Cheplick, Gregory .
Reproductive allocation in the invasive cleistogamous grass Microstegium vimineum.
Allocation to chasmogamous (CH) and cleistogamous (CL) reproduction was investigated in the highly invasive,
summer annual Microstegium vimineum in relation to light conditions. This shade-tolerant grass weed of Asian
origin forms dense populations in the understory of moist deciduous forests in eastern North America. Each
flowering tiller produces one terminal raceme with CH spikelets and 2 to 7 sheath-enclosed axillary racemes
with CL spikelets at the uppermost nodes. In a greenhouse, plants were reared from seeds collected from
subpopulations of shady (2 to 8% full sun) or sunny, edge habitats. At maturity, tillers of plants from the shade
subpopulation showed greater allocation to leaves, but reduced allocation to CH and CL, compared to those
from the sunny subpopulation, suggesting adaptive differentiation to light conditions in the field. For tillers
collected directly from the field habitats, allocation to CH and CL was lowest, and allocation to leaves was
greatest, in deep shade. CH and CL allocation averaged 16% and 11%, respectively, in the sunny habitat, but
only 6% and 7%, respectively, in the shady habitat. There was no evidence of a trade-off in allocation to CH vs.
CL in field-collected or greenhouse tillers. The ability to grow and allocate limited resources to seed production
in CH and CL spikelets under deep shade where other herbs are uncommon, is crucial to the ecological
success of M. vimineum as an aggressive colonizer of disturbed forests.
1 - College of Staten Island, City Univ. of New York, Department of Biology, Staten Island, New York, 10314, USA
Presentation Type: Poster
Location: Special Event Center (Cliff Lodge)
Date: Tuesday, August 3rd, 2004
Time: 12:30 PM