Plant Ecosystem Research Articles

Causes of Missing Snowmelt Following Drought

AbstractWater management in snowy mountainous regions hinges on forecasting snowmelt runoff. However, droughts are altering snowpack‐runoff relationships with ongoing debate about the driving mechanisms. For example, in 2021 in California, less than half of predicted streamflow arrived. Mechanisms proposed for this “missing” streamflow included changes in evapotranspiration (ET), rainfall, and subsurface moisture conditions. Here, we demonstrate that ET in drought years generates dry subsurface conditions that reduce runoff in subsequent years. A model including this legacy of depleted moisture storage reduced median error in 2021 forecasts from 60% to 20% at 15 minimally disturbed basins and from 18% to 2% at 6 water supply basins in the Sierra Nevada (basins range in area from 5 to 23,051 km2 and mean annual precipitation from 814 to 1,549 mm). Our findings indicate that the relationship between snowpack and runoff will evolve as plant ecosystems respond to climate change and alter subsurface water storage dynamics.

Aplikasi Pengukuran Luas Daun Tanaman Menggunakan Pengolahan Citra Digital Berbasis Android

Leaves are the most important organ in plants in the process of photosynthesis and will affect plant growth and productivity. Leaves also have a function as the main food maker. Leaf area is a very important parameter in the science of plant nutrition, measurement of plant protection, the relationship between water and soil in plants, plant ecosystems, plant fertility, etc. The use of leaf area measuring instruments that exist today has its drawbacks in terms of portability and practicality. The development of smartphone technology, one solution that can be used to overcome this is to design an application to measure the area of leaves by utilizing an android based smartphone camera. This research has been successfully made a leaf area calculation application that utilizes smartphone cameras using the OpenCV library. The application provided in this study is able to provide convenience and speed up the calculation of the leaf image area with an error rate of 4.9% and an accuracy of 95.1% from the average results of 10 leaf samples tested. Keywords : Image Processing, Leaf Area, Opencv, Android.

Metagenomics reveals N-induced changes in carbon-degrading genes and microbial communities of tea (Camellia sinensis L.) plantation soil under long-term fertilization

Soil organic carbon (SOC) is an important C pool of the global ecosystem and is affected by various agricultural practices including fertilization. Excessive nitrogen (N) application is an important field management measure in tea plantation systems. However, the mechanism underlying the impact of N fertilization on SOC, especially the microscopic mechanism remain unclear. The present study explored the effects of N fertilization on C-cycling genes, SOC-degrading enzymes and microbes expressing these enzymes by using a metagenomic approach in a tea plantation under long-term fertilization with different N rates. Results showed that N application significantly changed the abundance of C-cycling genes, SOC-degrading enzymes, especially those associated with labile and recalcitrant C degradation. In addition, the beta-glucosidase and chitinase-expressing microbial communities showed a significant difference under different N rates. At the phylum level, microbial taxa involved in C degradation were highly similar and abundant, while at the genus level, only specific taxa performed labile and recalcitrant C degradation; these SOC-degrading microbes were significantly enriched under N application. Redundancy analysis (RDA) revealed that the soil and pruned litter properties greatly influenced the SOC-degrading communities; pH and DOC of the soil and biomass and total polyphenol (TP) of the pruned litter exerted significant effects. Additionally, the random forest (RF) algorithm revealed that soil pH and dominant taxa efficiently predicted the beta-glucosidase abundance, while soil pH and DOC, pruned litter TP, and the highly abundant microbial taxa efficiently predicted chitinase abundance. Our study indicated that long-term N fertilization exerted a significant positive effect on SOC-degrading enzymes and microbes expressing these enzymes, resulting in potential impact on soil C storage in a perennial tea plantation ecosystem.

