Advances in Molecular Regulatory Mechanisms of Fruit Trees under Low Temperature Stress

The most recent research findings on the tolerance of fruit trees to cold stress are reviewed from a molecular perspective,including the perception and transduction of low temperature calcium signaling,CBF-dependent molecular regulatory mechanisms,non-CBF-dependent molecular regulatory mechanisms,and so forth.The objective is to provide a reference basis for further improving the cold resistance of fruit trees and cultivating new varieties of hardy plants.

Influence of Fruit Tree Types and Arrangements on Yield, Quality and Economic Returns of Cotton of Intercropping System in Southern Xinjiang

[Objective] The aim was to provide a theoretical basis for stable and highly effective intercropping arrangements and scientific management measures by selecting apple, pear, peach, apricot, walnut, jujube and other fruit trees to study their influence on yield, fiber quality and economic returns of intercropped cotton in southern Xinjiang. [Method] Based on major cropping pattern in production, randomized block design was adopted to explore growth indicators, canopy micrometeorological indicators, yield and fiber quality in key growth stage. [Result] Shading has a significant effect on cotton canopy micro-environment and canopy diameter is proportional to shading effect. According to comparisons of the same tree type, the change of canopy micro-environment was as follows： under canopyouter canopymiddle points and peachpearapplewalnutjujube for comparisons among different tree types. Canopy diameter is directly proportional to the number of tree branch and boll weight reductions and shading is the main cause of yield reduction. The canopy expansion is the major cause of decline of light intensity, temperature and humidity of cotton canopy. [Conclusion] Fruit trees, which will promote cotton yield,quality and canopy-environment, are as follows： jujube walnut apple pear peach trees. In practice, trees, which are small in canopy or well trimmed, are popular in production, such as jujube trees, to improve cotton yield and fiber quality.

Study on Curative Effect of Perforated Injection of Zinc-ammonia Complex on Rosette Disease of Fruit Tree

[ Objective ] The paper was to explore a kind of zinc preparation suitable for injection on trees with fast, efficient and safe cure effect on physiological disease of zinc deficiency. [Method] Taking three years old apple, pear, peach and grape trees as the materials, the author studied the absorption condition of these trees to six kinds of zinc substances and their security. The sealed curative effects of the injected zinc substances which were harmful and could be absorbed steadily by the fruit trees against rosette disease were studied. [ Result] The results of absorption condition and security experiments showed that only zinc-mmnonia complex could be absorbed steadily and safely throughout four seasons. When apple, pear, peach and grape trees affected by rosette disease were injected with zinc- ammonia complex, the leaves of those trees started to grow obviously after 10 d; the internodes of diseased branches elongated, the leaves turned bigger, and the ap- pearance of branches became normal after about 25 d. [ Conclusion] The curative effect of perforated injection of zinc-ammonia complex on fruit tree rosette disease was remarkable. The results also provided a new way for the cure of deficiency diseases of other trace elements.

Growth simulation and yield prediction for perennial jujube fruit tree by integrating age into the WOFOST model

Mathematical models have been widely employed for the simulation of growth dynamics of annual crops,thereby performing yield prediction,but not for fruit tree species such as jujube tree(Zizyphus jujuba).The objectives of this study were to investigate the potential use of a modified WOFOST model for predicting jujube yield by introducing tree age as a key parameter.The model was established using data collected from dedicated field experiments performed in 2016-2018.Simulated growth dynamics of dry weights of leaves,stems,fruits,total biomass and leaf area index(LAI) agreed well with measured values,showing root mean square error(RMSE) values of 0.143,0.333,0.366,0.624 t ha^-1 and 0.19,and R2 values of 0.947,0.976,0.985,0.986 and 0.95,respectively.Simulated phenological development stages for emergence,anthesis and maturity were 2,3 and 3 days earlier than the observed values,respectively.In addition,in order to predict the yields of trees with different ages,the weight of new organs(initial buds and roots) in each growing season was introduced as the initial total dry weight(TDWI),which was calculated as averaged,fitted and optimized values of trees with the same age.The results showed the evolution of the simulated LAI and yields profiled in response to the changes in TDWI.The modelling performance was significantly improved when it considered TDWI integrated with tree age,showing good global(R2≥0.856,RMSE≤0.68 t ha^-1) and local accuracies(mean R2≥0.43,RMSE≤0.70 t ha^-1).Furthermore,the optimized TDWI exhibited the highest precision,with globally validated R2 of 0.891 and RMSE of 0.591 t ha^-1,and local mean R2 of 0.57 and RMSE of 0.66 t ha^-1,respectively.The proposed model was not only verified with the confidence to accurately predict yields of jujube,but it can also provide a fundamental strategy for simulating the growth of other fruit trees.

