Ott, Jacqueline P , Hartnett, David C. .
Belowground bud morphology, production, and dynamics of a C3 and a C4 perennial grass.
Annual regeneration and sustainability of perennial grass populations rely heavily on the belowground population of meristems (the bud bank), yet the dynamics, morphology, and population sizes of grass bud banks have not been explored. C3 grasses grow before and after the hottest months of the summer whereas C4 grasses maintain a single warm-season growth period. In the C3 grass Dichanthelium oligosanthes, flowering tillers develop from dormant buds during its spring growth period, and smaller vegetative tillers emerge during its fall growth period. A complete turnover of tillers occurs when the spring tillers senesce in early autumn and are replaced by photosynthesizing fall tillers. D. oligosanthes maintains buds in various stages of development throughout the dormant season, while the C4 grass, Andropogon gerardii, maintains synchrony in bud development and dormancy during the winter months. However, A. gerardii keeps a greater quantity of buds per parent tiller than D. oligosanthes during the dormant season indicating interspecific differences in bud production. A. gerardii and D. oligosanthes differ in bud morphology and arrangement. The yellow-white glabrous dormant bud of A. gerardii is encased by a single scale with strigose margins which splits open abaxial to the parent tiller while the smaller white-pink bud of D. oligosanthes initially forms without a distinctive scale but eventually develops a hirsute surface. Although the buds of both species are closely associated with parent tillers, D. oligosanthes buds are arranged in a radial form around the central parent tiller while A. gerardii buds are arranged in two linear columns growing along opposite sites of the parent tiller. As sessile modular organisms, variation in the placement and demography of plant parts determines grass growth form and architecture and is key to understanding their population dynamics, interactions, and responses to environmental change.
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1 - Kansas State University, Division of Biology, 104 Ackert Hall, Manhattan, KS, 66506, USA
C3 and C4 grasses
Presentation Type: Oral Paper:Papers for Sections
Date: Tuesday, July 29th, 2008
Time: 2:45 PM