Impacts of Industrialization on Plant Species Composition, Diversity, and Tree Population Structure in Tropical Moist Deciduous Forest in Bangladesh

Industrial activities have various effects on biodiversity, posing significant threats to forest ecosystems. The current study describes the species composition, taxonomic diversity, and stand structure at Bhawal Sal forest, Gazipur, Bangladesh, as they are affected by industrialization. To achieve the goal, 30 different categorized industries within the forest were considered sampling points and three distance gradient sites viz. Site-1 = Adjacent to industries (0 m), Site-2 = 160 m distance and Site-3 = 320 m distance from industries were designated as treatments. A total of 90 quadrate plots (10 m × 10 m) were taken randomly, of which 30 plots were from each site. Through forest inventory, 46 species (24 trees, 8 shrubs, 5 climbers, and 9 saplings) were recorded from three sites. The study revealed that the stand density and basal area of mature trees (257 stems ha−1 and 8.06 ± 0.60 m2·ha−1) at Site-1 were significantly lower due to diverse industrial operations than other sites. Statistically, all the biodiversity indices of mature trees; Shannon–Wiener’s index (1.72), Simpsons index (0.82), Margalef’s index (1.38), Pielou’s evenness Index (0.39) was found to be lower at proximity to industries. The lowest species richness (12) of all plants was recorded from Site-1. However, the diameter and height distributions of Site-1 comprised young (10–20 cm·dbh) to medium-sized (20.1–30 cm·dbh) trees, while the medium to large sized (>30 cm·dbh) trees was contained at Site-3 in this study. The population structure of tree species at Site-1 also showed a fluctuating curve. Overall, this study highlights that plant ecosystems and tree population structure have declined tremendously due to industrialization. Hence, the current research could be significant for developing the management framework for the disturbed deciduous forest.

Cadmium (Cd) and Copper (Cu) Exposure and Bioaccumulation Arrays in Farm Ruminants: Impact of Forage Ecotypes, Ecological Sites and Body Organs

Copper (Cu) and cadmium (Cd) metal distribution in soil–plant ecosystems and their public health risk impact on ruminants (cows, buffalo, and sheep) are explored in the present investigation. Five different forage crops were selected, and the foraging responses of three types of ruminants (cows, buffalo, and sheep) at three ecological sites were evaluated. The soil of these three ecological sites was metal polluted (due to wastewater irrigation) and was studied to evaluate the metal contamination and pollution load index. For the assessment of Cd and Cu, soil, vegetation, blood, hair, and feces samples were collected and analysed using an atomic absorption spectrophotometer. High consumption of fodder crops (Sorghum bicolor Kuntze, Sesbania bispinosa (Jacq.) W. Wight, Cynodon dactylon (L.) Pers., Suaeda fruticosa (L.) Forssk., and Tribulus terrestris L.) by cows and buffalo at site-III resulted in an increase in daily Cu and Cd intake. The pollution load index was higher at site-II and site-III, indicating a severe health risk scenario for local inhabitants. Cd and Cu were at their maximum levels in fodder crops. A significant increase in the concentrations of Cd and Cu was found in the blood, hair, and feces of cows and buffalo at site-III. Ecological indicators such as the bioaccumulation factor, the pollution load index, and the enrichment factor were found to be higher in buffalo than cows. The Cd level in forages was highest at the site-III Cd level and in the order of S. bispinosa > S. fruticosa > T. terresteris > C. dactylon > S. bicolor. Although these levels were lower than the permissible maximum limit, they were generally higher in the forage crops. Exposure of local inhabitants to the consumption of milk and meat from these cattle showed the serious health risks consequences. This situation can be properly managed by general monitoring of soil and vegetation pollution, avoiding metal contamination in the soil and food chain components, and using treated waste water and other alternate water sources for forage irrigation.

Empirical analysis of the influences of meteorological factors on the interannual variations in carbon fluxes of a Quercus variabilis plantation

