Plant Populations Research Articles

Performance of Gobhi Sarson (Brassica napus L.) under Integrated Nutrient Management

A field experiment was conducted during rabi season (2023-24) at Agricultural Research Farm, School of Agricultural Sciences and Technology, RIMT University Mandi Gobindgarh, to study the effect of integrated nutrient management (INM) in Gobhi Sarson (Brassica napus L.). The experimental field was laid out in randomized complete block design with 10 treatments and replicated thrice. The experiment comprised of 10 treatments i.e. T1 -Control, T2 -100% Recommended Dose of Fertilizers (RDF) (40:20::N:P2O5 kg ha-1), T3 -125% RDF, T4 -150% RDF, T5 -50% RDF + 15 t Farm Yard Manure (FYM) ha-1, T6 -50% RDF + 20 t FYM ha-1, T7 -75% RDF + 15 t FYM ha-1, T8 -75% RDF + 20 t FYM ha-1, T9 -100% RDF + 15 t FYM ha-1 and T10 -100% RDF + 20 t FYM ha-1. The result revealed that growth parameters were significantly higher in treatment T10 -100% RDF + 20 t FYM ha-1 plant population (21.79 m-2), plant height (157.9 cm), number of branches plant-1 (17.15), chlorophyll content (55.74) and yield and yield attributes were also significantly higher in treatment T10 -100% RDF + 20 t FYM number of siliquae plant-1 (291.0), siliqua length (8.423 cm), number of seeds siliqua-1 (23.01), 1000 seed weight (3.45 g), seed yield (23.45 q ha-1), straw yield (59.04 q ha-1) and harvest index (28.80 %) were observed. From this study it may be concluded that the combination of RDF and FYM enhanced the overall growth, yield and yield attributes of Gobhi Sarson.

Heatwaves exacerbate pollen limitation through reductions in pollen production and pollen vigour.

Increasingly frequent heat waves threaten the reproduction of flowering plants; compromising the future persistence, adaptive capacity, and dispersal of wild plant populations, and also the yield of fruit-bearing crop plants. Heat damages the development of sensitive floral organs and gametes, which inhibits pollen germination, pollen tube growth, and fertilization. However, the role of heat has not been integrated into the framework of pollen quantity and quality limitation and how heat influences the success of cross and self-pollination. We exposed developing flowers to either controlled temperature (25 °C:20 °C) or extreme heat (35 °C:20 °C) over 72h. We then hand-pollinated them with either crossed or self-derived pollen from the same temperature treatment to determine the direct and interactive effects of simulated heatwaves on pollen tube growth and resulting seed set. We also collected anthers from virgin flowers to measure heat impacts on pollen production. Under cooler control temperatures pollen tube survival of self-derived pollen was approximately 27% lower than that of crossed pollen. Pollen tube survival in heat-treated cross-pollinated and heat-treated self-pollinated flowers were 71% and 77% lower compared to flowers cross-pollinated at control temperatures. These differences in pollen tube survival rate between heat-treated cross-pollinated and heat-treated self-pollinated flowers were insignificant. Furthermore, extreme heat reduced seed set by 87%, regardless of pollen origin, and also reduced pollen production during flower development by approximately 20%. Our results suggest flowers that develop during heatwaves are likely to experience exacerbated pollen quantity and quality limitation driven by changes in pollen production and pollen vigour. Heatwave-induced pollen limitation will likely reduce crop yields in agricultural systems, and depress mating and reproduction in wild plant species, the latter of which may hinder the adaptive capacity of plants to a rapidly changing world.

Unravelling drivers of local adaptation through evolutionary functional-structural plant modelling.

Local adaptation to contrasting environmental conditions along environmental gradients is a widespread phenomenon in plant populations, yet we lack a mechanistic understanding of how individual agents of selection contribute to this evolutionary process. Here, we developed a novel evolutionary functional-structural plant (E-FSP) model that recreates local adaptation of virtual plants along an environmental gradient. First, we validate the model by testing if it can reproduce two elevational ecotypes of Dianthus carthusianorum occurring in the Swiss Alps. Second, we use the E-FSP model to disentangle the relative contribution of abiotic (temperature) and biotic (competition and pollination) selection pressures to elevational adaptation in D. carthusianorum. Our results suggest that elevational adaptation in D. carthusianorum is predominantly driven by the abiotic environment. The model reproduced the qualitative differences between the elevational ecotypes in two phenological (germination and flowering time) and one morphological trait (stalk height), as well as qualitative differences in four performance variables that emerge from G × E interactions (flowering time, number of stalks, rosette area and seed production). Our approach shows how E-FSP models incorporating physiological, ecological and evolutionary mechanisms can be used in combination with experiments to examine hypotheses about patterns of adaptation observed in the field.