Overview of Relation between Mineral Nutrient Elements and Growth and Development of Fruit Trees

Mineral nutrition is the material basis for growth and development,yield and quality of fruit trees. It exerts a great effect on the growth and development,fruit quality,yield,and resistance of fruit trees. On the basis of reading a large number of references both at home and abroad,this paper elaborated the relationship between mineral nutrient elements and growth and fruit yield and quality of fruit trees,so as to make proper fertilizer mixing,balance the fertilizer application,promote growth and development of fruit trees,and increase the yield of fruit trees and improve the fruit quality.

Plantation of Fruit Tree and Its Application in Qiqihar’s Garden Greening

The sample survey methodology was used to investigate the concept of fruit trees planted in the Qiqihar City landscaping. The application effects of fruit trees in landscape were compared and the utilization features of fruit trees were analyzed. The most appropriate fruit trees species were selected and the optimum configuration types were proposed. The research results showed that from the perspective of the utilization of fruit tress in landscape in Qiqihar, the fruit trees species were not abundant and the quality was also not enough. The mostly used trees genera included Lonicera of Caprifoliaceae family, Viburnum, Sambucus, and Prunus, Ceraras, Pyrus, Malus belonging to Rosaceae family.

Application of Fruit Trees in Suzhou Classical Gardens

The application of fruit trees in four Suzhou classical gardens involving the Humble Administrator's Garden,the Lingering Garden,the Lion Forest Garden and the Garden of Cultivation was investigated. The result showed that:firstly,fruit trees had been widely applied in each garden;secondly,the number and species of fruit trees differed from garden to garden;thirdly,the management of fruit trees was poor,resulting in poor growth of plants. In view of these problems,corresponding suggestions had been put forward and meanwhile creative fruit trees' planting had been proposed in order to achiever better landscape effect.

Molecular Phylogeny of the “True Citrus Fruit Trees” Group (Aurantioideae, Rutaceae) as Inferred from Chloroplast DNA Sequence

The genus Citrus L. has a long controversial taxonomy history, and a well-resolved molecular phylogeny of the ＂true citrus fruit trees＂ group in the future will provide new information for advancing breeding techniques and developing better conservation strategies. In the present study, three cpDNA fragments （TrnL-TrnF, PsbH-PetB, and TrnS-TrnG） of 30 genotypes chosen from the six genera of the ＂true citrus fruit trees＂ group were analyzed. A molecular phylogenetic tree of the ＂true citrus fruit trees＂ group ＂~as reconstructed based on plastid DNA sequences. The results confirmed that the ＂true citrus fruit trees＂ group was monophyletic, and thereby the group was divided into genera as previously suggested based on morphological characters. The cpDNA data also suggested that Poncirus might be the first genus separated from the other five genera in the group. The genus Fortunella were of hybrid origin and Citrus might be as its putative paternal parent. The genera Microcitrus, Eremocitrus, and Clymenia were possibly monophyletic and their common ancestor might branch out from Citrus. Furthermore, the phylogenetic relationships within the Citrus genus were discussed.

Second Bloom of Fruit Trees and Preventive Measures

Second bloom of fruit trees refers to the flowering and fruit-bearing of fruit trees after autumn harvest, which seriously influences the yield and economic benefits of fruit trees. By analyzing the causes of second bloom, remedies are given to make scientific preventive measures and realize high-quality and high-yield cultivation of fruit trees.

Application of Fruit Trees in Urban Landscaping

By reviewing application history of fruit trees in gardens, application principles of fruit trees in urban garden landscapes were proposed in view of its landscape components, such as flower, fruit, foliage, figure and cultural connotations. Application principles included "right tree for right land", "fully playing ecological effects of fruit trees", "improving rhythmic sense and artistic quality of plant furnishings", and "using characteristic fruit trees". Its application in different garden green spaces such as by roadside, in residential districts, in parks, in sightseeing orchards was respectively analyzed, examples were given to show application range of different species. Finally, attentions were proposed to provide references for the future application of fruit trees in urban garden landscapes.

