Effects of the Duration of Cold Storage on the Growth and the Quality of Cut Flowers of Forced Tree Paeony(Paeonia suffruticosa Andr.)

Abstract

The present study was undertaken to establish forcing system for tree peony. Flower bud differentiation and development in tree peony was observed, and the effects of duration of cold storage on flowering time and quality of cut flowers of forced tree peony were investigated. The differentiation of leaves was finished and the differentiation of petals began Aug. 27. Stamens in a few sample plants and pistils in the majority of sample plants were forming on Sept. 27 and Oct. 18, respectively. As the storage at 0.degree. C was prolonged, the sprouting and flowering became earlier. The number of days and cumulative temperature from sprouting to flowering differed little with the duration of 3 cold storage treatments, within 5-7 wk. The flowering percentage was highest after 5-wk storage and lowest after 7-wk storage. The weight of cut flower and the number of petals did not differ significantly with the storage duration. Flower diameter was increased and leaf area decreased with shortened duration of cold storage. Development of lower leaves tended to be suppressed. Cut flowers looked well-balanced and were superior in figure after the trees were chilled 6-7 wk. The stage of flower bud development before cold storage and the temperature and duration of cold storage have a great influence on the flowering time, flowering percentage and the quality of cut flowers of forced tree peony.