Influences of meteorological factors on the carbon fluxes of a forest ecosystem can vary with time scales. While many studies were made on daily to annual variations of measured carbon flux of forest ecosystems, few were conducted on the variations of observed carbon fluxes over longer (decadal or more) time scale. This study quantified the influences of meteorological variables on the measured carbon fluxes in a Quercus variabilis plantation from 2006 to 2021 using principal component analysis (PCA) and cluster analysis (CA). PCA was used to identify the most important meteorological variables. They are monthly mean daily maximum global radiation (Rg), monthly effective accumulated temperature (Tac), monthly mean daily maximum vapor pressure deficit (VPD), and monthly precipitation (PP). CA was used to group 192 observed months into four groups based on those four meteorological variables and their effects on the observed carbon fluxes. Structural equation modeling (SEM) was then used to quantify the relative importance and direct or indirect effects of those four meteorological factors on carbon fluxes at the interannual timescale in each of the four groups. The results showed that air temperature had dominant influence on net ecosystem productivity (NEP) and ecosystem respiration (Re) with its relative importance measured by standardized coefficients (SC) of 0.59 and 0.97, respectively. PP directly impacted gross primary production (GPP) with an SC of 0.40 and indirectly influenced NEP and Re. The importance of a given meteorological factor on carbon fluxes and the dominant meteorological factors varied among the four groups. Tac mainly influenced Re with a SC of 0.79 in Group 1 (the nongrowing season). The direct effects of PP on NEP and GPP and indirect effects on Re were most prominent in Group 2 (the transition stage between the nongrowing season and the growing season). Tac and PP had greater influences than other two variables in Group 3 (the transitional stage of early growth and vigorous growth and the transitional stage of steady growth and dormant period). NEP increased with Tac, while excessive rainy weather accompanied by a decrease in temperature and radiation reduced Re and GPP in Group 4 (the wet season). The short-term seasonal droughts with warm air temperatures but little precipitation (mainly in June) led to significant reductions in both GPP and NEP of the Quercus variabilis plantation ecosystem in the warm-temperate continental monsoon climate zone. Our results can be used to guide managing forest plantations in temperate region in China to maximize their carbon sequestration.

C, N, P, K stoichiometric characteristics of the “leaf-root-litter-soil” system in dryland plantations

• Tree species and afforestation years affected nutrient cycling of plantations. • The highest C was in fine roots and the highest N, P and K was in green leaves. • Green leaves absorbed more P and maintained P homeostasis to alleviate P limitation. • Caragana korshinskii was more suitable for ecological restoration in drylands. Plantation’s nutrient cycling can regulate and affect the material cycling of ecosystems, which is the key to maintain the sustainable development of the plantation ecosystem. However, the current understanding of the nutrient cycling characteristics of the “leave-root-litter-soil” continuum of dryland plantation ecosystems is limited. Therefore, in the Longzhong Loess Plateau of China, we selected nine typical dryland plantations to carry related research, including two evergreen ( Platycladus orientalis (13-years and 50-years) and Pinus tabuliformis ) and four deciduous ( Caragana korshinskii (13-years, 35-years and 55-years), Armeniaca sibirica , Populus hopeiensis and Tamarix chinensis ) tree species, and measured C, N, P and K contents of green leaves, fine roots, leaf litter and surface soil (0–20 cm). Results showed tree species and afforestation years strongly changed C, N, P and K contents and ratios of green leaves, fine roots, leaf litter and soil components, and also significantly affected leaf N, P and K reabsorption efficiencies. The average N, P and K contents of four components and soil available nitrogen (AN), available phosphorus (AP) and available potassium (AK) contents in deciduous plantations were higher than those in evergreen plantations, resulting in the lower C:N:P:K stoichiometry of deciduous plantations than evergreen plantations. Especially in 55-years C. korshinskii plantation, its soil C, N, AN, AP and AK contents were higher than those in A. sibirica , P. hopeiensis , P. orientalis and P. tabuliformis plantations. Moreover, soil C, N, P, AN, AP and AK contents in C. korshinskii plantations increased significantly with the increase of afforestation years. Thus, C. korshinskii was more suitable for ecological restoration in drylands. Due to the P limitation in plantations, P reabsorption efficiency was higher than N reabsorption efficiency, and significantly negatively correlated with P contents of four components. And green leaves had the homeostasis to soil AP, which may be the nutrient utilization strategies for plantations to alleviate P limitation. Correlation analysis revealed that the C cycling appeared in green leave-fine root and green leave-leaf litter, the N cycling appeared in green leave-leaf litter-soil-fine root, and the P cycling and K cycling appeared in green leave-leaf litter- soil and leaf litter-fine root. These results will provide guidance for ecological restoration and plantation management in drylands.

