Flower bud formation of chinese kale (Brassica oleracea L.var.alboglabra L.H. Bailey) under controlled temperatures

摘要

The effects of growing temperature on flower bud formation were investigated in Chinese kale (Brassica oleracea L.var.alboglabra L.H. Bailey); cultivars with white petals of ‘Hakushin', ‘Kairan-T', ‘Kairan-M', ‘Chugoku-kairan', ‘Shirobana-kuroba'and ‘Kairan-K', cultivars with yellow petals of ‘Chugoku-kairan (Y)' and ‘Kibana-kakurin'.The developmental process of flower bud in Chinese kale was divided into eight stages. Cultivars with white petals or yellow petals were grown in a phytotron. Flower bud formation of cultivars with white petal occurred earlier and at higher temperatures than that of cultivars with yellow petals. The number of nodes from cotyledon to flower decreased with exposure to low temperatures.When cultivars with white petals held 3.2-4.1 unfolding leaves, they were transferred to the phytotron rooms. ‘Hakushin', ‘Kairan-T'and ‘Kairan-M'formed flower buds at temperatures below 30 deg C, ‘Chugoku-kairan', 'Shirobana-kuroba'and ‘Kairan'formed buds at temperatures below 25 deg C. The number of nodes from cotyledon to flower decreased with exposure of low temperatures.These results indicated that cultivars with white petals have a quantitative cold requirment for flower bud initiation in response to low temperatures.