Variation Characteristics of Root Traits of Different Alfalfa Cultivars under Saline-Alkaline Stress and their Relationship with Soil Environmental Factors

Soil salinization is the main factor that threatens the growth and development of plants and limits the increase of yield.It is of great significance to study the key soil environmental factors affecting plant root traits to reveal the adaptation strategies of plants to saline-alkaline-stressed soil environments.In this study,the root biomass,root morphological parameters and root mineral nutrient content of two alfalfa cultivars with different sensitivities to alkaline stress were analyzed with black soil as the control group and the mixed saline-alkaline soil with a ratio of 7:3 between black soil and saline-alkaline soil as the saline-alkaline treatment group.At the same time,the correlation analysis of soil salinity indexes,soil nutrient indexes and the activities of key enzymes involved in soil carbon,nitrogen and phosphorus cycles was carried out.The results showed that compared with the control group,the pH,EC,and urease(URE)of the soil surrounding the roots of two alfalfa cultivars were significantly increased,while soil total nitrogen(TN),total phosphorus(TP),organic carbon(SOC),andα-glucosidase activity(AGC)were significantly decreased under saline-alkaline stress.There was no significant difference in root biomass and root morphological parameters of saline-alkaline tolerant cultivar GN under saline-alkaline stress.The number of root tips(RT),root surface area(RS)and root volume(RV)of AG were reduced by 61.16%,44.54%,and 45.31%,respectively,compared with control group.The ratios of K^(+)/Na^(+),Ca^(2+)/Na^(+)and Mg^(2+)/Na^(+)of GN were significantly higher than those of AG(p<0.05).The root fresh weight(RFW)and dry weight(RDW),root length(RL),RV and RT of alfalfa were positively regulated by soil SOC and TN,but negatively regulated by soil pH,EC,and URE(p<0.01).Root Ca^(2+)/Na+ratio was significantly positively correlated with soil TN,TP and SOC(p<0.01).The absorption of Mg and Ca ions in roots is significantly negatively regulated by soilβ-glucosidase activity(BGC)and acid phosphatase activity(APC)(p<0.05).This study improved knowledge of the relationship between root traits and soil environmental factors and offered a theoretical framework for elucidating how plant roots adapt to saline-alkaline stressed soil environments.

The effect of abiotic stresses on plant C:N:P homeostasis and their mitigation by silicon

In crop plants, various environmental stresses affect the balance of carbon, nitrogen, and phosphorus(C:N:P), leading to biochemical and physiological alterations and reductions in yield. Silicon(Si) is a beneficial element that alleviates plant stress. Most studies involving silicon have focused on physiological responses, such as improvements in photosynthetic processes, water use efficiency, and antioxidant defense systems. But recent research suggests that stressed plants facing either limited or excessive resources(water, light, nutrients, and toxic elements), strategically employ Si to maintain C:N:P homeostasis, thereby minimizing biomass losses. Understanding the role of Si in mitigating the impact of abiotic stresses on plants by regulating C:N:P homeostasis holds great potential for advancing sustainable agricultural practices in crop production. This review presents recent advances in characterizing the influence of environmental stresses on C:N:P homeostasis, as well as the role of Si in preserving C:N:P equilibrium and attenuating biological damage associated with abiotic stress. It underscores the beneficial effects of Si in sustaining C:N:P homeostasis and increasing yield via improved nutritional efficiency and stress mitigation.

