Hasil untuk "Plant ecology"

J. P. Grime, R. Hunt

G. Bodner, A. Nakhforoosh, H. Kaul

Drought is a predominant cause of low yields worldwide. There is an urgent need for more water efficient cropping systems facing large water consumption of irrigated agriculture and high unproductive losses via runoff and evaporation. Identification of yield-limiting constraints in the plant–soil–atmosphere continuum are the key to improved management of plant water stress. Crop ecology provides a systematic approach for this purpose integrating soil hydrology and plant physiology into the context of crop production. We review main climate, soil and plant properties and processes that determine yield in different water-limited environments. From this analysis, management measures for cropping systems under specific drought conditions are derived. Major findings from literature analysis are as follows. (1) Unproductive water losses such as evaporation and runoff increase from continental in-season rainfall climates to storage-dependent winter rainfall climates. Highest losses occur under tropical residual moisture regimes with short intense rainy season. (2) Sites with a climatic dry season require adaptation via phenology and water saving to ensure stable yields. Intermittent droughts can be buffered via the root system, which is still largely underutilised for better stress resistance. (3) At short-term better management options such as mulching and date of seeding allow to adjust cropping systems to site constraints. Adapted cultivars can improve the synchronisation between crop water demand and soil supply. At long term, soil hydraulic and plant physiological constraints can be overcome by changing tillage systems and breeding new varieties with higher stress resistance. (4) Interactions between plant and soil, particularly in the rhizosphere, are a way towards better crop water supply. Targeted management of such plant–soil interactions is still at infancy. We conclude that understanding site-specific stress hydrology is imperative to select the most efficient measures to mitigate stress. Major progress in future can be expected from crop ecology focussing on the management of complex plant (root)–soil interactions.

Aaron Marc Saunders, M. Albertsen, J. Vollertsen et al.

Understanding the microbial ecology of a system requires that the observed population dynamics can be linked to their metabolic functions. However, functional characterization is laborious and the choice of organisms should be prioritized to those that are frequently abundant (core) or transiently abundant, which are therefore putatively make the greatest contribution to carbon turnover in the system. We analyzed the microbial communities in 13 Danish wastewater treatment plants with nutrient removal in consecutive years and a single plant periodically over 6 years, using Illumina sequencing of 16S ribosomal RNA amplicons of the V4 region. The plants contained a core community of 63 abundant genus-level operational taxonomic units (OTUs) that made up 68% of the total reads. A core community consisting of abundant OTUs was also observed within the incoming wastewater to three plants. The net growth rate for individual OTUs was quantified using mass balance, and it was found that 10% of the total reads in the activated sludge were from slow or non-growing OTUs, and that their measured abundance was primarily because of immigration with the wastewater. Transiently abundant organisms were also identified. Among them the genus Nitrotoga (class Betaproteobacteria) was the most abundant putative nitrite oxidizer in a number of activated sludge plants, which challenges previous assumptions that Nitrospira (phylum Nitrospirae) are the primary nitrite-oxidizers in activated sludge systems with nutrient removal.

