Water availability determines many ecological processes, especially in dryland ecosystems. The capacity of extreme weather events to trigger responses in vegetation from the molecular to regional scales is well known. In addition, changing environment not only has impacts on contemporary plants, but also on their next generations through mechanisms not completely understood. The parental mediated response of the offsprings to environmental stimuli can extend beyond the effects of transmitted genes (i.e., epigenetic processes). However, nowadays is not clear if epigenetic processes could offer adaptive advantages to extreme precipitation events promoted by climate change. To test this question, we are using a long-term manipulated rainfall experiment located in Jornada Basin (New Mexico). Since 2006, a population of the perennial grass Bouteloua eriopoda has been subjected to three precipitation regimes: -80%, +80%, and natural precipitation. This year, three shoots in each plot have been transplanted to each treatment. Phenotypic and performance changes of the parental plants to the long-term experiment have been evaluated at the beginning of this transplant experiment using as functional and performance traits: leaf nitrogen content, tiller and stolon density, number of total buds and viable buds, production per tiller, above-ground net primary production (ANPP).
Results/Conclusions
All traits responded to water availability treatments except leave nitrogen content and viable buds. The effect of previous precipitation on production per tiller and ANPP was significant. The negative effect of previous drought treatment was stronger than the positive effect to the previous irrigation treatment. Tiller and stolon density also responded positively to the increasing gradient of previous precipitation. The number of total buds only responded negatively to the drought treatment. These results showed that B. eriopoda possesses several traits highly sensitive to extreme precipitation events. This, together with its genome characteristics (low degree of ploidy, genome size of 709 Mbp/1C, similar to sorghum’s one and likely low level of heterozygosity due its mainly vegetative reproduction), dominance in drylands of Southwest US, and importance for livestock activities, make this species a strong candidate for a transgenerational experiment where adaptive mechanisms to these treatments will be evaluated through whole-RNA sequencing and DNA and epigenetic assays.