Testing phaeophytinization as an index of ozone stress in trees

Ground-level ozone pollution is a menace for vegetation in the northern hemisphere,limiting photosynthetic pigments and suppressing photosynthesis in trees and other types of plants.Phaeophytinization is the process of converting chlorophylls into phaeophytins,for example by acidifi cation.Ozone is a highly oxidizing molecule and well known to degrade chlorophylls;however,the eff ect of ozone on phaeophytinization in leaves of higher plants is largely unknown.To reveal ozone eff ect on phaeophytinization and evaluate the potential of phaeophytinization as an index of ozone stress in trees,the absorbance at the optical density of 665 nm was measured before(OD_(665))and after(OD_(665a))acidifi cation in three independent experiments with nearly 30 conditions of ozone exposure.Both current ambient and elevated ozone widely aff ected phaeophytinization,as indicated by decreases or increases in the phaeophytinization quotient OD_(665)/OD_(665a).These eff ects were commonly moderate to large in magnitude and practically signifi cant,and occurred even in ozone-asymptomatic leaves.It emerges that the ozone eff ect on phaeophytinization is bimodal,likely depending on the intensity of ozone stress.These results indicate a promising feature of OD_(665)/OD_(665a)as a thorough index of ozone stress in the future,but further studies are needed to reveal the underlying biochemical mechanisms of the bimodal eff ect on phaeophytinization.

Genetic Diversity Caused by Environmental Stress in Natural Populations of Niupidujuan as Revealed by RAPD Technique

Multiplex environmental factors are generally expected to have significant effects on genetic diversity of plant populations.In this study,randomly amplified polymorphic DNA（RAPD） technique was used to reveal the genetic diversity in the same species of four populations collected from Niupidujuan（Rhododendron chrysanthum） at different altitudes,an endangered species,endemic to Northeast China.Initially,twenty informative and reproducible primers were chosen for final RAPD analysis.A total of 152 clear bands were obtained,including 143 polymorphic ones.With the help of POPGENE software,the poly rate was calculated to be 94.07% and the evenness of amplified bands for every primer was 6.8.Additionally,the mean observed number of alleles was 1.7265 with an effective number of 1.3608.An examination of the gene indicated a diversity of 0.2162 with an information diversity index of 0.3313.For these data,the clustering blurred analysis was performed with the aid of NTSYS-pc software to define the Nei＇s gene diversity and the Shannon information diversity index of the four plant populations.The relationships between the genetic diversity indexes on the one hand and the geographic and climatic factors on the other hand were estimated by the Pearson correlation with SPSS 11.0 software.The results of the correlation analysis show that there were significant（P〈0.05） or highly significant（P〈0.01） correlations between each of the genetic diversity indexes and the different temperature which were mainly caused by the altitude different populations located.These data highlight the importance of native populations in shaping the spatial genetic structure in Niupidujuan.

Temporal species distributions of planktonic protist communities in semi-enclosed mariculture waters and responses to environmental stress

In order to evaluate the relationships between temporal species succession of planktonic protists and physical-chemical parameters in semi-enclosed mariculture waters, species distributions in response to environmental stress were investigated in a shrimp-farming pond near Qingdao, China during a complete shrimp-culture cycle （May to October 2002）. A clear temporal succession in species distribution was found over the complete farming cycle. For example, before the introduction of the shrimp larvae there was low-variability of species distribution in the protist communities whereas during the stages immediately after, there was higher variability in species composition. Multiple linear/logistic regression analyses demonstrate that 12 protist taxa （e.g., Gyrodinium spirale, Teleaulax acuta, Prorocentrum spp. and Mesodinium pupula） were related to the nutrients, in particular ammonia and phosphates, alone or in combination with water temperature. These results suggest that temporal variations in species distribution of planktonic protist communities might be used in assessing water quality of semi-enclosed mariculture waters.

Numerical analysis on mechanical difference of sandstone under in-situ stress,pore pressure preserved environment at depth

