Molecular characterization of the SAUR gene family in sweet cherry and functional analysis of PavSAUR55 in the process of abscission

Small auxin up RNA(SAUR) is a large gene family that is widely distributed among land plants. In this study, a comprehensive analysis of the SAUR family was performed in sweet cherry, and the potential biological functions of PavSAUR55 were identified using the method of genetic transformation. The sweet cherry genome encodes 86 SAUR members, the majority of which are intron-less. These genes appear to be divided into seven subfamilies through evolution. Gene duplication events indicate that fragment duplication and tandem duplication events occurred in the sweet cherry. Most of the members mainly underwent purification selection pressure during evolution. During fruit development, the expression levels of Pav SAUR16/45/56/63 were up-regulated, and conversely, those of Pav SAUR12/61were down-regulated. Due to the significantly differential expressions of PavSAUR13/16/55/61 during the fruitlet abscission process, they might be the candidate genes involved in the regulation of physiological fruit abscission in sweet cherry. Overexpression of PavSAUR55 in Arabidopsis produced earlier reproductive growth, root elongation, and delayed petal abscission. In addition, this gene did not cause any change in the germination time of seeds and was able to increase the number of lateral roots under abscisic acid(ABA) treatment. The identified SAURs of sweet cherry play a crucial role in fruitlet abscission and will facilitate future insights into the mechanism underlying the heavy fruitlet abscission that can occur in this fruit crop.

Effects of Controlled Atmospheres with High_O_2 or High_CO_2 Concentrations on Postharvest Physiology and Storability of "Napoleon" Sweet Cherry

Sweet cherries ( Prunus avium L. cv. Napoleon) were stored in controlled atmospheres (CA) of high O(2) (70% O(2) + 0% CO(2)) or high CO(2) (5% O(2) + 10% CO(2)), in modified atmosphere package (MAP, (13% - 18%) O(2) + (2% -4%) CO(2)) and in air (control) at 1 degreesC to investigate the effects of different O(2) and CO(2) concentrations on physiological properties, quality and storability of the fruits during storage. The results indicated that compared with other treatments, CA with high O(2) concentration decreased fruit decay and ethanol content, but increased the accumulation of malondialdehyde (MDA) and stimulated browning. CA with high CO(2) concentration inhibited polyphenol oxidase (PPO) activity, reduced MDA content, maintained vitamin C content and firmness, decreased fruit decay and browning. Soluble solids contents (SSC) were not significantly affected by different atmosphere treatments. 'Napoleon' fruits stored in 5% O(2) + 10% CO(2) for as long as 80 d were of good quality, but only 40, 20 and 30 d stored in MAP, 70% O(2) + 0% CO(2) and air, re-spectively.

Effects of Different Preservative Treatments on Physiological Metabolism and Preservation of Sweet Cherry

[Objective] This study aimed to investigate the effects of different preservative treatments on physiological metabolism and preservation of sweet cherry. [Method] Sweet cherry （Prunus avium var. Summit） was soaked into benziothiazolinone （1 000 ppm）, lysozyme （500 ppm）, lysozyme （500 ppm） ＋ NPS polysaccharide （5 000 ppm） and water for 5 min, respectively. Non-treated sweet cherry was set as control. All the sweet cherries were then put into 3 mm thick PE bags and preserved at （-0.5±0.5） ℃. [Result] The results showed that the malate dehydrogenase （MDH） activity of benziothiazolinone treatment researched a significant peak on the 14 th d, while the MDH activity of Lysozyme （500 ppm）, Lysozyme （500 ppm） ＋ NPS polysaccharide （5 000 ppm） and water treatments began to increase on the 20 th d; the polyphenol oxidase （PPO） activity in various treatments showed a decreasing trend during the experiment, which researched a significant peak on the 14 th d, while that in water treatment was decreased consistently; on the 21 st d, the PPO activity in each treatment increased slowly; the titratable acid （TA） content in preservative treatments was higher than that in both water treatment and control; the soluble solid （SSC） content showed no significant difference between various treatments and between experimental treatment and control; on the 40 th d, the healthy fruit rate in preservative treatments was significantly higher than that in water treatment and control. [Conclusion] Benziothiazolinone, lysozyme and other preservatives show good effects on preservation of sweet cherry; lysozyme treatment can decrease the activity of malate dehydrogenase, maintain the relatively high content of organic acid and significantly improve the healthy fruit rate within a certain period of time.

