Preharvest application of 1-methylcyclopropene and Ethephon altered cuticular wax biosynthesis and fruit quality of apples at harvest and during cold storage

To investigate the roles of Harvista(a sprayable 1-methylcyclopropene,1-MCP,available component is 150 g·hm^(-2))and Ethephon(1 mL·L^(-1))applied at preharvest in apple(Malus domestica Borkh.'Golden Delicious')fruit cuticular wax biosynthesis,the expression of genes related to fruit cuticular wax biosynthesis and ethylene biosynthesis and signaling,ethylene production rate,respiration rate,wax constituents and structure,and fruit quality were determined at harvest and during cold storage.The results showed that 1-MCP inhibited the expression levels of ethylene biosynthesis and signaling-related genes,decreased fruit ethylene production,and inhibited the expression of Md LACS1,Md CER6,Md CER4 and Md WSD1,which resulted in decreases in alcohols,acids,and esters content in fruit cuticular wax.1-MCP also reduced fruit dropping rate from 17.17%to 12%;maintained fruit firmness,soluble solids,titratable acidity during cold storage;showed about as one fifth in the total length and one third in the widest width of wax crack as that in control at harvest.In contrast,Ethephon produced the opposite effects.In conclusion,1-MCP inhibited fruit ethylene biosynthesis and signaling,and influenced fruit cuticular wax biosynthesis.Thus,the fruit cuticular wax constituents and structure was altered,and the fruit quality were maintained at harvest and during cold storage.The results provide a new technology for improving apple fruit harvest and postharvest quality by preharvest application of sprayable 1-MCP.

Large contributions of emission reductions and meteorological conditions to the abatement of PM_(2.5)in Beijing during the 24th Winter Olympic Games in 2022

To guarantee the blue skies for the 2022 Winter Olympics held in Beijing and Zhangjiakou from February 4 to 20,Beijing and its surrounding areas adopted a series of emission control measures.This provides an opportunity to determine the impacts of large-scale temporary control measures on the air quality in Beijing during this special period.Here,we applied the WRF-CMAQ model to quantify the contributions of emission reduction measures and meteorological conditions.Results show that meteorological conditions in 2022 decreased PM_(2.5)in Beijing by 6.9 and 11.8μg/m^(3)relative to 2021 under the scenarios with and without emission reductions,respectively.Strict emission reduction measures implemented in Beijing and seven neighboring provinces resulted in an average decrease of 13.0μg/m^(3)(-41.2%)in PM_(2.5)in Beijing.Over the entire period,local emission reductions contributed more to good air quality in Beijing than nonlocal emission reductions.Under the emission reduction scenario,local,controlled regions,other regions,and boundary conditions contributed 47.7%,42.0%,5.3%,and 5.0%to the PM_(2.5)concentrations in Beijing,respectively.The results indicate that during the cleaning period with the air masses from the northwest,the abatements of PM_(2.5)were mainly caused by local emission reductions.However,during the potential pollution period with the air masses from the east-northeast and west-southwest,the abatements of PM_(2.5)were caused by both local and nonlocal emission reductions almost equally.This implies that regional coordinated prevention and control strategies need to be arranged scientifically and rationally when heavy pollution events are forecasted.

Baicalin attenuates dexamethasone-induced apoptosis of bone marrow mesenchymal stem cells by activating the hedgehog signaling pathway

Background:Perturbations in bone marrow mesenchymal stem cell(BMSC)differentiation play an important role in steroid-induced osteonecrosis of the femoral head(SONFH).At present,studies on SONFH concentrate upon the balance within BMSC osteogenic and adipogenic differentiation.However,BMSC apoptosis as well as proliferation are important prerequisites in their differentiation.The hedgehog(HH)signaling pathway regulates bone cell apoptosis.Baicalin(BA),a well-known compound in traditional Chinese medicine,can affect the proliferation and apoptosis of numerous cell types via HH signaling.However,the potential role and mechanisms of BA on BMSCs are unclear.Thus,we aimed to explore the role of BA in dexamethasone(Dex)-induced BMSC apoptosis in this study.Methods:Primary BMSCs were treated with 10-6 mol/L Dex alone or with 5.0μmol/L,10.0μmol/L,or 50.0μmol/L BA for 24 hours followed by co-treatment with 5.0μmol/L,10.0μmol/L,or 50.0μmol/L BA and 10-6 mol/L Dex.Cell viability was assayed through the Cell Counting Kit-8(CCK-8).Cell apoptosis was evaluated using Annexin V-fluorescein isothiocyanate/propidium iodide(PI)staining followed by flow cytometry.The imaging and counting,respectively,of Hochest 33342/PI-stained cells were used to assess the morphological characteristics and proportion of apoptotic cells.To quantify the apoptosis-related proteins(e.g.,apoptosis regulator BAX[Bax],B-cell lymphoma 2[Bcl-2],caspase-3,and cleaved caspase-3)and HH signaling pathway proteins,western blotting was used.A HH-signaling pathway inhibitor was used to demonstrate that BA exerts its anti-apoptotic effects via the HH signaling pathway.Results:The results of CCK-8,Hoechst 33342/PI-staining,and flow cytometry showed that BA did not significantly promote cell proliferation(CCK-8:0μmol/L,100%;2.5μmol/L,98.58%;5.0μmol/L,95.18%;10.0μmol/L,98.11%;50.0μmol/L,99.38%,F=2.33,P>0.05),but it did attenuate the effect of Dex on apoptosis(Hoechst 33342/PI-staining:Dex+50.0μmol/L BA,12.27%vs.Dex,39.27%,t=20.62;flow cytometry:Dex+50.0μmol/L BA,12.68%vs.Dex,37.43%,t=11.56;Both P<0.05).The results of western blotting analysis showed that BA reversed Dex-induced apoptosis by activating the HH signaling pathway,which down-regulated the expression of Bax,cleaved-caspase 3,and suppressor of fused(SUFU)while up-regulating Bcl-2,sonic hedgehog(SHH),and zinc finger protein GLI-1(GLI-1)expression(Bax/Bcl-2:Dex+50.0μmol/L BA,1.09 vs.Dex,2.76,t=35.12;cleaved caspase-3/caspase-3:Dex+50.0μmol/L BA,0.38 vs.Dex,0.73,t=10.62;SHH:Dex+50.0μmol/L BA,0.50 vs.Dex,0.12,t=34.01;SUFU:Dex+50.0μmol/L BA,0.75 vs.Dex,1.19,t=10.78;GLI-1:Dex+50.0μmol/L BA,0.40 vs.Dex,0.11,t=30.68.All P<0.05).Conclusions:BA antagonizes Dex-induced apoptosis of human BMSCs by activating the HH signaling pathway.It is a potential candidate for preventing SONFH.