【草地土壤功能】Iain J. Gould et al. Plant diversity and root traits benefit physical properties key to soil function in grasslands. Ecology Letters Volume 19 Issue 9 September 2016 Pages 1140–1149
Abstract
Plant diversity loss impairs ecosystem functioning including important effects on soil. Most studies that have explored plant diversity effects belowground however have largely focused on biological processes. As such our understanding of how plant diversity impacts the soil physical environment remains limited despite the fundamental role soil physical structure plays in ensuring soil function and ecosystem service provision. Here in both a glasshouse and a long-term field study we show that high plant diversity in grassland systems increases soil aggregate stability a vital structural property of soil and that root traits play a major role in determining diversity effects. We also reveal that the presence of particular plant species within mixed communities affects an even wider range of soil physical processes including hydrology and soil strength regimes. Our results indicate that alongside well-documented effects on ecosystem functioning plant diversity and root traits also benefit essential soil physical properties.
【群落物种演变】Shao-peng Li et al. Convergence and divergence in a long-term old-field succession: the importance of spatial scale and species abundance. Ecology Letters Volume 19 Issue 9 September 2016 Pages 1101–1109
Abstract
Whether plant communities in a given region converge towards a particular stable state during succession has long been debated but rarely tested at a sufficiently long time scale. By analysing a 50-year continuous study of post-agricultural secondary succession in New Jersey USA we show that the extent of community convergence varies with the spatial scale and species abundance classes. At the larger field scale abundance-based dissimilarities among communities decreased over time indicating convergence of dominant species whereas incidence-based dissimilarities showed little temporal tend indicating no sign of convergence. In contrast plots within each field diverged in both species composition and abundance. Abundance-based successional rates decreased over time whereas rare species and herbaceous plants showed little change in temporal turnover rates. Initial abandonment conditions only influenced community structure early in succession. Overall our findings provide strong evidence for scale and abundance dependence of stochastic and deterministic processes over old-field succession.
【DELLA是植物-根瘤菌和植物-菌根共生关键基因】Yue Jin et al. DELLA proteins are common components of symbiotic rhizobial and mycorrhizal signalling pathways. Nature Communications 7 Article number: 12433 (2016)
Abstract
Legumes form symbiotic associations with either nitrogen-fixing bacteria or arbuscular mycorrhizal fungi. Formation of these two symbioses is regulated by a common set of signalling components that act downstream of recognition of rhizobia or mycorrhizae by host plants. Central to these pathways is the calcium and calmodulin-dependent protein kinase (CCaMK)–IPD3 complex which initiates nodule organogenesis following calcium oscillations in the host nucleus. However downstream signalling event