Cluster Analysis of Characteristics of Different Sweet Cherry Varieties

In order to compare the characteristics of different varieties of sweet cherry and to formulate corresponding pruning scheme, hierarchical cluster analysis was conducted for the 14 sweet cherry varieties that were mainly planted in Shanxi Province. The results showed that the 14 varieties of sweet cherry could be divided into two types, Hongmanao and Rainier. Fruit setting rate, branching rate, medium fruit shoot proportion, spur proportion and yield per plant were significantly different between these two types of sweet cherry. The key points of pruning management, to improve the yield of Rainier type, were to increase the fruit setting rate and spur proportion, and to control properly the long and medium fruit shoot proportion.

Study on Chilling Requirement of Different Fruit Branch of a Sweet Cherry Cultivar ‘Hongmanao'

With ＇Hongmanao＇, a sweet cherry cultivar from central Shanxi Province, as the experimental material, the chilling requirements of different types of fruit branches （including mixed fruit branch, long fruit branch, medium fruit branch, short fruit branch and blossom fruit branch） were studied by the 0-7.2 ℃ model in a solar greenhouse during 2012-2013. In the greenhouse, the fruit branches of ＇Hongmanao＇ were cultured in water in a thermostatic environment. The results showed that the chilling requirement of leaf buds of ＇Hongmanao＇ was lower than that of its flower buds; and the chilling requirements of the five types of fruit branches ranked as blossom fruit branch＇s〈short fruit branch＇s〈medium fruit branch＇s〈long fruit branch＇s〈mixed fruit branch＇s,

Interaction Between Cryptococcus laurentii,Monilinia fructicola,and Sweet Cherry Fruit at Different Temperatures

The present study was performed mainly to investigate the antagonist-pathogen-host interaction in wounds of the sweet cherry fruits. The antagonistic yeast Cryptococcus laurentii could significantly reduce the brown rot of the sweet cherry fruit caused by Monilinia fructicola at 25 and 1 ℃. The populations of yeast increased faster in the presence of the pathogen initially, but then decreased rapidly. In the fruits inoculated with M. fructicola alone or combined with C. laurentii, an induction of lipid peroxidation as well as activities of the antioxidant enzymes, such as, superoxide dismutases （SOD）, catalase （CAT）, and peroxidase （POD）, was observed. The isoenzyme pattern of polypheno/oxidase （PPO） changed greatly after the symptoms appeared, with new PPO isoforms being induced. By contrast, the induction of lipid peroxidation and activities of SOD, CAT, and POD were low, although no significant changes were found in the PPO isoenzyms in the fruits inoculated with antagonist C. laurentii alone. The inhibition of brown rot during the antagonist- pathogen-host interaction in wounds of the sweet cherry fruits was mainly on account of the stimulated growth of C. laurentii as well as the induction of antioxidant enzymes of the fruits by M. fructicola.

Changes of Aroma Components in Hongdeng Sweet Cherry During Fruit Development

To study the changes of aroma components in sweet cherry during fruit development, the aroma components in sweet cherry fruit from the green stage, the color stage, the commercial stage, and the ripe stage were collected using head-space solid phase microextraction （HS-SPME）, and were analyzed using a gas chromatograph-mass spectrophotometer （GC- MS）. A total of 37 compounds were identified from the sample extracts. Aldehydes, alcohols, and esters were the major constituents. The aroma components behaved differently during the fruit developmental period. C6 aldehydes and aromatic aldehydes were the main aldehydes in the sweet cherry fruit. The contents of C6 aldehydes increased quickly to 84.16% in the color stage, then decreased as ripening proceeded, and then, the contents decreased to 59.20 and 55.58% at the commercial stage and the ripe stage, respectively. The aromatic aldehydes （benzaldehyde） increased as ripening proceeded, and the maximum was found at the ripe stage. Alcohols of sweet cherry fruit included C6 alcohols and aromatic alcohols. The content of （E）-2-hexen-l-ol increased as ripening proceeded. The maximum was found at the commercial stage; alcohol was only found at the ripe stage. Ester components included ethyl acetate, butanoic acid ethyl ester, hexanoic acid ethyl ester, which increased as the fruit ripened. Hexanal, （E）-2-hexenal, benzaldehyde, （E）-2-hexen-l-ol, ethyl acetate, and hexanoic acid ethyl ester were the characteristic aroma components of sweet cherry fruit. These aroma components started to form drastically at the color stage, and the main aroma was formed at the commercial stage, which then turned bad at the ripe stage because of the presence of alcohol. So the optimal harvest time of sweet cherry was at the commercial stage.

