Colony morphology is important for Microcystis to sustain a competitive advantage in eutrophic lakes. The mechanism of colony formation in Microcystis is currently unclear. Extracellular polysaccharide （EPS） has bee...Colony morphology is important for Microcystis to sustain a competitive advantage in eutrophic lakes. The mechanism of colony formation in Microcystis is currently unclear. Extracellular polysaccharide （EPS） has been reported to play an important role in cell aggregate formation of some phytoplankton. Microcystis aeruginosa was cultivated under varied abiotic conditions, including different nutrient, light, and temperature conditions, to investigate their effects on EPS production and morphological change. The results show that nutrient concentration and light intensity have great effects on EPS production in M. aeruginosa. There was a considerable increase in EPS production after M. aeruginosa was cultivated in adjusted culture conditions similar to those present in the field （28.9 mg C/L, 1.98 mg N/L, 0.65 mg P/L, light intensity： 100 μtmol/（m2.s））. These results indicate that abiotic factors might be one of the triggers for colony formation in Microcystis.展开更多
Natural regeneration is the interaction of natural processes to restore the forest ecosystem. Its dynamics are influenced by the intensity and extent of a series of abiotic and biotic factors, which may be intrinsic o...Natural regeneration is the interaction of natural processes to restore the forest ecosystem. Its dynamics are influenced by the intensity and extent of a series of abiotic and biotic factors, which may be intrinsic or extrinsic. Knowing the importance of establishing natural regeneration within forest ecosystems, this work aimed to evaluate whether litter depth and trail distance influenced seedling abundance and richness in a forest fragment undergoing natural restoration. The hypothesis tested in this research was that abiotic factors influence the natural regeneration of this forest since they are factors that are directly linked to seed germination and seedling establishment. 30 plots of 1 m2 were randomly analyzed within the forest located on the brown trail. A millimeter ruler was used to diagnose the litter depth and a measuring tape to measure the distance from the plot to the edge. In each plot the seedlings were morpho-specified and each morphospecies had the number of individuals counted. Linear regression tests were performed to assess the relationships between species richness and trail distance and litter depth. The same was done for species abundance. All results showed that there is no relationship pattern between any of the variables. Other factors also influence the regeneration of a forest, such as luminosity and seed bank. Furthermore, litter depth is related to the successional stage of the forest. It was concluded that the abiotic factors tested do not influence the regeneration of the study area.展开更多
Plant photosynthesis assimilates CO_(2)from the atmosphere,and CO_(2)diffusion efficiency is mainly constrained by stomatal and mesophyll resistance.The stomatal and mesophyll conductance of plants are sensitive to ab...Plant photosynthesis assimilates CO_(2)from the atmosphere,and CO_(2)diffusion efficiency is mainly constrained by stomatal and mesophyll resistance.The stomatal and mesophyll conductance of plants are sensitive to abiotic stress factors,which affect the CO_(2)concentrations at carboxylation sites to control photosynthetic rates.Early studies conducted relevant reviews on the responses of stomatal conductance to the environment and the limitations of mesophyll conductance by internal structure and biochemical factors.However,reviews on the abiotic stress factors that systematically regulate plant CO_(2)diffusion are rare.Therefore,in this review,the rapid and long-term responses of stomatal and mesophyll conductance to abiotic stress factors(such as light intensity,drought,CO_(2)concentration and temperature)and their physiological mechanisms are summarized.Finally,future research trends are also investigated.展开更多
Strawberry (Fragaria ananassa) is well known among consumers because of its attractive color, delicious taste, and nutritional benefits. It is widely grown worldwide, but its production has become a significant challe...Strawberry (Fragaria ananassa) is well known among consumers because of its attractive color, delicious taste, and nutritional benefits. It is widely grown worldwide, but its production has become a significant challenge due to changing climatic conditions that lead to abiotic stresses in plants, which results in poor root development, nutrient deficiency, and poor plant health. In this context, the major abiotic stresses are temperature fluctuations, water shortages, and high levels of soil salinity. The accumulation of salts in excessive amounts disrupts the osmotic balance and impairs physiological processes. However, drought reduces fruit size, yield, and quality. Similarly, heat and cold stresses directly affect the rate of photosynthesis. Plants respond to these changes by producing growth-promoting hormones to ensure their survival. In the context of these abiotic stresses, beneficial microbes support plant growth. Among these fungi, the most extensively studied are plant growth-promoting rhizobacteria (PGPR) and arbuscular mycorrhizal fungi (AMF). When applied as bioinoculants, they are associated with roots and subsequently improve soil health, fruit quality, and overall crop yield. This review highlights the impacts of abiotic stresses on strawberry roots, growth, and hormonal pathways. Moreover, it focuses on the role of beneficial soil microbes in the mitigation of these responses.展开更多
This study assesses the effects of vegetation natural tree and shrub regeneration in semi-arid forests patterns and environmental factors on the abundance of of the Zagros Mountains, western Iran. We sampled 120 relev...This study assesses the effects of vegetation natural tree and shrub regeneration in semi-arid forests patterns and environmental factors on the abundance of of the Zagros Mountains, western Iran. We sampled 120 releves at different topographic positions in a protected area of the studied region. Floristic composition, slope, elevation and soil properties were recorded at each releve, and woody seedling density was measured. We have first discerned five floristic groups using two-way indicator species analysis （TWINSPAN）, detrended correspondence analysis （DCA）, and canonical correspondence analysis （CCA） and then explored the relationships among the floristic group compositions, environmental factors and seedling densities. The indicator species of the five groups were Quercus brangi, Acer monspessulanum, Cerasus microcarpa, Rhamnus arvensis and Astragalus licyoides. Our results indicated that these groups were significantly affected by elevation and soil properties and the soil properties refer to： EC （electrical conductivity）, N （nitrogen）, K （potassium）, OM （organic matter）, and bulk density. Woody regeneration was composed of Q. brangi, A. monqJessulanum, C microcarpa, Amygdalus scopada and Crataeguspongca seedlings. The highest density of seedlings was found for Q. brantii （97.14 （_＋48.00） plants/hm2） and the lowest for A. scoparia （2.28 （＋1.50） plants/hm2）. Quercus brantii was the dominant species and the seedling density was positively correlated with soil pH and P （phosphorus） values. Amygdalus scoparia regeneration was negatively correlated with elevation, and the seedling density peaked in C. microcarpa group. There was no significant variation in distribution of C. pongca seedlings among the groups, but the seedling density of this species was positively correlated with slope and K. Cerasus microcarpa seedlings were more abundant in the Q. brantii group than in other groups. This study showed that the regeneration of tree and shrub species was unequally distributed in different floristic groups for some species （A. scopada and C microcarpa） but not for other （Q. branlii and C. pongca） and was generally correlated with some environmental factors, particularly elevation, slope and soil nutrients （P and K）. These results are a first step to implement future management and restoration strategies for promoting forest regeneration.展开更多