The evolutionary ecology of inbreeding depression in wild plant populations and its impact on plant mating systems.

Inbreeding depression, the reduced fitness of inbred relative to outbred individuals was described more than two centuries ago, long before the development of population genetics. Its impact is central to evolutionary ecology and the evolution of mating systems, in particular self-fertilization in hermaphrodites. In the first half of the 20th century, population genetics revealed a mechanism for inbreeding depression through homozygosity. Numerous theoretical studies have modeled inbreeding depression as a function of genetic architecture and analyzed how it varies with population selfing rates. A major concept in these models is purging, i.e., the purging of recessive deleterious mutations through inbreeding. Consequently, inbreeding depression is expected to decrease with increasing population selfing rates. Along with these theoretical studies, many experimental studies, particularly on plants, have measured inbreeding depression using experimental crosses or directly in the field. The results of these studies have revealed that the evolutionary ecology of inbreeding depression is difficult to capture and that empirical data do not exactly match model predictions, specifically purging efficacy. In addition, the lability of inbreeding depression in natural populations can qualitatively affect the selective role of inbreeding depression in the evolution of mating systems. Recently, several studies have demonstrated the role of epigenetics in shedding new light on the dynamics of inbreeding depression in natural populations. This review provides a general overview of the studies on inbreeding depression and how various angles can help capture its selective role in natural populations.

Assessing Seed Treatments to Control Sudden Death Syndrome Caused by Fusarium virguliforme and Seedling and Root Disease Caused by Rhizoctonia sp. on Mungbean (Vigna radiata)

There is growing interest in producing mungbean ( Vigna radiata L. Wilczek) in the United States, which is driven by increased consumer demand. Strategies are needed for United States farmers to take advantage of this high-value crop and its environmental sustainability. Recommendations for the management of mungbean seedling and root diseases are lacking. Preliminary research in central Iowa mungbean fields from 2019 to 2023 has shown that mungbean is particularly vulnerable to Fusarium virguliforme, the cause of soybean sudden death syndrome (SDS), and Rhizoctonia sp., the cause of damping-off, root decay, premature defoliation, and pod abortion. The purpose of this study was to screen a variety of fungicides as a seed treatment or a soil band application to control root rot in mungbean. We performed three field studies over 2 years using mungbean cultivars Berken and OK2000. Seed treatments Evergol Energy + fluopyram and Evergol Energy + pydiflumetofen showed the highest performance ( P < 0.05), with approximately 30% more healthy roots than nontreated controls. Other treatments exhibited about 20% more healthy roots than the nontreated control. Biotam in-furrow application showed the highest plant population for ‘OK2000’, but we observed no treatment differences in plant stand for ‘Berken’.

Consequences of Local Conspecific Density Effects for Plant Diversity and Community Dynamics.

Conspecific density dependence (CDD) in plant populations is widespread, most likely caused by local-scale biotic interactions, and has potentially important implications for biodiversity, community composition, and ecosystem processes. However, progress in this important area of ecology has been hindered by differing viewpoints on CDD across subfields in ecology, lack of synthesis across CDD-related frameworks, and misunderstandings about how empirical measurements of local CDD fit within the context of broader ecological theories on community assembly and diversity maintenance. Here, we propose a conceptual synthesis of local-scale CDD and its causes, including species-specific antagonistic and mutualistic interactions. First, we compare and clarify different uses of CDD and related concepts across subfields within ecology. We suggest the use of local stabilizing/destabilizing CDD to refer to the scenario where local conspecific density effects are more negative/positive than heterospecific effects. Second, we discuss different mechanisms for local stabilizing and destabilizing CDD, how those mechanisms are interrelated, and how they cut across several fields of study within ecology. Third, we place local stabilizing/destabilizing CDD within the context of broader ecological theories and discuss implications and challenges related to scaling up the effects of local CDD on populations, communities, and metacommunities. The ultimate goal of this synthesis is to provide a conceptual roadmap for researchers studying local CDD and its implications for population and community dynamics.

