Inherent allocation patterns and potential growth rates of herbaceous climbing plants
den Dubbelden KC; Verburg RW
Plant and Soil
We tested the hypothesis that herbaceous climbing plants unlike non-climbing herbs maximize height growth and leaf area with minimal expenditure in support structures. The enhanced investment in leaf area was expected to result in high relative growth rates in terms of biomass increment.\n\nFour leguminous herbaceous climbers from nutrient-poor sites and four non-leguminous herbaceous climbers from nutrient-rich sites were compared with non-climbing self-supporting leguminous and non-leguminous herbaceous species from similar habitats. Plants were grown in hydroponic cultures in controlled environment chambers.\n\nAll climbers had inherently taller shoots than self-supporting plants when compared at an equal amount of total plant dry weight due to longer stems per unit of support biomass. In contrast to the hypothesis the relative growth rates of all climbers were relatively low compared to the range found for self-supporting species. The biomass allocation patterns of the non-leguminous climbers were similar to those of the self-supporting species. Leguminous climbers allocated more biomass to support tissue and less biomass to leaves than non-climbers. As a result height growth was even more emphasized in leguminous climbers than in non-leguminous climbers. Climbing legumes had high rates of net carbon gain which partly compensated the lower relative leaf weight.\n\nWe conclude that leguminous herbaceous climbers maximize height growth by a large investment in support biomass enabling them to keep a large proportion of their leaves in the better illuminated environment at the top of the vegetation canopy.