Wood density(WD)is an important quality and functional trait of wood.However,despite the relationships between WD and abiotic factors being important to model or predict spatial distributions of functional traits,as w...Wood density(WD)is an important quality and functional trait of wood.However,despite the relationships between WD and abiotic factors being important to model or predict spatial distributions of functional traits,as well as responses of vegetation to climate changes,in current Earth system models or dynamic global vegetation models(ESMs/DGVMs),WD is often oversimplified,being defined as a globally uniform constant either for all plant functional types(PFTs)or for each individual PFT.Such oversimplifications may lead to simulation biases in the morphology of woody PFTs,as well as ecosystem transition and vegetation-atmosphere interactions.Moreover,existing conclusions about the relationships between WD and abiotic factors drawn from field observations remain mixed,making model parameterization improvements difficult.This study systematically investigated the influences of climate and soil factors on WD across various PFTs.Optimal fitting models for predicting WD within each PFT were then constructed by utilizing our collated global database of 138604 observations.For WDs of tree PFTs,climate emerges as a more influential factor than soil characteristics,whereas for shrub PFTs the effects of climate and soil are of equivalent significance.Across all six PFTs,correlation coefficients between predictions by fitting models and observed WD range from 0.49 to 0.93.The predicted and observed WD exhibit good agreement across climate space.It is expected that the incorporation of our research findings into DGVMs will improve the simulation of tree height and forest fractional coverage,particularly in the central forest areas and forest transition zones.展开更多
A study to list Dinoflagellates species belonging to the genera Ceratium and Protoperidinium and some abiotic factors associated with them was carried out in the Kribi coast from February 2020 to February 2021 followi...A study to list Dinoflagellates species belonging to the genera Ceratium and Protoperidinium and some abiotic factors associated with them was carried out in the Kribi coast from February 2020 to February 2021 following a monthly sampling frequency. For the inventory, 60 L of water including 20 L on the surface, 20 L in the trophogen layer and 20 L in the tropholytic layer were filtered through a sieve of 20 μm and the retentate obtained was fixed whith lugol for identification and counting operations using an Olympus microscope. The morphotypes of the taxa were filmed using an Omax Toupvix eye camera. Physico-chemical results showed very good water oxygenation (89.35%), low Suspended Solid concentration (6.36 ± 4.71 mg/L), basic pH (8.53 ± 0.4 U.C), average salinity of 15.87 ± 3.1 g/L and conductivity around 26.73 ± 4.96 mS/cm. The average water temperature hovered around 29.51°C ± 1.28°C. The average values of nitrates and orthophosphates showed a progressive enrichment of the waters of the studied section with nitrate (1.52 ± 0.87 mg/L) and orthophosphate (1.84 ± 3.98 mg/L). This work allowed to identify 17 species of the genera Ceratium and 22 of Protoperidinium. The genera Protoperidinium was the most diverse while it was the taxa belonging to the genera Ceratium that had the highest densities. Ceratium furca was the only spatially and seasonally regular species with occurrence frequencies of 75.31% and 79.16% respectively. According to similar studies, 06 species reconized harmful were inventoried during this study. These are Ceratium furca, Ceratium fusus, Ceratium tripos, Protoperidinium divergens, Protoperidinium steinii, Protoperidinium crassipes. Temperature and oxygen are the abiotic factors that showed more affinities with the taxa inventoried in view of the significant correlations obtained. With a view to preventing blooms on the Cameroonian Atlantic coast, regular monitoring of the harmful species identified is desirable.展开更多
Few studies have been carried out to date on the influence of bacteria on variations in the abiotic properties of water. The aim of the present work was to evaluate the influence of Escherichia coli and Aeromonas hydr...Few studies have been carried out to date on the influence of bacteria on variations in the abiotic properties of water. The aim of the present work was to evaluate the influence of Escherichia coli and Aeromonas hydrophila on some abiotic properties of groundwater stored under aerobic or anaerobic conditions. Experiments were performed in the presence of monospecific cells and bispecific cells. The incubation temperatures were 4˚C and 23˚C. The incubation (storage) times were 6 h, 12 h, 24 h, 48 h and 72 h. Bacteriological analyses were carried out using culture and physicochemical analyses using appropriate techniques. The results show that in the presence of monospecific cells and under aerobic conditions, E. coli abundances were relatively lower than under anaerobic conditions. The opposite was observed in the presence of bispecific cells. In most cases, minimum cell abundances were observed after 6 hours of storage. The same was true for A. hydrophila cells. The values of pH, electrical conductivity and ammonium ions in the water on the day of sampling varied over time. The pH values were relatively higher at 4˚C in the presence of E. coli cells alone, and at 23˚C in the presence of A. hydrophila cells. Ammonium ion levels were relatively higher at 4˚C under anaerobic conditions for both bacterial species. The highest electrical conductivity value was observed at 23˚C in the presence of E. coli cells, and at 4˚C in the presence of A. hydrophila cells, under anaerobic conditions. Electrical conductivity is higher in the presence of A. hydrophila with fluctuations from 169 to 285 µS/cm after 24 h incubation and 259 µS/cm after 6 hours incubation at 4˚C and 23˚C respectively. Under anaerobic conditions and in the presence of E. coli, the conductivity varied from 169 µS/cm at sampling to 274 µS/cm after 72 hours of incubation at 4˚C and from 169 to 289 after 24 hours. Under the same experimental conditions and in the presence of A. hydrophila, the electrical conductivity is higher at 4˚C with a value of 299 µS/cm after 24 hours. In the monospecific condition and under aerobic and anaerobic conditions and at an incubation temperature of 4˚C, the increase in the abundance of E. coli cells is significantly and positively correlated with the increase in pH values. In the mixed condition, pH is very significantly and positively correlated with the abundance of commensal Escherichia coli in anaerobic conditions (P NH4+) is significantly and negatively correlated with cellular concentrations of A. hydrophila in both aerobic and anaerobic conditions.展开更多