Behavioural Thermoregulation of Flowers via Petal Movement.

Widely documented in animals, behavioural thermoregulation mitigates negative impacts of climate change. Plants experience especially strong thermal variability but evidence for plant behavioural thermoregulation is limited. Along a montane elevation gradient, Argentina anserina flowers warm more in alpine populations than at lower elevation. We linked floral temperature with phenotypes to identify warming mechanisms and documented petal movement and pollinator visitation using time-lapse cameras. High elevation flowers were more cupped, focused light deeper within flowers and were more responsive to air temperature than low; cupping when cold and flattening when warm. At high elevation, a 20° increase in petal angle resulted in a 0.46°C increase in warming. Warming increased pollinator visitation, especially under cooler high elevation temperatures. A plasticity study revealed constitutive elevational differences in petal cupping and stronger temperature-induced floral plasticity in high elevation populations. Thus, plant populations have evolved different behavioural responses to temperature driving differences in thermoregulatory capacity.

Woody plant communities in different land management types and implications on mountain biodiversity conservation in central Ethiopia

The prominence of mountains as social-ecological systems and the need for sustainable mountain development have increasingly been recognized in global agendas and international conventions. This study aims to investigate woody plant diversity, composition, and population structure in two different land management types: lands managed by the Wanchi Ecotourism Association (WETA) and non-WETA members at the slopes of Wanchi Mountain. Trees and shrubs with diameter at breast height (DBH) ≥ 5 cm were recorded from 20 m by 20 m plots and those with DBH<5 cm were counted within sub-plots of 10 m by 10 m. Tree seedlings were recorded from five 3 m by 3 m sub-sub-plots. The quasi-Poisson generalized linear model with a log-link function was used to analyze the richness of woody species and their association with environmental variables. Non-metric multidimensional scaling with Bray-Curtis distance in two-dimensional space was employed for the woody species composition. Tree species population structure was analyzed using tree diameter distribution classes. The study identified 104 woody plants belonging to 82 genera and 52 families. Woody species richness in WETA-managed lands is significantly (P=0.009) greater than that of non-WETA-managed lands. The study found that woody species richness significantly declined with increasing anthropogenic disturbance (P<0.001) and slope (P<0.001) in both WETA and non-WETA-managed land. Woody species richness also showed negative associations with aspect. The tree species in both the land management types revealed nearly similar population structures. The study highlighted the importance of sustainable land management practices such as ecotourism in areas of significant natural endowments like that of the Wanchi Mountain. Such practices can guide more sustainable mountain biodiversity conservation while realizing appropriate local livelihood improvement strategies.

Plant traits determine seed retention times in frugivorous birds: Implications for long‐distance seed dispersal

Abstract Seed dispersal by frugivorous animals is a key process for plant populations and communities. When frugivores consume fruits, seeds are temporarily retained inside their guts until seed deposition. Hence, information on retention times is essential to estimate seed‐dispersal distances. Although it is well known that retention times are affected by the body size of frugivores, there is an important knowledge gap on the effects of plant species traits, such as seed size and pulp content. Here, we comprehensively address whether and which plant traits affect seed retention times in frugivorous birds. On the one hand, we conducted a first set of experiments to assess variation in retention times among 31 plant species dispersed by a single bird species, and a second set to assess variation among five plant species dispersed by a guild of five frugivorous passerines. On the other hand, we conducted a literature review retrieving retention times for 231 interactions involving 155 plant species and 55 bird species from nine different avian orders. Seed size had negative effects on retention times at the three levels addressed in this study: the larger the seeds, the shorter the times. The effects of seed size were higher within a single bird species, intermediate for the small assemblage of five passerine species, and lower for all frugivorous birds included in the compilation. Notably, the effects of seed size on retention times were comparable to that of frugivore body size in Passeriformes. We analysed the effects of the pulp content on a single bird species, but these lacked predictive power. Importantly, the effects of seed size were indirect and mediated by the type of seed ejection (digestive processing): birds generally defecate smaller seeds and regurgitate the larger ones. We provide comprehensive evidence that retention times are intrinsically linked to plant traits and to frugivores' response to such traits, particularly to seed size and the type of seed ejection, respectively. Thus, our study unveils a source of interspecific variability in the capacity of plants to disperse at long distances. Moreover, we provide methodological improvements to trait‐based models that estimate mean retention times and seed‐dispersal distances. Read the free Plain Language Summary for this article on the Journal blog.

