Document: PET-3-33-1

Hormonal control of resource sharing in the clonal plant, Fragaria chiloensis.

ALPERT, P.*, C.HOLZAPFEL and J.M.BENSON

Univ. of Massachusetts, Amherst, MA 01003-5810 ¹

Abstract:
Rhizomatous and stoloniferous plants can increase their overall growth by redistributing resources such as carbon and nitrogen among connected, separately rooted plant units, or ramets. In many cases, ramets with relatively low access to resources import them from connected ramets, and resource sharing equalizes the performance of ramets. However, when ramets of Fragaria chiloensis, the beach strawberry, are rooted in patches with relatively high soil nitrogen availability, resource sharing can make the growth of connected ramets less equal; ramets with high nitrogen grow more, and ramets with low nitrogen grow less if they are connected. We hypothesized that hormonal direction of resource translocation is a mechanism by which clonal plants can concentrate resources in particular ramets in favorable microsites. To test this hypothesis, we applied IAA or cytokinin to the shoot apex of one ramet, fed ¹⁵N or ¹⁴C to a connected ramet, and measured ¹⁵N or ¹⁴C in the ramets, using mass spectrophotometry or autoradiography and scintillation counting. IAA increased the import of N by younger but not older ramets, and had no effect on translocation of C. Cytokinin had no effect on translocation of N. We conclude that auxin synthesis is a mechanism by which F. chiloensis can concentrate growth in young ramets in nutrient-rich microsites.

Keywords: Clonal plant, Fragaria, Hormone, Physiological Integration

This abstract is being presented at: 11:15 AM in session:
Oral Session #1: Plant Carbon Allocation.