[Objective]This study aims to explore the photosynthetic physiological response mechanisms of Hosta ventricosa(Salisb.)Stearn under different light conditions and planting densities,in order to provide theoretical and practical guidance for its understory cultivation and landscape application.[Method]Three shading treatments were set:30%-35%transmittance(L1),45%-50%(L2),and 60%-70%(L3),along with three planting densities:10 cm×10 cm(D1),12 cm×12 cm(D2),and 21 cm×21 cm(D3).By analyzing photosynthetic gas exchange parameters,chlorophyll fluorescence,chlorophyll content,osmotic adjustment substances,antioxidant enzyme activities,and morphological indicators of Hosta ventricosa leaves,we investigated the effects of shading,planting density,and their interaction on the growth and photosynthetic adaptation of the plant.[Result](1)In terms of physiological adaptability,H.ventricosa exhibited optimal photosynthetic performance under moderate shading(L2,45%-50%light transmittance),with the net photosynthetic rate reaching 5.55 μmol/(m²·s).It enhanced low-light adaptation and oxidative stress resistance by increasing total chlorophyll content,reducing the chlorophyll a/b ratio(1.91-2.15),and activating the antioxidant enzyme system(e.g.,POD activity reached 388.4 U/g FW).(2)In cultivation mode,moderate density(D2)combined with moderate shading(L2)significantly improved water-use efficiency(up to 8.73 μmol/mmol)and maximized biomass accumulation.(3)Two-factor analysis showed a significant interaction between shading and density,with the combination of moderate shading and moderate density(L2+D2)most effectively promoting the overall optimization of photosynthetic physiological function and morphological development.[Conclusion]The response of H.ventricosa to shading and planting density demonstrates clear physiological plasticity and resource trade-off characteristics.The results indicate that the combination of moderate shading(L2)and moderate density(D2)(L2+D2)can effectively coordinate light distribution within the population,alleviate photoinhibition,enhance antioxidant defense,and improve water-use efficiency.This represents a superior cultivation configuration for achieving both high-quality individual growth and stable population yield.The findings provide direct guidance for the scientific cultivation of H.ventricosa in understory economy,multi-layer landscape construction,and ecological restoration in karst regions.
[Objective]This study aims to investigate the effects of dynamic water temperature changes during overwintering on the growth performance,physiological status,and tissue structure of the red claw crayfish(Cherax quadricarinatus),and to reveal its adaptation mechanisms to low-temperature stress under actual aquaculture conditions,thereby providing a theoretical basis for addressing the bottleneck of low overwintering survival rates that restricts industrial development.[Method]Based on natural water temperature fluctuations,the overwintering process was divided into four stages:pre-overwintering(19.5±2.6)℃,mid-overwintering(13.0±2.2)℃,late-overwintering(15.5±1.3)℃,and post-overwintering(19.5±2.4)℃.Growth indices,digestive enzyme activities,antioxidant capacity,immune parameters,and hepatopancreatic histology of C.quadricarinatus were systematically measured at each stage.[Result](1)The body weight of C.quadricarinatus showed a trend of initial decrease followed by an increase during overwintering:Compared with the pre-overwintering stage,body weight decreased at the mid-overwintering stage but increased significantly thereafter,reaching higher levels in the late and post-overwintering stages(P<0.05).(2)The activities of lipase(LPS),amylase(AMS),and trypsin(TPS)initially decreased at the mid-overwintering stage and then increased in the late and post-overwintering stages(P<0.05).The activities of superoxide dismutase(SOD),catalase(CAT),and glutathione peroxidase(GSH-Px)increased significantly at the mid-overwintering stage(P<0.05),while the total antioxidant capacity(T-AOC)decreased significantly by the post-overwintering stage(P<0.05).Immune indices—lysozyme(LZM),acid phosphatase(ACP),alkaline phosphatase(AKP)—and the expression of the immune-related LZM gene decreased with lowering temperature and were significantly lower than those at the pre-overwintering stage(P<0.05).(3)Histological observation revealed vacuolar damage with dilated in the hepatopancreas during overwintering.[Conclusion]This study preliminarily reveals the dynamic responses of growth,digestion,antioxidant capacity,immunity,and tissue structure in C.quadricarinatus during overwintering under real aquaculture conditions.It delineates the physiological thresholds and structural reversibility characteristics of low-temperature adaptation,providing critical theoretical and data support for formulating precise temperature control and health management strategies during the overwintering period.
[Objective]The study analyzes the impact of agricultural technology training on farmers'fertilizer reduction behaviours and the resulting income effects,aiming to clarify the vital role of agricultural technology training in promoting fertilizer reduction behaviours and to provide a reference for collaborating agricultural green development with farmers'agricultural income.[Method]Based on the data collected from 926 rice farmers in Jiangxi Province,the binary Probit model,propensity score matching and the mediating effect model were applied to investigate the impact and mechanism of agricultural technology training on farmers'chemical fertilizer reduction behaviours.The endogenous switching model was used to systematically assess the income effect of farmers'chemical fertilizer reduction behaviors.[Result]Agricultural technology training significantly promotes farmers'chemical fertilizer reduction behaviours,increasing the adoption probability by an average of 7.7 percentage,and the conclusion remains valid after robustness tests and resolving endogeneity problems.Farmers'environmental cognition and organic fertilizer application behaviours play partial intermediary effects in it.Agricultural technology training has a greater influence on the chemical fertilizer reduction behaviours of elder farmers,highly educated farmers and large-scale farmers,whereas its impact is relatively weaker on younger and small-scale farmers,and statistically insignificant for those with lower education levels.Farmers'chemical fertilizer reduction behaviours increase farmers'agricultural income.In detail,the agricultural income of farmers who actually reduced chemical fertilizer would decrease if they decided against it.[Conclusion]In the future,efforts should be made to improve the content and methods of agricultural technology training to enhance effectiveness,expand science popularization and establish comprehensive supporting policies and services,implement differentiated support for different groups of farmers,and smooth the marketing channels for green agricultural products to promote the development of fertilizer reduction,while increasing their income.
