Plant and Soil最新文献

Aims

Understanding the influence of different forms of phosphorus (P) over the different root traits and how those traits are related to increasing the efficiency of nutrient acquisition strategies.

Methods

Investigation of switchgrass (Panicum virgatum L.) root morphology responses to inorganic P (Pi) soluble (Potassium-P), insoluble (Aluminum-P), and organic P (Po) (Inositol Hexa-Phosphate, IHex-P) in rhizoboxes. Roots were traced over the root box and scanned using WinRhizoTM. The CRootbox model was employed to simulate root growth.

Results

Significant plasticity observed under IHex-P treatment, with a 46% increase in root branching, leading to a 74% rise in total root length and a 65% increase in root surface area compared to inorganic P forms. IHex-P resulted in a 73% higher root biomass than Aluminum-P and a 26% increase compared to Potassium-P. Most of the differences were attributed to the elongation of root branches.

Conclusions

The study emphasizes the dynamic nature of switchgrass root architecture and morphology in response to varying P forms in the soil. The absence of Pi in the soil triggered increased plasticity in root traits, facilitating root access to Po and uptake of P. These findings offer valuable insights into the adaptive mechanisms of perennial plants, with significant implications for optimizing nutrient acquisition strategies in both agricultural and natural ecosystems.

Background and aims

Ecological restoration increasingly use mycorrhizal symbiosis to boost plant growth and stress resilience, with research focusing on optimizing inoculum propagation using trap plants. Arbuscular mycorrhizal fungi (AMF) are obligate symbionts with a degree of specificity in their plant associations, potentially leading to co-adaptation processes. Consequently, properties of plant communities such as cover, diversity, and the presence of native species can influence AMF abundance in natural settings and controlled environments. Our study hypothesises that 1) AMF spore density increases in areas with high plant diversity and permanent vegetation cover; and 2) native AMF propagation thrives best in native and phylogenetically diverse plants consortia.

Methods

In an arid and heterogeneous Mediterranean environment, we sampled seven representative microenvironments, conducted a floristic inventory and quantified AMF spores in soil. The AMF propagation capacity was assessed through a pot experiment under controlled conditions using different trap plant consortia (native/non-native, single/multi-family).

Results

In natural sites, spore density varied significantly by microenvironment, from 1 (badlands) to 10 (vegetation islands) spores/g of soil. Vegetation cover, rather than plant diversity or richness, increased AMF spore density. Under controlled conditions, spore propagation was 1.28 and 1.19 times higher in native and phylogenetically diverse plant consortia respectively, compared to allochthonous and less diverse ones.

Conclusions

Our results support the importance of vegetation cover in conserving AMF abundance in arid environments. The research also highlights the efficiency of using native and diverse plant consortia to propagate AMF inoculum, contributing to optimize non-conventional ecological restoration techniques using nature-based solutions.

Aims

The genus Cuscuta comprises nearly 200 parasitic plant species. Sympatric Cuscuta species are considered to occur in different habitat types. We investigated the reasons for the observed habitat preference addressing the following questions: Can host specificity explain the habitat preference? Can soil characteristics influence habitat preference?

Methods

We sampled 543 vegetation plots and collected 56 soil samples from the habitats of C. europaea, C. campestris, C. epithymum, C. lupuliformis, and C. australis in Hungary. The percent cover, maximum height, and parasitism status of each species were recorded in every plot. The species composition and soil parameters of the habitats were compared using multivariate data analysis.

Results

Habitats of the examined parasites significantly differed from each other based on species number and composition, as well as vegetation cover and height. However, species compositions in the habitat of the same Cuscuta species also varied considerably in different localities. We also found that the host range of the same Cuscuta species differed greatly in different locations. None of the dodders had any essential host species without which they could not survive and develop. Additionally, the habitats of the examined Cuscuta species significantly differed from each other based on soil conditions.

Conclusion

Host specificity alone does not explain the strong preference of these host generalist parasites for certain habitats. Rather, the complex system of biotic and abiotic factors, including the mineral composition of the soil, determines the habitats of dodders.

Background and aims

Boron (B) deficiency is widespread in boreal forests, but it can be prevented by fertilization. As B deficiency reduces root growth, it may affect the uptake of other nutrients. We assessed the persistence of the effects of a one-time B application on growth and nutrition of Norway spruce (Picea abies).

Methods

A single-tree B-fertilization experiment was established in a highly productive stand in eastern Finland in 2000 and followed until 2018. The applied B dose was 2 kg ha⁻¹.