Ecosystem photosynthesis depends on increased water availability to enhance carbon assimilation in semiarid desert steppe in northern China

The amount and intensity of precipitation may have important effects on plant growth and ecosystem carbon exchange in semiarid desert steppes; further understanding of how the dryland carbon cycle responds to changes in precipitation and its underlying mechanisms is necessary for an accurate understanding of the global carbon cycle. A field experiment was conducted in a semiarid desert steppe in Ningxia, China, to clarify the response patterns of ecosystem carbon fluxes along five levels of precipitation gradients (Simulating the natural precipitation percentages of 33 % (−33 %, 84 mm), 66 % (−66 %, 167 mm), 100 % (CK, 253 mm), 133 % (+33 %, 336 mm) and 166 % (+66 %, 420 mm) by rain shelters and sprinklers; CK is natural precipitation). The result showed that the trends of net ecosystem CO 2 exchange (NEE) and gross ecosystem photosynthesis (GEP) were consistent and those of ecosystem respiration (ER) and Soil respiration (SR) and autotrophic (Ra) and heterotrophic (Rh) components of SR were also consistent. NEE, ER, GEP and SR all reached their highest values in August. Changes in precipitation significantly affected ecosystem carbon fluxes, with NEE, ER and SR decreasing with decreasing precipitation and NEE, ER and GEP increasing with increasing precipitation. Soil respiration was more sensitive to the decreased precipitation treatment. During the growing season, NEE, ER, GEP, and SR were significantly positively correlated with precipitation, soil moisture (SM) and aboveground biomass (AGB). With the increase of precipitation variability, the promotion effect of increasing precipitation on GEP will exceed the promotion effect on ER, causing changes in carbon exchange and carbon sinks. Photosynthesis and respiration appeared tightly coupled, indicating that photosynthetic products regulate above- and belowground carbon cycling in semiarid steppe. Our study highlights the importance of water availability in carbon exchange processes in semiarid desert steppe of northern China. Decreased precipitation can lead to significant changes in SM and AGB, with negative impacts on GEP and SR, resulting in uncertainty in regional carbon sequestration. These findings will help us understand the vulnerability of semiarid steppe ecosystems under the influence of future precipitation changes and aim to provide a scientific reference for ecological management and restoration of semiarid desert steppes. • Effect of precipitation changes on above- and below-ground carbon fluxes was studied. • Increased precipitation promotes GEP more than ER, leading to carbon sinks. • Soil respiration was more sensitive to the decreased precipitation treatment. • There is a strong coupling between photosynthesis and soil respiration.

Callus Induction In Leucaena (Leucaena leucocephala (Lam.) de Wit) As An Effort To Provide Target Transformation Through Agrobacterium tumefaciens

Leucaena is a plant that produces biomass productivity in the form of hardwood for fuel with low humidity and high calorific value. However, Leucaena is also classified as an invasive plant which can cause the urgency of native plant species and ecosystems in Indonesia. Therefore, the formation of sterile Leucaena needs to be done, one of which is through genetic transformation using Agrobacterium tumefaciens. Callus is used as a target for transformants in the genetic transformation process, so it is necessary to use appropriate media and PGR. This study aimed to determine the type of media and the concentration of 2,4-D on callus induction. This research is an experimental study with a completely randomized design (CRD) method with two factors. The first factor is the type of media (MS and WPM) and the second factor is the concentration of 2,4-D (0; 0.25; 0.50; 0.75; 1.00; 1.25 and 1.50 mgL-1 ). Each treatment was repeated three times so that 42 experimental units were obtained. Parameters observed were callus initiation, callus fresh weight (gram), callus texture and color. Quantitative data is analyzed by analysis of variance (ANOVA). The results showed that the use of media had a significant effect (P<0.05) on callus fresh weight. The use of 2,4- D concentration had a significant effect (P>0.05) on callus texture. The use of WPM media resulted in the fastest callus emergence time (6.67±0.57), the best callus texture (crumb callus type 2) and the best callus color (green). Meanwhile, the highest fresh weight (2,48±0.83) was in the use of MS media. The fastest callus emergence time occurred in the control (without the addition of 2,4-D) (7.33±0.57 and 6.67±0.57), the highest average fresh callus weight (2,48±0.83 and 2.35±0.32) occurred in the treatment with the addition of 1.00 mgL-1 2,4-D with a crumb callus texture of type 2 and callus green color only appeared in the treatment with a concentration of 0.25 mgL-1.

