The intrinsic developmental age signal defines an age-dependent climbing behavior in cucumber

The tendril is a climbing organ in cucurbits and functions in physical support and to avoid shading by neighboring vegetation.However,how cucurbits produce tendrils to obtain climbing ability is largely unknown.In this study,tendril phenotypes were investigated during different developmental stages.Our results revealed that tendril growth exhibited an age-dependent pattern in cucurbits.Tendril growth was inhibited,and the tendril was formed as a short tendril[nonfunctional tendril(nonF-tendril),approximately 0.1 cm]during the seedling stage.In contrast,enhanced cell proliferation and cell expansion led to rapid elongation of the tendril during the climbing stage,and the tendril formed as a functional tendril(F-tendril,approximately 30 cm)to obtain climbing ability.RT-qPCR detection showed that age-dependent tendril growth correlated negatively with the abundance of the conserved age regulator CsmiR156.Defoliation induced CsmiR156 to inhibit CsSPLs,and F-tendril formation and climbing ability were delayed in defoliated cucumbers,which confirmed the role of CsmiR156 in regulating tendril growth in vivo.Additionally,exogenous gibberellin(GA)treatment showed that GA positively regulated tendril growth,and RT-qPCR detection showed that the GA bio-synthetic genes and metabolic genes were affected by age pathway,suggesting that the age pathway depended on GA bio-synthetic and metabolic pathway to regulate cell expansion to determine tendril growth.In summary,our work reveals that change in tendril type is an important marker of phase transition in cucumber,and tendril growth is regulated by an intrinsic developmental age signal,ensuring that the cucumber obtains climbing ability at a suitable age.

Dynamics of a Stochastic Epidemic Model with Age-group

A stochastic epidemic model with two age groups is established in this study,in which the susceptible(S),the exposed(E),the infected(I),the hospitalized(H)and the recovered(R)are involved within the total population,the aging rates between two age groups are set to be constant.The existence-and-uniqueness of global positive solution is firstly showed.Then,by constructing several appropriate Lyapunov functions and using the high-dimensional Itô’s formula,the sufficient conditions for the stochastic extinction and stochastic persistence of the exposed individuals and the infected individuals are obtained.The stochastic extinction indicator and the stochastic persistence indicator are less-valued expressions compared with the basic reproduction number.Meanwhile,the main results of this study are modified into multi-age groups.Furthermore,by using the surveillance data for Fujian Provincial Center for Disease Control and Prevention,Fuzhou COVID-19 epidemic is chosen to carry out the numerical simulations,which show that the age group of the population plays the vital role when studying infectious diseases.

Association between age at diagnosis of diabetes and ocular disease:Insights from a recent article

In this article,we discuss Ye et al's recent article on the association between age at diabetes diagnosis and subsequent risk of age-related ocular diseases.The study,which utilized United Kingdom Biobank data,highlighted a strong link between early diabetes onset and major eye conditions,such as cataracts,glaucoma,agerelated macular degeneration,and vision loss,independent of glycemic control and disease duration.This finding challenges the previous belief that diabetic eye disease primarily correlates with hyperglycemia.As lifestyles evolve and the age of diabetes diagnosis decreases,understanding this relationship may reveal the complex pathogenesis underlying diabetes-related complications.This editorial summarizes potential mechanisms connecting the age of diabetes onset with four types of ocular diseases,emphasizing the significance of early diagnosis.