Sexual differetiation of Rhodiola rosea L. populations in the high-mountain zone of the Ukrainian Carpathians

Background. Individual (morphological) and group parameters (the number of male and female individuals, their sex ratio, and the range of sex ratio displacement) are an important indicator of sexual differentiation of Rhodiola rosea L. populations. To date, indicators of these parameters in natural plant populations have not been studied sufficiently. Therefore, for the analysis of the state of the populations of the species, it is important to study the parameters of their sexual differentiation and the main trends of changes that affect the ability to recover in high-mountain conditions. Methods. In order to obtain data, conventional stationary and route-based research methods were used. To record individuals of different sexes, long-term monitoring plots were used, which were laid in the characteristic habitats of the species’ populations in 2000–2022. The ratio of male and female individuals is determined based on their quantitative distribution per unit area. The sexual potential index that determines the proportion of females and their participation in generative reproduction was used. Results. The main differences in the morphological and quantitative parameters of male and female individuals in high-mountain conditions were determined. It was found that a characteristic feature during long-term research is a decrease in the number of generative individuals of both male and female sexes. In the studied populations, there is a shift in the sex ratio towards males (73 %) and this trend has been maintained over the last dozen of years. Therefore, the number of females compared to males is very small, which affects the sexual potential of populations. Conclusions. The ratio of male and female individuals, the range of its displacement and potential participation in the realization of sexual potential in R. rosea was determined. The present study showed that the general trend in the populations of the species is a decrease in the number of female individuals. Male biased sex ratio has an impact on sexual potential and ability to generative reproduction.

Soybean response to high‐speed planting in Mississippi

AbstractMississippi soybean [Glycine max (L.) Mer.] producers are under pressure to plant as much land as possible within narrow planting windows. The 5‐year average planting progress is 45% of the total at the end of the optimal soybean planting window. New metering and seed delivery technology claims faster planting without sacrificing singulation, stand, or yield, but these tools need to be validated before recommendation. This study aimed to quantify soybean response to planting speeds using a precision planter (John Deere MaxEmerge 2 row units retrofitted with Ag Leader SureSpeed and SureForce) and a mechanical planter (John Deere 1700 ground‐driven mechanical planter equipped with eSet meters) for a total of 7 site‐years across Mississippi. In 2022, both planters were evaluated at four actual ground speeds of 7.9, 10.8, 13.5, and 16.4 km h−1 in a 2 × 4 factorial design. The experimental design was modified in 2023, where the mechanical planter served as the current farmer practice check at 9.7 km h−1and the precision planter speeds were 9.7, 14.5, and 17.7 km h−1 at research station sites and 9.7 and 14.5 km h−1 at an on‐farm site. Across sites, increased planting speed generally increased plant spacing, in‐row spacing variability, and decreased plant population. However, increased speed did not affect soybean yield. The precision planter at 17.7 km h−1 was no different from the mechanical planter in terms of soybean plant population, spacing, and yield in 2023. Results suggest soybean producers can plant soybean at 17.7 km h−1 without compromising yield.

Niche of woody plant populations in Picea purpurea community in the upper Taohe River

