Publication
Modules of reproduction in females of the dioecious shrub Oemleria cerasiformis
Publisher:
Canadian Science Publishing
Date:
03-2004
DOI:
10.1139/B04-018
Abstract: Plants are composed of modules that may be integrated to varying degrees. To examine the extent of integration for photosynthate in female Oemleria cerasiformis (H. & A.) Landon at different times during reproduction, we defoliated terminal branch systems at two scales (0.25 and 1.0 m) just after flowering. Fruit set and mass in the current year were unaffected by defoliation, indicating that developing fruits were strong sinks that could effectively draw on photosynthate from leaves at least 1 m away. In the subsequent year, however, defoliated branches grew very little and produced few flowers and almost no fruits, indicating that storage, growth, and the initiation of flowers and fruit did not utilize carbon resources from leaves only 0.25 m away. Thus, there is no single module size for photosynthate in O. cerasiformis. Because fruits are a strong sink that can draw carbon resources from a considerable distance, high fruit set followed by adverse conditions can lead to generalized resource depletion within a plant, which may result in mortality and contribute to the male-biased sex ratios often observed in O. cerasiformis.Key words: costs of reproduction, defoliation, fruit set, fruit mass, integrated physiological units.