Gut microbiota-astrocyte axis: new insights into age-related cognitive decline

With the rapidly aging human population,age-related cognitive decline and dementia are becoming increasingly prevalent worldwide.Aging is considered the main risk factor for cognitive decline and acts through alterations in the composition of the gut microbiota,microbial metabolites,and the functions of astrocytes.The microbiota–gut–brain axis has been the focus of multiple studies and is closely associated with cognitive function.This article provides a comprehensive review of the specific changes that occur in the composition of the gut microbiota and microbial metabolites in older individuals and discusses how the aging of astrocytes and reactive astrocytosis are closely related to age-related cognitive decline and neurodegenerative diseases.This article also summarizes the gut microbiota components that affect astrocyte function,mainly through the vagus nerve,immune responses,circadian rhythms,and microbial metabolites.Finally,this article summarizes the mechanism by which the gut microbiota–astrocyte axis plays a role in Alzheimer’s and Parkinson’s diseases.Our findings have revealed the critical role of the microbiota–astrocyte axis in age-related cognitive decline,aiding in a deeper understanding of potential gut microbiome-based adjuvant therapy strategies for this condition.

Age-dependent eradication of Helicobacter pylori in Japanese patients

AIM:To determine the general risk factors affecting the failure rate of first-line eradication therapy in Japanese patients with Helicobacter pylori(H.pylori)infection.METHODS:The present study enrolled 253 patients who had an H.pylori infection,underwent gastroendoscopy,and were treated with H.pylori eradication therapy.Eradication therapy consisted of 30 mg lansoprazole plus 750 mg amoxicillin and 400 mg clarithromycin twice daily for 7 d.All of the patients underwent a 13 C urea breath test at least 1 mo after the completion of eradication therapy.The current study investigated the independent factors associated with successful H.pylori eradication using a multiple logistic regression analysis.RESULTS:The overall success rate in the patients was 85.8%.Among the general factors examined in the multivariate analyses,only having an age less than 50 years was found to be significantly associated with a poor response to H.pylori eradication.Moreover,side effects were the only clinical factors in the patients who were under 50 years of age that significantly influenced the poor response to H.pylori eradication.CONCLUSION:H.pylori-positive elderly patients should undergo eradication therapy.In addition,it is necessary to improve H.pylori eradication therapy in younger patients.

Age-dependent impact of the SYNTAX-score on longer-term mortality after percutaneous coronary intervention in an all-comer population

Background The Synergy between Percutaneous Coronary Intervention with TAXUS and Cardiac Surgery （SYNTAX）-score is a validated tool for risk stratification and revascularization strategy selection in patients with complex coronary artery disease. The aim of this study was to analyse its age-related prognostic value. Methods SYNTAX-score was calculated in 1331 all-comer patients undergoing percutaneous coronary intervention （PCI）： 463 patients ≥ 75 years and 868 patients 〈 75 years. Outcomes of interest were all-cause mortality at one and two years. Results A significant interaction of age and SYNTAX-score for mortality was observed at two-year （Pinteraction= 0.019） but not at one-year follow-up （Pinteraction= 0.594）. In multivariable analysis, SYNTAX-score independently predicted 1-year mortality in both age groups （〈 75 years, hazard ratio （HR）： 1.43, 95% confidence intervals （CI）： 1.03-2.00, P = 0.034; and 〉 75 years, HR： 1.37, 95% CI： 1.01-1.85, P = 0.042）, but only two-year mortality among younger patients （〈 75 years, HR： 1.33, 95% CI： 1.01-1.76, P = 0.041; and ≥ 75 years, HR： 1.11, 95% CI： 0.87-1.41, P = 0.394）. SYNTAX-score tertiles were useful to stratify 1-year mortality in both, patients 〈 75 years （SYNTAX-score 〈 9, 3.8%; 9-20, 5.3%; 〉 20, 10.3%; P = 0.004） and 〉 75 years （SYNTAX-score 〈 11, 5.7%; 11-22.5, 16.1%; 〉 22.5, 18.7%; P = 0.003）, but two-year mortality only among patients 〈 75 years （SYNTAX-score 〈 9, 6.5%; 9-20, 7.6%; ≥ 20, 15%; P 〈 0.001） and not among ≥ 75 years old patients （SYNTAX-score 〈 11, 19.4%; 11-22.5, 26.3%; _〉 22.5, 27.9%; P = 0.138）. Conclusions Age modi- fies the impact of the SYNTAX-score on longer-term mortality after PCI. Among patients 〈 75 years, the SYNTAX-score independently predicts the risk of death at one and two years after PCI, while among patients 〉 75 years its predictive role is limited to the first year after PCI. Further studies are needed to evaluate the value of SYNTAX-score for selecting the most appropriate revascularization strategy among elderly patients.

