JrATHB-12 mediates JrMYB113 and JrMYB27 to control the anthocyanin levels in different types of red walnut

Red walnut has broad market prospects because it is richer in anthocyanins than ordinary walnut.However,the mechanism driving anthocyanin biosynthesis in red walnut is still unknown.We studied two types of red walnut,called red walnut 1(R1),with a red pericarp and seed coat,and red walnut 2(R2),with a red seed coat only.R1 mostly contained cyanidin-3-O-galactoside,while R2 contained a various amounts of cyanidin-3-Ogalactoside,cyanidin-3-O-arabinoside,and cyanidin-3-O-glucoside.The LDOX-2(LOC109007163)and LDOX-3(LOC109010746)genes,which encode leucoanthocyanidin dioxygenase/anthocyanidin synthase(LDOX/ANS),were preliminarily indicated as the crucial genes for anthocyanin biosynthesis in R1 and R2,respectively.The MYB differential genes analysis showed that MYB27 and MYB113 are specifically expressed in the red parts of R1 and R2,respectively,and they are regarded as candidate regulatory genes.Ectopic expression in Arabidopsis and transient injection in walnut showed that both MYB27 and MYB113 were located in the nucleus and promoted anthocyanin accumulation,while MYB27 promoted the expression of LDOX-2,and MYB113 promoted the expression of LDOX-3and UAGT-3.Yeast one-hybrid and electrophoretic mobility shift assays showed that MYB27 could only bind to the LDOX-2 promoter,while MYB113 could bind to the promoters of both LDOX-3 and UAGT-3.In addition,we also identified an HD-Zip transcription factor,ATHB-12,which is specifically expressed in the pericarp.After silencing the expression of ATHB-12,the R2 pericarp turned red,and MYB113 expression increased.Further experiments showed that ATHB-12 could specifically interact with MYB113 and bind to its promoter.This suggests that MYB27controls R1 coloration by regulating LDOX-2,while MYB113 controls R2 coloration by regulating LDOX-3 and UAGT-3,but ATHB-12 can specifically bind to and inhibit the MYB113 of the R2 pericarp so that it becomes unpigmented.This study reveals the anthocyanin biosynthetic mechanisms in two different types of red walnut and provides a scientific basis for the selection and breeding of red walnut varieties.

Transcriptional regulation of MdPIN7 by MdARF19 during gravityinduced formation of adventitious root GSA in self-rooted apple stock

Self-rooted apple stock is widely used for apple production.However,the shallowness of the adventitious roots in self-rooted apple stock leads to poor performance in the barren orchards of China.This is because of the considerable difference in the development of a gravitropic set-point angle(GSA)between self-rooted apple stock and seedling rootstock.Therefore,it is crucial to study the molecular mechanism of adventitious root GSA in self-rooted apple stock for breeding self-rooted and deep-rooted apple rootstock cultivars.An apple auxin response factor MdARF19 functioned to establish the adventitious root GSA of self-rooted apple stock in response to gravity and auxin signals.MdARF19 bound directly to the MdPIN7 promoter,activating its transcriptional expression and thus regulating the formation of the adventitious root GSA in 12-2 self-rooted apple stock.However,MdARF19 influenced the expression of auxin efflux carriers(MdPIN3 and MdPIN10)and the establishment of adventitious root GSA of self-rooted apple stock in response to gravity signals by direct activation of MdFLP.Our findings provide new information on the transcriptional regulation of MdPIN7 by auxin response factor MdARF19 in the regulation of the adventitious root GSA of self-rooted apple stock in response to gravity and auxin signals.