Protoporphyrin Ⅸ(PPⅨ), a basic porphyrin system found in nature, all “porphyrin-type”tetrapyrroles with a biological function are biosynthetically derived thereof. PPⅨ is a metalloprosthetic group of numerous pro...Protoporphyrin Ⅸ(PPⅨ), a basic porphyrin system found in nature, all “porphyrin-type”tetrapyrroles with a biological function are biosynthetically derived thereof. PPⅨ is a metalloprosthetic group of numerous proteins involved in diverse metabolic and respiratory processes across all domains of life, and is thus considered essential for respiring organisms. Determining the biotic and abiotic factors that influence marine microbial growth and community structure is critical for understanding global biogeochemical cycles. Here,we present vertical profiles of intracellular PPⅨ and four derivative products(Chlorophylla/b and Pheophytin-a/b) from two coastal sediment cores, alongside ancillary geochemical and 16S rRNA microbial community data. Our findings indicated that PPⅨ is present in the natural sediment environment and displays a decreasing trend with depth, revealing a significant positive correlation with both organic matter and microbial abundance. Cooccurrence networks revealed that the environmental distribution of PPⅨ was positively correlated with the microbial porphyrin producer(high genetic completeness), but negatively correlated with auxotrophs(absence or low genetic completeness). It emphasized the critical role of PPⅨ as a biological molecule involved in key physiological processes. These results suggest that PPⅨ is a prominent component of the shared extracellular metabolite pool, especially in anoxic marine sediments where it exists at physiologically relevant concentrations for microbial metabolism. This study highlighted the significance of PPⅨ in microbial ecology and its potential impact on biogeochemical cycles in marine sedimentary environments.展开更多
Extreme weather events pose an ever-greater threat to people,infrastructure,and nature.Forest ecosystems are highly sensitive to extreme cold events that can disrupt ecosystem functions,especially in montane regions.I...Extreme weather events pose an ever-greater threat to people,infrastructure,and nature.Forest ecosystems are highly sensitive to extreme cold events that can disrupt ecosystem functions,especially in montane regions.Ice storms can be particularly destructive,with rapid ice accretion causing tree branches to break,even snapping or uprooting entire trees.In March 2022,the Shennongjia forest in central China experienced severe ice storm conditions that severely damaged over 230,300ha.We utilized this opportunity to assess the vulnerability of different tree types(coniferous,deciduous,and evergreen broad-leaved)and stand compositions to damage resulting from ice glaze along an elevation gradient from 1,200 to 2,400m a.s.l.Among the 7,144 trees surveyed,10.1%suffered some extent of damage,which was most prolific in the middle elevation zone.While 96.8%of all damage occurred to deciduous broadleaved trees that dominated the forest community,the most severe damage(uprooting and lower trunk breakage)occurred to coniferous trees.The extent and severity of tree damage were moderated by forest composition,with secondary effects of forest structure and slope.Abiotic factors predominantly affected coniferous trees.We emphasize that more research and monitoring are needed to better understand the full impact of extreme weather events on forests,especially as the frequency and intensity of these events increases due to climate change.展开更多
To measure the contribution of root respiration (Rr) to total soil respiration (Rt) in arid cotton fields, eighteen plots, nine for girdling and nine control, were built in an arid cotton field in the Aksu National Ex...To measure the contribution of root respiration (Rr) to total soil respiration (Rt) in arid cotton fields, eighteen plots, nine for girdling and nine control, were built in an arid cotton field in the Aksu National Experimental Station of Oasis Farmland Ecosystem, Xinjiang of China. Given the difference of soil respiration between girdled plots and non-girdled control plots, the components of soil respiration, root respiration (Rr) and respiration originating from decomposition (Rd) were divided. The temperature sensitivities of R r and R d were analyzed, respectively. The results showed that the average contribution of R r to R t in arid cotton field was about 32% during the study period. The temperature-response curve of R r differed from that of Rd . The dynamic variation of R d was more related to the change of soil temperature as compared to Rr . Rr and Rd had different responses to the variation of environment, and thus new models capable of differentiating between Rr and Rd are needed for evaluating the different factors controlling these two components of soil respiration in arid cotton field.展开更多
We quantified deviations in regional forest biomass from simple extrapolation of plot data by the biomass expansion factor method（BEF） versus estimates obtained from a local biomass model,based on large-scale empiri...We quantified deviations in regional forest biomass from simple extrapolation of plot data by the biomass expansion factor method（BEF） versus estimates obtained from a local biomass model,based on large-scale empirical field inventory sampling data.The sources and relative contributions of deviations between the two models were analyzed by the boosted regression trees method.Relative to the local model,BEF overestimated accumulative biomass by 22.12%.The predominant sources of the total deviation （70.94%） were stand-structure variables.Stand age and diameter at breast height are the major factors.Compared with biotic variables,abiotic variables had a smaller overall contribution （29.06%）,with elevation and soil depth being the most important among the examined abiotic factors.Large deviations in regional forest biomass and carbon stock estimates are likely to be obtained with BEF relative to estimates based on local data.To minimize deviations,stand age and elevation should be included in regional forest-biomass estimation.展开更多
