Seasonal patterns of starch and sugar accumulation in herbaceous peony (Paeonia lactiflora Pall.)

Peonies are popular garden plants and have been grown for their attractive flowers for many years. Peonies grown for cut flower production are generally derived from the herbaceous species Paeonia lactiflora Pall. As this plant is deciduous and Winter dormant, the carbon required for the initial flush of growth in Spring can only be supplied from reserves stored in the roots. We are interested in the dynamics of carbon supply and demand in peony plants. Consequently, the aim of this paper was to identify and quantify the non-structural carbohydrates found in peony plants, and to describe their seasonal dynamics in relation to overall plant growth and development. The major sugars detected in peony plants, in order of decreasing concentration, were: fructose, glucose, sucrose and myo-inositol. The main storage carbohydrate was starch. Starch accumulated in flower buds throughout their development, to a maximum concentration immediately before flower opening (approx. 54 d after shoot emergence) and declined during flower opening. Starch concentrations in the roots declined with the resumption of growth in Spring, but began increasing again within 45 d of shoot emergence, and continued to increase throughout flowering until mid-Summer, when they again declined with the onset of cooler temperatures. The ability to grow quickly and to flower, while simultaneously accumulating starch reserves in the roots, may provide a significant adaptive advantage for peonies, allowing them to survive the vagaries of climate and herbivory, particularly in environments with short growing seasons. This may explain, in part, why the genus Paeonia is geographically so widespread.