Interaction of Apple Cultivars with Populations of Cedar-Apple Rust

Five physiological populations of Gymnosporangium juniperi-virginianae Schw. were identified on the basis of pycnial and aecial lesion formation when seven apple cultivars grown in a glasshouse were inoculated with basidiospores of rust populations collected from six locations in the U.S.A. The relationship between cultivars and rust populations was explored quantitatively using the parameters N, D, and DR, where N was the highest number of pycnial lesions on a leaf/plant; D was the largestdiameter measurement of pycnial lesions on a leaf/plant; and DR, the disease rating, was proportional to the diseased area of the leaf and calculated as ND². Statistically significant differences among cultivars over all rust populations for variables N, D, and DR were obtained, indicating the possible existence of race non-specific resistance in apple to cedar-apple rust. Moreover, significant differences among the rust populations over all cultivars for variable N and DR were obtained, confirming the existence of physiologically different rust populations of the pathogen. A change in the pathogenicities of these physiological populations must have occurred over time (10-year period). A significant interaction between cultivars and rust populations was observed for lesion size (D) only, indicating a probable existence of race specific resistance in apple as well.     

Soil microstructure as an under-explored feature of biological soil crust hydrological properties: case study from the NW Negev Desert

Biological soil crusts (BSCs) can play an important role in hydrological cycles, especially in dryland ecosystems where the availability of water is limited. Many factors influence the hydrological behavior of BSCs, one of which is the microstructure. In order to describe the influence of the soil microstructure of BSCs on water redistribution, we investigated the change of the pore system of three different successional stages of BSCs, as well as their respective subcrusts in the NW Negev desert, Israel, using 2-dimensional thin sections, as well as non-invasive X-ray 3D computed microtomography (XCMT) and mercury intrusion porosimetry. Our results show that the pore system undergoes significant changes during crust succession. Both the total porosity, as well as the pore sizes significantly increased from cyano- to lichen- to mosscrust and the pore geometry changed from tortuous to straight pore shapes. We introduce two new mechanisms that contribute to the hydrological properties of the BSCs in the NW Negev that impede infiltration: (i) vesicular pores and (ii) a discontinuous pore system with capillary barrier effects, caused by a rapid change of grain sizes due to sand burial. Since both of these mechanisms are present mostly in early stage cyanobacterial crusts and their abundance decreases strongly with succession, it is very likely that they influence BSC hydrology to different extents in the various crust types and that they are partly responsible for differences in runoff in the NW Negev.     

Significance of skin flavonoids for UV-B-protection in apple fruits

An attempt has been made to assess the UV-B-protective capacity of phenolic compounds accumulated in superficial structures of plants using apple fruit as a model. Two apple (Malus domestica Borkh.) cultivars (Braeburn and Granny Smith) differing in response to high fluxes of solar radiation were selected and exposed to increasing doses of UV-B radiation. The extent of UV-B-induced damage to photosystem II of apple skin correlated with its quercetin glycoside (but not anthocyanin) content. Granny Smith apples did not demonstrate a pronounced response to high sunlight in terms of the accumulation of phenolic substances in the skin and exhibited similar patterns of Fo, Fm, and Fv/Fm changes in the course of UV-B irradiation both on sun-exposed and shaded surfaces of a fruit. Unlike Granny Smith, Braeburn fruits were characterized by a significant accumulation of quercetin glycosides in sun-exposed skin, however, shaded skin contained these compounds in similar amounts to those in Granny Smith. Accordingly, photosystem II in sun-exposed skin of Braeburn apples was resistant to high doses of UV-B radiation (up to 97 kJ m-2), whereas the susceptibility of the photosynthetic apparatus in shaded skin of Braeburn to UV-B-induced damage was much higher and similar to that of both sun-exposed and shaded skin of Granny Smith fruits. Anthocyanins, at least in the amounts found in Braeburn, did not show an additional effect in UV-B protection.     