V. Jung, C. Violle, Cédric P. Mondy et al.

J. H. Langenheim

E. Post, N. Stenseth

L. Schoonhoven, T. Jermy, J. Loon

V. Kosmalla, O. Lojek, J. Carus et al.

<p>This study investigates the biomechanical properties of marram grass (<i>Calamagrostis arenaria</i>, formerly <i>Ammophila arenaria</i>) over a 12-month period on the island of Spiekeroog, Germany, to enhance the modeling of coastal dune dynamics. The research reveals significant seasonal variations in the stiffness and Young modulus of the vegetation, with higher values observed in winter, indicating increased mechanical resistance important for dune stability during storm events. In summer, increased flexibility and density are prominent, enhancing dune accretion. To account for these dynamics, the study emphasizes the importance of incorporating seasonally adjusted parameters into models, particularly accounting for the increased horizontal density, the presence of flower stems in summer, and the longer leaf lengths in winter. The differentiation among plant parts is highlighted, with flower stems providing the highest structural support due to their greater stiffness, while leaves contribute more to flexibility and dynamic responses. Interestingly, the minimal differences between green and brown leaves suggest that these can be treated similarly in modeling efforts, simplifying parameterization without compromising accuracy. Additionally, the study found no consistent evidence that wind exposure significantly affects the biomechanical properties of marram grass, suggesting that wind influence may not need to be factored into biomechanical models. The results also demonstrate that the biomechanical properties of marram grass are broadly transferable between fixed and dynamic dune systems, supporting their applicability across various coastal environments. The key outcome of this research is the detailed compilation of the biomechanical traits of marram grass's aboveground vegetation, reflecting the seasonal dynamics found in dune processes, which will serve as a valuable resource for future modeling efforts of dune vegetation and their surrogates.</p>

Rupali Gupta, Meirav Leibman-Markus, Gautam Anand et al.

Cytokinins (CKs) regulate numerous biological processes in plants, and are involved in plant growth and development as well as responses to biotic and abiotic stresses. Although CKs have been reported to prime plant immunity, thus far, research on CK hormopriming has focused on classical synthetic CKs such as kinetin or 6-benzylaminopurine (BAP). Here, we show that synthetic aromatic CK derivatives—specifically, 3‑methoxy-6-benzylaminopurine-9-arabinosides—effectively induce immune responses and promote resistance to Botrytis cinerea in tomato (Solanum lycopersicum) primarily via a salicylic acid (SA)-dependent mechanism. Additionally, like 6-BAP, these compounds directly inhibit B. cinerea. Transcriptomic analyses of B. cinerea treated with CK arabinosides revealed significant changes in expressed gene profiles, notably in pathways associated with sugar metabolism. Unlike classical CKs, CK arabinosides do not alleviate growth inhibition under sugar-limited conditions, contributing to their stronger antifungal effects. Furthermore, CK arabinosides induce tomato immune responses more robustly than classical CKs, yet without activating canonical cytokinin signaling pathways, likely owing to their exceptional chemical stability which prevents release of the free active CK base, and due to their inability to directly bind CK receptors. Altogether, our findings suggest that CK arabinosides act via a dual mechanism—immune priming and direct pathogen inhibition—and hold promise as next-generation hormopriming agents for sustainable crop protection.

Sahar Sadaqat, Muhammad Awais, Abdul Qayyum Rao

Abiotic stresses like drought and salinity severely impact cotton productivity by triggering excessive accumulation of reactive oxygen species (ROS), leading to oxidative damage. In this study, we functionally characterized GhPQT3, a homolog of Paraquat tolerance 3 from the Arabidopsis thaliana E3 ligase family, and its role in regulating oxidative stress responses. Computational analysis identified two GhPQT3 homologs in the Gossypium hirsutum, showing high sequence conservation with Arabidopsis and rice PQT3. Protein sequence alignment, phylogenetic analysis, conserved motif, and domain annotation confirmed that GhPQT3 shares structural and functional similarity with its dicot homologs. CRISPR-Cas12 mediated knock out mutants were generated for functional characterization of the protein. Functional studies revealed that GhPQT3 acts as a negative regulator of antioxidant defenses, and its suppression in mutant lines Ghpqt3–4 and Ghpqt3–6 significantly enhanced tolerance to drought and salinity. These mutant lines exhibited elevated gene expression and enzymatic activity of APX and GPX especially Ghpqt3–6, which consistently maintained higher antioxidant activity and reduced oxidative damage. The DPPH radical scavenging assay, quantification of chlorophyll content and leaf necrosis further confirmed improved cellular integrity, improved redox homeostasis. These findings establish GhPQT3 as a promising target for genetic improvement, offering a robust strategy to develop stress-resilient cotton cultivars capable of withstanding climate-induced abiotic stresses.

Gianmaria Bonari, Irena Axmanová, Gianluigi Bacchetta et al.