Review of Research on Nutritional Physiological Mechanism and Nutritional Diagnosis of Magnesium in Fruit Trees

Magnesium is an essential nutrient element for the growth and development of fruit trees.It not only participates in photosynthesis of plants,but also promotes physiological and biochemical reactions such as carbohydrate and protein synthesis,enzyme activation,and reactive oxygen species(ROS)metabolism.Magnesium deficiency in fruit trees will directly influence the growth and development of trees and the improvement of fruit quality.This study mainly reviews the nutritional and physiological mechanism of magnesium in plants and the nutritional diagnosis of magnesium deficiency in fruit trees,in order to provide a theoretical basis for further research on magnesium nutrition in fruit trees,and accordingly provide a certain reference for the application of magnesium fertilizer.

Control effect of boring pests on fruit trees by high-pressure injection of pesticides

This research is to control the pests inside fruits and buds by injecting pesticides into the tree with the high-pressure injector. The soluable pesticides injected into the trunk can transported insides to every part of the tree to kill pests. The change of pesticides inside the tree was observed. The result showed that injecting pesticides once a year could kill above 80% of the pests which happened once annually. The effect of injection lasts longer than that of applying the pesticide outside. The pesticides injected into the tree are not affected by environment and do not kill natural enemies directly,and the residual amount of pesticides is below the international standard level.

Indigenous Fruit Trees of Tropical Africa: Status, Opportunity for Development and Biodiversity Management

Tropical fruit trees constitute important biological resources in the global agrobiodiversity context. Unlike the tropical fruit trees of American and Asian origin, indigenous fruit trees (IFT) of tropical Africa have scarcely achieved the status of international recognition in commodity markets and research arena outside Africa. This paper presented a critical review of the status of IFT in the Tropical African sub-regions (of West Africa, Central Africa, East Africa, Southern Africa and the Indian Ocean Islands) in relation to the introduced naturalised fruit trees from tropical America and Asia, threats to the diversity and sustainable use of IFT, analysis of the opportunities and challenges of developing IFT, as well as targets for crop improvement of the rich IFT of Tropical Africa. Domestication programme via relevant vegetative propagation techniques for priority IFT of the sub-regions was examined and advocated, in addition to the adoption of complementary conservation strategies, including Field GeneBanks in the management of the continent’s IFT diversity.

Managing irrigation of fruit trees using plant water status

Optimum growth and production of fruit crops is strongly linked to managing irrigation water. Various method of estimating tree water requirements have been utilized such as direct and indirect soil, water, and climatic measurements. Due to differences in fruit tree anatomical and morphological structures and their adaptation to excess and deficit soil water content, such estimates of irrigation water requirements may be more suitable for herbaceous plants but not as accurate for trees. Studies on temperate and tropical fruit trees, using apple (Malus domestica) and star-fruit (Averrhoa carambola), respectively, showed that tree water potential is highly correlated to soil water status. Irrigation based on climate data (ET) and monitoring of soil water resulted in no significant differences in soil or tree water status of orchard-grown fruit trees under temperate and subtropical climatic conditions. The results indicated the need for better understanding and utilization of tree physiological parameters for management of irrigation water of fruit crops. This will ultimately lead to achieving optimum yield and fruit quality while conserving water resources.

Method for the fruit tree recognition and navigation in complex environment of an agricultural robot

To realize the visual navigation of agricultural robots in the complex environment of orchards,this study proposed a method for fruit tree recognition and navigation based on YOLOv5.The YOLOv5s model was selected and trained to identify the trunks of the left and right rows of fruit trees;the quadratic curve was fitted to the bottom center of the fruit tree recognition box,and the identified fruit trees were divided into left and right columns by using the extreme value point of the quadratic curve to obtain the left and right rows of fruit trees;the straight-line equation of the left and right fruit tree rows was further solved,the median line of the two straight lines was taken as the expected navigation path of the robot,and the path tracing navigation experiment was carried out by using the improved LQR control algorithm.The experimental results show that under the guidance of the machine vision system and guided by the improved LQR control algorithm,the lateral error and heading error can converge quickly to the desired navigation path in the four initial states of[0 m,−0.34 rad],[0.10 m,0.34 rad],[0.15 m,0 rad]and[0.20 m,−0.34 rad].When the initial speed was 0.5 m/s,the average lateral error was 0.059 m and the average heading error was 0.2787 rad for the navigation trials in the four different initial states.Its average driving was 5.3 m into the steady state,the average value of steady state lateral error was 0.0102 m,the average value of steady state heading error was 0.0253 rad,and the average relative error of the robot driving along the desired navigation path was 4.6%.The results indicate that the navigation algorithm proposed in this study has good robustness,meets the operational requirements of robot autonomous navigation in orchard environment,and improves the reliability of robot driving in orchard.

