Multivariate analysis between meteorological factor and fruit quality of Fuji apple at different locations in China

China has the largest apple planting area and total yield in the world, and the Fuji apple is the major cultivar, accounting for more than 70％ of apple planting acreage in China. Apple qualities are affected by meteorological conditions, soil types, nutrient content of soil, and management practices. Meteorological factors, such as light, temperature and moisture are key environmental conditions affecting apple quality that are difficult to regulate and control. This study was performed to determine the effect of meteorological factors on the qualities of Fuji apple and to provide evidence for a reasonable regional layout and planting of Fuji apple in China. Fruit samples of Fuji apple and meteorological data were investigated from 153 commercial Fuji apple orchards located in 51 counties of 11 regions in China from 2010 to 2011. Partial least-squares regression and linear programming were used to analyze the effect model and impact weight of meteorological factors on fruit quality, to determine the major meteorological factors influencing fruit quality attributes, and to establish a regression equation to optimize meteorological factors for high-quality Fuji apples. Results showed relationships between fruit quality attributes and meteorological factors among the various apple producing counties in China. The mean, minimum, and maximum temperatures from April to October had the highest positive effects on fruit qualities in model effect loadings and weights, followed by the mean annual temperature and the sunshine percentage, the temperature difference between day and night, and the total precipitation for the same period. In contrast, annual total precipitation and relative humidity from April to October had negative effects on fruit quality. The meteorological factors exhibited distinct effects on the different fruit quality attributes. Soluble solid content was affected from the high to the low row preface by annual total precipitation, the minimum temperature from April to October, the mean temperature from April to October, the temperature difference between day and night, and the mean annual temperature. The regression equation showed that the optimum meteorological factors on fruit quality were the mean annual temperature of 5.5-18°C and the annual total precipitation of 602-1121 mm for the whole year, and the mean temperature of 13.3-19.6°C, the minimum temperature of 7.8-18.5°C, the maximum temperature of 19.5°C, the temperature difference of 13.7°C between day and night, the total precipitation of 227 mm, the relative humidity of 57.5-84.0％, and the sunshine percentage of 36.5-70.0％ during the growing period （from April to October）.

Analysis of Aroma Volatile Compounds in Fuji Apple Using SPME with Different Fiber Coatings

The aroma volatile compounds in Fuji apple were isolated by solid-phase microextraction( SPME),and detected by gas chromatography-mass spectrometry( GC-MS). The results showed that the optimal retention time of the heating up of capillary columns was 5 min. Of the seven fibers used in this work,DVB/CAR/PDMS was found to be the most suitable to extract the aroma volatile compounds in Fuji apple. A total number of 43 volatile compounds were identified according to their retention time on capillary columns and their mass spectra,including eleven esters,ten alcohols,ten aldehydes,seven alkenes,two anhydrides,one ketone,one phenol and one ether. This detection method will provide a new foundation for analysis of volatile compounds in apple were identified.

Effect of Metaxenia on Sugars and Organic Acids and Taste Quality of Bagged Fuji Apple Fruits

In order to provide reference for the selection of appropriate pollination varieties facilitating the improvement of the flavor quality of bagged Fuji apple, the metaxenia effects of 5 pollination varieties on sugars, organic acids and flavor quality of bagged Fuji fruit were studied. The results showed that the 5 pollination varieties had significant metaxenia effects on sugars, organic acids and flavor quality of bagged Fuji fruit. For the sugar components, the fruits pollinated with Golden Delicious and Jinxiuhaitang showed higher glucose contents, and the fruit pollinated with Gala had the highest sucrose content; the fruits pollinated by Gala, Golden Delicious and Ruby exhibited higher malic acids, and the oxalic acid content and the succinic acid content were higher in the fruits pollinated with Jinxiuhaitang and Ruby ; and the fruit pollinated with Gala had the highest total sugar content, and the total acid content was higher in the fruits pollinated by Jinxiuhaitang and Ruby. The sugar-acid ratio was higher in the fruits pollinated with Gala and Golden Delicious, and the lowest in the fruit pollinated with Ruby. The senso- ry evaluation of fruits showed that the fruit pollinated with Ruby tasted sour-sweet, while the fruits pollinated with other 4 pollination varieties were sour and sweet moderately.