Diapause is defined as a period of suspended development in insects and other invertebrates during unfavorable environmental conditions. Diapause is commonly confused with term ＂quiescence＂ as both are dormant devel...Diapause is defined as a period of suspended development in insects and other invertebrates during unfavorable environmental conditions. Diapause is commonly confused with term ＂quiescence＂ as both are dormant development stages. Here this paper aimed to review the research work done on different aspects of diapause. Attempt was made to explain definitions of diapause, incidence, stages and termination of diapause, genetic control, factors affecting diapauses, including temperature, photoperiod, moisture and food, etc..展开更多
Lasioderma serricorne is known to be pest of tobacco, besides of attacking other products in storage. Anisopteromalus calandrae is an ectoparasitoid of coleopteran larvae also parasitizing the tobacco beetle. This stu...Lasioderma serricorne is known to be pest of tobacco, besides of attacking other products in storage. Anisopteromalus calandrae is an ectoparasitoid of coleopteran larvae also parasitizing the tobacco beetle. This study was aimed to evaluate the parasitism of A. calandrae on different densities of L. serricorne larvae grown in different diets and photoperiods, and to record the longevity and reproductive potential of A. calandrae. Individuals of L. serricorne were raised in three diets: wheat flour (F);wheat flour and brewer’s yeast (FY) and wheat flour and dried tobacco (FT). Different amounts of host larvae (10, 20, 50 and 100) for each diet were exposed to a couple of parasitoids. The same larval densities from diet F were exposed for 24 h to a couple of adult parasitoids maintained in three photoperiods (0:24, 12:12 and 24:0 - scotophase: photophase). The highest values of apparent parasitism were in the density of 50 larvae in the FY diet (96.34%) and 100 F (92.91%). There was no significant difference in the parameters in each photoperiod in all larval densities. However, the treatment in which hosts and parasitoids always remained in scotophase, was the one that had a significantly higher sex ratio. Females had longer longevity than males surviving for up to 25 days. On the fourth day of larvae exposure occurred, the maximum number of offspring generated. It is inferred that A. calandrae has potential to be used as a control agent for coleopterans that attack stored products.展开更多
The semi-arid mangroves of the Gulf of Kachchh,the largest ecosystems on the west coast of India,are poorly studied in terms of vegetation structure and environmental parameters in spite of their conservation signific...The semi-arid mangroves of the Gulf of Kachchh,the largest ecosystems on the west coast of India,are poorly studied in terms of vegetation structure and environmental parameters in spite of their conservation significance.Therefore,it is necessary to document the structural features of these mangroves in view of ongoing coastal industrial development.Mangrove forest structure in 10 locations on the northern and southern coasts of the Gulf of Kachchh were assessed using the line intercept transect method.Descriptions included density of young and mature age classes,tree heights,diameters at breast height(DBH)and aboveground biomass,along with seven significant environmental variables.Mature tree densities ranged from 350 to 1567 ind.ha-1,while average height and girth at breast height ranged from 1.0 to 6.8 m and 3.0 to 137.0 cm,respectively.The majority of trees(55.6%)were in B 1.8 m height class followed by a 1.9 to 2.4 m class(25.1%).DBH was most often in class 2 cm or lower than that.Among the canopy index classes,more trees were recorded in class ≤2 cm.The regeneration density was greater than the recruitment class.This study indicates that the poor structural attributes of Avicennia marina Vierth.var.acutissima Stapf and Mold dominated mangroves are largely due to aridity induced by scarce and erratic rainfall and high soil and water salinities.The results should be valuable in conserving and sustainably managing these mangroves in the face of developmental activities.展开更多
Globally,urbanization and a steady increase in population generate a huge amount of wastes,which leads to a series of economic,social,and environmental changes,mainly in developing countries.There is an utmost need fo...Globally,urbanization and a steady increase in population generate a huge amount of wastes,which leads to a series of economic,social,and environmental changes,mainly in developing countries.There is an utmost need for efficient management strategies for the beneficial utilization of these wastes into useful products.Among these strategies,composting is gaining attention due to its benefits of solid waste management,such as proper sterilization,and economical and effective bioconversion of lignocellulosic wastes to valuable products.Composting is an effective and sustainable approach for the management of various lignocellulosic wastes.This process comprises a series of effective waste treatment steps to ensure sustainable agriculture.Different composting methods have been explored for solid waste management.Furthermore,the influence of various factors relevant to composting has been elucidated.Microbes play a significant role in enhancing the degradation of lignocellulosic residues by secreting different hydrolytic enzymes.Compost has been utilized for increasing soil properties and improving plant growth.展开更多
Although important,phenological studies comparing congeneric species or the same species growing in different habitats are still scarce for the tropics.Herein,we integrate phylogeny,ecology and biometeorology to verif...Although important,phenological studies comparing congeneric species or the same species growing in different habitats are still scarce for the tropics.Herein,we integrate phylogeny,ecology and biometeorology to verify whether the phenophases of congeneric species Myrcia laruotteana and Myrcia amazonica or Clethra scabra differ when their populations inhabit wetland and drained habitats and to determine what abiotic factors affect the vegetative and reproductive phenophases of these species in distinct habitat patches.We collected data on phenological events of 80 trees for 1 year in Itacolomi State Park,Brazil,and related them to abiotic local factors.Contrary to our expectation,the phenophases of the congeneric species did not differ between habitats,but the reproductive phenophases of C.scabra did and was greater in drained soil.Phenophases of C.scabra were affected by the depth of the water table and maximum temperature in the wetland soil.Insolation,precipitation,maximum temperature and relative humidity influenced Myrcia and Clethra in the drained soil.The differences between C.scabra populations suggest that this species is phenotypically plastic and can present distinct phenophases depending on the habitat it inhabits.On the other hand,the congeneric Myrcia species may have similar phenophases in distinct habitats because of their shared similarities during their evolution.This study provides a better understanding of the ecology of these species and their adaptations to different abiotic conditions.Data of this nature are important in a changing world and can inform strategies for adaptive management.展开更多
The article presents the biology of flowering and the daily dynamics of flowering of two species from the Lamiaceae family: ph. anisochila va ph. sogdiana of the distribution out in the Nuratau Mountains range.