The niche of plant populations is affected by the environment, species characteristics and anthropogenic disturbance. Picea purpurea, as a major constructive species in the northeastern Qinghai-Tibetan Plateau, had been severely damaged. Although the national project for the protection of natural forests has promoted the recovery of its community, its structure, survival status, development trend, and the factors affecting it are still unclear. We selected P. purpurea communities in Zecha, Dayugou and Yeliguan forest zones at different altitudes and disturbance levels. We analyzed niche characteristics of the woody plants and the relationship between niche and altitude, and disturbance. P. purpurea has absolute advantages as a constructive species, and its population dominance and niche width in the tree layer show a decreasing trend with decreasing altitude, there is niche overlap between all species pairs. In the shrub layer, the dominant species are mostly Caprifoliaceae and Rosaceae besides P. purpurea seedlings, the proportion of species pairs with niche overlap is YLG>ZC>DYG, and all appeared niche divergence and convergence species pairs. In addition, P. purpurea seedlings had niche overlap with most woody species, and this overlap index was the highest. The mean values of the niche overlap index between species in the tree and shrub layers were all YLG>DYG>ZC. The niche overlap index between species in the tree layer was greater than that in the shrub layer in the same forest zones, indicating that the tree layer is more stable than the shrub layer, providing evidence that niche overlap maintains community stability. Regression analyses showed that minimum temperature was the main factor affecting dominance, niche, niche overlap and shrub layer species richness of the P. purpurea population. Disturbance did not significantly affect dominance and niche of P. purpurea seedling populations, but promoted niche differentiation of shrub layer species. We conclude that the P. purpurea community is mainly influenced by altitude and anthropogenic disturbance. Altitude-induced climatic variation fundamentally determines the distinct community composition and population niche. Anthropogenic disturbance has altered habitat heterogeneity and enriched community structure. Furthermore, the P. purpurea populations show a trend towards expansion. Understanding the structure and niche characteristics of P. purpurea communities on different environmental gradients enriches our ideas for implementing vegetation restoration and sustainable forest management in subalpine zones in the context of climate change, and is conducive to improving the conservation capacity of this population or community type.

Substitutive Effects of Upland Rice and Soybean Plant Populations on the Performance of the Component Crops in Intercropping System

Substitutive Effects of Upland Rice and Soybean Plant Populations on the Performance of the Component Crops in Intercropping System

Bed, ridge and planting configurations influence crop performance in field-transplanted hybrid potato crops

Current cultivation practices for field transplanted potato crops grown from nursery-raised hybrid potato seedlings are mostly borrowed from the tuber-based conventional system. Most studies on field performance of field transplanted seedling crops have largely reported the use of ridged rows and in exceptional cases, the use of beds. It is therefore critical to assess the feasibility of the use of alternative ridge or bed systems for cultivation of field-transplanted nursery-raised potato seedlings considering the differences in physiological behaviour of crops grown from different starting materials. This study assessed the effects of six systems which included bed and ridge systems of different dimensions and planting configurations for field transplanted seedling crops. Field crop establishment, canopy growth and development as well as yield and yield components were assessed. In general, systems that boasted high plant densities resulted in faster canopy development and higher number of tubers and tuber yield. Bed systems (raised and flat beds; 8.0 plants m−2) therefore gave the highest numbers of tubers and tuber yield across all treatments. These systems also produced the most tubers in all tuber size classes resulting in the highest yields in all classes. Standard ridge systems (full- and half ridges; 0.75 m row distance), had the lowest plant populations (5.3 plants m−2) which resulted almost always in fewer tubers and lower yield. Other ridge systems (0.9-m and 0.5-m ridge systems), although having higher plant densities than the standard ridge systems (8.9 and 8.0 plants m−2, respectively) still performed poorer than the bed systems. The small and compact ridges in the 0.5-m ridge system and the compact arrangement of plants in the 0.9-m ridge system caused these effects. Conclusively, based on this study, productivity in field transplanting systems is highly influenced by plant density. Further, cultivation systems boasting higher planting densities should be recommended when the goal for production is to produce large quantities of seed tubers (> 35; ≤ 50 mm).

Paddy seed viability prediction based on feature fusion of color and hyperspectral image with multivariate analysis

Seed viability is essential to have a homogeneous plant population. The seed industry cannot adopt traditional procedures for seed viability evaluation since they are destructive, time-consuming, and need chemicals. This study aimed to investigate the potential of combining hyperspectral and color image features to differentiate viable and non-viable paddy seeds. The hyperspectral and color image of the 355 paddy seeds was captured and later used to examine their viability. An image processing algorithm was developed to extract features from color images of paddy seeds and investigated significant differences in the retrieved feature data using variance analysis. The spectra were extracted from the selected region of interest (ROI) of the hyperspectral paddy seed image and averaged. In the next step, the partial least square discrimination analysis (PLS-DA) model was developed to distinguish viable and non-viable paddy seeds. Initially, the PLS-DA model was developed using spectral data with different preprocessing techniques, and the result obtained an accuracy of 88.9 % in the calibration set and 86.1 % in the prediction set using Savitzky-Golay 2nd derivative preprocessed spectra. With the fusion of spectral and significant color image features, the model's accuracy improved to 93.3 % and 90.9 % in the calibration and prediction sets, respectively. Results also showed that the fusion of selected color image features with Savitzky-Golay 2nd derivative preprocessed spectra could achieve higher F1-score, recall, and precision values. The visualization map for the viable and non-viable paddy seeds was also developed utilizing the most effective predictive model. The results demonstrate the possibility of using the fusion of the hyperspectral and color image features to sort seeds according to viability, which may be applied in developing an online seed sorting method.

