Plant growth contributes to mineral weathering, but this contribution remains poorly understood. Weathering rates in an aggrading forested watershed in subtropical China were studied by means of geochemical mass balan...Plant growth contributes to mineral weathering, but this contribution remains poorly understood. Weathering rates in an aggrading forested watershed in subtropical China were studied by means of geochemical mass balance. Rainfall, dry deposition, and streamwater were monitored from March 2007 to February 2012. Samples of vegetative components, rainfall, dry deposition, streamwater, representative soils, and parent rock were collected and determined for mass balance calculation and clarifying plant-driven weathering mechanisms stoichiometrically. Ignoring biomass, weathering rates of Ca^2＋, Mg^2＋, Na^＋, and Si were 25.6, 10.7, 2.8, and 51.0 kg ha^-1 year^-1, respectively. Taking biomass into consideration, weathering rates of Ca^2＋, Mg^2＋, and Si and the sum of weathering rates of Ca^2＋, Mg^2＋, Na^＋, K^＋, and Si were 2.6, 1.8, 1.2, and 1.5-fold higher than those ignoring biomass, respectively. This is attributed to plant-driven weathering due to the nutrient （e.g., Ca^2＋, Mg^2＋, and K^＋） absorption by vegetation and substantial proton production during assimilation of these nutrients, with the former acting as a pump for removing weathering products and the latter being a source of weathering agents solubilizing mineral components. The same pattern of weathering, i.e., higher rates of weathering with than without including biomass in mass balance calculation, was reported in previous studies; however, the extent to which plants drive weathering rates varied with vegetation types and climatic zones. The documented biological weathering driven by plants is expected to play a critical role in regulating nutrient cycling and material flows within the Earth＇s Critical Zone.展开更多
Soil biotic communities can strongly impact plant performance.In this paper,we ask the question:how longlasting the effect of the soil microbial community on plant growth is.We examined the plant growth rates at three...Soil biotic communities can strongly impact plant performance.In this paper,we ask the question:how longlasting the effect of the soil microbial community on plant growth is.We examined the plant growth rates at three stages:early,mid and late growth.We performed two growth experiments with Jacobaea vulgaris,which lasted 49 and 63 days in sterilized soil or live soil.In a third experiment,we examined the effect of the timing of soil inoculation prior to planting on the relative growth rate of J.vulgaris with four different timing treatments.In all experiments,differences in biomass of plants grown in sterilized soil and live soil increased throughout the experiment.Also,the relative growth rate of plants in the sterilized soil was only significantly higher than that of plants in the live soil in the first two to three weeks.In the third experiment,plant biomass decreased with increasing time between inoculation and planting.Overall,our results showed that plants of J.vulgaris grew less well in live soil than in sterilized soil.The negative effects of soil inoculation on plant mass appeared to extend over the whole growth period but arise from the negative effects on relative growth rates that occurred in the first weeks.展开更多
The pollution of freshwater ecosystems is threatening freshwater plant species diversity worldwide.Freshwater plants,such as the common duckweed(Lemna minor),are potentially sensitive to novel stressful environments.T...The pollution of freshwater ecosystems is threatening freshwater plant species diversity worldwide.Freshwater plants,such as the common duckweed(Lemna minor),are potentially sensitive to novel stressful environments.To test if ecotype diversity could increase resistance to stressful environments,I used seven L.minor populations and measured their growth rates with and without moderate salt stress across an ecotype diversity gradient.The L.minor populations were grown over 5 months in 92 experimental mesocosms,either in ecotype monocultures or in polyculture with either one or three conspecific ecotypes(23 unique compositions).After growing the duckweed in unperturbed conditions(phase 1),the cultures were subjected to moderate salt stress(50 mmol/L NaCl)for several weeks(phase 2).The experiment was conducted in the presence of the natural epimicrobial community associated with the different ecotypes.In phase 2,a subset of these algae added an unintentional second stressor to the experiment.The ecotypes differed in their growth rates,the fastest growing at twice the rate of others.The diversity context further shaped the ecotype growth rates.Ecotype polycultures showed higher abundances towards the end of the experiment,thus over time,as the environment deteriorated,ecotype diversity gained in importance.These findings show that within-species variation in growth rates can translate to a positive effect of ecotype diversity on population abundance.Exposure of L.minor to moderate salt levels did not significantly impact growth rates,although the effect may have been masked by reduced algal stress in the saline environments.展开更多
