Factors influencing flower bud formation on the pear tree cultivar 'Doyenne du Comice'. III. Saccharides, nitrogen compounds and some mineral elements contents in pear leaves and shoots

Abstract

Long shoots inhibited in growth by treatment with chlormequate contained more reducing sugars in mid July than did the control ones growing vigorously. Storage starch accumulation was earlier in the former shoots than in he control ones, and they also contained more nitrogen compounds, especially protein, and significantly more calcium, magnesium, iron and zinc then the controls. Comparison of long shoots with growth partly inhibited by the action of chlormequate, on which flower buds form in the subapical part, and of spurs on which an apical flower bud forms, with the long shoots of control vigorously growing trees where flower buds do not form, indicates that initiation of flowering in the pear tree is associated with a high level of storage compounds, both organic and inorganic, in the stem.