Deep in-situ rock mechanics considers the influence of the in-situ environment on mechanical properties,differentiating it from traditional rock mechanics.To investigate the effect of in-situ stress,pore pressure preserved environment on the mechanical difference of sandstone,four tests are numerically modeled by COMSOL:conventional triaxial test,conventional pore pressure test,in-situ stress restoration and reconstruction test,and in-situ pore pressure-preserved test(not yet realized in the laboratory).The in-situ stress restoration parameter is introduced to characterize the recovery effect of in-situ stress on elastic modulus and heterogeneous distribution of sandstone at different depths.A random function and nonuniform pore pressure coefficient are employed to describe the non-uniform distribution of pore pressure in the in-situ environment.Numerical results are compared with existing experimental data to validate the models and calibrate the numerical parameters.By extracting mechanical parameters from numerical cores,the stress-strain curves of the four tests under different depths,in-situ stress and pore pressure are compared.The influence of non-uniform pore pressure coefficient and depth on the peak strength of sandstone is analyzed.The results show a strong linear relationship between the in-situ stress restoration parameter and depth,effectively characterizing the enhanced effect of stress restoration and reconstruction methods on the elastic modulus of conventional cores at different depths.The in-situ pore pressurepreserved test exhibits lower peak stress and peak strain compared to the other three tests,and sandstone subjected to non-uniform pore pressure is more prone to plastic damage and failure.Moreover,the influence of non-uniform pore pressure on peak strength gradually diminished with increasing depth.

Research Progress on Lonicera japonica Thunb.Affected by Environmental Stress

Lonicera japonica Thunb.is widely distributed in China.It has strong adaptability to the environment and can maintain normal growth and development under a variety of stress conditions.It is commonly used as a medicine with its dry flower buds or newly opened flowers,named honeysuckle,and with both economic value and ecological application value.The research progress of L.japonica Thunb.under stress conditions such as temperature,drought,light,salt,heavy metals and diseases,pests and endophytic bacteria was reviewed,and the current research situation of the physiological and biochemical response mechanism,changes of photosynthetic fluorescence and accumulation of secondary metabolites of honeysuckle under different stresses was discussed,so as to provide a reference for deep-level exploring the resistance mechanism of L.japonica Thunb.in the future and lay a theoretical foundation for the high-quality authentic ecological cultivation of L.japonica Thunb.

Study on Eco-environmental Stress Trend of Inner Mongolia Based on Ecological Stress Index

[Objective] The study aimed to analyze the eco-environrnental stress trend of Inner Mongolia using ecological stress index method. [Methed] On the basis of the improved ecological stress index （ESI） analysis method, the eco-environmental stress trend of Inner Mongolia from 1996 to 2009 was analyzed, as well as the changes of eco-environmental stress in major industrial cities of Inner Mongolia in 2008. [ Result] With the economic development of Inner Mongolia from 1996 to 2009, the U-shape change could be found in the eco-environmental stress, showing an upward trend on the whole, especially since 2003, and there was a sharp raise in the environmental pollution index. In addition, the eco-enviren- mental stress lessened in most major cities of Inner Mongolian in 2008, but it was in a polarization state, that is, Baotou, Wuhai and Hohhot biased resource and energy consumption, while Ordos and Chifeng biased environmental pollution. [ Conclusion] The research could provide scientific ref- erences for the protection of ecological environment and the adjustment of industrial structure in Inner Mongolia.

Impact of work environment on job satisfaction and stress among hemodialysis staff in Klang Valley

Objective:To investigate the factors contributing to satisfaction with the work environment,job satisfaction(JS),and stress among hemodialysis(HD)staff in the central region of Malaysia.Methods:A quantitative cross-sectional study was conducted on 215 HD staff working at private and non-government(NGO)dialysis centers using self-administered questionnaires.The chi-square test was used to determine factors associated with HD staff's JS,stress,and working environment.Results:The scientific proof was apparent that the working environment had an effect on JS and stress among employees at HD centers.Conclusions:This research offers useful insights into the essence and complexities of HD staff's work and will help nurses,dialysis managers,other dialysis personnel,and organizations to better understand the benefits and stresses faced by these workers.