Evaluation of genetic variability in choosen apple (<Emphasis Type="Italic">Malus</Emphasis> × <Emphasis Type="Italic">domestica</Emphasis> Borkh.) cultivars by ISSR-PCR analysis

The aim of the study was to determine the genetic variability in eight apple cultivars: Delikates, Cortland, James Grieve, Lired, Jonathan, Golden Delicious, Jonagold, and Idared from the collection of Fruit Growing Research Station in Rajkowo of the West Pomeranian University of Technology, Szczecin. The cultivar Delikates was obtained from the crossing of two cultivars: Cortland, and James Grieve, whereas cultivar Lired is a James Grieve’s sport. The second one cultivar—Jonagold was obtained from the crossing of Jonathan and Golden Delicious. The cultivar Idared is a hybrid obtained from the crossing of Jonathan and Wagener. Out of 40 primers, 17 were chosen for the final study. Those amplified a total of 183 loci (872 amplicons) out of which 34 (18.5%) were monomorphic, 128 (69.5%) were polymorphic and 22 (12%) cultivar-specific. Specific ISSR products were detected for each apple cultivar. A dendrogram was constructed using the UPGMA method which revealed two distinct clusters: I—Delikates, Cortland, James Grieve and Lired, II—Jonathan, Golden Delicious, Jonagold and Idared. Genetic similarity between Delikates, Cortland and James Grieve was 68.6, 70.8%, respectively and between cultivar Jonagold, Jonathan and Golden Delicous was 79.8, 85.2%, respectively.     

Three-dimensional analysis of the canal network of an Indonesian <Emphasis Type="Italic">Stylaster</Emphasis> (Cnidaria,Hydrozoa, Stylasteridae) by means of X-ray computed microtomography

This study describes the architecture of the coenosteal network in an Indonesian Stylaster species investigated by means of the X-ray computed microtomography (μ-CT) technique. The 3D approach allowed to characterize all internal cavity structures: a network of thin canals, gastropores, dactylopores, and ampullae. The main feature highlighted by this reconstruction is a dense network of thin canals extended to the entire colony. This network gives rise to and surrounds each cyclosystem. Moreover, the 3D analysis made it possible to study the reciprocal relationship between adjacent cyclosystems and to hypothesize the growth process of the branches of Stylaster sp.: each new cyclosystem buds between the gastropore and the dactylopores of the last formed one. The dactylopores of each cyclosystem are partially derived from the precedent one and are partially newly formed. The thin canals enveloping the dactylopores are actively involved in both the formation of a new gastropore and in the re-establishment of the typical amount of dactylopores in each cyclosystem. This growth process was confirmed by the scanning electron microscopy (SEM) observations of apical cyclosystems of several specimens. Results indicate that the non-destructive X-ray μ-CT technique can be fruitfully applied to characterize the coenosteal structures of stylasterids allowing the repetitive study of a specimen by means of virtually infinite section planes and different kinds of analyses (e.g., channel width and porosity).     

苹果绵蚜在不同寄主果园中的种群数量动态比较

【背景】在我国,苹果绵蚜对苹果等寄主的危害日益严重,发生面积不断扩大,而品种抗性是害虫治理的一种重要手段。【方法12007—2009年于山东莱阳地区系统调查了苹果绵蚜在不同寄主果园的发生动态规律,比较了不同寄主对苹果绵蚜的抗性差异。【结果】苹果绵蚜在红富士、乔纳金、新红星苹果园和西府海棠果园中1a有2个发生高峰,5月底到7月下旬是第1个高峰,也是全年发生的最高峰,9月初到10月底是全年发生的第2个高峰,而7月底到8月底是苹果绵蚜发生的低谷期。苹果绵蚜在红富士苹果上的发生数量显著高于在乔纳金、新红星苹果和西府海棠上的发生数量。在3a的调查时间内,苹果绵蚜在红富士、乔纳金、新红星苹果上每次平均发生量分别为153．2、31．6、30．3头·株^-1。越冬前调查表明,苹果绵蚜对红富士的为害率显著高于青香蕉、乔纳金、新红星和小国光,小国光的被害率以及虫落数量最低。【结论与意义】红富士是苹果绵蚜的感虫品种,而小国光、乔纳金和新红星相对抗虫。文中讨论了苹果绵蚜抗性品种的筛选方法,为掌握不同寄主对苹果绵蚜的抗性差异以及制定苹果绵蚜的抗性治理策略提供了依据。     

A main effects meta principal components analysis of netting effects on fruit: using apple as a model crop