基金supported by the National Natural Science Foundation of China(Nos.41471176 and41130530)
文摘Plant growth contributes to mineral weathering, but this contribution remains poorly understood. Weathering rates in an aggrading forested watershed in subtropical China were studied by means of geochemical mass balance. Rainfall, dry deposition, and streamwater were monitored from March 2007 to February 2012. Samples of vegetative components, rainfall, dry deposition, streamwater, representative soils, and parent rock were collected and determined for mass balance calculation and clarifying plant-driven weathering mechanisms stoichiometrically. Ignoring biomass, weathering rates of Ca^2＋, Mg^2＋, Na^＋, and Si were 25.6, 10.7, 2.8, and 51.0 kg ha^-1 year^-1, respectively. Taking biomass into consideration, weathering rates of Ca^2＋, Mg^2＋, and Si and the sum of weathering rates of Ca^2＋, Mg^2＋, Na^＋, K^＋, and Si were 2.6, 1.8, 1.2, and 1.5-fold higher than those ignoring biomass, respectively. This is attributed to plant-driven weathering due to the nutrient （e.g., Ca^2＋, Mg^2＋, and K^＋） absorption by vegetation and substantial proton production during assimilation of these nutrients, with the former acting as a pump for removing weathering products and the latter being a source of weathering agents solubilizing mineral components. The same pattern of weathering, i.e., higher rates of weathering with than without including biomass in mass balance calculation, was reported in previous studies; however, the extent to which plants drive weathering rates varied with vegetation types and climatic zones. The documented biological weathering driven by plants is expected to play a critical role in regulating nutrient cycling and material flows within the Earth＇s Critical Zone.
文摘Soil biotic communities can strongly impact plant performance.In this paper,we ask the question:how longlasting the effect of the soil microbial community on plant growth is.We examined the plant growth rates at three stages:early,mid and late growth.We performed two growth experiments with Jacobaea vulgaris,which lasted 49 and 63 days in sterilized soil or live soil.In a third experiment,we examined the effect of the timing of soil inoculation prior to planting on the relative growth rate of J.vulgaris with four different timing treatments.In all experiments,differences in biomass of plants grown in sterilized soil and live soil increased throughout the experiment.Also,the relative growth rate of plants in the sterilized soil was only significantly higher than that of plants in the live soil in the first two to three weeks.In the third experiment,plant biomass decreased with increasing time between inoculation and planting.Overall,our results showed that plants of J.vulgaris grew less well in live soil than in sterilized soil.The negative effects of soil inoculation on plant mass appeared to extend over the whole growth period but arise from the negative effects on relative growth rates that occurred in the first weeks.
基金the University of Zurich,Switzerland(UZH Forschungskredit)according to the CRediT taxonomy of contributor roles,Owen Petchey contributed in the"Funding Acquisition".
文摘The pollution of freshwater ecosystems is threatening freshwater plant species diversity worldwide.Freshwater plants,such as the common duckweed(Lemna minor),are potentially sensitive to novel stressful environments.To test if ecotype diversity could increase resistance to stressful environments,I used seven L.minor populations and measured their growth rates with and without moderate salt stress across an ecotype diversity gradient.The L.minor populations were grown over 5 months in 92 experimental mesocosms,either in ecotype monocultures or in polyculture with either one or three conspecific ecotypes(23 unique compositions).After growing the duckweed in unperturbed conditions(phase 1),the cultures were subjected to moderate salt stress(50 mmol/L NaCl)for several weeks(phase 2).The experiment was conducted in the presence of the natural epimicrobial community associated with the different ecotypes.In phase 2,a subset of these algae added an unintentional second stressor to the experiment.The ecotypes differed in their growth rates,the fastest growing at twice the rate of others.The diversity context further shaped the ecotype growth rates.Ecotype polycultures showed higher abundances towards the end of the experiment,thus over time,as the environment deteriorated,ecotype diversity gained in importance.These findings show that within-species variation in growth rates can translate to a positive effect of ecotype diversity on population abundance.Exposure of L.minor to moderate salt levels did not significantly impact growth rates,although the effect may have been masked by reduced algal stress in the saline environments.
