Articles
CARBON AND NITROGEN STATUS OF FLOWER-INDUCED STRAWBERRY AS REVEALED BY 13C- AND 15N-TRACER STUDIES
Strawberry (cv. ‘Toyonoka’) plants were grown under flower-inductive conditions (low temperature + short photoperiod) or non-inductive conditions (high temperature + long photoperiod). On the 15th day, 15N was applied as a solution of KNO3. 13C-labelled carbon dioxide (13CO2) was fed at a constant concentration for 6 hours in an assimilation chamber on the 17th day, when the flower buds were induced under flower-inductive conditions.
Plant samples were harvested immediately after and 24 hours after 13C feeding.
The 13C and 15N abundances were analyzed with an ANCA-SL mass spectrometer.
In flower-induced plants, slightly more C was allocated to roots, and less C to young leaves and petioles than in non-induced plants.
In contrast, more N was allocated to shoot apices, crowns and roots of induced plants than those of non-induced plants.
From a central part of a crown, 1.8mm-thick sections were cut in vertical direction to analyze the location of contents and allocation of 13C and 15N within a crown.
In the crown of flower-induced plants, more 15N was allocated to the shoot apex and the upper part of the crown, while the allocation gradient of C was not affected by the treatments.
These results suggest stimulation of N metabolism in shoot apex and crown in induced plants and little contribution of recently assimilated carbohydrates to the flower induction process.