Investigation on Diseases and Pests of Grape Under Rain Shelter Cultivation in Shandong Province

In order to make clear the effects of rain shelter cultivation on the incidence of diseases and pests of grape in Shandong Province,with Summer Black as the material,the diseases and pests of grape under rain shelter cultivation and open field cultivation in Tai'an and Jining were investigated.The results showed that under the rain shelter cultivation condition,the phenological period of grape delayed 5-8 d.The types of grape diseases and pests under the rain shelter cultivation were the same as those in the open filed cultivation.The most serious pests were Apolygus lucorum,followed by Lycorma delicatula,Erythreura apicalis and Thrips tabaci.The most serious leaf disease was downy mildew,and the most serious disease of grape berries was grape sour rot.Compared with the open field cultivation,the rain shelter cultivation could effectively reduce the incidence of pests and diseases in grape leaves and fruit.At the end of May 2018 and 2019,the occurrence rate of grape pests under the rain shelter cultivation in Tai'an reduced by 57.69%and 60.47%,respectively,and those in Jining reduced by 72.22%and 62.50%,respectively.In the middle of July of 2018 and 2019,the incidence of grape fruit diseases under the rain shelter cultivation in Tai'an reduced by 62.49%and 50.07%,respectively,and that in Jining reduced by 49.96%and 100%,respectively.

Industrial Economy Analysis of Main Pear-producing Counties in Central and Western Shandong Province(2011-2020)

This paper selected five main producing counties of Yangxin,Guanxian,Feixian,Tengzhou and Licheng in central and western Shandong Province.Based on the basic economic data of pear industry from 2011 to 2020,the cultivation areas,yields,main cultivars,production costs and garden prices of pears in the main producing counties in the past 10 years were analyzed,so as to provide reference for the development of pear industry in Shandong Province.

Identification and functional analysis of arabinogalactan protein expressed in pear pollen tubes

Arabinogalactan proteins(AGPs)are widely distributed in the plant kingdom and play a vital role during the process of plant sexual reproduction.In this study,we performed a comprehensive identification of the PbrAGPs expressed in pear pollen and further explored their influences on pollen tube growth.Among the 187 PbrAGPs that were found to be expressed in pear pollen tubes,38 PbrAGPs were specifically expressed in pollen according to the RNA-seq data.The PbrAGPs were divided into two groups of highly expressed and specifically expressed in pear pollen.We further tested their expression patterns using RT-PCR and RT-qPCR.Most of the PbrAGPs were expressed in multiple tissues and their expression levels were consistent with reads per kilobase per million map reads(RPKM)values during pollen tube growth,implying that PbrAGPs might be involved in the regulation of pear pollen tube growth.We also constructed phylogenetic trees to identify the functional genes in pear pollen tube growth.Therefore,19 PbrAGPs(PbrAGP1 to PbrAGP19)were selected to test their influences on pollen tube growth.Recombinant proteins of the 19 PbrAGP-His were purified and used to treat pear pollen,and 11 of the PbrAGP-His recombinant proteins could promote pear pollen tube growth.Additionally,pollen tube growth was inhibited when the expression levels of PbrAGP1 and PbrAGP5 were knocked down using an antisense oligonucleotide assay.PbrAGP1 and PbrAGP5 were localized in the plasma membrane and might not alter the distribution of pectin in the pollen tube.In summary,this study identified the PbrAGPs expressed in pear pollen and lays the foundation for further exploring their functions in pollen tube growth.

MdWRKY40is directly promotes anthocyanin accumulation and blocks MdMYB15L, the repressor of MdCBF2, which improves cold tolerance in apple