Results

After 19 growing seasons, height growth was higher in B-fertilized trees and the effect was not waning. Diameter growth was not affected. The mean needle-B concentration without B fertilizer was 1.7 mg kg⁻¹ and with B-fertilizer, 4.8 mg kg⁻¹. Boron-fertilized trees had higher foliar aluminium (Al), carbon (C), copper (Cu) and sulfur (S) concentrations, and lower soluble silicon (Si).

Conclusions

The positive B effect on growth persisted after 19 years. Boron concentrations remained higher in fertilized trees, although lower than at the early stages of the experiment. Boron fertilization maintained Cu and S levels above deficiency limits. The small but consistent change in C indicates a change in needle compounds. Increased Al may result from reduced Si accumulation, as Al co-deposition with Si alleviates Al toxicity. Further studies are required to optimize B-fertilization practices and to elucidate the mechanisms behind the effects on height growth and the levels of other elements. A combination of soluble and sparingly soluble fertilizers could further increase the duration of the effect.

Background

The Sub-Saharan African food system is facing multiple threats, including soil nutrient depletion, monoculture cereal farming, population expansion, and climate change. These factors collectively pose a risk to agricultural productivity and food security in the region.

Scope

Bambara groundnut (BGN) (Vigna subterranea [L.] Verdc) yield has been in decline due to various abiotic factors such as high temperature, drought, and salinity, as well as biotic factors like nitrogen-fixing symbiont host specificity. These challenges have negatively impacted crop productivity and food security. This review highlights the significance of BGN in addressing food insecurity and explores its potential advantages for small-scale farmers. BGN provides a good example for strong effects of the microbiome, particularly specific symbionts for nitrogen-fixing root nodules, on production systems. A focus of this review is to highlight the potential applications of nitrogen-fixing symbionts as biofertilizers for Bambara groundnut.

Conclusion

The review emphasizes the potential of BGN to improve agricultural production and soil fertility, particularly using inoculation technology, which could benefit small-scale farmers and contribute to enhancing food security. Bradyrhizobium inoculants may have to be designed specifically for the cultivar level of BGN.

Background and aims

Karst landscapes, characterized by large limestone outcrops and shallow, thin soils, are extensively distributed in Southwest China. Tree species found in karst forests encounter frequent drought, phosphorus (P) deficiency, and excess calcium (Ca) and magnesium (Mg). We aimed to elucidate leaf strategies for karst and non-karst forest species grown on different soil substrates.

Methods

We selected a total of 100 typical tree species from karst and non-karst forests in tropical-subtropical China, and measured leaf hydraulic traits and nutrient concentrations. We compared differences in leaf traits between the two forest types using t-test and their differences in trait relationships using trait network analysis.

Results

Karst tree species exhibited lower leaf turgor loss point (π_tlp) and midday leaf water potential, and narrower hydraulic safety margins than non-karst tree species. Furthermore, karst species had higher nitrogen, potassium, Ca, and Mg, but lower P levels than non-karst species; however, they showed similar Ca/Mg ratios. Trait network analysis revealed a higher degree of leaf traits relationships in karst species, with saturated water content, P, and π_tlp showing high connectivity with other traits. Particularly, karst species with higher leaf Ca, and lower P levels tended to have lower π_tlp and vulnerability to cavitation, indicating a co-variation between leaf nutrients and drought resistance under unique chemical and physical conditions of karst environment. However, these relationships were not observed in non-karst species, resulting in weak leaf trait relationships.

Conclusion

This study suggests that strong associations between leaf nutrient and hydraulic traits in karst species promote their adaptation to soil water and nutrient stresses.

Aims and Background

Cellulosic, hemicellulosic and pectinaceous mucilages produced by certain angiosperms as adaptation in myxodiaspory are investigated in the past to understand their role in seed dispersal. The present understanding of zoochory and telechory are based on mucilage amount, state of hydration and to a limited extent, role of mucilage microstructure studied using adhesion and friction. However, in the case of cellulosic mucilages, the role played by the cellulosic fibrils in seed dispersal is not clear, especially since they have a negative correlation with endozoochory.

Methods

Using fresh cellulosic seed mucilages from sweet basil (Ocimum basilicum) and chia (Salvia hispanica) we investigate the role of microstructure of the mucilage in two key behaviours: anchoring and adhesion properties of the seeds through Large Amplitude Oscillatory Shear (LAOS) rheological experiments carried out on seed mucilages along with wet tack strength studies.