Size-and leaf age-dependent effects on the photosynthetic and physiological responses of Artemisia ordosica to drought stress

Drought is one of the most significant natural disasters in the arid and semi-arid areas of China.Populations or plant organs often differ in their responses to drought and other adversities at different growth stages.At present,little is known about the size-and leaf age-dependent differences in the mechanisms of shrub-related drought resistance in the deserts of China.Here,we evaluated the photosynthetic and physiological responses of Artemisia ordosica Krasch.to drought stress using a field experiment in Mu Us Sandy Land,Ningxia Hui Autonomous Region,China in 2018.Rainfall was manipulated by installing outdoor shelters,with four rainfall treatments applied to 12 plots(5 m×5 m).There were four rainfall levels,including a control and rainfall reductions of 30%,50%and 70%,each with three replications.Taking individual crown size as the dividing basis,we measured the responses of A.ordosica photosynthetic and physiological responses to drought at different growth stages,i.e.,large-sized(>0.5 m^(2))and small-sized(≤0.5 m^(2))plants.The leaves of A.ordosica were divided into old leaves and young leaves for separate measurement.Results showed that:(1)under drought stress,the transfer efficiency of light energy captured by antenna pigments to the photosystem II(PSII)reaction center decreased,and the heat dissipation capacity increased simultaneously.To resist the photosynthetic system damage caused by drought,A.ordosica enhanced its free radical scavenging capacity by activating its antioxidant enzyme system;and(2)growth stage and leaf age had effects on the reaction of the photosynthetic system to drought.Small A.ordosica plants could not withstand severe drought stress(70%rainfall reduction),whereas large A.ordosica individuals could absorb deep soil water to ensure their survival in severe drought stressed condition.Under 30%and 50%rainfall reduction conditions,young leaves had a greater ability to resist drought than old leaves,whereas the latter were more resistant to severe drought stress.The response of A.ordosica photosynthetic system reflected the trade-off at different growth stages and leaf ages of photosynthetic production under different degrees of drought.This study provides a more comprehensive and systematic perspective for understanding the drought resistance mechanisms of desert plants.

Detection of Ca^(2+)-dependent acid phosphatase activity identifies neuronal integrity in damaged rat central nervous system after application of bacterial melanin

The study aims to confirm the neuroregenerative effects of bacterial melanin （BM） on central nervous system injury using a special staining method based on the detection of Ca^2＋-dependent acid phosphatase activity. Twenty-four rats were randomly assigned to undergo either unilateral destruction of sensorimotor cortex （group I; n = 12） or unilateral rubrospinal tract transection at the cervical level （C3-4） （group II; n = 12）. In each group, six rats were randomly selected after surgery to undergo intramuscular injection of BM solution （BM subgroup） and the remaining six rats were intramuscularly in）ected with saline （saline subgroup）. Neurological testing confirmed that BM accelerated the recovery of motor function in rats from both BM and saline subgroups. Two months after surgery, Ca^2＋-dependent acid phosphatase activity detection in combination with Chilingarian＇s calcium adenoside triphosphate method revealed that BM stimulated the sprouting of fibers and dilated the capillaries in the brain and spinal cord. These results suggest that BM can promote the recovery of motor function of rats with central nervous system injury; and detection of Ca^2＋-dependent acid phosphatase activity is a fast and easy method used to study the regeneration-promoting effects of BM on the injured central nervous system.

x_F(or y)-Dependence of Nuclecir Absorption and Energy Loss Effects on J/ψ Production

By means of the nuclear parton distribution studied only with lepton deep-inelastic scattering experimental data, the J/ψ ＂normal nuclear absorption＂ and energy loss effects are studied in a GIauber formalism at HERA and RHIC energies. Assuming that the absorption cross section σabs increases with the charmonium-nucleon center of mass energy, the results reveal a significant dependence of the aabs on rapidity g at RHIC energies. The initial-state energy loss effect, which is found important only at HERA energies, is also considered, and its influence should be eliminated when we studied the absorption effect at low collision energies. Finally, we also present the theoretical prediction for LHC.