Environmental stress upon hepatopancreatic cells of freshwater prawns (Decapoda: Caridea) from the floodplain of ParanáRiver

In order to evaluate the influence of stressed environments on hepatopancreatic cells of fre- shwater prawns, Macrobachium borellii Nobili, 1896 and Palaemonetes argentinus Nobili 1901, (Crustacea, Decapoda, Palaemonidae) were collected at three different aquatic environments with different relationship to urban development in Argentina. Furthermore the effects of several cypermethryn concentration on hepa- topancreatic cell of M. borellii and P. argentinus were evaluated in a laboratory assays. The “N&#176;1” lake (Santa Fe Argentina) which is more affected by the anthropogenic pressure and “Don Felipe” lake which is still not strongly by human activities were the studied sites from the floodplain of Paran&#225;river. While Alejandra lake was the intermedia effects sites. Different damaged ultra-structures were found in F- and R-cells of prawns in the stressed lake. The predominant features were: disrupted the microvillous border, swelled mitochondria, reduction of endoplasmic reticulum, dyctiosomes, glycoproteins, desna-turalization of vacuole membrane and premature autolysis. Moreover the F-cell number was higher in the environment near to city than in the others sites. Similar effects were observed in the cypermethryn assays. The observations clearly indicate that the ultrastructure of midgut gland in the both palaemonids varies depending on the site from which animals are collected and the biocid presence. So, in this case it can be stated that the hepatopancreas histology of fre- shwater prawns is a good tool to monitor the impact of a stressed environment upon freshwater prawns.

Amino terminus mutant OmpA from an isolated antibiotic resistant <i>Escherichia</i><i>coli</i>still possess resistance to environmental stresses

Antibiotic resistant Escherichia coli strains are becoming more common recently. OmpA is a very important antigen protein of E. coli, which consists of two separate domains, N-terminal and C-terminal domain. The N-terminal domain contains eight β- barrel regions that plays important roles in the multifaceted functions of OmpA. In the present study, we cloned a mutant OmpA gene from a multi-antibiotic resistant E. coli strain. Sequence analysis indicated that the N-terminal DNA sequence of the mutant OmpA shared 81.05% homology with the modeled OmpA from E. coli K12 and the N-terminal amino acid sequence of the mutant OmpA was 81.22% identical to that of the E. coli K12 OmpA. Moreover, several amino acids located in the β-barrel region were mutated. The mutant OmpA was expressed in BL21 suggested by SDS-PAGE. Resistance to environmental stress assay indicated that the N-terminus mutant OmpA still possessed excellent activities in pH, temperature and osmotic pressure resistance. Our pre- sent study may supply insights into better and deeper understand the relationships between OmpA N-terminal regions and its functions in environmental stress conditions and the mechanisms on antibiotic resistance of E. coli.

Contributions of aversive environmental stress to migraine chronification:Research update of migraine pathophysiology

Clinical studies have suggested that internal and/or external aversive cues may produce a negative affective-motivational component whereby maladaptive responses(plasticity)of dural afferent neurons are initiated contributing to migraine chronification.However,pathophysiological processes and neural circuitry involved in aversion(unpleasantness)-producing migraine chronification are still evolving.An interdisciplinary team conducted this narrative review aimed at reviewing neuronal plasticity for developing migraine chronicity and its relevant neurocircuits and providing the most cutting-edge information on neuronal mechanisms involved in the processing of affective aspects of pain and the role of unpleasantness evoked by internal and/or external cues in facilitating the chronification process of migraine headache.Thus,information presented in this review promotes the understanding of the pathophysiology of chronic migraine and contribution of unpleasantness(aversion)to migraine chronification.We hope that it will bring clinicians’attention to how the maladaptive neuroplasticity of the emotion brain in the aversive environment produces a significant impact on the chronification of migraine headache,which will in turn lead to new therapeutic strategies for this type of pain.

Interplay between microglia and environmental risk factors in Alzheimer's disease