基金Supported by the National Natural Science Foundation of China (No.31200296)the CAS International Partnership Creative Group (No.KZZD-EW-TZ-08-01)
文摘Colony morphology is important for Microcystis to sustain a competitive advantage in eutrophic lakes. The mechanism of colony formation in Microcystis is currently unclear. Extracellular polysaccharide （EPS） has been reported to play an important role in cell aggregate formation of some phytoplankton. Microcystis aeruginosa was cultivated under varied abiotic conditions, including different nutrient, light, and temperature conditions, to investigate their effects on EPS production and morphological change. The results show that nutrient concentration and light intensity have great effects on EPS production in M. aeruginosa. There was a considerable increase in EPS production after M. aeruginosa was cultivated in adjusted culture conditions similar to those present in the field （28.9 mg C/L, 1.98 mg N/L, 0.65 mg P/L, light intensity： 100 μtmol/（m2.s））. These results indicate that abiotic factors might be one of the triggers for colony formation in Microcystis.
文摘Natural regeneration is the interaction of natural processes to restore the forest ecosystem. Its dynamics are influenced by the intensity and extent of a series of abiotic and biotic factors, which may be intrinsic or extrinsic. Knowing the importance of establishing natural regeneration within forest ecosystems, this work aimed to evaluate whether litter depth and trail distance influenced seedling abundance and richness in a forest fragment undergoing natural restoration. The hypothesis tested in this research was that abiotic factors influence the natural regeneration of this forest since they are factors that are directly linked to seed germination and seedling establishment. 30 plots of 1 m2 were randomly analyzed within the forest located on the brown trail. A millimeter ruler was used to diagnose the litter depth and a measuring tape to measure the distance from the plot to the edge. In each plot the seedlings were morpho-specified and each morphospecies had the number of individuals counted. Linear regression tests were performed to assess the relationships between species richness and trail distance and litter depth. The same was done for species abundance. All results showed that there is no relationship pattern between any of the variables. Other factors also influence the regeneration of a forest, such as luminosity and seed bank. Furthermore, litter depth is related to the successional stage of the forest. It was concluded that the abiotic factors tested do not influence the regeneration of the study area.
基金supported by National Natural Science Foundation of China(32071963)the Chengdu Science and Technology Project,China(2020-YF09-00033-SN)+1 种基金a grant from the International S&T Cooperation Projects of Sichuan Province,China(2020YFH0126)the China Agriculture Research System of MOF and MARA(CARS04-PS19)。
文摘Plant photosynthesis assimilates CO_(2)from the atmosphere,and CO_(2)diffusion efficiency is mainly constrained by stomatal and mesophyll resistance.The stomatal and mesophyll conductance of plants are sensitive to abiotic stress factors,which affect the CO_(2)concentrations at carboxylation sites to control photosynthetic rates.Early studies conducted relevant reviews on the responses of stomatal conductance to the environment and the limitations of mesophyll conductance by internal structure and biochemical factors.However,reviews on the abiotic stress factors that systematically regulate plant CO_(2)diffusion are rare.Therefore,in this review,the rapid and long-term responses of stomatal and mesophyll conductance to abiotic stress factors(such as light intensity,drought,CO_(2)concentration and temperature)and their physiological mechanisms are summarized.Finally,future research trends are also investigated.
文摘Strawberry (Fragaria ananassa) is well known among consumers because of its attractive color, delicious taste, and nutritional benefits. It is widely grown worldwide, but its production has become a significant challenge due to changing climatic conditions that lead to abiotic stresses in plants, which results in poor root development, nutrient deficiency, and poor plant health. In this context, the major abiotic stresses are temperature fluctuations, water shortages, and high levels of soil salinity. The accumulation of salts in excessive amounts disrupts the osmotic balance and impairs physiological processes. However, drought reduces fruit size, yield, and quality. Similarly, heat and cold stresses directly affect the rate of photosynthesis. Plants respond to these changes by producing growth-promoting hormones to ensure their survival. In the context of these abiotic stresses, beneficial microbes support plant growth. Among these fungi, the most extensively studied are plant growth-promoting rhizobacteria (PGPR) and arbuscular mycorrhizal fungi (AMF). When applied as bioinoculants, they are associated with roots and subsequently improve soil health, fruit quality, and overall crop yield. This review highlights the impacts of abiotic stresses on strawberry roots, growth, and hormonal pathways. Moreover, it focuses on the role of beneficial soil microbes in the mitigation of these responses.
文摘This study assesses the effects of vegetation natural tree and shrub regeneration in semi-arid forests patterns and environmental factors on the abundance of of the Zagros Mountains, western Iran. We sampled 120 releves at different topographic positions in a protected area of the studied region. Floristic composition, slope, elevation and soil properties were recorded at each releve, and woody seedling density was measured. We have first discerned five floristic groups using two-way indicator species analysis （TWINSPAN）, detrended correspondence analysis （DCA）, and canonical correspondence analysis （CCA） and then explored the relationships among the floristic group compositions, environmental factors and seedling densities. The indicator species of the five groups were Quercus brangi, Acer monspessulanum, Cerasus microcarpa, Rhamnus arvensis and Astragalus licyoides. Our results indicated that these groups were significantly affected by elevation and soil properties and the soil properties refer to： EC （electrical conductivity）, N （nitrogen）, K （potassium）, OM （organic matter）, and bulk density. Woody regeneration was composed of Q. brangi, A. monqJessulanum, C microcarpa, Amygdalus scopada and Crataeguspongca seedlings. The highest density of seedlings was found for Q. brantii （97.14 （_＋48.00） plants/hm2） and the lowest for A. scoparia （2.28 （＋1.50） plants/hm2）. Quercus brantii was the dominant species and the seedling density was positively correlated with soil pH and P （phosphorus） values. Amygdalus scoparia regeneration was negatively correlated with elevation, and the seedling density peaked in C. microcarpa group. There was no significant variation in distribution of C. pongca seedlings among the groups, but the seedling density of this species was positively correlated with slope and K. Cerasus microcarpa seedlings were more abundant in the Q. brantii group than in other groups. This study showed that the regeneration of tree and shrub species was unequally distributed in different floristic groups for some species （A. scopada and C microcarpa） but not for other （Q. branlii and C. pongca） and was generally correlated with some environmental factors, particularly elevation, slope and soil nutrients （P and K）. These results are a first step to implement future management and restoration strategies for promoting forest regeneration.