Effects of straw return and straw biochar on soil properties and crop growth: A review.

Straw return is an effective method for disposing agricultural residues. It not only utilizes agricultural waste but also improves soil. In the current review, different crop straw and its characteristics were highlighted, and patterns of straw return were explored (including straw return, straw biochar return, and their combined with fertilizer return), as well as their environmental impacts were outlined. In addition, the effects of straw return and straw biochar amendment on soil properties [e.g., pH, soil organic carbon (SOC), soil nitrogen (N)/phosphorus (P)/potassium (K), soil enzyme activities, and soil microbes] were discussed. Information collected from this review proposed that straw return and straw biochar return or in combination with fertilizer is an applicable way for improving soil fertility and enhancing crop production. Straw return is beneficial to soil physicochemical properties and soil microbial features. The rice straw has positive impacts on crop growth. However, there are different climate types, soil types and crops in China, meaning that the future research need long-term experiment to assess the complex interactions among straw, soil, and plant eco-systems. Accordingly, this review aims to provide available information on the application of straw return in terms of different patterns of its to justify and to expand their effective promotion.

Floristic diversity of Threatened medicinal plants at two major reservoirs associated regions in Lahaul Valley, Western Himalayas, India

Agriculture is the leading sector in Ethiopia and its economy The present study emphasizes the quantitative estimation of plant species diversity and ecosystems at Lahaul-Spiti two lake reservoirs, Deepak tall (DT) and Suraj Tall (ST). These are the finest visiting spots in Keylong (Himachal Pradesh), India, during summer. Despite huge anthropogenic pressure and environmental disturbance, the reservoir-associated regions still harbor numerous angiosperm species, including various grasses and medicinal herbs. Two-year surveys were conducted in six-landscape elements at an altitude of 3752 m and 4890 m. Plant diversity assessment was based on their numbers in each Landscape element (LSEs) using a 2m2 quadrant followed by random sampling methods for herbs, shrubs, and grasses. Within the total 32 specimens belonging to 17 families (most dominated by Asteraceae), 29 plants show medicinal importance. The east landscape of ST was observed with maximum species richness (Shannon wiener H =1.07), followed by the Northeast (H =1.05) dominated by Saxifraga mucronulata royle (35), Tussilago farfara (l), and T. farfara (26). The maximum species richness value was for Impatiens glandulifera (26 plants/m2), while Gentianella moorcroftiana (43 plants/m2) and categorized as vulnerable species. Highest population of the endangered plant was recorded in ST where Allardia tomentosa (9 plants/m2), Nepeta longibracteata (7 plants/m2), Pleurospermum candollei (6 plants/m2), and S. mucronulata (35 plants/m2) comparatively to DT enriched with five vulnerable species (G. moorcroftiana, Chamerion latifolium, Ranunculus hirtellus and Rheum emodii). Considering the floristic diversity value, effective attention towards conserving valuable plant bio-resources is suggested.

Soil clay is a key factor affecting soil phosphorus availability in the distribution area of Masson pine plantations across subtropical China

