Department of Biological Sciences, University of Cape Town, Rondebosch, 7701, Cape Town, South Africa.
Published: June 2018
AI Article Synopsis
Article Abstract
Shade cast by trees, which suppresses grass growth, and fire fuelled by grass biomass, which prevents tree sapling establishment, are mutually exclusive and self-reinforcing drivers of biome distribution in savanna-forest mosaics. We investigated how shade depth, represented by canopy leaf area index (LAI), is generated by adult trees across savanna-forest boundaries and how a shade gradient filters tree functioning, and grass composition and biomass. Forest trees exerted greater shading through increased stem density and greater light interception per unit biomass. A critical transition at LAI c. 1.5 was linked to tree shifts from savanna to forest species, functional shifts from fire-tolerant to light-competitive species, and grass composition shifts from C to C pathways. A second transition to grass fuel loads too low to support fires, occurred at a lower canopy density (LAI > 0.5), accompanied by shifts in C subtype dominance. This pattern suggests that shade suppression of grass biomass is an essential first step for the maintenance of alternative stable states.
Tall fescue ( ) is a widely adopted forage and turf grass. This is partly due to a fungal endophyte, which confers both abiotic and biotic stress tolerance. Although PCR primers exist to test for endophyte presence, these were not designed to quantitatively analyze the amount of fungus in the plant.
The urban setting notwithstanding, rice cultivation prevails on the outskirts of Hanoi, with the burning of rice straw in the fields posing a significant challenge. Therefore, it is crucial to conduct spatial mapping of rice distribution, assess dry biomass, and determine emissions from rice straw burning within Hanoi city. The efficacy of the deep convolutional neural networks (DCNN) model has been evident in accurately mapping the spatial distribution of rice in Hanoi, where rice cultivation extensively thrives in suburban areas.
Nitrogen deposition continues to change grassland plant community composition particularly in more mesic systems; however, whether these altered plant communities will respond differently to other global change factors remains to be seen. Here, we explore how nutrient-altered tallgrass prairie responds to drought. Seven years of nutrient treatments (control, nitrogen (N), phosphorus (P), and N + P) resulted in significantly different plant communities.
Here we report growth promoting effects of Cupriavidus metallidurans on plants, and provide evidence for the underlying mechanisms of the growth promoting effects. In a series of greenhouse experiments on tomato, maize, and wheat, complemented with genetic analysis of Arabidopsis mutants, we tested the effects of the bacteria on seed germination, root and shoot growth, metal uptake, gas exchange parameters, and stomatal and xylem traits in maize, wheat, and tomato plants. Results showed that the bacteria substantially accelerate seed germination, increase shoot and root biomass, enhance photosynthetic performance, acidify the rhizosphere, increase metal uptake, and modulate stomatal and xylem traits.