Cold stress is an important factor that limits apple production. In this study, we examined the tissue-cultured plantlets of apple rootstocks ‘M9T337' and ‘60-160', which are resistant and sensitive to cold stress, respectively. The enriched pathways of differentially expressed genes(DEGs) and physiological changes in ‘M9T337' and ‘60-160' plantlets were clearly different after cold stress(1°C) treatment for 48 h, suggesting that they have differential responses to cold stress. The differential expression of WRKY transcription factors in the two plantlets showed that MdWRKY40is and MdWRKY48 are potential regulators of cold tolerance. When we overexpressed MdWRKY40is and MdWRKY48in apple calli, the overexpression of MdWRKY48 had no significant effect on the callus, while MdWRKY40is overexpression promoted anthocyanin accumulation, increased callus cold tolerance, and promoted the expression of anthocyanin structural gene MdDFR and cold-signaling core gene MdCBF2. Yeast one-hybrid screening and electrophoretic mobility shift assays showed that MdWRKY40is could only bind to the MdDFR promoter. Yeast twohybrid screening and bimolecular fluorescence complementation showed that MdWRKY40is interacts with the CBF2inhibitor MdMYB15L through the leucine zipper(LZ). When the LZ of MdWRMY40is was knocked out, MdWRKY40is overexpression in the callus did not affect MdCBF2 expression or callus cold tolerance, indicating that MdWRKY40is acts in the cold signaling pathway by interacting with MdMYB15L. In summary, MdWRKY40is can directly bind to the MdDFR promoter in order to promote anthocyanin accumulation, and it can also interact with MdMYB15L to interfere with its inhibitory effect on MdCBF2, indirectly promoting MdCBF2 expression, and thereby improving cold tolerance.These results provide a new perspective for the cold-resistance mechanism of apple rootstocks and a molecular basis for the screening of cold-resistant rootstocks.

Technical Studies of Controlling Jujube Witches Broom Disease with Resistant Rootstock

[Objectives]The paper was to screen and identify the control effect of resistant rootstock on jujube witches broom disease.[Methods]The seeds or branches of disease-free plants were collected from wild jujube bushes infected by witches broom disease,and 5434 seedlings were obtained by sowing or cutting.The virus was inoculated by grafting diseased bark.After 6 years of preliminary screening,40 plants with resistance to jujube witches broom disease were obtained.Taking these resistant plants as the rootstocks,the susceptible variety‘long red jujube’was grafted at a height of 40 cm.When the plants grew to appropriate thickness,diseased bark was grafted to‘long red jujube’and rootstock to transmit the virus.After 18 years of observation and judgment,4 rootstock strains with high resistance or immunity to jujube witches broom disease were finally determined,namely 90801,90803,90806 and 908011.The susceptible variety‘long red jujube’was grafted to 4 rootstocks and inoculated the virus through diseased bark grafting method.[Results]The resistant rootstock had obvious disease resistance effect.When the branches of 90801 and 90803 rootstocks were grafted to the trunk of diseased trees,the symptoms of jujube witches broom disease gradually alleviated till disappeared.[Conclusions]Using germplasm with high resistance or immunity to jujube witches broom disease as rootstock can effectively prevent the spread of jujube witches broom disease,and bridging the trunk of diseased trees with branches from resistant rootstock has certain therapeutic effect.

The WRKY transcription factor PlWRKY65 enhances the resistance of Paeonia lactiflora(herbaceous peony)to Alternaria tenuissima

In this study,the disease resistance gene PlWRKY65 was isolated from the leaves of Paeonia lactiflora and analyzed by bioinformatics methods,and the localization of the encoded protein was explored.Quantitative real-time PCR(qRTPCR)was also used to explore the response of this gene to Alternaria tenuissima.The results showed that the gene sequence contained multiple cis-acting elements involved in the response to hormone signaling molecules belonging to the IIe subgroup of the WRKY family,and the encoded proteins were located in the nucleus.The PlWRKY65 gene has a positive regulatory effect on A.tenuissima infection.After silencing the PlWRKY65 gene via virus-induced gene silencing(VIGS),it was found that the gene-silenced plants were more sensitive to A.tenuissima infection than the wild plants,exhibiting more severe infection symptoms and different degrees of changes in the expression of the pathogenesis-related(PR)genes.In addition,we showed that the endogenous jasmonic acid(JA)content of P.lactiflora was increased in response to A.tenuissima infection,whereas the salicylic acid(SA)content decreased.After PlWRKY65 gene silencing,the levels of the two hormones changed accordingly,indicating that PlWRKY65,acting as a disease resistance-related transcriptional activator,exerts a regulatory effect on JA and SA signals.This study lays the foundation for functional research on WRKY genes in P.lactiflora and for the discovery of candidate disease resistance genes.