[Objective]The effects of soil microbial community diversity on different planting patterns of Carya illinoensis with medicinal plants were investigated to determine appropriate patterns.[Method]High-throughput sequencing was used to analyze,the changes of alpha diversity,beta diversity,community structure and correlations with soil environmental factors of rhizosphere and non-rhizosphere soil microorganisms under Carya illinoensis+Salvia miltiorrhiza,Carya illinoensis+Belamcanda and monoculture planting patterns for 3 years.[Result]There was no significant difference in the ACE,Chao1,Shannon,and Simpson indices of bacteri-al and fungal communities in the rhizosphere and non-rhizosphere soil among Carya illinoensis+Salvia miltior-rhiza,Carya illinoensis+Belamcanda and monoculture,but the interplanting was improved compared with di-versity indices.In the bacterial community,Pseudomonadota and Acidobacteriota were significantly dominant fungal phyla,compared with monoculture,the relative abundance of pseudomonadota was decreased and Acido-bacteriota was increased in interplanting Salvia miltiorrhiza and shoot soil.α-Proteobacteria,β-Proteobacteria,Gp 6 group,Gp 4 group and Thermoleophilia were the significantly dominant groups.Compared with single crop-ping,the relative abundance of α-proteobacteria and β-proteobacteria was reduced in interplanting Salvia milt-iorrhiza and shoot soil,and the relative abundance of Gp 6 group,Gp 4 group and Thermoleophilia was in-creased.The soil bacteria in different cultivation patterns were dominated by Unclassified,Gp6,Gp4 and Gp3.The relative abundance of Gp6 and Gp4 was higher in intercropping Belamcanda chinensis and Salvia miltior-rhiza than in single cropping.In the fungal community,Basidiomycota and Ascomycota were significantly domi-nant bacteria.Compared with single cropping,the relative abundance of interplanting Salvia miltiorrhiza and shoot soil was significantly increased,and Basidiomycota decreased significantly.Agaricomycetes,Sordariomy-cetes,Dothideomyce,Mortierellomycetes and Eurotiomycetes were the significantly dominant groups.Compared with non-intercropping,the relative abundance of Agaricomycetes significantly decreased,while the relative abun-dances of Sordariomycetes,Dothideomycetes,and Mortierellomycetes significantly increased.The soil fungi were dominated by Unclassified,Mortierella and Fusarium.The relative abundance of Mortierella and Fusarium was higher in intercropping Belamcanda chinensis and Salvia miltiorrhiza than in single cropping.pH and sucrase were important environmental factors affecting the soil bacterial communities.[Conclusion]The planting pat-terns of Carya illinoensis+Salvia miltiorrhiza and Carya illinoensis+Belamcanda chinensis significantly affect soil microbial community structure,can improve the soil organic matter content and promote the transformation of soil insoluble phosphorus into effective phosphorus.At the same time,there may be continuous cropping ob-stacles,so crop rotation pattern is recommended.
[Objective]This study aims to provide a theoretical basis for exploring the endangered mechanism and ex situ conservation of Sinomanglietia glauca by systematically comparing the growth and diurnal photosynthetic responses of Sinomanglietia glauca and Schima superba under different light and fertilization treatments.[Method]Seedlings of S.glauca and S.superba were used as experimental materials.Three shading regimes(S0,S1,S2)were established under two fertilization treatments:nitrogen and phosphorus application(N1P1)and no nitrogen and phosphorus application(N0P0),yielding six simulated cultivation treatments.Growth performance and diurnal changes in photosynthetic parameters were then compared between the two species under these treatments.[Result](1)Ground diameter and plant height growth of S.glauca were significantly affected by shading(P<0.001),whereas the effect of fertilization was not significant(P>0.05).In contrast,the growth of S.superba was less affected by shading and fertilization and was even promoted under mild shading.(2)Across all treatments,the diurnal course of net photosynthetic rate(Pn)in both species exhibited a single-peaked pattern,and no midday depression of photosynthesis was observed.Fertilization had no significant effect on Pn in S.glauca(P>0.05).Stomatal conductance(Cond)showed a single-peaked pattern in S.glauca but tended to be bimodal in S.superba.Intercellular CO2 concentration(Ci)generally showed a U-shaped pattern.Transpiration rate(Tr)and water use efficiency(WUE)both showed single-peak patterns in the two species.Light use efficiency(LUE)fluctuated with small amplitude in both species.(3)Under low-light conditions,Pn in S.glauca was constrained by multiple environmental factors,and its adaptability to environmental conditions was significantly lower than that of S.superba,which may help explain its narrow ecological niche.[Conclusion]The growth of S.glauca seedlings is primarily limited by shading,whereas fertilization has little effect.In contrast,S.superba seedlings are less responsive to both shading and fertilization.Compared with S.superba,S.glauca seedlings demand more stringent environmental conditions under various shading levels and exhibit weaker photosynthetic acclimation.Therefore,for ex situ conservation of S.glauca,priority should be given to well-lit sites such as forest gaps,forest edges,and thinned stands,so as to facilitate population conservation and recovery.