Evaluating the environmental effects on soil phosphorus (P) availability is the key to understanding P cycling and regulating forest productivity. However, what and how environmental factors affect soil P availability in regional plantation ecosystems remains unclear. The study evaluated the effects of climatic factors, nitrogen deposition rate, stand attributes, litter characteristics, and soil-associated properties on soil P availability in Masson pine plantations across subtropical China using stepwise regression and structural equation modelling (SEM) analyses. At the 0–20 cm and 20–40 cm soil depths, soil total P ranged from 0.24 to 0.43 g kg−1 and from 0.24 to 0.48 g kg−1, respectively. Similarly, soil available P varied from 0.35 to 7.55 mg kg−1 and from 0.14 to 4.34 mg kg−1, respectively. Soil total and available P had high values in the eastern and northern distribution areas of subtropical China. Soil total P linearly decreased with an increase in bulk density, clay and pH but linearly increased with an increase in DBH. These four factors had a similar contribution (15.5–35.1 %) to soil total P. Soil available P linearly decreased with an increase in bulk density and clay. The relative contribution of clay (48.1–75.7 %) to soil available P was higher than that of bulk density (16.2–33.5 %). Soil total P decreased during the initial 30 years of plantations and then increased. But other variables (e.g., climate, nitrogen deposition, and litter) had no significant impacts on soil P. Overall, the SEM explained 35.4 % and 28.1 % of soil available P variations at the 0–20 cm and 20–40 cm soil depths, respectively, and revealed that clay had strong total effects (β = -0.526 and −0.396) on the soil available P. These results reveal the dominant roles of soil texture (especially clay) in affecting soil P availability in Masson pine plantations and suggest that extending the rotation period benefits soil P recovery in pine plantation ecosystems of subtropical China.

Why Do Plant-Pathogenic Fungi Produce Mycotoxins? Potential Roles for Mycotoxins in the Plant Ecosystem.

For many plant-pathogenic or endophytic fungi, production of mycotoxins, which are toxic to humans, may present a fitness gain. However, associations between mycotoxin production and plant pathogenicity or virulence is inconsistent and difficult due to the complexity of these host-pathogen interactions and the influences of environmental and insect factors. Aflatoxin receives a lot of attention due to its potent toxicity and carcinogenicity but the connection between aflatoxin production and pathogenicity is complicated by the pathogenic ability and prevalence of nonaflatoxigenic isolates in crops. Other toxins directly aid fungi in planta, trichothecenes are important virulence factors, and ergot alkaloids limit herbivory and fungal consumption due to insect toxicity. We review a panel discussion at the American Phytopathological Society's Plant Health 2021 conference, which gathered diverse experts representing different research sectors, career stages, ethnicities, and genders to discuss the diverse roles of mycotoxins in the lifestyles of filamentous fungi of the families Clavicipitaceae, Trichocomaceae (Eurotiales), and Nectriaceae (Hypocreales).

The Carbon Sink of Mangrove Ecological Restoration between 1988–2020 in Qinglan Bay, Hainan Island, China

As the world’s largest reactive carbon reservoir, the ocean plays a critical role in global climate change. Among coastal plant ecosystems, mangroves have the highest carbon storage efficiency and are prone to the impact of anthropogenic activities. In this study, taking the mangrove wetland of Qinglan Bay as an example, we extracted information on mangrove coastal surface change from 1988 to 2020 based on multi-temporal Landsat remote sensing data through field ground surveys and laboratory analysis and used the InVEST model to calculate the spatial and temporal structure of blue carbon in the mangrove area to investigate the effects of mangrove change in an ecological restoration context. The result shows that the overall area of mangrove forests exhibited a decreasing trend from 1988 to 2020, and the area of mangroves decreased from 1559.34 ha to 737.37 ha of which 52.71% was transformed into aquiculture, construction, and farm land. Accordingly, the mangrove carbon sinks from 1988 to 2020 were significantly reduced and the carbon stock decreased at an annual tendency from 1,025,901.71 tons to 712,118.69 tons. With the implementation of mangrove restoration, the decline of mangrove forests has decreased since 2003, promoting the stabilization and enhancement of carbon sinks in the mangrove wetlands of Qinglan Bay. The results of this study provide a technical method to evaluate the carbon sink contribution of mangrove wetland restoration in Hainan Province, a scientific basis and methodological innovation to monitor the carbon sink of mangrove cover change in larger regions of China, a theoretical basis to select criteria for mangrove restoration, and a scientific and systematic management strategy for ecological and mangrove restoration on Hainan Island.

