Effects of climate and snow depth on Bromus tectorum population dynamics at high elevation

Invasive plants are thought to be especially capable of range shifts or expansion in response to climate change due to high dispersal and colonization abilities. Although highly invasive throughout the Intermountain West, the presence and impact of the grass Bromus tectorum has been limited at higher elevations in the eastern Sierra Nevada, potentially due to extreme wintertime conditions. However, climate models project an upward elevational shift of climate regimes in the Sierra Nevada that could favor B. tectorum expansion. This research specifically examined the effects of experimental snow depth manipulations and interannual climate variability over 5 years on B. tectorum populations at high elevation (2,175 m). Experimentally-increased snow depth had an effect on phenology and biomass, but no effect on individual fecundity. Instead an experimentally-increased snowpack inhibited population growth in 1 year by reducing seedling emergence and early survival. A similar negative effect of increased snow was observed 2 years later. However, a strong negative effect on B. tectorum was also associated with a naturally low-snow winter, when seedling emergence was reduced by 86%. Across 5 years, winters with greater snow cover and a slower accumulation of degree-days coincided with higher B. tectorum seedling density and population growth. Thus, we observed negative effects associated with both experimentally-increased and naturally-decreased snowpacks. It is likely that the effect of snow at high elevation is nonlinear and differs from lower elevations where wintertime germination can be favorable. Additionally, we observed a doubling of population size in 1 year, which is alarming at this elevation

An Intelligent Automatic Irrigation System for Arid Region

International audienc

Genetic Improvement of Perennial Forage Plants for Salt Tolerance

The difficulties of genetic improvement of forage species are further complicated by the intricacies of salinity stress. Multiple evidence of the effects of salinity on germination and establishment highlight some of the limitations that must be overcome in order to carry out successful breeding programs for pastures. Different sources of variation feasible to be used in such breeding programs areanalyzed. The application of morpho-physiological selection criteria such as “salt glands” or “Na exclusion,” simulation of the saline environment to assess germination behavior, initial growth or production before defoliation are considered. Methodological advances in sequencing and bioinformatics allow us to predict a prominent role in the application of “Genomic Selection”. On the other hand, the advances in gene technologies have allowed direct the changes to specific sites by “Gene Edition” techniques, which are also very promising. The different methodologies of population management are largely dependent on reproductive systems, and it is a field where knowledge and “art” combine for successful results in plant breeding. Conclusions are drawn from the experiences carried out, and future perspectives for the improvement of perennial forage are analyzed. Both classical and molecular breeding come together not as alternatives but as complements.Fil: Schrauf, Gustavo Enrique. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Alonso Nogara, Flavia Alejandra. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Rush, Pablo. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Peralta Roa, Pablo Leonel. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Musacchhio, Eduardo. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Sergio Ghio. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Couso, Luciana Laura. Universidad de Buenos Aires. Facultad de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ramos, Elena. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Schrauf, Matías Florián. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Voda, Lisandro. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Giordano, Andrea Mariana. La Trobe University; Australia. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Giavedoni, Julio Alberto. Universidad Nacional del Litoral; ArgentinaFil: Pensiero, José F.. Universidad Nacional del Litoral; ArgentinaFil: Tomas, Pablo. Universidad Nacional del Litoral; ArgentinaFil: Zabala, Juan M.. Universidad Nacional del Litoral; ArgentinaFil: Spangenberg, Germán. La Trobe University; Australi

Variation in phenotypic plasticity for native and invasive populations of Bromus tectorum

Phenotypic plasticity is often considered important for invasive plant success, yet relatively few studies have assessed plasticity in both native and invasive populations of the same species. We examined the plastic response to temperature for Bromus tectorum populations collected from similar shrub-steppe environments in the Republics of Armenia and Georgia, where it is native, and along an invasive front in California and Nevada. Plants were grown in growth chambers in either ‘warm’ (30/20 °C, day/night) or ‘cold’ (10/5 °C) conditions. Invasive populations exhibited greater adaptive plasticity than natives for freezing tolerance (as measured by chlorophyll a fluorescence), such that invasive populations grown in the cold treatment exhibited the highest tolerance. Invasive populations also exhibited more rapid seedling emergence in response to warm temperatures compared to native populations. The climatic conditions of population source locations were related to emergence timing for invasive populations and to freezing tolerance across all populations combined. Plasticity in growth-related traits such as biomass, allocation, leaf length, and photosynthesis did not differ between native and invasive populations. Rather, some growth-related traits were very plastic across all populations, which may help to dampen differences in biomass in contrasting environments. Thus, invasive populations were found to be particularly plastic for some important traits such as seedling emergence and freezing tolerance, but plasticity at the species level may also be an important factor in the invasive ability of B. tectorum