Results

We report a special large deformation mechanism operational in these cellulosic mucilages triggered through ‘strain stiffening’. In comparison to pectin gels which also exhibit strain stiffening at lower strains, these mucilages show strain stiffening under large deformations along with higher wet adhesion strength. From the LAOS rheological studies and microstructure, we have shown that cellulosic components have a significant role towards the observed behaviour.

Conclusions

The unique strain stiffening behaviour and strong wet adhesion characteristics observed in basil and chia seed mucilage strongly point to the plausible role of cellulosic components in supporting the antitelechory found commonly in plants of arid habitats.

Background and aims

Pulses- grain legumes are vulnerable to waterlogging (WL) in South Asia. This study examined the effects of WL on two pulses at germination and reproductive stages and tested hypotheses: Mungbean (Vigna radiata L.) and blackgram (Vigna mungo L.) differ in WL tolerance; and the differences are due to phenotypic and growth traits.

Methods

Three mungbean and one blackgram cultivar were grown in pot-soil system. The treatments were at germination stage, 0 (drained control), 3, 5 and 7 d WL, while at the reproductive stage 0 (drained control), 3, 6 and 9 d WL and then drained to allow recovery (RE).

Results

Seed emergence decreased with longer WL duration. Blackgram cultivar showed 38% emergence, while mungbean cultivars had 14–18% after 7 d of WL. At the reproductive stage, WL reduced shoot and root growth compared to drained control. After 30 d of recovery, the chlorophyll concentration of first trifoliate leaves increased by 15% in blackgram cultivar, while it decreased in mungbean cultivars compared to their drained controls. Blackgram had higher relative growth rate (RGR) than mungbean at 9 d WL. After 9 d of WL, blackgram seed yield was reduced by 40% and mungbean cultivars by 52–60% compared to drained controls.

Conclusions

This study has provided evidence of a difference in WL tolerance between two summer pulses at both stages for the particular soil used here. Seedling emergence, RGR and yield attributed the variation. These new findings will allow growers to select suitable crops for different cropping systems.

Aims

Variabilities of vegetation and soil cause uncertainty to the factor of safety (FoS) of unsaturated vegetated slopes, yet the significance of these variabilities on the uncertainty of FoS is unclear. This study aims to quantify the effect of the uncertainties of root reinforcement and soil hydromechanical properties to the uncertainty of the FoS.

Methods

The variance‐based global sensitivity analysis was adopted to evaluate how the variance of FoS of vegetated slopes can be apportioned by the variabilities of soil and root parameters. A copula theory was applied to model the correlation amongst the parameters.

Results

For slip depths shallower than 0.30 m, the major source of the variance of the FoS included the parameters that define root reinforcement, followed by the parameters of soil shear strength. The variation of transpiration‐induced soil suction had limited effect on the FoS variance under heavy rainfall. Taking into account the correlations amongst the parameters had minor influence on their contribution to the variance of the FoS.

Conclusions

We observed threshold slip depths, where the relative contribution of uncertainties in root and soil parameters on the FoS uncertainty underwent a transition. Root reinforcement for slips as deep as 0.60 m can provide reliable slope stabilisation effects.

Background and aims

Attapulgite has been widely used to reclaim saline soils because it can affect the processes of nitrogen (N) transport and transformation through adsorption. However, the impact of attapulgite on crop uptake of N and the underlying mechanisms remain poorly understood.

Methods

We conducted a pot experiment over two seasons involving a rotation of barley (Hordeum vulgare) and maize (Zea mays) in which distinct ¹⁵N-labellled fertilizers (low N [LN], 180 kg N ha⁻¹; high N [HN], 240 kg N ha⁻¹) and attapulgite (no attapulgite; 5% attapulgite) were utilized. The effects of attapulgite on the utilization of N fertilizer and its residues were analysed along with the utilization of residual N fertilizers by subsequent crops.

Results

Barley utilized 42.91–46.79% ¹⁵N fertilizer. Notably, the LN treatment involving attapulgite reduced ¹⁵N fertilizer utilization by barley by 3.33%, whereas it increased it by 4.62% in the HN treatment. A total of 14.26–20.55% of the ¹⁵N fertilizer remained in the soil, and attapulgite had no significant effect on the ¹⁵N fertilizer residual levels or its utilization by maize. The addition of attapulgite significantly reduced the abundance of genes involved in nitrification and denitrification, thereby decreasing the risk of N loss by denitrification.

Conclusion

Attapulgite offers significant benefits in terms of N fertilizer absorption and crop N utilization efficiency and mitigates the loss of N when high levels of fertilizers are applied.