Bioassay and Identification of Root Exudates of Three Fruit Tree Species

A laboratory bioassay was designed to determine the aileiopathic potential of root exudates of three fruit tree species on apple germination. The results showed that root exudates of apple （Malus pumila L.） and peach （Prunus persica L.）, each at concentrations of 0.02 and 0.2 mg/L, inhibited germination and radicle growth of apple seeds by 56.7%, 60.7%, 51.5%, and 59.3%, respectively. The corresponding shoot growth inhibition rate was 49.5%, 46.7%, 36. 4%, and 44%, respectively. Root exudates of jujube （Ziziphus jujuba Mill.） had no significant effect on apple seeds. Qualitative determination of root exudates of apple, peach, and jujube tree was developed with gas chromatography-mass spectrometry. The root exudates of apple seedlings mainly contain organic acids, glycol, esters, and benzenphenol derivatives. Peach root exudates contained phenolic acids and benzenphenoi derivatives in addition to two unidentified compounds. The root exudates of jujube did not contain any phenolic acids.

A novel method for extracting skeleton of fruit treefrom 3D point clouds

Tree skeleton could be useful to agronomy researchers because the skeleton describes the shape and topological structure of a tree.The phenomenon of organs’mutual occlusion in fruit tree canopy is usually very serious,this should result in a large amount of data missing in directed laser scanning 3D point clouds from a fruit tree.However,traditional approaches can be ineffective and problematic in extracting the tree skeleton correctly when the tree point clouds contain occlusions and missing points.To overcome this limitation,we present a method for accurate and fast extracting the skeleton of fruit tree from laser scanner measured 3D point clouds.The proposed method selects the start point and endpoint of a branch from the point clouds by user’s manual interaction,then a backward searching is used to find a path from the 3D point cloud with a radius parameter as a restriction.The experimental results in several kinds of fruit trees demonstrate that our method can extract the skeleton of a leafy fruit tree with highly accuracy.

Determination of the Geographical Origin of Fruits by Using 26S rDNA Fingerprinting of Yeast Communities by PCR-DGGE： An Application to Shea Tree Fruits

International trade intensifies the process of globalization which has extended to the entire planet and extends to the entire planet. In view of the difficulties of installing these documentary systems in developing countries, in particularly the countries of sub-Saharan Africa, the new strategies of traceability emerge. Among the new tools of tracing the products of vegetable origin, a ＂biological code bar＂ based on the analysis of the DNA of micro-organisms present on the fruits is an interesting tool. A molecular technique employing 26S rDNA profiles generated by PCR-DGGE was used to detect the variation in yeast community structures of Shea tree fruits （Vitellaria paradoxa） from Senegal, Ghana and Mali. When the 26S rDNA profiles were analyzed by image analysis and multivariate analysis, distinct microbial communities were detected on Shea tree fruits. The band profiles of yeasts from different countries were specific for each location and could be used as a bar code to discriminate the origin of the fruits. This method is a new traceability tool which provides fruit products with an unique biological bar code and makes it possible to trace back the fruits to their original location.

