Title

Hydrothermal and thermal time models for the invasive grass, Arundo donax

Author Info

Anthony Graziani, California Polytechnic State University - San Luis ObispoFollow
Scott J. Steinmaus, California Polytechnic State University - San Luis ObispoFollow

Recommended Citation

Postprint version. Published in Aquatic Botany, Volume 90, Issue 1, January 1, 2009, pages 78-84.

The definitive version is available at https://doi.org/10.1016/j.aquabot.2008.06.003.

Abstract

Controlled laboratory and field experiments were performed to determine the developmental response to temperature and moisture of Arundo donax, a riparian invasive grass and potential bioenergy crop. A logistic function was parameterized and used to predict thermal times to sprouting and the nine-leaf stage. Consistent estimates of the base temperature (T_b) and base water potential (ψ_b) below which development ceases were obtained from various statistical and mathematical analyses. Estimates of T_b and ψ_b were 12.7 ± 1.7 °C and −1.56 ± 0.43 MPa, respectively, for the median fraction of sprouting rhizomes. Median hydrothermal time to sprouting was 124.1 MPa °Cd under laboratory conditions and median thermal times, or degree-day (°Cd), to sprouting and nine-leaf stage was estimated to be 94 and 129 °Cd under field conditions, respectively. A degree-day is defined as one day (24 h) spent one degree above T_b. Results demonstrated that thermal time alone is sufficient to accurately predict time to sprouting under field conditions. Further, there may be a fixed moisture threshold of about 6% volumetric water content above which sprouting rate was constant. This threshold corresponded very closely to the −1.5 MPa for ψ_b that was estimated under laboratory conditions for the soil typically infested by A. donax. This information is crucial for assessing risk of invasive spread for A. donax.

Disciplines

Biology

Copyright

2009 Elsevier B.V. All rights reserved.