The Relation Between Endogenous Hormones and Late-Germination in Buds of Avrolles Apple

In order to provide the physiological bases for selecting late-germination cultivars that can avoid late frost damage, the very late-germination variety Avrolles （Malus domestica） was used to study the relation between the dynamic changes and balance of endogenous hormones and germination time. The concentrations of endogenous GA3, ABA, IAA, and ZR were determined in buds of Avrolles and Judeline （Malus domestica） from dormancy releasing to germination by capillary electrophoresis. The dynamic changes of endogenous hormones concentration in buds of Avrolles and Judeline were similar; but the magnitude and time of the change were significantly different between the two varieties, especially for GA3. GA3 concentration increased with dormancy releasing, then decreased, and increased again before germination in the two varieties. GA3 concentration in Avrolles was 1.72 times that in Judeline at the first peak, the gap increased to 2.22 times at germination. ZR concentration exhibited a continuous increase trend, but it decreased sharply before germination. ZR accumulation in Avrolles took 36 days longer than in Judeline, the peak value was 44% higher than in Judeline. Before germination, ZR concentration in Avrolles was 2.12 times that in Judeline. The differences between IAA and ABA concentration were relatively small in the two varieties, while the ratios of GA3/ABA and （GA3 ＋ IAA ＋ ZR）/ABA in Avrolles were 2.08 and 1.58 times those in Judeline, respectively. The germination of apple bud was regulated by the endogenous hormones. For the late-germination apple Avrolles, its germination requires higher concentration of GA3 and ZR, which leads to the high ratios of GA3/ABA and （GA3＋ IAA＋ ZR）/ABA.

Chromosome-scale genome assembly of sweet cherry(Prunus avium L.)cv.Tieton obtained using long-read and Hi-C sequencing

Sweet cherry(Prunus avium)is an economically significant fruit species in the genus Prunus.However,in contrast to other important fruit trees in this genus,only one draft genome assembly is available for sweet cherry,which was assembled using only Illumina short-read sequences.The incompleteness and low quality of the current sweet cherry draft genome limit its use in genetic and genomic studies.A high-quality chromosome-scale sweet cherry reference genome assembly is therefore needed.A total of 65.05 Gb of Oxford Nanopore long reads and 46.24 Gb of Illumina short reads were generated,representing~190x and 136x coverage,respectively,of the sweet cherry genome.The final de novo assembly resulted in a phased haplotype assembly of 344.29 Mb with a contig N50 of 3.25 Mb.Hi-C scaffolding of the genome resulted in eight pseudochromosomes containing 99.59%of the bases in the assembled genome.Genome annotation revealed that more than half of the genome(59.40%)was composed of repetitive sequences,and 40,338 protein-coding genes were predicted,75.40%of which were functionally annotated.With the chromosomescale assembly,we revealed that gene duplication events contributed to the expansion of gene families for salicylic acid/jasmonic acid carboxyl methyltransferase and ankyrin repeat-containing proteins in the genome of sweet cherry.Four auxin-responsive genes(two GH3s and two SAURs)were induced in the late stage of fruit development,indicating that auxin is crucial for the sweet cherry ripening process.In addition,772 resistance genes were identified and functionally predicted in the sweet cherry genome.The high-quality genome assembly of sweet cherry obtained in this study will provide valuable genomic resources for sweet cherry improvement and molecular breeding.

The regulatory network behind maize seed germination: Effects of temperature, water, phytohormones, and nutrients

Seed germination is the process by which an organism grows from a seed. It requires suitable conditions and environmental factors. Maize is one of the most important crops worldwide. Germination influences both final maize yield and quality. Seed germination is regulated by a complex gene network. It is also influenced by endogenous(phytohormones and nutrients) and exogenous(temperature and water)inputs, involving molecular networks only partly identified to date. This review describes current understanding of the influence of temperature, water, phytohormones, and nutrients in regulating maize seed germination, and indicates knowledge gaps that should be addressed.

