If you add CO2 or nitrogen to a single plant it will likely grow more, but the amount by which each resource stimulates growth differs widely across species. When you add either resource to a whole ecosystem, total plant growth will likely also increase, but there will be winners and losers, causing a change in the relative abundance of plant species, and therefore altering the way the whole ecosystem responds to the added resource, a “community feedback”. Recent studies have shown that (1) shifts in plant community structure cannot be reliably predicted from short-term plant physiological response to global change and (2) the ecosystem response to multi-factored change is commonly less than the sum of its parts. In a new review published in AoB PLANTS, Langley and Hungate survey the results from long-term field manipulation to examine the role community shifts may play in explaining these common findings. They use a simple model to examine the potential importance of community shifts in governing ecosystem response and show that community dynamics can have a large impact on ecosystem response to any single factor. Understanding tradeoffs in the ability of plants to respond positively to, or to tolerate, different global change drivers may help identify generalizable patterns of covariance in responses to different drivers of change across plant taxa.
In several genera evolutionary chromosome change involves variation in DNA amount in diploids and genome downsizing in polyploids. In a new study in AoB PLANTS, Poggio et al. analysed the genome size and karyotypical parameters of Hippeastrum species with different ploidy levels.The constancy of bimodal karyotypes, even with changes in ploidy level, and DNA content per basic genome indicate that the distribution of DNA within the complement is not random and suggest the presence of mechanisms selecting for constancy, or against change, in the karyotype morphology.
White-tailed deer browsing has been implicated in the loss of species diversity from forests throughout eastern North America. In a new study published in AoB PLANTS, Begley-Miller et al. build on this previous research by examining how browsing also affects phylogenetic community structure in order to better understand the role of deer browsing in the community assembly process. In browsed plots, they found that reductions in phylogenetic diversity were much greater than reductions in species richness or diversity. Species persisting in browsed communities were also closely related. Their findings indicate that deer browsing acts as a biotic filter during the community assembly process. Their study also highlights the importance of utilizing new tools in assessing the influence of deer herbivory on plant communities, and should encourage future advances in our understanding of coexistence in communities.
For many species of conservation significance, multiple factors limit reproduction. In a new study published in AoB PLANTS, Walsh et al. examined the contribution of plant height, number of flowers, number of stems, as well as the joint impacts of mutualists and antagonists on the pollination biology and seed production of the imperiled, deceptive orchid, Cypripedium candidum. They found flowering stem height to be the only morphological feature significant in reproduction, with taller flowering stems simultaneously receiving increased pollination and decreased seed predation. Furthermore they found decreased seed mass in individuals subjected to hand-self pollination treatments. Their results may help explain the factors limiting seed production in other Cypripedium and further emphasize the importance of management in orchid conservation.
Invasive species cause ecological, economic and social impacts and are key drivers of global change. This is the case for the genus Prosopis (mesquite; Fabaceae) where several taxa are among the world’s most damaging invasive species. Prosopis taxa are currently naturalised or invasive in 103 countries and are bioclimatically suitable for many more. There are numerous management practices available to control Prosopis invasions, each with their benefits and costs, however, in most areas management has had only limited success. In a new article published in AoB PLANTS, Shackleton et al. present a global review of Prosopis, focusing on its distribution, impacts, benefits and approaches to management. Key gaps in knowledge and promising options for management are highlighted.
Genome doubling and changes in genome size are fundamental evolutionary processes, with polyploidy being one of the most important forces influencing plant diversification. However, little is currently known about the extent of genome size variation within taxa and the evolutionary forces acting on this variation. Arabidopsis kamchatica has been reported to contain both diploid and tetraploid individuals (2 or 4 copies of every chromosome). In a new study in AoB PLANTS, Wolf et al. found genome size differences among populations, and among populations genome size varied by 7%. However, all sampled A. kamchatica plants from a wide geographic range were tetraploids. This level of intraspecific genome size variation in A. kamchatica is lower than in other Arabidopsis taxa. Due to its close relationship to A. thaliana, A. kamchatica has the potential to be very useful in the study of polyploidy and genome evolution.
Clonal plants are common in frequently flooded habitats because of their resilience to disturbance. In a new study published in AoB PLANTS, Huber et al. investigated whether submergence prior to fragmentation of clones of two clover species reduced survival and regrowth of clonal fragments, and whether these fitness parameters differed between genotypes from highly disturbed river forelands and less disturbed coastal dune slacks. They found that soil flooding severely decreased survival and regrowth, and that plants from the more disturbance-prone habitat were less negatively affected by fragmentation. However, internode size was, surprisingly, often negatively correlated with survival after fragmentation, but positively correlated with regrowth. Apparently, contrasting selection pressures exist on internode size in stoloniferous species growing in disturbed habitats.
The energetic cost of plant organ construction is a functional trait that is useful in understanding carbon investment during growth (e.g., the resource acquisition vs. tissue longevity tradeoff), as well as in response to global change factors like elevated CO2 and N. Despite the enormous importance of roots and rhizomes in acquiring soil resources and responding to global change, construction costs have been studied almost exclusively in leaves. In a new study in AoB PLANTS, the energetic costs of tissue construction were compared in two subspecies of Phragmites australis, the common reed – namely the primary native and introduced lineages in North America. Caplan et al. report that the introduced lineage has lower construction costs than the native under all environmental conditions assessed, driven mainly by its lower cost rhizomes. These results highlight the fact that belowground energetics, which are seldom investigated, can influence the performance advantages that drive many plant invasions. The authors also demonstrate that tissue construction costs in organs not typically assessed can shift with global change, suggesting that they may have increasingly important implications into the future.
AoB PLANTS, the premier open-access journal for plant sciences, is seeking a part-time social media editor to develop features for our website and to expand the journal’s presence on Facebook, Twitter, blogs and other social media outlets, with the general objective of increasing the visibility, influence and reputation of our journal.
The ideal candidate will meet the following criteria:
• a graduate degree in biology
• demonstrated research experience in some area of the plant sciences
• in-depth knowledge of social-media tools and applications
• evidence of social-media publishing experience
For details see http://bit.ly/1wfniSJ. Interested individuals should contact the Chief Editor Hall Cushman (firstname.lastname@example.org) and/or Managing Editor Gail Rice (email@example.com).
Most investigations of plant responses to changes in temperature have focused on a constant increase in temperature. However, changes in fluctuation in temperature, even if the mean temperature is the same, may affect plant growth. In a new article published in AoB PLANTS, Cerasoli et al. tested the effects of weekly warm and then cool moderate (5oC) and large (10oC) fluctuation in temperature (with the same biweekly temperature sum) on plant growth. They found that, while the ratio of photosynthesis to respiration did not change, fluctuations in temperature did increase biomass accumulation and alter biomass allocation. Their findings suggest that, like mean temperature, fluctuation in temperature can significantly impact plant growth.