Physiological evaluation of nitrogen use efficiency of different apple cultivars under various nitrogen and water supply conditions

Nitrogen(N) deficiency is a common problem for apple(Malus×domestica) production in arid regions of China.However,N utilization efficiency(NUE) of different apple cultivars grown under low N conditions in arid regions has not been evaluated.In this study,NUE was assessed for one-year-old seedlings of six apple cultivars,Golden Delicious,Qinguan,Jonagold,Honeycrisp,Fuji and Pink Lady,grafted onto Malus hupehensis Rehd.rootstocks.Four treatments were used,including control water with control N(CWCN),limited water with control N(LWCN),control water with low N(CWLN) and limited water with low N(LWLN).Our results showed that growth indices such as biomass,plant height and stem diameter,and photosynthetic rate of all cultivars decreased in the order CWCN>CWLN>LWCN>LWLN.When subjected to LWLN treatment,Qinguan showed better growth and photosynthetic characters than other tested cultivars.Additionally,Qinguan and Pink Lady had higher NUE,while Honeycrisp and Jonagold had lower NUE,based on the determination of biomass,photosynthetic parameters,chlorophyll content,the maximal photochemical efficiency of PSII(Fv/Fm),15 N and N contents.

Effects of 1-aminobenzotriazole on the growth and physiological characteristics of Tamarix chinensis cuttings under salt stress

vegetation restoration is a main ecological remediation technology for greening saline and alkaline soils.The objectives of this study were to determine the effect of1-aminobenzotriazole(ABT-1) on the growth and physiology of Tamarix chinensis under salt stress and to determine a suitable ABT-1 concentration and soil salinity(Sc) for propagating T.chihehsis-cuttings.Cuttings were soaked in water and ABT-1 solutions at three concentrations(50,100,and 200 mg L^(-1)) and propagated in pots containing four soil salinity levels,mild(0.3%),moderate(0.6%),and severe(0.9% and 1.2%),and compared with a control.The cuttings were measured to determine growth indices and physiological and biochemical indices(e.g.,chlorophyll content,superoxide dismutase activity,peroxidase activity,and malondialdehyde content).ABT-1 was effective in improving survival,growth,and physiological processes of cuttings under salt stress.However,there was a threshold effect when using ABT-1 to facilitate propagation under salt stress.ABT-1 effects were insignificant when applied at low concentrations(<100 mg L^(-1)).At a high concentration(> 100 mg L^(-1)),ABT-1 limited growth and physiological activities.Under a salt stress level(Sc ≤0.9%),ABT applied at a 100 mg L^(-1)concentration increased chlorophyll content and superoxide dismutase and peroxidase activities in the leaves and reduced malondialdehyde accumulation and membrane lipid peroxidation effects.As a result,ABT-1 enhanced the resistance of T.chinensis to salt stress.However,under high salt stress(>0.9%) and ABT-1 concentration(> 100 mg L^(-1)),the physiological regulatory ability of T.chinensis seedlings weakened.T.chinensis grew well at a salt stress ≤0.9% and ABT ≤100 mg L^(-1) and exhibited relatively high physiological regulatory ability and high salt adaptability.

Effect of foot reflexology on pain and physiological indicators in postoperative patients:A systematic review and meta-analysis

Aim:To determine the effect of foot reflexology intervention on pain and physiological indicators in postoperative patients.Data resources:The Cochrane library,PubMed,EMBASE,MEDLINE,SCOPUS,CINAHL,China National Knowledge Infrastructure(CNKI),VIP,and Wan Fang Data were searched from inception until January2020.Review methods:Studies were screened according to the PICOS principle.The methodological quality was assessed with Cochrane Risk of Bias Tool.Meta-analysis was performed using RevMan 5.3 software.Results:5 randomized clinical trials involving 318 participants were included in the meta-analysis.There were significant differences in pain and heart rate in postoperative patients between the two groups.Conclusion:The foot reflexology intervention decrease the postoperative pain and heart rate for the postoperative patients.It can be considered to be an effective non-pharmaceutical therapy to reduce the postoperative pain and heart rate.The evidence is not enough to prove the effectiveness of reducing postoperative blood pressure,respiratory rate,pulse rate and oxygen saturation using the foot reflexology.