The regulation of cell wall lignification and lignin biosynthesis during pigmentation of winter jujube

Fruit lignification is due to lignin deposition in the cell wall during cell development.However,there are few studies on the regulation of cell wall lignification and lignin biosynthesis during fruit pigmentation.In this study,we investigated the regulation of cell wall lignification and lignin biosynthesis during pigmentation of winter jujube.The cellulose content decreased,while the lignin content increased in the winter jujube pericarp during pigmentation.Safranin O-fast green staining showed that the cellulose content was higher in the cell wall of winter jujube prior to pigmentation,whereas the lignin in the cell wall increased after pigmentation.The thickness of the epidermal cells decreased with pericarp pigmentation.A combined metabolomics and transcriptomics analysis showed that guaiacyl-syringyl(G-S)lignin was the main lignin type in the pericarp of winter jujube,and F5H(LOC107424406)and CCR(LOC107420974)were preliminarily identified as the key genes modulating lignin biosynthesis in winter jujube.Seventeen MYB and six NAC transcription factors(TFs)with potential regulation of lignin biosynthesis were screened out based on phylogenetic analysis.Three MYB and two NAC TFs were selected as candidate genes and further studied in detail.Arabidopsis ectopic expression and winter jujube pericarp injection of the candidate genes indicated that the MYB activator(LOC107425254)and the MYB repressor(LOC107415078)control lignin biosynthesis by regulating CCR and F5H,while the NAC(LOC107435239)TF promotes F5H expression and positively regulates lignin biosynthesis.These findings revealed the lignin biosynthetic pathway and associated genes during pigmentation of winter jujube pericarp and provide a basis for further research on lignin regulation.

The Physiological Response of Three <i>Narcissus pseudonarcissus</i>under NaCl Stress

In order to explore the salt-tolerance of Narcissus pseudonarcissus and enrich its cultivation and application forms. In this experiment, “Manly”, “Dutch” and “Wilden” daffodils were used as test materials. NaCl stress was applied at different concentrations, and the corresponding physiological indexes were measured at three time nodes: bolting stage, early flowering stage and blooming stage. The results showed that all three showed some resistance under low concentration salt stress, in which, SOD, POD enzyme activity, chlorophyll proline and soluble sugar content increased, while MDA content decreased. The physiological metabolism of the three was disturbed under high concentration of salt stress, in which, SOD, POD enzyme activity and chlorophyll content decreased, while MDA, proline and soluble sugar content increased. With the extension of stress time, the injury was gradually deepened and the salt tolerance of the three varieties is “Dutch”, “Wilden” and “Manly” in order.

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.

High Performance Liquid Chromatography Analysis of Sugars and Acid Components in ’Xintai Tianhong’ Hawthorn Fruit

[Objectives]This study was conducted to provide basic information for the utilization,quality control and deep processing of‘Xintai Tianhong’hawthorn fruit resources.[Methods]The contents of sugar and acid components in‘Xintai Tianhong’hawthorn fruit were determined by high performance liquid chromatography(HPLC).[Results]‘Xintai Tianhong’hawthorn fruit contained such four kinds of sugar components as fructose,sorbitol,glucose and sucrose,and such six kinds of organic acid components as oxalic acid,tartaric acid,malic acid,acetic acid,citric acid and succinic acid.The fruit had the highest sucrose content,accounting for 70.53%of the total sugar content,followed by fructose,glucose and sorbitol.For the organic acid components,the content of succinic acid was the highest,accounting for 47.32%of the total acid content,followed by citric acid,malic acid,oxalic acid and tartaric acid,and acetic acid had the lowest content.[Conclusions]‘Xintai Tianhong’hawthorn should be a succinic acid-type hawthorn variety,which can be used as a parent in genetic research and breeding practice.