Recurrent Selection as a Basis for the Widespread Dissemination and Cultivation of Onions: Examples From Northeastern Brazil

Goal: This study aimed to review phenotypic recurrent selection (PRS) in the onion development for northeastern Brazil. Theoretical Framework: Domesticated in the Central Asia (35°N and 50°N), onion is one of the main vegetable species widely cultivated around the globe. PRS methods are efficient for genetic gains (GG), maintaining variability in the population. Method: Cultivars of two onion-breeding programs for the Brazil Northeast region were analyzed to evaluate the PRS efficiency. Results and discussion: 1. PRS resulted in the development of cultivars Valeouro Ipa 11 and Franciscana IPA 10, at Belém do São Francisco (08°45'S, 38°57'W), replacing 70% of imported cultivars. 2. PRS for resistance to Thrips tabaci (09°09’S, 40°22’W), a pest of global importance, in the 'BRS Alfa São Francisco' resulted in GG of 6%/cycle, with a bulb yield of 32.1 ton.ha-1, contrasting with 15.9 and 14.0 ton.ha-1 of 'Alfa Tropical' and 'IPA 10', respectively (p&lt;0.01). In direct planting and high population density, BRS Alfa São Francisco produced 60 ton.ha-1 in the second semester. 3. The PRS for external brownish or purplish cataphylls and greater thickness (09°09’S, 40°22’W), in the CNPH 6400, resulted in GG/cycle of 6.83% and 11.54% in the brownish population and 7.84% and 10.92% in the purplish population, evaluated in two locations. Research implications: These examples emphasize the efficiency of PRS for accumulating favorable alleles, allowing the recommendation of onion cultivars in areas different from the domestication region. Originality/Value: The adopted approach have distinguished the massal selection from recurrent selection.

Growth response of dominant species and companion species to grazing and precipitation addition in a typical steppe

Growth strategies of plant populations plays an important role in biodiversity and productivity of community while over half 77% of global terrestrial ecosystem is used for grazing and simultaneously 30%-40% is exposed to precipitation addition (PA). However, the combined effects of grazing and PA on plant population growth and their relationship with community characteristics remain poorly understood, largely due to the limited number and quality of field experiments. Hereby, a four-year PA experiment was conducted in long-term grazed paddocks in a typical steppe, which aimed to compare the effects of both grazing and PA on the growth, reproduction, and trade-offs between dominant and companion species. The interaction between grazing and PA prompted the dominant species to adopt a horizontal growth strategy and sexual reproduction, allocating 69 % of its resources to offspring production, whereas the companion species opted for a vertical growth strategy and asexual reproduction, allocating 87 % of its resources to individual survival and dispersal. This trade-off strategy increased the proportion of dominant species while companion species remained stable, and PA mitigated this trend while concurrently decreasing the proportion of other species within the community. The interaction between grazing and PA promotes the coupling of aboveground biomass and species riches in community by decreasing plant height of dominant and companion species and increasing canopy diameter of companion species. There were mainly four biotic response curves of dominant and companion species to grazing and PA interaction: full saturation, sufficient saturation, equal saturation, and deficit saturation. Correspondingly, there were three pairs of threshold values for three phases of each pattern. Our study reveals how communities improve their adaptability by regulating population growth, providing important insights for developing sustainable grazing management strategies under global climate change.

