PARENT SESSION
Poster Session 12: Physiology
Tuesday, August 9, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Resource dynamics for shoot recovery during the growing season in temperate tree seedlings.
Sakai, Akiko*,1, 1 Yokohama National University, Yokohama, Japan
ABSTRACT- Although plants sometimes reserve resources in roots for shoot recovery in highly disturbed areas, such function of root has not yet been fully studied in temperate trees. Quercus species usually have a disproportionately large tap root, and previous studies suggest that it relates high sprouting ability. In this study, I conducted cutting experiments in May, June, July and August for three-year old Quercus serrata seedlings. All current shoots were removed and shoot recovery process was investigated with dynamics of total non-structural carbohydrates (TNC). Intact seedlings allocated considerably large amount of resources to root: it had 40 - 60% of whole plant biomass and contained 20% of TNC when the initial leaf-flash was completed in May. Root TNC concentration abruptly increased from May to June and retained high level, i.e., 30 - 50%, during the growing season. Above ground biomass strongly correlated with structural part of roots rather than whole root biomass, suggesting TNC had a function that was not directly related to the ordinal growth. Once a seedling was cut, root TNC dramatically decreased: it diminished to ca. 25% of the initial level one month after, while structural part of root did not markedly change. Almost seedlings sprouted new shoots during the first month, and its dry mass could be explained with the root TNC at the time of cutting, indicating the high content of TNC is for shoot recovery after disturbance. Recovery rate in biomass depended on the cutting time and light condition, and best performed seedlings, cut in June at an open site, showed 60 % dry-mass of the intact seedlings. Nevertheless, all seedlings tended to complete recovering root: shoot ratio to the intact level at the end of the season, and TNC restoration was also finished for the seedlings cut in May or June. These suggest that Q. serrata seedlings advance resource re-allocation not only for subsequent growth but also for risk-control in terms of repeated loss of shoots.
Key words: tree sprouting, total non-structural carbohydrate, Quercus serrata, re-allocation strategy