Alzheimer s disease,among the most common neurodegenerative disorders,is chara cterized by progressive cognitive impairment.At present,the Alzheimer’s disease main risk remains genetic ris ks,but major environmental fa ctors are increasingly shown to impact Alzheimer’s disease development and progression.Microglia,the most important brain immune cells,play a central role in Alzheimer’s disease pathogenesis and are considered environmental and lifestyle"sensors."Factors like environmental pollution and modern lifestyles(e.g.,chronic stress,poor dietary habits,sleep,and circadian rhythm disorde rs)can cause neuroinflammato ry responses that lead to cognitive impairment via microglial functioning and phenotypic regulation.However,the specific mechanisms underlying interactions among these facto rs and microglia in Alzheimer’s disease are unclear.Herein,we:discuss the biological effects of air pollution,chronic stress,gut micro biota,sleep patterns,physical exercise,cigarette smoking,and caffeine consumption on microglia;consider how unhealthy lifestyle factors influence individual susceptibility to Alzheimer’s disease;and present the neuroprotective effects of a healthy lifestyle.Toward intervening and controlling these environmental risk fa ctors at an early Alzheimer’s disease stage,understanding the role of microglia in Alzheimer’s disease development,and to rgeting strategies to to rget microglia,co uld be essential to future Alzheimer’s disease treatments.

Environmental Stress Effect on Animal Reproduction

The aim of this review is to present some aspects of environmental stress effect on reproduction of farm animals. It describes the following: neuroendocrinology of stress, types of stress, stress characteristics in the reproductive process and recommendations for control environmental stress. Stress is the result of confinement and an ambitious vision and uncaring by the man, who is in the interest of improving production, has participated unconsciously, by manipulating animal production in its way, even trying to tame new species, impossible to adapt to our environment healthy. At present, it has been concluded that stress is one of the environmental factors that affect handling and decrease the production of livestock, it is considered that the main factor which should be controlled in units animal production, since it is closely related to pathogens and infectious agents that may try to the health of animals. Finally, some recommendations are outlined to lessen stress for heat, by handling and by feeding.

The Role of Environmental Stress in Determining Gut Microbiome:Case Study of Two Sympatric Toad-headed Lizards

The gut microbiota has gained attention because of its importance in facilitating host survival and evolution.However,it is unclear whether gut microbial communities are determined by the host(heritable factor) or environment(environmental factor).In this study,we investigated the gut microbial communities and potential functional signatures of two sympatric species distributed along an elevation gradient,the toadheaded lizards Phrynocephalus axillaris and P.forsythii.Our results indicated that at high elevations,the gut microbial communities of P.axillaris and P.forsythii did not significantly differ,and the phylogenetic relationships of gut microbial communities contradicted their hosts.At low altitudes,the two lizards could be distinguished based on their significantly different gut microbial communities.Compared to low-altitude populations,Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analysis showed that at higher altitudes,energy metabolism,such as carbohydrate,lipid,and amino acids metabolism were higher in both lizards.While a larger number of pathogenic bacteria were found in the lowaltitude population of P.forsythii.This suggests that the convergence of gut microbiota of two lizards at highaltitude stem from environmental factors,as they were exposed to the same environmental stress,whereas the divergence at low-altitude stemmed from heritable factors,as they were exposed to different environmental stresses.These results provide a new perspective regarding whether heritable or environmental factors dominate the gut microbiota during exposure to environmental stress.

Influence of environmental enrichment on hippocampal synapses in adolescent offspring of mothers exposed to prenatal stress

Environmental enrichment attenuates hippocampal synaptic injury induced by prenatal stress in offspring. However, the influence of hippocampal synaptic changes and regional differences in prenatal stress remains poorly understood. The present study induced stress in Sprague Dawley rats, which were at gestational age 13-19 days. Following weaning, the offspring were raised in an enriched environment to establish models of stress ＋ enriched environment. Dendritic spine density and synaptophysin expression were detected in hippocampal neurons using Golgi staining and western blot analysis, respectively. Results showed that enriched environment increased dendritic spine density of apical dendrites in CA1 pyramidal cells and basal dendrites of granular cells in the outer layer of the dentate gyrus. In addition, hippocampal synaptophysin expression increased and the effects of prenatal stress on neuronal dendritic spines were reversed in adolescence.