基金supported by the National Natural Science Foundation of China(Grant No.42275177)the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2021B0301030007)the National Key Scientific and Technological Infrastructure project“Earth System Numerical Simulation Facility”(EarthLab).
文摘Wood density(WD)is an important quality and functional trait of wood.However,despite the relationships between WD and abiotic factors being important to model or predict spatial distributions of functional traits,as well as responses of vegetation to climate changes,in current Earth system models or dynamic global vegetation models(ESMs/DGVMs),WD is often oversimplified,being defined as a globally uniform constant either for all plant functional types(PFTs)or for each individual PFT.Such oversimplifications may lead to simulation biases in the morphology of woody PFTs,as well as ecosystem transition and vegetation-atmosphere interactions.Moreover,existing conclusions about the relationships between WD and abiotic factors drawn from field observations remain mixed,making model parameterization improvements difficult.This study systematically investigated the influences of climate and soil factors on WD across various PFTs.Optimal fitting models for predicting WD within each PFT were then constructed by utilizing our collated global database of 138604 observations.For WDs of tree PFTs,climate emerges as a more influential factor than soil characteristics,whereas for shrub PFTs the effects of climate and soil are of equivalent significance.Across all six PFTs,correlation coefficients between predictions by fitting models and observed WD range from 0.49 to 0.93.The predicted and observed WD exhibit good agreement across climate space.It is expected that the incorporation of our research findings into DGVMs will improve the simulation of tree height and forest fractional coverage,particularly in the central forest areas and forest transition zones.
文摘A study to list Dinoflagellates species belonging to the genera Ceratium and Protoperidinium and some abiotic factors associated with them was carried out in the Kribi coast from February 2020 to February 2021 following a monthly sampling frequency. For the inventory, 60 L of water including 20 L on the surface, 20 L in the trophogen layer and 20 L in the tropholytic layer were filtered through a sieve of 20 μm and the retentate obtained was fixed whith lugol for identification and counting operations using an Olympus microscope. The morphotypes of the taxa were filmed using an Omax Toupvix eye camera. Physico-chemical results showed very good water oxygenation (89.35%), low Suspended Solid concentration (6.36 ± 4.71 mg/L), basic pH (8.53 ± 0.4 U.C), average salinity of 15.87 ± 3.1 g/L and conductivity around 26.73 ± 4.96 mS/cm. The average water temperature hovered around 29.51°C ± 1.28°C. The average values of nitrates and orthophosphates showed a progressive enrichment of the waters of the studied section with nitrate (1.52 ± 0.87 mg/L) and orthophosphate (1.84 ± 3.98 mg/L). This work allowed to identify 17 species of the genera Ceratium and 22 of Protoperidinium. The genera Protoperidinium was the most diverse while it was the taxa belonging to the genera Ceratium that had the highest densities. Ceratium furca was the only spatially and seasonally regular species with occurrence frequencies of 75.31% and 79.16% respectively. According to similar studies, 06 species reconized harmful were inventoried during this study. These are Ceratium furca, Ceratium fusus, Ceratium tripos, Protoperidinium divergens, Protoperidinium steinii, Protoperidinium crassipes. Temperature and oxygen are the abiotic factors that showed more affinities with the taxa inventoried in view of the significant correlations obtained. With a view to preventing blooms on the Cameroonian Atlantic coast, regular monitoring of the harmful species identified is desirable.
文摘Few studies have been carried out to date on the influence of bacteria on variations in the abiotic properties of water. The aim of the present work was to evaluate the influence of Escherichia coli and Aeromonas hydrophila on some abiotic properties of groundwater stored under aerobic or anaerobic conditions. Experiments were performed in the presence of monospecific cells and bispecific cells. The incubation temperatures were 4˚C and 23˚C. The incubation (storage) times were 6 h, 12 h, 24 h, 48 h and 72 h. Bacteriological analyses were carried out using culture and physicochemical analyses using appropriate techniques. The results show that in the presence of monospecific cells and under aerobic conditions, E. coli abundances were relatively lower than under anaerobic conditions. The opposite was observed in the presence of bispecific cells. In most cases, minimum cell abundances were observed after 6 hours of storage. The same was true for A. hydrophila cells. The values of pH, electrical conductivity and ammonium ions in the water on the day of sampling varied over time. The pH values were relatively higher at 4˚C in the presence of E. coli cells alone, and at 23˚C in the presence of A. hydrophila cells. Ammonium ion levels were relatively higher at 4˚C under anaerobic conditions for both bacterial species. The highest electrical conductivity value was observed at 23˚C in the presence of E. coli cells, and at 4˚C in the presence of A. hydrophila cells, under anaerobic conditions. Electrical conductivity is higher in the presence of A. hydrophila with fluctuations from 169 to 285 µS/cm after 24 h incubation and 259 µS/cm after 6 hours incubation at 4˚C and 23˚C respectively. Under anaerobic conditions and in the presence of E. coli, the conductivity varied from 169 µS/cm at sampling to 274 µS/cm after 72 hours of incubation at 4˚C and from 169 to 289 after 24 hours. Under the same experimental conditions and in the presence of A. hydrophila, the electrical conductivity is higher at 4˚C with a value of 299 µS/cm after 24 hours. In the monospecific condition and under aerobic and anaerobic conditions and at an incubation temperature of 4˚C, the increase in the abundance of E. coli cells is significantly and positively correlated with the increase in pH values. In the mixed condition, pH is very significantly and positively correlated with the abundance of commensal Escherichia coli in anaerobic conditions (P NH4+) is significantly and negatively correlated with cellular concentrations of A. hydrophila in both aerobic and anaerobic conditions.