Effects of Different Density-reducing Methods on Canopy Microenvironment, Tree Growth and Fruit Quality in Closed Apple Orchard

In order to optimize and transform closed mature apple orchards with standard rootstocks and improve the quality of fruit,taking a closed Red Fuji apple orchard as the test object,the effects of different density-reducing methods(deinterlacing,removing every other plant in each row,removing every other plant every other row)on the canopy microenvironment,tree structure,leaf photosynthesis and fruit quality were studied.The results showed that different density-reducing methods significantly reduced the orchard coverage and increased the crown transmittance.Among them,the deinterlacing treatment was the best in improving the population structure of the closed orchard,as it reduced the orchard coverage rate by 55.68 percentage points and the canopy transmittance by 82.38 percentage points,compared with the control(CK).Different density-reducing methods all could significantly reduce the branch amount in the closed orchard and optimized the branch composition.The three density-reducing methods decreased the number of branches per plant by 18.96%,12.41%and 19.58%,respectively,compared with the CK.And compared with the CK,the proportion of short branches and leafy branches to the total branches was increased by 17.13%,14.27%and 7.37%,respectively,and the proportion of long branches and developmental branches to the total branches was decreased by 24.47%,18.04%and 10.79%,respectively.The effects of the different density-reducing methods on the temperature,relative light intensity,SPAD and leaf photosynthetic rate in canopies all followed an order of deinterlacing>removing every other plant in each row>removing every other plant every other row>CK,while those on the relative humidity showed an order of deinterlacing>removing every other plant in each row>removing every other plant every other row>CK,while those on the relative humidity showed an order of deinterlacing<removing every other plant in each row<removing every other plant every other row<CK.The average single fruit weight(238.3 g),coloring index(89.2),smoothness index(83.2),soluble solid content(15.1%)and high quality fruit rate(82.4%)of the deinterlacing treatment were higher than those of other treatments,and the values were 18.2%,11.4%,5.85%,26.9%and 25.2%higher than the CK,respectively.The use of dein￣terlacing to reduce density is the best for improving the microenvironment of closed apple orchards and improving the photosynthetic efficiency and fruit quality.

平邑甜茶高位嫁接丽嘎拉苹果树冠层内枝类结构和果实品质、产量的分布

【目的】掌握以平邑甜茶为砧木,采用高位嫁接方式的丽嘎拉苹果树冠层内枝类结构、果实产量和品质的分布特点,为辽宁寒地苹果园建设中应用该种栽培模式,提升果品质量、优化栽培措施提供参考。【方法】以丽嘎拉/GM256/平邑甜茶、丽嘎拉/平邑甜茶(高接)和丽嘎拉/平邑甜茶(低接)苹果树为试材,按照冠层分格的方法,将试验树从地面到顶部分成4个冠层,比较不同冠层高度内枝类结构、果实产量和品质的分布差异。【结果】丽嘎拉/平邑甜茶(高接)苹果树高、冠径、覆盖率生长速度高于丽嘎拉/GM256/平邑甜茶,丽嘎拉/平邑甜茶(高接)树体外观表现为“小脚”现象,而丽嘎拉/GM256/平邑甜茶表现为“大脚”现象。丽嘎拉/平邑甜茶(高接)苹果树枝量、短枝比例高于丽嘎拉/平邑甜茶(低接)和丽嘎拉/GM256/平邑甜茶。丽嘎拉/平邑甜茶(高接)、丽嘎拉/平邑甜茶(低接)和丽嘎拉/GM256/平邑甜茶枝量分布集中区域为冠层高度>2.00~3.00 m、>3.00 m和>1.00~2.00 m,占全树枝量比例的43.51%、45.37%和47.96%。相同冠层高度内,丽嘎拉/平邑甜茶(高接)果实单果质量、果形指数、硬度、可滴定酸含量、色差L和a值高于丽嘎拉/GM256/平邑甜茶。随着冠层高度的增加,丽嘎拉/平邑甜茶(高接)、丽嘎拉/平邑甜茶(低接)和丽嘎拉/GM256/平邑甜茶果实硬度、可滴定酸含量呈现下降趋势,而固酸比和色差值(L、a、b)呈现上升趋势。丽嘎拉/平邑甜茶(高接)和丽嘎拉/平邑甜茶(低接)果实产量主要分布在冠层高度>2.00 m的空间区域,占全树产量的69.79%和75.55%,而丽嘎拉/GM256/平邑甜茶为>1.00~3.00 m,占比全树产量的74.59%。【结论】以平邑甜茶为砧木,采用高位嫁接的丽嘎拉苹果树枝条数量多、短枝比例高、外观色泽好,树体枝量和果实产量分布集中区域为冠层高度>2.00~3.00 m,该冠层生产的苹果单果质量大、果形指数适中、可溶性固形物含量高。