Age-specific differences in the association between prediabetes and cardiovascular diseases in China:A national cross-sectional study

BACKGROUND Cardiovascular disease(CVD)is a leading cause of morbidity and mortality worldwide,the global burden of which is rising.It is still unclear the extent to which prediabetes contributes to the risk of CVD in various age brackets among adults.To develop a focused screening plan and treatment for Chinese adults with prediabetes,it is crucial to identify variations in the connection between prediabetes and the risk of CVD based on age.AIM To examine the clinical features of prediabetes and identify risk factors for CVD in different age groups in China.METHODS The cross-sectional study involved a total of 46239 participants from June 2007 through May 2008.A thorough evaluation was conducted.Individuals with prediabetes were categorized into two groups based on age.Chinese atherosclerotic CVD risk prediction model was employed to evaluate the risk of developing CVD over 10 years.Random forest was established in both age groups.SHapley Additive exPlanation method prioritized the importance of features from the perspective of assessment contribution.RESULTS In total,6948 people were diagnosed with prediabetes in this study.In prediabetes,prevalences of CVD were 5(0.29%)in the younger group and 148(2.85%)in the older group.Overall,11.11%of the younger group and 29.59% of the older group were intermediate/high-risk of CVD for prediabetes without CVD based on the Prediction for ASCVD Risk in China equation in ten years.In the younger age group,the 10-year risk of CVD was found to be more closely linked to family history of CVD rather than lifestyle,whereas in the older age group,resident status was more closely linked.CONCLUSION The susceptibility to CVD is age-specific in newly diagnosed prediabetes.It is necessary to develop targeted approaches for the prevention and management of CVD in adults across various age brackets.

Association of age at diagnosis of diabetes with subsequent risk of age-related ocular diseases and vision acuity

BACKGROUND The importance of age on the development of ocular conditions has been reported by numerous studies.Diabetes may have different associations with different stages of ocular conditions,and the duration of diabetes may affect the development of diabetic eye disease.While there is a dose-response relationship between the age at diagnosis of diabetes and the risk of cardiovascular disease and mortality,whether the age at diagnosis of diabetes is associated with incident ocular conditions remains to be explored.It is unclear which types of diabetes are more predictive of ocular conditions.AIM To examine associations between the age of diabetes diagnosis and the incidence of cataract,glaucoma,age-related macular degeneration(AMD),and vision acuity.METHODS Our analysis was using the UK Biobank.The cohort included 8709 diabetic participants and 17418 controls for ocular condition analysis,and 6689 diabetic participants and 13378 controls for vision analysis.Ocular diseases were identified using inpatient records until January 2021.Vision acuity was assessed using a chart.RESULTS During a median follow-up of 11.0 years,3874,665,and 616 new cases of cataract,glaucoma,and AMD,respectively,were identified.A stronger association between diabetes and incident ocular conditions was observed where diabetes was diagnosed at a younger age.Individuals with type 2 diabetes(T2D)diagnosed at<45 years[HR(95%CI):2.71(1.49-4.93)],45-49 years[2.57(1.17-5.65)],50-54 years[1.85(1.13-3.04)],or 50-59 years of age[1.53(1.00-2.34)]had a higher risk of AMD independent of glycated haemoglobin.T2D diagnosed<45 years[HR(95%CI):2.18(1.71-2.79)],45-49 years[1.54(1.19-2.01)],50-54 years[1.60(1.31-1.96)],or 55-59 years of age[1.21(1.02-1.43)]was associated with an increased cataract risk.T2D diagnosed<45 years of age only was associated with an increased risk of glaucoma[HR(95%CI):1.76(1.00-3.12)].HRs(95%CIs)for AMD,cataract,and glaucoma associated with type 1 diabetes(T1D)were 4.12(1.99-8.53),2.95(2.17-4.02),and 2.40(1.09-5.31),respectively.In multivariable-adjusted analysis,individuals with T2D diagnosed<45 years of age[β95%CI:0.025(0.009,0.040)]had a larger increase in LogMAR.Theβ(95%CI)for LogMAR associated with T1D was 0.044(0.014,0.073).CONCLUSION The younger age at the diagnosis of diabetes is associated with a larger relative risk of incident ocular diseases and greater vision loss.