基金supported by the Doctoral Research Initiation Fund Project of Hebei Normal University(No.L2025B19)PhD Fellowship of the State Key Laboratory of Marine Environmental Science at Xiamen University.
文摘Protoporphyrin Ⅸ(PPⅨ), a basic porphyrin system found in nature, all “porphyrin-type”tetrapyrroles with a biological function are biosynthetically derived thereof. PPⅨ is a metalloprosthetic group of numerous proteins involved in diverse metabolic and respiratory processes across all domains of life, and is thus considered essential for respiring organisms. Determining the biotic and abiotic factors that influence marine microbial growth and community structure is critical for understanding global biogeochemical cycles. Here,we present vertical profiles of intracellular PPⅨ and four derivative products(Chlorophylla/b and Pheophytin-a/b) from two coastal sediment cores, alongside ancillary geochemical and 16S rRNA microbial community data. Our findings indicated that PPⅨ is present in the natural sediment environment and displays a decreasing trend with depth, revealing a significant positive correlation with both organic matter and microbial abundance. Cooccurrence networks revealed that the environmental distribution of PPⅨ was positively correlated with the microbial porphyrin producer(high genetic completeness), but negatively correlated with auxotrophs(absence or low genetic completeness). It emphasized the critical role of PPⅨ as a biological molecule involved in key physiological processes. These results suggest that PPⅨ is a prominent component of the shared extracellular metabolite pool, especially in anoxic marine sediments where it exists at physiologically relevant concentrations for microbial metabolism. This study highlighted the significance of PPⅨ in microbial ecology and its potential impact on biogeochemical cycles in marine sedimentary environments.
基金supported by the National Natural Science Foundation of China(Nos.31971541 and 32201545).
文摘Extreme weather events pose an ever-greater threat to people,infrastructure,and nature.Forest ecosystems are highly sensitive to extreme cold events that can disrupt ecosystem functions,especially in montane regions.Ice storms can be particularly destructive,with rapid ice accretion causing tree branches to break,even snapping or uprooting entire trees.In March 2022,the Shennongjia forest in central China experienced severe ice storm conditions that severely damaged over 230,300ha.We utilized this opportunity to assess the vulnerability of different tree types(coniferous,deciduous,and evergreen broad-leaved)and stand compositions to damage resulting from ice glaze along an elevation gradient from 1,200 to 2,400m a.s.l.Among the 7,144 trees surveyed,10.1%suffered some extent of damage,which was most prolific in the middle elevation zone.While 96.8%of all damage occurred to deciduous broadleaved trees that dominated the forest community,the most severe damage(uprooting and lower trunk breakage)occurred to coniferous trees.The extent and severity of tree damage were moderated by forest composition,with secondary effects of forest structure and slope.Abiotic factors predominantly affected coniferous trees.We emphasize that more research and monitoring are needed to better understand the full impact of extreme weather events on forests,especially as the frequency and intensity of these events increases due to climate change.
基金Supported by the National Natural Science Foundation of China(Nos.31000208 and 40830640)the National Basic Research Program(973 Program) of China(No.2009CB421302)
文摘To measure the contribution of root respiration (Rr) to total soil respiration (Rt) in arid cotton fields, eighteen plots, nine for girdling and nine control, were built in an arid cotton field in the Aksu National Experimental Station of Oasis Farmland Ecosystem, Xinjiang of China. Given the difference of soil respiration between girdled plots and non-girdled control plots, the components of soil respiration, root respiration (Rr) and respiration originating from decomposition (Rd) were divided. The temperature sensitivities of R r and R d were analyzed, respectively. The results showed that the average contribution of R r to R t in arid cotton field was about 32% during the study period. The temperature-response curve of R r differed from that of Rd . The dynamic variation of R d was more related to the change of soil temperature as compared to Rr . Rr and Rd had different responses to the variation of environment, and thus new models capable of differentiating between Rr and Rd are needed for evaluating the different factors controlling these two components of soil respiration in arid cotton field.
基金supported by the Major Research Development Program of China(2016YFC0502704)National Science Foundation of China(31670645,31470578 and 31200363)+4 种基金National Forestry Public Welfare Foundation of China(201304205)Fujian Provincial Department of S&T Project(2013YZ0001-1,2015Y0083,2016Y0083,2016T3037 and 2016T3032)Key Laboratory of Urban Environment and Health of CAS(KLUEH-C-201701)Youth Innovation Promotion Association CAS(2014267)Key Program of the Chinese Academy of Sciences(KFZDSW-324)
文摘We quantified deviations in regional forest biomass from simple extrapolation of plot data by the biomass expansion factor method（BEF） versus estimates obtained from a local biomass model,based on large-scale empirical field inventory sampling data.The sources and relative contributions of deviations between the two models were analyzed by the boosted regression trees method.Relative to the local model,BEF overestimated accumulative biomass by 22.12%.The predominant sources of the total deviation （70.94%） were stand-structure variables.Stand age and diameter at breast height are the major factors.Compared with biotic variables,abiotic variables had a smaller overall contribution （29.06%）,with elevation and soil depth being the most important among the examined abiotic factors.Large deviations in regional forest biomass and carbon stock estimates are likely to be obtained with BEF relative to estimates based on local data.To minimize deviations,stand age and elevation should be included in regional forest-biomass estimation.