Fine‐scale alpine plant community assembly: Relative roles of environmental sorting, dispersal processes and species interactions

Abstract Besides environmental sorting, other processes like biotic interactions and dispersal limitation are vital for the assembly of plant communities in high mountains and their re‐assembly under changing climatic conditions. Nevertheless, studies that compare the impact of these factors on plant community assembly above the tree line are largely lacking so far. We analysed occurrence changes in vascular plant communities of 492 permanent 1‐m2 plots in the alpine‐nival ecotone of Mt. Schrankogel, Austrian Alps by comparing resurvey data from 2014 with data from the initial survey in 1994. We combined these data with species inventories from 899 additional plots sampled in 2021 and 2022 across a larger landscape above the tree line covering an elevational range of 1700 m, which we used for fine‐scale habitat suitability modelling. We assessed the relative effects of projected habitat suitability, propagule pressure from surrounding populations and biomass density of neighbours on 1532 colonization and 372 extirpation events of 31 species observed on the permanent plots. We found that all three factors are significantly related to both colonisations and extirpations, with habitat suitability having the strongest, propagule pressure a slightly weaker, and vegetation density the weakest effect. Colonisations can be better explained by the three process proxies than extirpations. Our results indicate a crucial role of dispersal limitation besides the predominant effect of environmental filtering on the (re‐)assembly of the alpine‐nival plant community, while competitive/facilitative effects between plants tend to play a minor role. The strong imprint of nearby source plant populations on colonization/extirpation events suggests that recent plant migrations predominantly occur in small steps. This implies that while the topographically complex alpine terrain offers climatic microrefugia for plants, it may also pose potential barriers, hindering species from following their suitable climatic niches upwards. Synthesis: Besides filtering by environmental conditions dispersal limitation had a strong effect on the observed changes in a local alpine plant community over two decades. Limited dispersal capacities of plant species may counteract the ability of isolated cold areas to effectively shelter high alpine plants from the effects of climate warming.

Exploring ecotypic plant adaptations and the influence of microbiota on mitigating environmental challenges

The idea of ecotypes, which refer to unique groups of plants that have evolved to flourish in specific habitats, is gaining attention owing to climate fluctuations and changes in the associated microbiota. The term "ecotype" described plant populations that are specially adapted to particular environments, as revealed by common garden experiments showcasing genetically distinct characteristics. This concept remains relevant in modern plant science, where garden experiments continue to uncover how natural selection promotes species diversity, underscoring the crucial role of the plant microbiota in adaptation. Recent research has highlighted the microbial interactions that aid plants in adapting to environmental stress. Plants that shape soil microbial communities exhibit differential responses along ecological gradients owing to environmental stressors that influence interactions with soil microorganisms. Understanding the differentiation within plant populations and the emergence of new species is vital for discerning natural selection patterns. Environmental stressors profoundly impact global crop production, whereas plant-microbiota symbioses significantly influence plant growth and defense through nutrient acquisition and metabolite synthesis. Plant adaptation mechanisms include enzymatic antioxidant production and osmolyte accumulation, which are regulated by phytohormones that orchestrate responses to biotic and abiotic stressors, respectively. Despite breeding and genetic engineering efforts, progress in enhancing plant tolerance to extreme conditions remains limited, necessitating the development of sustainable agricultural alternatives. This study offers a comprehensive overview of recent advances in plant ecotype research, particularly focusing on symbiotic relationships with the microbiota and traits that contribute to improved nutrient uptake and plant health.

Determinants of tree population temporal stability in a temperate mixed forest over a gradient of nitrogen addition

Nitrogen (N) deposition is a significant threat to the functioning of forests and negatively impacts the delivery of forest goods and services. Contemporary management approaches seek to adapt forests to such N-deposition stressors, but to date how plant populations in natural forests respond to N deposition and what factors determine the contrasting responses among populations are still unclear. Here, we investigated the impact of N-addition (control: 0 kg ha−1 yr−1; low: 25 kg ha−1 yr−1; medium: 50 kg ha−1 yr−1; high: 75 kg ha−1 ha yr−1) on tree population temporal stability and how initial tree size, mycorrhizal type, and leaf N content (LNC; as a surrogate for functional trait composition) mediate tree population responses to N-addition in a Korean pine and mixed broadleaved dominated temperate forest in northern China. We quantified tree species population temporal stability as the ratio of mean to standard deviation of the year-by-year stem increments recorded in individual trees from 2015 to 2022 experimental period. The results showed different temporal stabilities of tree species among four N-addition levels, with the highest population stability observed within the high N-addition plots. Furthermore, initial tree size had significantly (p < 0.001) positive effects on population temporal stability. The effect of LNC and initial tree size were also contingent on the level of N applied. Specifically, increase in tree population LNC reduced population temporal stability in all plots where N was added. Our results imply that retention of large-sized trees and species with resource-conservative strategies (e.g., low LNC) could enhance forest stability under N deposition.