Non-linear relationship between age and subfoveal choroidal thickness in Chinese patients with proliferative diabetic retinopathy

BACKGROUND No study has investigated the change regularity between age and subfoveal choroidal thickness(SFCT)in proliferative diabetic retinopathy(PDR).AIM To investigate the relationship between the SFCT and age in Chinese patients with PDR.METHODS This was a cross-sectional retrospective study.The participants were hospitalized individuals with type 2 diabetes who underwent vitrectomy for PDR.Contralateral eyes that met the criteria were included in the study.All necessary laboratory tests were performed at the time of admission.Central macular thickness(CMT)and SFCT were two quantitative assessments made using enhanced depth imaging optical coherence tomography.CMT was measured automatically and SFCT was measured manually with digital calipers provided by the Heidelberg Eye Explorer software.RESULTS The final analysis included a total of 234 individuals with PDR.The average age was 55.60 years old±10.03 years old,and 57.69%of the population was male.Univariate analysis revealed a significant negative connection between age and SFCT in patients with PDR[β=-2.44,95%confidence interval(95%CI):-3.46 to-1.42;P<0.0001].In the fully adjusted model,the correlation between SFCT and age remained steady(β=-1.68,95%CI:-2.97 to-0.39;P=0.0117).Spline smoothing showed that the relationship between SFCT and age in patients with PDR was non-linear,with an inflection point at 54 years of age.CONCLUSION Our findings suggest that age is a key determinant of choroidal thickness.The non-linear link between SFCT and age in PDR patients should be taken into account.

Polymetamorphism of the ultrahigh-temperature granulites in the Rauer Group,East Antarctica:new evidence from zircon SHRIMP U-Pb ages

The Rauer Group is located on the eastern margin of the early Paleozoic Prydz Belt in East Antarctica,and the typical ultrahigh-temperature(UHT,>900℃)granulites outcrop on Mather Peninsula.However,the timing of UHT metamorphism and P–T path of the UHT granulites have long been debated,which is critical to understanding the tectonic nature and evolution history of the Prydz Belt.Thus,both a sapphirine-bearing UHT metapelitic granulite and a garnet-bearing UHT mafic granulite are selected for zircon SHRIMP U-Pb age dating.The results show that metamorphic zircon mantles yield weighted mean^(206)Pb/^(238)U ages of 918±29 Ma and 901±29 Ma for the metapelitic and mafic granulites,respectively,while zircon rims and newly grown zircons yield weighted mean^(206)Pb/^(238)U ages of 523±9 Ma and 532±11 Ma,respectively.These new zircon age data suggest that the UHT granulites may have experienced polymetamorphism,in which pre-peak prograde stage occurred in the early Neoproterozoic Grenvillian orogenesis(1000–900 Ma),whereas the UHT metamorphism occurred in the late Neoproterozoic to early Paleozoic Pan-African orogenesis(580–460 Ma).This implies that P–T path of the UHT granulites should consist of two separate high-grade metamorphic events including the Grenvillian and Pan-African events,which are supposed to be related to assembly of Rodinia and Gondwana supercontinents respectively,and hence the overprinting UHT metamorphic event may actually reflect an important intracontinental reworking.

