Seasonal fluctuation of root carbohydrates in hybrid aspen clones and its relationship to the sprouting efficiency of root cuttings

Abstract

We examined the relationship between root carbohydrates and sprouting efficiency in four hybrid aspen ( Populus tremula × Populus tremuloides ) clones. Our hypothesis was that the interclonal variation in sprouting efficiency is due to the concentration of carbohydrates. In addition to that relationship, we wanted to study seasonal fluctuation of carbohydrates and how the –18 °C storage conditions of stock plants affects the stability of carbohydrate content and thus sprouting ability of roots cuttings. Clones varied in root carbohydrate content, and sucrose showed the greatest variation throughout the year. Sucrose levels were highest in the clone with the highest sprouting efficiency and lowest in the clone with the lowest sprouting efficiency. Carbohydrate concentrations were highest in winter and lowest in early autumn. In general, root cuttings sprouted most efficiently when root carbohydrate levels peaked. Although root cuttings taken from frozen (–18 °C) stock plants sprouted poorly in summer and autumn, they had high and almost constant carbohydrate concentrations throughout the year.