Impact of chilling accumulation and hydrogen cyanamide on floral organ development of sweet cherry in a warm region

The microscopic investigation of the floral development of sweet cherry（Prunus avium L. cv. Hongdeng） from a warm winter climate（Shanghai） and cold winter climate（Tai＇an, Shandong Province, China） was conducted to explore the reason of low fruit set. The effect of hydrogen cyanamide（HCN） on floral development under warm winter conditions was also investigated. Trees grown in Shanghai with insufficient chilling accumulation exhibited little difference in the progression of microspore development compared to trees in Tai＇an that accumulated adequate chilling, but showed substantial delays in ovule and embryo sac development. The growth of nucelli did not proceed beyond the macrospore mother cell and macrospore stages with abortion rates of 13, 15 and 45% by 6, 3 and 0 d before full bloom, respectively. These abnormalities in the ovule and embryo sac in the Shanghai-grown trees were eliminated by HCN application. These results suggest that chilling regulates the development of female floral organs in winter dormancy; therefore, insufficient chilling accumulation, causing abnormality of the female floral organs, restricts the cultivation of sweet cherry in warm winter regions. Interestingly, HCN application, which decreased the chilling requirements for Hongdeng, may be a potential strategy for sweet cherry cultivation in warm winter regions.

Transcriptome analysis for understanding the mechanism of dark septate endophyte S16 in promoting the growth and nitrate uptake of sweet cherry

Sweet cherry is one of the most popular fresh fruits in the world.Previously,we isolated a soilborne dark septate endophyte(DSE)strain,S16,which promoted the growth of Gisela 5 sweet cherry rootstock.However,little is known about the molecular mechanism of the effect of S16 on the growth of sweet cherry.In this study,the physiological parameters and transcript profiles of sweet cherry roots were analyzed under S16 treatment compared with a control to elucidate the molecular mechanisms of the effect of this strain on sweet cherry growth.After inoculation with S16,sweet cherry seedlings exhibited more vigorous growth.Moreover,we identified 4249 differentially expressed genes(DEGs)between S16-treated plants and the control.Many of the DEGs are involved in pathways related to plant growth,such as cellular metabolic and plant hormone pathways.Additionally,some genes involved in nitrate regulation were also enriched;and these genes may be involved in the regulation of nitrate uptake in plants.Physiological index detection demonstrated that S16 could improve the nitrate assimilation of sweet cherry via NO3–transporters.This RNA-seq dataset provides comprehensive insight into the transcriptomic landscape to reveal the molecular mechanisms whereby the DSE influences the growth of sweet cherry.

Effects of Different Atmospheres on the Postharvest Physiology and Quality of the Sweet Cherry

The changes in physiological characteristics, quality and storability of the sweet cherry (Pru-mus avium L. cv. Hongdeng) stored in controlled atmospheres (CA), in modified atmosphere packages (MAP) and in air (CK) were investigated in this paper. The results showed that CA and MAP treatments significantly inhibited fruit rot and flesh browning, kept firmness and fruit color, reduced ethylene and ethanol content in pulp, slowed down the increase of polyphenol oxidase (PPO) and peroxidase (POD) activity and malondialdehyde (MDA) content in comparison with CK. Meanwhile, CA treatments showed a better benefit of reducing ethylene and ethanol contents, inhibiting PPO and POD activities, declining rot rate and browning index compared to MAP. The fruit could be stored in CA conditions for 60 days without any off-flavor. The sweet cherries kept in CA with 5% O2 + 10% CO2 showed a better storability than that in CA with 5% O2 + 5% CO2.