The current issue is the first one of the journal Vegetation Ecology and Diversity, formerly Plant Sociology, the international peer-reviewed journal of the Italian Society of Vegetation Science (SISV). Vegetation Ecology and Diversity (VED) publishes original research articles covering all aspects of vegetation, ranging from plant communities to landscapes, including dynamic processes and community ecology. It prioritizes papers that emphasize plant community ecology and vegetation surveys to advance ecological models, interpret and classify vegetation, map ecosystems, assess environmental quality, manage and conserve plant biodiversity, and interpret and monitor European habitats. All the articles are freely available in Open Access (OA). In the present Editorial, we introduce the new journal name, the new Editorial Board and Social Media Team, several Topical Collections, and initiatives to support young researchers.

Yannan Chen, Xue Pan, Jing-Ting Chen et al.

Tree species richness affects biodiversity and ecosystem functioning. Investigating its effect on soil animals and their trophic ecology is crucial for understanding soil food web functioning. Despite this, the relationship between tree species richness and soil microarthropods trophic structure has rarely been evaluated. Here, we investigated the effects of tree species richness (1, 2, 4, 8, 16, 24 species) on soil oribatid mites at an experimental field site in the subtropics (BEF-China). We measured the impacts of tree species richness and oribatid mite functional traits, including body mass and reproductive mode, on oribatid mite trophic ecology using stable isotopes (15N, 13C). Moreover, we inspected if litter functional diversity, litter quality (C/N ratio) and canopy cover affect oribatid mites. The results highlighted that tree species richness influenced oribatid mite trophic ecology through litter functional diversity and canopy cover. High litter functional diversity increased the average and range of Δ15N signatures indicating an increase in trophic position and trophic plasticity of oribatid mites with increasing litter diversity. More open canopy was associated with lower Δ13C signatures and a larger range in Δ13C signatures indicating that soil food webs become more complex when light conditions are more variable. Further, high litter C/N ratio increased the average and range of 15N signatures indicating that low litter quality results in less taxa living as decomposers and more taxa living as fungal feeders or predators. Maximum Δ15N values were generally lower in parthenogenetic than sexual taxa indicating that parthenogenetic taxa more often function as primary decomposers feeding on plant litter, whereas sexual species more often function as secondary decomposers feeding on microorganisms. The Δ15N range was also higher in sexual than in parthenogenetic species indicating that sexual taxa cover a broader range of feeding types than parthenogenetic taxa. Oribatid mite species with a larger body mass had lower Δ15N and Δ13C signatures indicting that they feed on plant litter more intensively than smaller species which feed on microorganisms or live as predators more intensively. Overall, the results indicate that litter functional diversity and data on canopy cover should be included in forest management practices to modulate soil microarthropod trophic structure.

L. Gannes, Carlos Martínez del Rio, Paul L. Koch

Abir Das, Sayan Pal, Nilakshi Chakraborty et al.

In this experiment, we investigated salinity-induced oxidative stress in rice with the involvement of sub1A quantitative trait loci for reactive oxygen species metabolism. We pretreated 15-day-old seedlings of cv. Swarna sub1 (a salt-susceptible variety) and Gosaba 5 (a salt-tolerant variety) using either 10 µM abscisic acid (ABA) or absence. The seedlings were then transferred to hydroponic cultures with either 0 or 100 mM NaCl to induce stress. Oxidative stress in the rice plants was investigated through both in vitro and in vivo detection of superoxide, hydrogen peroxide, and biosynthetic enzymes, including NADP oxidase activity under salinity. cv. Swarna sub1 exhibited enhanced retention of relative water content, elevated K+/Na+ ratio, and membrane stabilization with ABA. ABA also mitigated cell viability loss, though to varying extents among the cultivars, as observed through fluorescence imaging and Evans blue staining. Additionally, ABA treatment reduced cell wall peroxidation, resulting in expanded endodermal lumens and a decrease in malondialdehyde content. Pigment fluorescence and NADP-malic enzyme activity supported oxidative tolerance. A higher ratio of oxidized to reduced states of glutathione and ascorbate indicated improved tolerance when treated with ABA. The biogenesis of ABA was found to correlate with cultivar-specific tolerance, particularly when exogenous ABA was applied. ABA treatment appeared to heighten the sensitivity of enzymatic antioxidant cascades and showed variations in gene polymorphism. The detoxification of methylglyoxal, regulated by ABA, accentuated glyoxalase activities as potential biomarkers for oxidative stress. The study further discusses the roles of ABA metabolism in managing salinity-induced oxidative stress in both sensitive and tolerant rice cultivars.