文摘Diapause is defined as a period of suspended development in insects and other invertebrates during unfavorable environmental conditions. Diapause is commonly confused with term ＂quiescence＂ as both are dormant development stages. Here this paper aimed to review the research work done on different aspects of diapause. Attempt was made to explain definitions of diapause, incidence, stages and termination of diapause, genetic control, factors affecting diapauses, including temperature, photoperiod, moisture and food, etc..
基金the Conselho Nacional de Pesquisa—CNPq for financial support in DTI-C scholarships and masters scholarship
文摘Lasioderma serricorne is known to be pest of tobacco, besides of attacking other products in storage. Anisopteromalus calandrae is an ectoparasitoid of coleopteran larvae also parasitizing the tobacco beetle. This study was aimed to evaluate the parasitism of A. calandrae on different densities of L. serricorne larvae grown in different diets and photoperiods, and to record the longevity and reproductive potential of A. calandrae. Individuals of L. serricorne were raised in three diets: wheat flour (F);wheat flour and brewer’s yeast (FY) and wheat flour and dried tobacco (FT). Different amounts of host larvae (10, 20, 50 and 100) for each diet were exposed to a couple of parasitoids. The same larval densities from diet F were exposed for 24 h to a couple of adult parasitoids maintained in three photoperiods (0:24, 12:12 and 24:0 - scotophase: photophase). The highest values of apparent parasitism were in the density of 50 larvae in the FY diet (96.34%) and 100 F (92.91%). There was no significant difference in the parameters in each photoperiod in all larval densities. However, the treatment in which hosts and parasitoids always remained in scotophase, was the one that had a significantly higher sex ratio. Females had longer longevity than males surviving for up to 25 days. On the fourth day of larvae exposure occurred, the maximum number of offspring generated. It is inferred that A. calandrae has potential to be used as a control agent for coleopterans that attack stored products.
基金financially supported by the Marine National Park and Sanctuary(MNP&S)Jamnagar,Gujarat State,India through the project,"Mangrove Vegetation Characteristics of Gulf of Kachchh"
文摘The semi-arid mangroves of the Gulf of Kachchh,the largest ecosystems on the west coast of India,are poorly studied in terms of vegetation structure and environmental parameters in spite of their conservation significance.Therefore,it is necessary to document the structural features of these mangroves in view of ongoing coastal industrial development.Mangrove forest structure in 10 locations on the northern and southern coasts of the Gulf of Kachchh were assessed using the line intercept transect method.Descriptions included density of young and mature age classes,tree heights,diameters at breast height(DBH)and aboveground biomass,along with seven significant environmental variables.Mature tree densities ranged from 350 to 1567 ind.ha-1,while average height and girth at breast height ranged from 1.0 to 6.8 m and 3.0 to 137.0 cm,respectively.The majority of trees(55.6%)were in B 1.8 m height class followed by a 1.9 to 2.4 m class(25.1%).DBH was most often in class 2 cm or lower than that.Among the canopy index classes,more trees were recorded in class ≤2 cm.The regeneration density was greater than the recruitment class.This study indicates that the poor structural attributes of Avicennia marina Vierth.var.acutissima Stapf and Mold dominated mangroves are largely due to aridity induced by scarce and erratic rainfall and high soil and water salinities.The results should be valuable in conserving and sustainably managing these mangroves in the face of developmental activities.
基金the financial assistance as Senior Research Fellowship(No.09/382(0179)/2016-EMR1)from the Council of Scientific and Industrial Research(CSIR),New Delhi,India during the tenure of this research workthe Haryana State Council for Science and Technology,Panchkula,India(Nos.1743 and HSCST/R&D/2017/62)for providing financial support during the tenure of this research work。
文摘Globally,urbanization and a steady increase in population generate a huge amount of wastes,which leads to a series of economic,social,and environmental changes,mainly in developing countries.There is an utmost need for efficient management strategies for the beneficial utilization of these wastes into useful products.Among these strategies,composting is gaining attention due to its benefits of solid waste management,such as proper sterilization,and economical and effective bioconversion of lignocellulosic wastes to valuable products.Composting is an effective and sustainable approach for the management of various lignocellulosic wastes.This process comprises a series of effective waste treatment steps to ensure sustainable agriculture.Different composting methods have been explored for solid waste management.Furthermore,the influence of various factors relevant to composting has been elucidated.Microbes play a significant role in enhancing the degradation of lignocellulosic residues by secreting different hydrolytic enzymes.Compost has been utilized for increasing soil properties and improving plant growth.
基金supported by the Research,Graduate and Innovation Department (PROPP) of the Federal University of Ouro Preto (UFOP)。
文摘Although important,phenological studies comparing congeneric species or the same species growing in different habitats are still scarce for the tropics.Herein,we integrate phylogeny,ecology and biometeorology to verify whether the phenophases of congeneric species Myrcia laruotteana and Myrcia amazonica or Clethra scabra differ when their populations inhabit wetland and drained habitats and to determine what abiotic factors affect the vegetative and reproductive phenophases of these species in distinct habitat patches.We collected data on phenological events of 80 trees for 1 year in Itacolomi State Park,Brazil,and related them to abiotic local factors.Contrary to our expectation,the phenophases of the congeneric species did not differ between habitats,but the reproductive phenophases of C.scabra did and was greater in drained soil.Phenophases of C.scabra were affected by the depth of the water table and maximum temperature in the wetland soil.Insolation,precipitation,maximum temperature and relative humidity influenced Myrcia and Clethra in the drained soil.The differences between C.scabra populations suggest that this species is phenotypically plastic and can present distinct phenophases depending on the habitat it inhabits.On the other hand,the congeneric Myrcia species may have similar phenophases in distinct habitats because of their shared similarities during their evolution.This study provides a better understanding of the ecology of these species and their adaptations to different abiotic conditions.Data of this nature are important in a changing world and can inform strategies for adaptive management.
文摘The article presents the biology of flowering and the daily dynamics of flowering of two species from the Lamiaceae family: ph. anisochila va ph. sogdiana of the distribution out in the Nuratau Mountains range.