Inhibitory Effect of 16 Fungicides on Persimmon Anthracnose Pathogen Colletotrichum horii

In this research,the inhibitory effect of 16 fungicides on Colletotrichum horri causing persimmon anthracnose was investigated using mycelial growth method and spore germination method. The results showed that among the 16 tested fungicides,10% of Difenoconazole WG,33. 5% of Copper quinolate SC,25%of Bromothalonil EC,70% of Mancozeb WP,430 g/L of Tebuconazole SC,50% of Prochloraz-manganese chloride and 400 g/L of Flusilazole EC achieved the best inhibitory effect on mycelial growth of C. horri,with the inhibition rate of 100%; 70% of Polyram WG,33. 5% of Copper quinolate SC,25% of Bromothalonil EC,70% of Mancozeb WP,50% of Chlorobromoisocyanuric acid AF,50% of Triram WP and 400 g/L of Flusilazole achieved the best inhibitory effect on spore germination of C. horri,with the germination rate of 0. In conclusion,33. 5% of Copper quinolate SC,25% of Bromothalonil EC,70% of Mancozeb WP and 400 g/L of Flusilazole EC achieved the best inhibitory effect both in mycelial growth and spore germination,which could be used as the preference fungicides for the control of persimmon anthracnose,and 70% of Polyram WG and 50% of Triram WP achieved the secondly best inhibitory effect,which could be used as alternative fungicides. The results of this research could provide scientific evidence for the effective control of persimmon anthracnose,and more optional pesticides for utilization in the production practice of persimmon industry.

Application of Bio-organic Fertilizer Containing High-efficient Nitrogen-fixing Bacillus amyloliquefaciens on Strawberry

With strawberry as a test material,the effects of the bio-organic fertilizer containing high-efficiency nitrogen-fixing Bacillus amyloliquefaciens on nutrient contents in strawberry-planted soil,wilt occurrence and strawberry yield and quality were studied by a plot experiment,so as to provide reference for scientific use of the bio-organic fertilizer and green production of strawberry.The results showed that after hole-applying the bio-organic fertilizer at a rate of 22.5 t/hm^2,the contents of NH^+_4-N,available P,available K and organic matter did not change much with time;and when replacing 50%of chemical fertilizers with the bio-organic fertilizer at a rate of 11.25 t/hm^2(K_3),the contents of NH^+_4-N and available P in the soil did not change much with time,and the contents of available K and organic matter decreased slightly with time,but were both higher than the CK(the unfertilized treatment).Meanwhile,the disease index values of strawberry wilt disease in treatments K_2 and K_3were significantly lower than those of the CK and the conventional fertilization treatment(K_1),and the vitamin C contents of strawberry fruit in the two treatments were significantly higher than that of the CK.The yield determination showed that the cumulative yields of treatments K_2 and K_3 increased by 9.8% and 3.3%,respectively,and the increase rates of the early yields(before the Spring Festival)were 30.6% and 21.9%,respectively.Therefore,the application of the bio-organic fertilizer can replace chemical fertilizers,and can achieve the effects of reducing the occurrence of wilt,improving the early yield of fruit commodity and improving fruit quality.

Effects of Different Times of Bagging on Fruit Quality and Disease and Pest Incidence of Fuji Apple

The effects of bagging at different times in Mengyin area on the fruit quality and disease and pest incidence of Huimin short-cut Fuji apple were investigated,with unbagged fruit as the control. The results showed that among the apples bagged on May 5,May 15,May 25,June 2 and June 12,the single fruit weight and fruit shape index of the apples bagged on June 2 were highest,308. 1 g and 0. 868,respectively; the peeled harness of the apples bagged during May 5-25 was higher than that of the control; the peeled harness of the apples bagged on June 2 and June 12 was lower than that of the control; the soluble solids content of bagged fruit was lower than that of unbagged ones,and no significant differences were found among different treatments; the coloring index of the apples bagged on June 2 was up to 100%; the smooth finish index of the apples bagged on May 5 reached 96. 67%,the highest; the red chromatic value( a*) of bagged fruit was higher than that of unbagged ones,and there were no significant differences among different bagging treatments. The earlier the bagging was,the higher the incidence of black spot and bitter pit was. The incidence of black spot and bitter pit in bagged fruit was higher than that in unbagged ones. In conclusion,in Mengyin area of Shandong Province,bagging is better to be carried out on June 2,45 d after the full bloom.

