptoms appear on the treated leaves. When the scions taken from the disordered shoots are top-grafted on the normal shoots, the newly sprouted shoots from the scions in the following year are all disordered, while those from the interstocks are all normal. On the contrary, when the scions taken from the normal shoots are top-grafted on the disordered shoots, the newly sprouted shoots from the scions in the following year are all normal, while those from the interstocks are all disordered. The newly sprouted shoots from the disordered scion are all disordered at least for three years successively, but, thereafter, normal shoots will sprout occasionally from the old parts of the scion. The hybrid progeny of the disordered Nijisseiki pear trees never shows any abnormal symptom. 6. By leaf analysis of the vigorous shoots from the tops of which the disordered shoots are expected to grow, it is evident that leaves at their terminal part contain more N, P, Mg, Mn and Zn, and less K and Ca than those at their middle part. Furthermore, the abnormal leaves contain less N, K, Ca, Mg, Fe, Mn, Zn and B, and more P than the normal leaves on the same tree. However, no deep relationship can be found between either application of N, P, K, Zn or B and the development of the disorder. Only when slag which contains lime, silica, magnesia and many other trace elements is applied, the development of the abnormal leaves seems to be slightly reduced. 7. Auxin content is lower in the terminal part of the disordered shoots than in that of the normal shoots, the difference being greatest in late May when abnormal leaves begin to appear on the disordered shoots. Sprays of IAA, GA or TIBA to the vigorous shoots have no influence on the development of the disordered shoots in the following year. Sprays of B995 to the vigoros shoots retard geartly their growth, which result to be very effective to reduce the development of the disordered shoots from their tops in the following year. 8. When the normal Nijisseiki pear trees are grown in a glass-house, none of abnormal leaves develop regardless of the training system, and when the disordered Nijisseiki pear trees are transplanted in a glass-house, their restoration is much promoted. Otherwise, covering them with the Filon (plastics with glassfiber) or oil paper gives a similar effect to them, while covering them with black cheese cloth, vinyl film or polyethylene film never produces the same result. These facts suggest that the development of the disorder might be closely related to the radiation of ultraviolet shorter than 310 mp which can not pass through a glass, Filon and oil paper. Defoliation of the vigorous shoots at their tops in summer when is the season of the strongest radiation of ultraviolet reduces thedevelopment of the disorder in the following year. 9. The abnormal leaves on the disordered shoots contain polyphenol more abundantly than the normal leaves on the same shoots or the normal ones. The terminal leaves of the vigorous shoots contain polyphenol more quantitatively than those of shoots of normal vigor. The isoelectric point of suspension of the terminal leaves of the vigorous shoots is comparatively low as same as that of the abnormal leaves on the disordered shoots., Article, 信州大学農学部紀要 4(4): 332-395(1967)}, pages = {332--395}, title = {二十世紀ナシの特殊整技法における異常葉の発生に関する研究}, volume = {4}, year = {1967} }