Plants as Mosaics: Leaf-, Ramet-, and Gender-Level Variation in the Physiology of the Dwarf Willow, Salix arctica

Plant ecophysiological investigations often fail to account for age-specific, tissue-or organ-specific, or life-history-specific effects on overall performance. To address this issue, aspects of gas exchange and water relations of a deciduous and dioecious dwarf willow, Salix arctica, were examined. The degree of physiological variation that occurred as leaves aged was investigated, within and among vegetative and reproductive ramets of a plant's canopy, and between the sexes. Significant differences were observed in rates of photosynthetic carbon assimilation, dark respiration and stomatal conductance, as well as in bulk tissue water relations of leaves at different ages, between reproductive and vegetative ramets within an individual, and between male and female individuals (...)