Automatic Monitoring of Chilling Requirement for Sweet Cherry and Its Application in Protected Cultivation

For sweet cherry, the economic benefit of protected cultivation is much higher than that of open field cultivation. However, problems such as nonuniform germination, aberrant flower, abortion, bad fruit setting and delayed maturation appear frequently due to the inaccurate regulation of chilling requirement. In order to solve the problems, an automatic system for monitoring, selecting and recording of chilling requirement in protected cultivation of sweet cherry was designed and developed. The system, which consisted of temperature detection, effective chilling temperature selection, signal conversion and output and chilling accumulation display, had been continuously used in protected cultivation of sweet cherry for 3 years and good effects had been achieved. The system monitored chilling accumu- lation accurately and made it more reasonable for the time selection of greenhouse covering, thus avoiding risks of nonuniform germination, bad fruit setting and de- layed maturation, etc. Under the coordinate application of this system with other modern measuring and controlling techniques such as automatic detection and alarming of temperature and humidity, the environment in greenhouses was regulated precisely that the uniform fruits were obtained and the expected yield, quality and harvest time were achieved.

The Effect of Different Potassium Fertilizers on Fruit Flavor Quality of ‘Xinliqihao’ Pear

[Objectives] This study was conducted to investigate the effects of different types of potassium fertilizers on the flavor and quality of pear fruit.[Methods] With ‘Xinliqihao’ as a research object,such three treatments as potassium sulfate (T1),potassium nitrate (T2) and potassium chloride (T3) were set up,with no application of potassium fertilizer as control (CK).All the fertilizers were applied into soil in the growing season.[Results] The total sugar content of ‘Xinliqihao’ was significantly higher in the potassium fertilizer treatments than that of the control.The total sugar content of T 2 (the potassium sulfate treatment) was the highest,which was 34.55% higher than that of the control,sequentially followed by T3 (the potassium nitrate treatment) and T1 (the potassium chloride treatment).The contents of fructose,glucose and sucrose in the potassium sulfate treatment were all the highest,which were 15.96%,27.32% and 52.81% higher than those of the potassium chloride treatment,respectively,and 11.36%,27.75% and 20.45% higher than the potassium nitrate treatment,respectively.The total acid content of ‘Xinliqihao’ fruit treated with different types of potassium fertilizers was higher than that of the control.The total acid content of the potassium nitrate treatment was the highest,which was 103.68% higher than that of the control,sequentially followed by the potassium sulfate treatment and the potassium chloride treatment.Both the control and potassium treatments of ‘Xinliqihao’ had the highest malic acid content,and except the potassium chloride treatment with the lowest fumaric acid content,other treatments all had the lowest tartaric acid content.Different types of potassium fertilizer treatments had different effects on the organic acid content of ‘Xinliqihao’ fruit.The types and contents of volatile aroma substances in the fruit of ‘Xinliqihao’ treated with potassium fertilizers were significantly higher than the control.The aroma substances in ‘Xinliqihao’ differed among different potassium fertilizer treatments.Specifically,78 kinds of aroma substances were detected in the potassium chloride treatment,and the total content of aroma components was the highest at 746.609 ng/g in the fruit of the potassium sulfate treatment.[Conclusions] The potassium fertilizer treatments improved the flavor and quality of ‘Xinliqihao’ pear fruit,and the potassium sulfate treatment exhibited the best effects.