Detection Method for Sweet Cherry Fruits Based on YOLOv4 in the Natural Environment

[Objectives]To explore a rapid detection method of sweet cherry fruits in natural environment.[Methods]The cutting-edge YOLOv4 deep learning model was used.The YOLOv4 detection model was built on the CSP Darknet5 framework.A mosaic data enhancement method was used to expand the image dataset,and the model was processed to facilitate the detection of three different occlusion situations:no occlusion,branch and leaf occlusion,and fruit overlap occlusion,and the detection of sweet cherry fruits with different fruit numbers.[Results]In the three occlusion cases,the mean average precision(mAP)of the YOLOv4 algorithm was 95.40%,95.23%,and 92.73%,respectively.Different numbers of sweet cherry fruits were detected and identified,and the average value of mAP was 81.00%.To verify the detection performance of the YOLOv4 model for sweet cherry fruits,the model was compared with YOLOv3,SSD,and Faster-RCNN.The mAP of the YOLOv4 model was 90.89%and the detection speed was 22.86 f/s.The mAP was 0.66%,1.97%,and 12.46%higher than those of the other three algorithms.The detection speed met the actual production needs.[Conclusions]The YOLOv4 model is valuable for picking and identifying sweet cherry fruits.

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.

Studies on Physiological Radiation Spectrum and Fruit Quality of Sweet Cherry in Different Canopies

[ Objective] The physiological radiation spectrum and fruit quality in different canopies of sweet cherry tree were studied. [ Method] Opti- cal fiber spectrum was applied to determine the physiological radiation spectrum in different canopies of sweet cherry tree. The fruit quality in differ- ent canopies was determined. [Result] The results showed that from the top part to the lower part and from the outer part to inner part of sweet cherry canopy, Me physiological radiation intensity and ratio of short wave light reduced significantly, while ratio of long wave light increased. Fruit mass, Vc, TSS and total sugar content were significantly decreasing, while organic acid content increasing, but the fruit edible percent was similar. Furthermore, the physiological radiation intensity was strong, fruit mass, TSS, Vc and total sugar content increased, but organic acid content re- duced. [ Condusion] The higher and bigger canopy of sweet cherry, the poor and lower physiological radiation intensity, photosynthesis accumula- tion and fruit quality. The study provided theoretical foundation and reference for the trim of sweet cherry.

Sweet Cherry (<i>Prunus avium</i>L.) Fruit Drop Reduction by Plant Growth Regulators (Naphthalene Acetic Acid NAA and Gibberellic Acid GA₃)

This study was conducted during 2019/2020 on sweet cherry trees (Prunus Avium L.) (Bing and Hardy Giant) cultivar planted at Sergaya-Al_Zabadani area of Rural Damascus, to reduce fruit drop of sweet cherry. The experiment included 4 foliar applications: T1: control, T2: GA3 (100 ppm), T3: NAA (20 ppm), T4: (100 ppm GA3 + 20 ppm NAA). Fruit set and fruit drop percentage, fruiting factor, and yield were recorded. The results showed that treatment with (100 ppm GA3 + 20 ppm NAA) recorded higher fruit set percentage (73.81% and 75.62%), and fruiting factor (48.38% and 50.04%) respectively; In addition to fruit yield (40.19 and 41.21 kg/tree) for both cultivars, compared to the control (9.13, 6.60 kg/tree). Therefore, it can be concluded that GA3 + NAA treatment reduced Sweet cherry fruit drop better than other treatments, where fruit drop percentage didn’t exceed (63.11% and 62.01%) in both cultivars (Bing and Hardy Giant) respectively, compared to the control (80.92% and 80.64%).

Preliminary Report on the Introduction of Zaodaguo/Rootstock Gisela 5 into Chaoyang,Liaoning

The sweet cherry Zaodaguo/rootstock Gisela 5 was introduced from Insti- tute of Fruit Tree Research in Shandong Province in 2009. It was planted in sun- light greenhouse. The results showed Gisela 5 flowered as early as 2 years after transplanting and a small part fruited. In the 3~ to 5~ year, the annual productions reached 1 125, 2 940 and 6 300 kg/hm2 correspondingly. The main technical mea- sures for early good harvest included planting high-quality seedlings, reasonable fer- tilizer and water management, appropriate tree shape, reasonable pruning, reason- able regulation of temperature and humidity, protecting flowers and fruits, pest con- trol, etc.

Telemetering system and its application for fruit cultivation in greenhouses

Circuit of the temperature measurement equipment was improved in order to develop temperature telemetering system for cultivating fruit facilities.The traditional temperature measuring equipments used in monitoring temperature changes in greenhouse include mercury column,merbromine column,kerosene column glass rod thermometer and mechanical inductive thermometer.Compared with the traditional method of temperature measurement the new system reduces the labor requirement and promotes precision monitoring and control of the temperature.In addition,the temperature in the greenhouse was very accurate especially at night or in rainy and snowy weather.This new temperature telemetering system will promote the development of the fruit protection cultivation.