Environmental Stress Cracking Resistance of Halloysite Nanoclay-Polyester Nanocomposites

The environmental stress cracking resistance of halloysite nanoclay-polyester nanocomposites was investigated using fracture mechanics approach. The incorporation of halloysite nanoclay was found to improve the environmental stress cracking resistance of the nano-composites. The storage modulus of nano-composites measured by dynamic mechanical analysis increased remarkably as a function of halloysite nanoclay content. At 0.7 wt% nanoclay, the Tg improved from 72°C to 76°C. The fracture toughness increased up to 33% and time to failure improved 155% with the addition of 0.7 wt% of halloysite nanoclay. The maximum microhardness was found 119% higher for the same nano-filler concentration compared to monolithic polyester. The reinforcement with 1 wt% showed lower fracture toughness due to agglomerations of nanoclay which act as flaws. The presence of agglomerates weakened the bond between nano-particles and matrix hence reduces the environmental stress cracking resistance by halloysite nanoclay reinforcement.

Sap flow response of Eucaylyptus （Eucalyptus urophyila） to environmental stress in South China

Sap flow and environmental conditions were monitored at two Eucalyptus (Eucalyptus urophylla S.T.Blake) plantations at Hetou and Jijia, located in Leizhou, Zhanjiang, Guangdong Province. It was found that daily sap flux density (SFD) of Eucalyptus was closely related to daily atmospheric vapor pressure deficit (VPD) (R^2=0.76, P=0.01 at Hetou and R^2=0.7021, P=0.01 at Jijia) at both sites. No significant relationship existed between daily SFD and mean daily air temperature at both sites. Daily SFD varied with wind speed Y=-17585X^3+15147X^2-1250.7X+2278.4 (R^2=0.68; P=0.01) at Hetou and Y=-101.67X^3-1.65X^2-376.4X+1914.8(R^2=0.40, P=0.05) at Jijia, where Ywas daily SFD, Xwas daily wind speed. Experimental observations yielded the following data: (1) the critical lower and upper daily VPD threshold were 0 and 2kPa, within which daily SFD varied from 540±70L/(m^2·d) to 4739±115L/(m^2·d) at Hetou site, from 397±26L/(m^2·d) to 3414±191L/(m^2·d) at Jijia site; (2) Diurnal SFDs at Hetou site were much higher under low relative humidity (<30%) and slightly lower under high relative humidity (>80%) compared with those at the Jijia site; (3) The upper and lower threshold of daily and diurnal RAD for the optimal water use of E. urophylla plantations were 18±2.7 and 2±1MJ/(m^2·d), 669 and 0J/(cm^2·h) during the observation period.

Observation of Environmental Stress Cracking in Polymethylmethacrylate by Using the Chemiluminescence Method

Polymethylmethacrylate (PMMA) is highly regarded for its transparency, and is used in such products as cameras and Video Tape Recorders as plastic lenses to take advantage of its excellent optical properties. Also, it is used in numerous other industrial fields like automobile lamp lenses, billboards, and lighting equipment. The phenomenon of environmental stress cracking is known to occur in PMMA due to ethanol, and there are cases when this may become a factor which causes damage of molded products. In the present paper, upon close observation by using the method of chemiluminescence in order to elucidate the mechanism by which this environmental stress cracking occurs, we report that we are able to capture the formation of a radical at the moment of cracking.

Application of Hydrogen Peroxide as an Environmental Stress Indicator for Vegetation Management

适应性植被管理非常耗时,其需要长时间的野外监测以获取可靠的数据。目前适应性植被管理手段虽已被广泛应用,但在进行栖息地状况评估时,仍然依赖于长时间的野外观测。目前的植被相关研究中,活性氧类(ROS)已经被视为一种环境胁迫指标。在这些ROS中,过氧化氢(H_2O_2)相对稳定,并且可以被准确、方便地量化。植物中H_2O_2含量可以被用作岸生和水生植被管理过程的胁迫指标,同时可以用来评估栖息地中单一植物物种的生长状况。本研究证明了植被管理中应用H_2O_2作为定量化环境胁迫指标的可行性。在实验室和野外(日本的真嗣湖、沙巴河、伊诺河和海河)条件下,分别开展了不同胁迫程度下大型水生植物和岸生植物生成H_2O_2情况的研究,结果表明H_2O_2可以作为环境管理中的胁迫指标。