Brassinosteroids Mediate Endogenous Phytohormone Metabolism to Alleviate High Temperature Injury at Panicle Initiation Stage in Rice

High temperatures cause physiological and biochemical changes and significantly affect young panicle development of rice(Oryza sativa L.).Brassinosteroids play important roles in enhancing crop stress resistance.In this study,we subjected rice cultivars Huanghuazhan(heat-resistant)and IR36(heat-sensitive)to high temperature(HT,40 oC)or normal temperature(NT,33 oC)for 7 d at the panicle initiation stage,in conjunction with application of 24-epibrassinolide[EBR,a synthetic brassinolide(BR)]or brassinazole(BRZ,a BR biosynthesis inhibitor)at the beginning of the treatments.HT exacerbated spikelet degeneration and inhibited young panicle growth,which were partially prevented by EBR application,while BRZ application aggravated the reduction in spikelet number.HT decreased the contents of BR,active cytokinins(aCTK),active gibberellins(aGA)and indole-3-acetic acid(IAA),but increased the content of abscisic acid(ABA)in young panicles.The activities of key enzymes involved in sucrose hydrolysis,glycolysis and the tricarboxylic acid cycle in young panicles were decreased with the change of endogenous hormone levels under HT.In addition,the contents of H2O2 and malondialdehyde(MDA)were increased and the activities of antioxidant enzymes were decreased in young panicles.Exogenous application of EBR induced the expression of phytohormone biosynthesis-related genes and down-regulated the expression of phytohormone catabolism-related genes to increase the contents of endogenous BR,aCTK,aGA and ABA,thus promoting the decomposition and utilization of sucrose in young panicles,enhancing the activities of superoxide dismutase,catalase and peroxidase,and reducing the accumulation of H2O2 and MDA in young panicles,whereas application of BRZ had the opposite physiological effects.These results showed that brassinosteroids mediate endogenous phytohormone metabolism to alleviate HT injury at the panicle initiation stage in rice.

UPLC-MS metabolomics provides insights into the diff erences between black- and white-shelled Pacifi c oysters Crassostrea gigas

A variety of shell colors are one of the most fundamental characteristics of molluscs,which have importantly ecological and economic signifi cance.The Pacifi c oyster Crassostrea gigas is distributed in many sea areas around the world and also an aquacultured mollusc with high nutritional value.In this study,the whole soft body and the mantle tissue of black-shelled Pacifi c oyster(BSO)and white-shelled Pacifi c oyster(WSO)with starkly diff erent melanin contents were compared,and the diff erences in physiology and metabolism between BSO and WSO were analyzed.The results of physiological indicators suggested BSO show more melanin,more dry matter,more crude lipid content,and stronger ability to scavenge free radicals than WSO.The altered metabolites of glycerophospholipids,fatty acyls,and steroids revealed diff erent regulatory mechanisms of lipids.The correlation analysis of metabolomics and previously published RNAseq data suggested that BSO and WSO mainly diff ered in the basal metabolic processes,such as lipid,amino acid and purine metabolisms.This study provides insights into the changes in the physiological indictors and the metabolites of oysters with varying melanin content.

