BayCEER Workshop 2019
October 10, 2019
NW III, University of Bayreuth
Annuals do not only escape, but also withstand drought: Insights on the mechanisms underlying differential drought resistance in winter annual species
2 Plant Ecology Group, Institute of Evolution and Ecology, University of Tübingen, Auf der Morgenstelle 3, 72076 Tübingen, Germany
3 Department of Agriculture and Natural Resources Sciences, Namibia University of Science and Technology (NUST), 13 Jackson Kaujeua Street, Private Bag 13388, Windhoek, Namibia
O 1.2 in Plant and soil responses to drought: Interdisciplinary approaches and views
10.10.2019, 11:30-11:45, H36, NW III
Introduction
Annual plants substantially contribute to the biomass production and livelihood security in semi-arid rangelands. These areas are characterized by drought periods, which are projected to increase with climate change and might affect the stability of these ecosystems.
The assessment of plant responses to climate change relies on the knowledge of species’ drought response strategies. However, this knowledge is almost missing for annual species. Annuals complete their life-cycle within one year and therefore are commonly considered to escape drought in time by an early onset of reproduction and seed dormancy. Drought response strategies at the plant level, such as tolerance to maintain function even at low tissue water potentials, or avoidance to reduce desiccation by early stomata closure and efficient water-use, should also be beneficial, but remain almost unexplored. Therefore, we investigated drought response traits and their influence on species’ fitness response to drought in annuals.
Material and Methods
We measured 22 traits hypothesized to influence plant drought responses in 30 winter annual species from Israel. Individual traits and their coordinations were linked to species’ fitness responses to simulated drought in the greenhouse and to their distribution along a regional rainfall gradient.
Results
The annual species exhibited a wide range of trait values, including not only drought escape, but also tolerance and avoidance traits. Tolerance and avoidance traits were negatively correlated with each other, but were independent from escape traits. As expected, species with more pronounced escape traits exhibited larger fitness declines to simulated drought. Unexpectedly, none of the trait coordinations influenced species' distribution along the rainfall gradient.
Conclusions
The present results provide insights how annual species cope with drought, highlighting that these species do not only evade drought as seeds but also withstand it as plants.
Keywords: drought response, greenhouse experiment, life-history strategy, rainfall gradient, semi-arid rangelands, species’ distribution
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