Seasonal difference of soluble carbohydrate metabolism in incurved malformed flowers of cut rose cultivar 'Yves Piaget'

摘要

Rosa xhybrida 'Yves Piagef is a fragrant cut rose cultivar that sometimes bears malformed flower designated as 'incurved flowering'. This 'incurved flowering' is characterized by adaxial curving of the petals, however its physiology is not clear. Theflower was harvested at three different flowering stages: stage 1, tight bud; stage 2, mature bud; stage 3, five opened petals. Their petals were separated into two parts; edge part including the petal periphery and other part including the petal base. The petal fresh weight and growth rate were measured and calculated. Ten outer petals were used to analyze soluble carbohydrate content by HPLC, and acid invertase activity. This experiment was conducted from April to June in 2017 (spring) and December toMarch in 2018 (winter). In winter, acid invertase activity of malformed flower was higher at stage 2 than normal flower, but tended to be lower at stage 3 than normal flower. However, at stage 3, growth rate in the edge of malformed flower petals was decreased. In spring, acid invertase activity of malformed flower was lower at all stages than normal flower. Because of the low invertase activity, it is possible that the hexose content at the end of the malformed flower petals have become lower than instages 2 and 3 of the normal flower petals. Thus, at stage 3, the growth rate at the end of the malformed petal may have decreased. Our results indicate the cause of 'incurved flowering' is different in winter and spring.