T. Tscharntke, R. Brandl

C. Lortie, R. Brooker, P. Choler et al.

F. Bazzaz

V. Heywood, R. Brummitt, A. Culham et al.

Zhen Zhang, Lin Hua Chen, Min Long Tao et al.

The Nanwan village, a green ecological village in Taizhou city, is used as a recycling area (recycling for heavy metal) for electronic circuit boards and as crushing and stacking sites of waste circuit boards for nearly 20 years from 1980s to 2000s. At present, although the e-waste recycling activities in Taizhou city have been effectively controlled, and many areas polluted by the e-dismantling activities have been gradually remediated except Nanwan village. Nanwan village seems to have been forgotten for its special geographical location, which has attracted our attention because of its ecological and food safety issues. Accordingly, the content of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in the surface soil around the ruins and four edible agricultural crops were investigated. The main conclusions are as follows: among the four dismantling ruins and surrounding soil samples investigated, the content of Σ20PCBs in vegetable field topsoil of 2(20) is 1,321.3 ± 132.1 μg kg−1; the content of Σ8PBDEs in the paddy soil of 3(1S) is 7,216.9 ± 232.0 μg kg−1; biological toxicity events are likely to occur frequently in 2(20) and 3(1S). PCBs and PBDEs have both horizontal diffusion in distance and vertical diffusion in depth. The lifetime carcinogenic and non-carcinogenic risks of PCBs and PBDEs are at a low risk level, except for the non-carcinogenic risk of PCBs for children in 3(1S). The lifetime carcinogenic and non-carcinogenic risks of PCBs and PBDEs in the edible parts of garlic, ginger, mung beans, and oranges were all at acceptable or negligible levels.

Zhongtong Peng, Qifeng Mo, Liangjun Zhu et al.

Global climate changes have significantly affected tree growth and forest structures and functions in some arid and semi-arid regions, which are becoming warmer and wetter. Due to natural factors such as climate and terrain, some tree species may form different forest patches at the edges of their distribution areas. However, how forest patches of various sizes respond to climate change is unclear. In this study, we collected 203 tree cores from six different sizes of forest patches at the edge of the distribution area of Picea crassifolia Kom. in the northeast Tibetan Plateau. And we used the dendrochronology method to study the response of tree growth and resilience in different forest patches to climate change from 1961 to 2020. We simultaneously measured the contents of non-structural carbohydrates (NSC), total nitrogen and total phosphorus of tree needles. Our results showed that the growth of trees in small- and medium-size forest patches (0.8–18.6 ​ha) has increased significantly. The early growing season (May–July) minimum temperature was the most important climate factor driving the growth of small- and medium-sized patch trees. The early growing season maximum temperature was the most important climate factor that inhibited the growth of trees in the largest patches (362.8 ​ha). The growth of individual trees in medium forest patches was better and the correlation with annual minimum temperature, maximum temperature, precipitation, actual evapotranspiration, and palmer drought severity index was stronger. The higher NSC content, stronger photosynthesis, and higher nitrogen utilization efficiency in leaves might be one of the reasons for the better growth of trees in moderate forest patches. In extreme drought years, as the forest patch area increased, the overall trend of tree growth resistance showed a unimodal pattern, with the highest at a forest patch area of 7.1 ​ha, while the overall trend of tree growth recovery was opposite. Therefore, we should strengthen the management of trees in large forest patches to cope with climate change.