Transcriptomic Analysis of the Tolerance Response to Dehydration and Rehydration in Wheat Seedlings

Drought is the main abiotic stress that restricts wheat production.The rapid development of sequencing technology and its widespread application to various fields have revealed the structural characteristics and regulation of related genes through gene expression analysis.Here,we studied responses of wheat plants under drought and rewatering conditions,using morphological and physiological indicators.Moreover,a transcriptome analysis was conducted on Jingmai 12,a drought-resistant wheat strain,to explore the mechanism underlying the response of drought-resistant wheat seedlings to drought stress at the transcriptome level.Drought stress caused morphological and physiological changes in both drought-resistant and-sensitive varieties,but to a greater extent in the drought-sensitive specimen.After re-watering,the drought-resistant wheat showed greater ability to recover than the drought-sensitive wheat.Transcriptome sequencing of Jingmai 12 revealed 97,422 genes,including 80,373 known genes and 17,049 newly predicted genes.The observed upregulation of genes was mostly involved in hormone and signal transduction,carbon metabolism,amino acid synthesis,small molecule production,transmembrane transport,ROS detoxification and defense,drought response protein,and protective enzyme activity.Downregulated genes were mostly involved in photosynthesis,lipid metabolism,signaling,and auxin response.Upon rehydration,these genes and metabolic pathways returned to normal.Our results suggest that all these changes are adaptations to drought stress.Through morphological adaptation,physiological regulation,and the expression of drought-induced genes,normal growth of drought-resistant varieties under drought stress can be promoted.These results increase our understanding of the transcriptomic changes taking place in drought-resistant wheat seedlings under drought stress,and provide a direction for future investigations.

Effects of Low-temperature and Herbicide on Membrane Stability, Antioxidant Capacity, and Product of Metabolism in Barley Seedlings

In order to investigate the physiological injury of barley caused by the low temperature after herbicides, tillering barley seedlings planted in plastic cups were pretreated in illumination incubator at 15℃ and 12 h-light per day for 7 days, and then subjected to herbicide treatment, prometryn (with the concentrations of 0, 0.15%, 0.30%, and 0.45%) or isoproturon (with the concentrations of 0, 0.30%, 0.60%, and 0.90%), and the SOD activity, the CAT activity, the POD activity, the MDA content, proline content, soluble protein content, electrical conductivity, and the rate of O2-were determined and analyzed. The results showed that the low-temperature was the most important, and the treatment-time of low-temperature was another significant influencing factor on the physiological and biochemical indices of barley seedlings. However, all of the physiological and biochemical indices determined were not affected by the kinds of herbicides and herbicide concentrations, and the SOD was stable and should play the more prominent role on extracting of free radicals according to the stepwise regression and correlation. The herbicide concentrations should be increased in the future research for truly reflecting the effects of the herbicide concentration on the physiological and biochemical indices of barley seedlings.

Land rehabilitation improves edaphic conditions and increases soil microbial biomass and abundance

Rehabilitation of farmland improves the local eco-environmental conditions.But to what extent this transformation influences soil microbial properties is less known.In our study we compared variations in soil microbial attributes following changes in land-use types to understand the influence of altered soil properties on microbial biomass and their community structure using chloroform fumigation extraction method and phospholipid fatty acid(PLFA)analysis.For this purpose,3 agricultural(AL)(farmland,apple orchard and 2 years abandoned land)and 4 rehabilitated lands(RL)of various vegetations grassland,shrubland,mixed forest(Amorpha fruticosa and Pinus tabuliformis Carr.)and forest(Robinia pseudoacacia)were selected.Our results showed higher soil organic carbon(SOC)contents in RL soils(forest>mixed forest>grassland>shrub land)than that in AL soils.In RL soils,soil microbial biomass and abundance of group specific PLFA were significantly higher than those in AL soils.Under different land-use types,microbial community was bacteria dominated over fungi.The microbial physiological indices(G^(+)/G^(-),cyc/prec and S/M)indicated decreased environmental stress in RL soils in comparison with AL soils.In loess soils,SOC and total N correlated positively(p<0.05)with microbial biomass C,N and P and also with fungal and bacterial PLFA,indicating a positive microbial mediation in improving soil fertility.Taking together,our findings suggest that land rehabilitation,especially Robinia pseudoacacia planation,improves overall edaphic conditions and accelerates soil microbial biomass accumulation in local regions.