Detection of Chlorpyrifos Residues in Akesu Red Fuji Apple based on Near Infrared Spectrum

[Objective] The paper was to explore a method for detecting chlorpyrifos residues in red Fuji apple. [Method] The original spectral data of apple samples sprayed with different volume fractions of chlorpyrifos were collected using near infrared spectrometer at the band of 4 000-10 000 cm^（-1）. The original spectra were pre-treated by a variety of methods, and partial least squares（PLS） model was established for predictive analysis. [Result] Near infrared spectrum showed sensitivity to apple samples sprayed with different volume fractions of chlorpyrifos, but had low precision on pesticide-free samples. Data of blank control group were further eliminated for modeling prediction. The results showed that the results were the best when pre-treated with first derivative（FD）： R=0.987 9; the square error of prediction（SEP） was 0.173 6; the root-mean-square error of cross-validation（RMSECV） was 0.120 5; and the precision was 0.923 4. [Conclusion] Near infrared spectrum can better predict chlorpyrifos residue, providing a new method for detecting chlorpyrifos residues in Akesu red Fuji apple.

Effects of 1-methylcyclopropene treatment on the quality of red‘Fuji’apples fruit during short-term storage

Objectives:The aim of this study is to determine the mechanism through which 1-methylcyclopropene(1-MCP)affects the quality of red'Fuji'apples,which were stored for a short duration.Materials and Methods:Red‘Fuji’apples were treated with 1-MCP(1.0μl/L),stored at 25℃for0,12,24,48,72,and 96 h,and ethylene pro-duction was measured.An integrated metabolomic and transcriptomic analysis was performed on apples stored for 24 h.Results:The release of ethylene was significantly delayed from red‘Fuji’apples subjected to 1-MCP treatment.By performing an integrated transcriptome and metabolome analyses,we identified 117 differentially expressed genes(DEGs)and 44 differentially accumulated metabol-ites(DAMs).By performing functional enrichment analysis,we found that DEGs were involved in the following pathways;carbon metabolism(LPD2,gpmA,LTA2,ACC,PSAT1,MdCAS2),phytohormone signal transduction(EBF 7),amino acid metabolism(MdACS-1),fatty acid metab-olism(LOX1.5,KCS4,KAST),energy metabolism(Lhcb1,Lhcb6,PsbY,GPDHC1,PUMP5I,metabolic pathways(TRE1,HEXO1)and cell wall metabolism(CSLG2).Thus,these DEGs were involved in the ripening of fruits,and they controlled the quality of fruits at the post-harvest stage.The metabolites were enriched with DAMs.These were found to be individually involved in the metabolic pathway,secondary metabolite bio-synthesis,phenylpropanoid biosynthesis,flavonoids,and flavonol synthesis.Conclusions:The results indicate that 1-MCP inhibits the biosynthesis of ethylene and suppresses energy metabolism.Moreover,it also downregulates metabolic pathways and the enzymatic genes related to fruit quality.Therefore,1-MCP delays the ripening of fruits at the post-harvest stage.This study helps us understand how 1-MCP treatment affects the ripening and quality of fruits.

Flavonols Induced by 5-Aminolevulinic Acid Are Involved in Regulation of Stomatal Opening in Apple Leaves

Flavonols, the main flavonoids in plant leaves, have newly been proposed as a H2O2 scavenger in guard cells. However, whether 5-aminolevulinic acid(5-ALA) is involved in regulating stomatal movement of apple(Malus × domestica Borkh. ‘Fuji') leaves through flavonol accumulation remains unclear. In this study, using diphenylboric acid 2-amino ethyl ester(DPBA, a flavonol fluorescent dye) and a laser scanning confocal microscope,we observed that 5-ALA pretreatment significantly improved flavonol accumulation in guard cells of apple leaves, especially around the nucleus.Then we demonstrated that 5-ALA pretreatment inhibited ABA-induced stomatal closure via decreasing reaction oxygen species(ROS) accumulation in guard cells. Pretreatment with quercetin or kaempferol, two main kinds of flavonols in plants, also inhibited ABA-induced stomatal closure by decreasing ROS content in the guard cells. Furthermore, exogenous flavonols could suppress H2O2-induced stomatal closure in apple leaves.Taken together, we conclude that ALA-induced flavonol accumulation in guard cells is involved in the inhibitory effect of ALA on ABA-induced ROS accumulation and stomatal closure in apple leaves.