Leaf water content contributes to global leaf trait relationships

Leaf functional traits are important indicators of plant growth and ecosystem dynamics. Despite a wealth of knowledge about leaf trait relationships, a mechanistic understanding of how biotic and abiotic factors quantitatively influence leaf trait variation and scaling is still incomplete. We propose that leaf water content (LWC) inherently affects other leaf traits, although its role has been largely neglected. Here, we present a modification of a previously validated model based on metabolic theory and use an extensive global leaf trait dataset to test it. Analyses show that mass-based photosynthetic capacity and specific leaf area increase nonlinearly with LWC, as predicted by the model. When the effects of temperature and LWC are controlled, the numerical values for the leaf area-mass scaling exponents converge onto 1.0 across plant functional groups, ecosystem types, and latitudinal zones. The data also indicate that leaf water mass is a better predictor of whole-leaf photosynthesis and leaf area than whole-leaf nitrogen and phosphorus masses. Our findings highlight a comprehensive theory that can quantitatively predict some global patterns from the leaf economics spectrum.

Scale Effects on the Relationship between Plant Diversity and Ecosystem Multifunctionality in Arid Desert Areas

Understanding the relationship between biodiversity and ecosystem multifunctionality is popular topic in ecological research. Although scale is an important factor driving changes in biodiversity and ecosystem multifunctionality, we still know little about the scale effects of the relationship between the different dimensions of biodiversity and ecosystem multifunctionality. Using plant communities in the northwest of the Qira Desert Ecosystem National Field Research Station of the Chinese Academy of Sciences in Qira County, Xinjiang, as the study object, we explored the scale effects of plant diversity and ecosystem multifunctionality at different sampling scales (5 m × 5 m, 20 m × 20 m, and 50 m × 50 m) and the relative contribution of different dimensions of diversity (species diversity, functional diversity, and phylogenetic diversity) to variation in ecosystem multifunctionality. At different scales, a significant scale effect was observed in the relationship between plant diversity and ecosystem multifunctionality. Species diversity dominated ecosystem multifunctionality at large scales (50 m × 50 m), and species diversity and ecosystem multifunctionality varied linearly between scales. Functional diversity made the greatest contribution in small scales (5 m × 5 m), and the relationship between phylogenetic diversity and ecosystem multifunctionality tended to show a single-peaked variation between scales, with a dominant effect on multifunctionality at the mesoscale (20 m × 20 m). The results of the study deepen the understanding of the scale effect of the relationship between plant diversity and ecosystem multifunctionality in arid desert areas, and help to further conserve plant diversity and maintain ecosystem multifunctionality.

Evaluation of Climate Change Impacts on the Geographic Distribution of Fritillaria imperialis L. (Liliaceae) (Turkey)

Abstract Fritillaria imperialis is a bulbous plant that has increased commercial value and contributes to rural development in Turkey. It is widely utilized in traditional medicine and pharmacy, and has great potential for use in modern pharmaceuticals in the future. As the effects of climate change on this plant have not been documented, this study aimed to understand how climate change might affect F. imperialis . The methodology of the study was divided into three steps: ( i ) database development, including the current distribution zones of F. imperialis and climatic parameters such as temperature and precipitation data; ( ii ) determination of the plant’s temperature and precipitation requirements; and ( iii ) Ecocrop’s plant climate suitability modeling (PCSM). As a result of the study, it was determined that climatic suitability would decrease below 20% in the plant’s current distribution area between 2,000 m and 3,000 m altitude. For the zones between 500–1,000 m altitude, the climatic suitability will be as high as 100%. Although there are zones where climatic suitability will increase by 2070, the general trend shows that suitability will decrease. This change in the plant ecosystem is explained by the decreased winter precipitation and snowfall but increased temperature and evaporation at higher altitudes. Fritillaria imperialis is expected to shift its geographic distribution to lower altitudes because of climate change.