Bowel preparation protocol for hospitalized patients ages 50 years or older:A randomized controlled trial

BACKGROUND The incidence and mortality rate of colorectal cancer progressively increase with age and become particularly prominent after the age of 50 years.Therefore,the population that is≥50 years in age requires long-term and regular colonoscopies.Uncomfortable bowel preparation is the main reason preventing patients from undergoing regular colonoscopies.The standard bowel preparation regimen of 4-L polyethylene glycol(PEG)is effective but poorly tolerated.AIM To investigate an effective and comfortable bowel preparation regimen for hospitalized patients≥50 years in age.METHODS Patients were randomly assigned to group 1(2-L PEG+30-mL lactulose+a lowresidue diet)or group 2(4-L PEG).Adequate bowel preparation was defined as a Boston bowel preparation scale(BBPS)score of≥6,with a score of≥2 for each segment.Non-inferiority was prespecified with a margin of 10%.Additionally,the degree of comfort was assessed based on the comfort questionnaire.RESULTS The proportion of patients with a BBPS score of≥6 in group 1 was not significantly different from that in group 2,as demonstrated by intention-to-treat(91.2%vs 91.0%,P=0.953)and per-protocol(91.8%vs 91.0%,P=0.802)analyses.Furthermore,in patients≥75 years in age,the proportion of BBPS scores of≥6 in group 1 was not significantly different from that in group 2(90.9%vs 97.0%,P=0.716).Group 1 had higher comfort scores(8.85±1.162 vs 7.59±1.735,P<0.001),longer sleep duration(6.86±1.204 h vs 5.80±1.730 h,P<0.001),and fewer awakenings(1.42±1.183 vs 2.04±1.835,P=0.026)than group 2.CONCLUSION For hospitalized patients≥50 years in age,the bowel preparation regimen comprising 2-L PEG+30-mL lactulose+a low-residue diet produced a cleanse that was as effective as the 4-L PEG regimen and even provided better comfort.

Age Identity and Elderly Job Participation in China

In the context of rising life expectancy,there is a significant discrepancy between Chinese seniors’self-perceptions of the start of old age and the expectations of society around this age.The traditional paradigm,which forecasts individual economic behavior and formulates economic policies based on societal standards of age,is put to the test by this disparity.This study,which draws from the China Longitudinal Aging Society Survey(CLASS),examines the factors,processes,and improvement strategies that affect how older people choose to work.The following are our conclusions:(i)Chinese elderly believe their old age starts from 70 years on average;delaying perceived old age is a denial of aging and raises the likelihood of finding work.Elders who are youthful at heart have a 2.4%higher chance of remaining employed than elders who are old at heart.(ii)In contrast to old-at-heart elders,young-at-heart elders are more likely to maintain their middle-age lifestyles,continue working,become motivated to engage in social activities,and gain the confidence to face challenges and continue in their career.(iii)If the perceived old age is above 70 years,the milestone event of aging is retirement from work,and there are external pressures,particularly pressures from family intergenerational support,the perception of old age will have a more proactive impact on older workers.(iv)Despite rising pension benefits,older people’s decision to remain in the workforce is still heavily influenced by their perception of their age.However,this effect is notably gender-specific,as older women’s decision to remain in the workforce is not greatly influenced by their own perception of their age.

Can serum immunoglobulin G4 levels and age serve as reliable predictors of relapse in autoimmune pancreatitis?

We are writing in response to the paper published in the World Journal of Gastroenterology by Zhou et al.The authors identified higher serum immunoglobulin(Ig)G4 levels and age over 55 years as independent risk factors for disease relapse.Despite notable strengths,it is crucial to address potential biases.Firstly,the cohort study included 189 patients with autoimmune pancreatitis(AIP)type 1(with higher IgG4 seropositivity and higher relapse)and 24 with type 2(with lower IgG4 seropositivity and lower relapse).Consequently,most,if not all,AIP type 2 patients were assigned to the normal group,possibly inflating the association of higher serum IgG4 levels with relapse and potentially exaggerating the association of older age with relapse.Secondly,the authors did not provide sufficient details regarding AIP diagnosis,such as the ratio of definitive vs probable cases and the proportion of biopsies.In cases where histological evidence is unavailable or indeterminate,AIP type 2 may be misdiagnosed as definitive type 1,and type 1 may also be misdiagnosed as probable type 2,particularly in cases with normal or mildly elevated serum IgG4 levels.Lastly,in this retrospective study,approximately one-third of the consecutive patients initially collected were excluded for various reasons.Accordingly,the impact of nonrandom exclusion on relapse outcomes should be carefully considered.In conclusion,the paper by Zhou et al offers plausible,though not entirely compelling,evidence suggesting a predictive role of elevated serum IgG4 levels and advanced age in AIP relapse.The foundation for future investigations lies in ensuring a reliable diagnosis and accurate disease subtyping,heavily dependent on obtaining histological specimens.In this regard,endoscopic ultrasound-guided fine-needle biopsy emerges as a pivotal component of the diagnostic process,contributing to mitigating biases in future explorations of the disease.

Age of Loop Information with Flexible Transmission Enabled Communication and Control Co-Design in Industrial IoT

Precise and low-latency information transmission through communication systems is essential in the Industrial Internet of Things(IIoT).However,in an industrial system,there is always a coupling relationship between the control and communication components.To improve the system's overall performance,exploring the co-design of communication and control systems is crucial.In this work,we propose a new metric±Age of Loop Information with Flexible Transmission(AoLI-FT),which dynamically adjusts the maximum number of uplink(UL)and downlink(DL)transmission rounds,thus enhancing reliability while ensuring timeliness.Our goal is to explore the relationship between AoLI-FT,reliability,and control convergence rate,and to design optimal blocklengths for UL and DL that achieve the desired control convergence rate.To address this issue,we first derive a closed-form expression for the upper bound of AoLI-FT.Subsequently,we establish a relationship between communication reliability and control convergence rates using a Lyapunov-like function.Finally,we introduce an iterative alternating algorithm to determine the optimal communication and control parameters.The numerical results demonstrate the significant performance advantages of our proposed communication and control co-design strategy in terms of latency and control cost.

Characteristics of different aged plantations of Ormosia hosiei with regards to soil microbial biomass and enzymatic activities

Stand age is an important indicator of tree growth and life cycle,and has implications for ecological and biological processes.This study examined changes in soil microbial biomass(SMB)as well as enzyme activities of different aged plantations and revealed their relationship to soil properties.SMB,microbial biomass carbon(MBC),microbial biomass nitrogen(MBN),microbial biomass phos-phorous(MBP)and enzyme activities(β-1,4-glucosidase(β-G),β-1,4-xylosidase(β-X),cellobiohydrolase(CBH),leucine aminopeptidase(LAP),β-1,4-n-acetylglucosamine(NAG)and acid phosphatase(ACP))were measured in Oro-mosia hosiei plantations of different ages.The soil qual-ity index(SQI)model assessed soil quality.SMB contents significantly decreased in young(7-year-old)and mature plantations(45-year-old)compared to middle-aged(20-year-old)plantations.Activity of soilβ-G,β-X,CBH and NAG in the 20-year-old plantations was markedly higher than in the other plantations except forβ-G,CBH and NAG in the 45-year-old plantations.Soil organic carbon(SOC),total potassium(TK),total porosity,dissolved organic carbon,nitrate nitrogen(NO_(3)--N)and non-capillary porosity were key factors affecting SMB,while soil bulk density,pH,SOC,NO_(3)--N,TK and forest litter(FL)were the main factors affecting soil enzyme activities.SQI decreased in the order:middle-aged>mature>young.The efficiency of soil organic matter conversion,the effect of nitrogen min-eralization and fixation by microorganisms,and the better efficiency of phosphorus utilization in mid-age plantations,which improves soil physical properties,better facilitates tree growth,and further improves the buffering of the soil against acidity and alkalinity.FL quality was the only soil biological factor affecting soil enzyme activity.Our findings demonstrate that different aged plantations affect soil micro-bial biomass,enzyme activity,and soil quality.