Potential of Organic Amendments for Heavy Metal Contamination in Soil–Coriander System: Environmental Fate and Associated Ecological Risk

Pollution by organic wastes and manures is an important problem in tropical and sub-tropical countries and novel solutions for their proper management and valorization are needed. Waste-derived organic manures may increase metal load in the soil–plant ecosystem and food chain, with potential risks to public health. The aim of this work was to evaluate the impact of three manures (poultry waste (PW), press mud (PM), and farmyard manure (FYM)) on heavy metals (HMs) (Cd, Co, Cr, Cu, Pb, Zn, Fe, Mn) toxicity in a soil and coriander (Coriandrum sativum L.) system and their environmental impact (bioaccumulation, pollution load) and the consequent risk to human health via consumption. Results demonstrated that HMs in coriander fluctuated from 0.40 to 0.43 for Cd, 1.84 to 3.52 for Co, 0.15 to 0.16 for Cr, 1.32 to 1.40 for Cu, 0.05 to 0.09 for Pb, 1.32 to 2.51 for Fe, 0.10 to 0.32 for Mn, and 2.01 to 8.70 mg/kg for Zn, respectively. Highest pollution load index value was 2.89 for Cd and Mn showed the lowest (0.005). Daily intake of metal was noticed to be higher for Zn (0.049 mg/kg/day) for PW and lower for Mn (0.0005) at FYM treatment. The health risk index value was <1 and in the range of 2.30–2.50 for Cd showing potential carcinogenicity. It was concluded that as the organic amendments have the widest application in vegetables, it should be prudent to avoid their contamination and mobilization in plant–soil ecosystems to protect public health perspectives.

Phyllosphere bacterial communities in urban green areas throughout Europe relate to urban intensity.

The phyllosphere harbours a diverse and specific bacterial community, which influences plant health and ecosystem functioning. In this study, we investigated the impact of urban green areas connectivity and size on the composition and diversity of phyllosphere bacterial communities. Hereto, we evaluated the diversity and composition of phyllosphere bacterial communities of 233 Platanus x acerifolia and Acer pseudoplatanus trees in 77 urban green areas throughout 6 European cities. The community composition and diversity significantly differed between cities but only to a limited extent between tree species. We could show that urban intensity correlated significantly with the community composition of phyllosphere bacteria. In particular, a significant correlation was found between the relative abundances for 29 out of the 50 most abundant families and the urban intensity: the abundances of classic phyllosphere families, such as Acetobacteraceae, Planctomycetes, and Beijerinkiaceae, decreased with urban intensity (i.e. more abundant in areas with more green, lower air pollution, and lower temperature), while those related to human activities, such as Enterobacteriaceae and Bacillaceae, increased with urban intensity. The results of this study suggest that phyllosphere bacterial communities in European cities are associated with urban intensity and that effect is mediated by several combined stress factors.

Elevated CO2 alleviates adverse effects of drought on plant water relations and photosynthesis: A global meta‐analysis

Abstract The elevated CO2 concentration (eCO2) is expected to improve plant water relations and carbon (C) uptakes, with a potential to mitigate drought stress. However, the interactive effects of eCO2 and drought on plant physiology and growth are not clear. We performed a meta‐analysis on the interactive effects of eCO2 and drought on plant water relations, photosynthesis, biomass production and allocation. We found that eCO2 did not lead to the conservation of soil water, but improved leaf water status under drought conditions as evidenced by a higher leaf relative water content (LRWC) and a less negative midday leaf water potential, resulting from reduced stomatal conductance (gs) and increased root to shoot ratio. Elevated CO2 retarded the response of gs to drought, which may be mediated by the decrease in leaf abscisic acid concentration under eCO2 and drought. Drought imposed stomatal limitations on photosynthesis (A), which was alleviated by eCO2 via increasing intercellular CO2 concentration (Ci). This led to a stronger A response to eCO2 under drought, supporting the ‘low Ci effect’. However, no interaction of eCO2 and drought was detected on plant biomass production. Intrinsic water use efficiency (iWUE) increased proportionally with eCO2, while plant‐scale WUE was less responsive to eCO2. C3 plants had advantages over C4 plants in terms of A and biomass production under eCO2 and well‐watered conditions rather than under eCO2 and drought conditions. Drought caused a greater reduction in biomass for woody plants than for herbs. Plants growing in pots showed greater decreases in the physiology and biomass under drought than those growing in field. Synthesis. These findings suggest that eCO2 can alleviate the adverse impacts of drought on plant water relations and C sequestration, and are of significance in the prediction of plant growth and ecosystem productivity under global changes.