Afforestation with an age-sequence of Mongolian pine plantation promotes soil microbial residue accumulation in the Horqin Sandy Land, China

Land use change affects the balance of organic carbon(C)reserves and the global C cycle.Microbial residues are essential constituents of stable soil organic C(SOC).However,it remains unclear how microbial residue changes over time following afforestation.In this study,16-,23-,52-,and 62-year-old Mongolian pine stands and 16-year-old cropland were studied in the Horqin Sandy Land,China.We analyzed changes in SOC,amino sugar content,and microbial parameters to assess how microbial communities influence soil C transformation and preservation.The results showed that SOC storage increased with stand age in the early stage of afforestation but remained unchanged at about 1.27-1.29 kg/m2 after 52 a.Moreover,there were consistent increases in amino sugars and microbial residues with increasing stand age.As stand age increased from 16 to 62 a,soil pH decreased from 6.84 to 5.71,and the concentration of total amino sugars increased from 178.53 to 509.99 mg/kg.A significant negative correlation between soil pH and the concentration of specific and total amino sugars was observed,indicating that the effects of soil acidification promote amino sugar stabilization during afforestation.In contrast to the Mongolian pine plantation of the same age,the cropland accumulated more SOC and microbial residues because of fertilizer application.Across Mongolian pine plantation with different ages,there was no significant change in calculated contribution of bacterial or fungal residues to SOC,suggesting that fungi were consistently the dominant contributors to SOC with increasing time.Our results indicate that afforestation in the Horqin Sandy Land promotes efficient microbial growth and residue accumulation in SOC stocks and has a consistent positive impact on SOC persistence.

How forest age impacts on net primary productivity: Insights from future multi-scenarios

Forest net primary productivity(NPP)constitutes a key flux within the terrestrial ecosystem carbon cycle and serves as a significant indicator of the forests carbon sequestration capacity,which is closely related to forest age.Despite its significance,the impact of forest age on NPP is often ignored in future NPP projections.Here,we mapped forest age in Hunan Province at a 30-m resolution utilizing a combination of Landsat time series stack(LTSS),national forest inventory(NFI)data,and the relationships between height and age.Subsequently,NPP was derived from NFI data and the relationships between NPP and age was built for various forest types.Then forest NPP was predicted based on the NPP-age relationships under three future scenarios,assessing the impact of forest age on NPP.Our findings reveal substantial variations in forest NPP in Hunan Province under three future scenarios:under the age-only scenario,NPP peaks in 2041(133.56TgC·yr^(−1)),while NPP peaks three years later in 2044(141.14TgC·yr^(−1))under the natural development scenario.The maximum afforestation scenario exhibits the most rapid increase in NPP,with peaking in 2049(197.95TgC·yr^(−1)).However,with the aging of the forest,NPP is projected to then decrease by 7.54%,6.07%,and 7.47%in 2060,and 20.05%,19.74%,and 28.38%in 2100,respectively,compared to their peaks under the three scenarios.This indicates that forest NPP will continue to decline soon.Controlling the age structure of forests through selective logging,afforestation and reforestation,and encouraging natural regeneration after disturbance could mitigate this declining trend in forest NPP,but implications of these measures on the full forest carbon balance remain to be studied.Insights from the future multi-scenarios are expected to provide data to support sustainable forest management and national policy development,which will inform the achievement of carbon neutrality goals by 2060.