To differentiate effects of netting and attribute them to crop, cultivar, planting density, climate, net type and colour, ca. 200 publications were scanned originally. Apple was chosen as a model crop due to the majority of reports, wide variation with many varieties and growing locations worldwide in the Northern and Southern hemisphere, but the results may be useful for other fruiting plants. After meeting strict selection criteria, a meta-analysis of 26 internationally published peer-reviewed articles was based on seven varieties and seventeen locations with a diverse range of climates. A novel Main Effects Meta Principal Components Analysis (ME Meta-PCA) was developed and provided unexpectedly uniform results: Location (climate), planting density and hail net (type and colour) had negligible impacts. Fruit (red) colour, most adversely affected by netting, correlated with TSS viz fruit sweetness, as often postulated in consumer studies, followed, to a smaller extent, by sugar/TSS, fruit firmness and acidity but small increase in fruit mass—i.e. maintenance of fruit quality under netting over all seven varieties (Braeburn, Gala, Elstar, Jonagold, Pinova and Fuji) examined and locations worldwide. While Jonagold and the early ripening Gala appeared suitable, unaffected and stable in the netting effects in the ME Meta-PCA, Pinova was the least suitable for cultivation under netting. Interestingly, late ripening cultivars (Braeburn and Cripps Pink) were both positively influenced by desired earlier ripening under netting. These effects on fruit quality are discussed with respect to shade adaptation under netting and countermeasures such as easy colouring mutants or reflective mulches.     

Physical limits of cell migration: Control by ECM space and nuclear deformation and tuning by proteolysis and traction force

Cell migration through 3D tissue depends on a physicochemical balance between cell deformability and physical tissue constraints. Migration rates are further governed by the capacity to degrade ECM by proteolytic enzymes, particularly matrix metalloproteinases (MMPs), and integrin- and actomyosin-mediated mechanocoupling. Yet, how these parameters cooperate when space is confined remains unclear. Using MMP-degradable collagen lattices or nondegradable substrates of varying porosity, we quantitatively identify the limits of cell migration by physical arrest. MMP-independent migration declined as linear function of pore size and with deformation of the nucleus, with arrest reached at 10% of the nuclear cross section (tumor cells, 7 µm²; T cells, 4 µm²; neutrophils, 2 µm²). Residual migration under space restriction strongly depended upon MMP-dependent ECM cleavage by enlarging matrix pore diameters, and integrin- and actomyosin-dependent force generation, which jointly propelled the nucleus. The limits of interstitial cell migration thus depend upon scaffold porosity and deformation of the nucleus, with pericellular collagenolysis and mechanocoupling as modulators.     

Morphological analysis of pore size and connectivity in a thick mixed‐culture biofilm

Morphological parameters are commonly used to predict transport and metabolic kinetics in biofilms. Yet, quantification of biofilm morphology remains challenging because of imaging technology limitations and lack of robust analytical approaches. We present a novel set of imaging and image analysis techniques to estimate internal porosity, pore size distributions, and pore network connectivity to a depth of 1 mm at a resolution of 10 µm in a biofilm exhibiting both heterotrophic and nitrifying activities. Optical coherence tomography (OCT) scans revealed an extensive pore network with diameters as large as 110 µm directly connected to the biofilm surface and surrounding fluid. Thin‐section fluorescence in situ hybridization microscopy revealed that ammonia‐oxidizing bacteria (AOB) distributed through the entire thickness of the biofilm. AOB were particularly concentrated in the biofilm around internal pores. Areal porosity values estimated from OCT scans were consistently lower than those estimated from multiphoton laser scanning microscopy, though the two imaging modalities showed a statistically significant correlation (r = 0.49, p < 0.0001). Estimates of areal porosity were moderately sensitive to gray‐level threshold selection, though several automated thresholding algorithms yielded similar values to those obtained by manually thresholding performed by a panel of environmental engineering researchers (±25% relative error). These findings advance our ability to quantitatively describe the geometry of biofilm internal pore networks at length scales relevant to engineered biofilm reactors and suggest that internal pore structures provide crucial habitat for nitrifier growth.     

Biochemical responses in leaves of two apple tree cultivars subjected to progressing drought

The influence of water deprivation on potted apple trees (Malus domestica Borkh.) was investigated. Biochemical responses including ascorbic acid, glutathione (GSH), tocopherols, chlorophylls, carotenoids, free amino acids, and soluble carbohydrates were measured in leaves of diploid ‘Elstar’ and triploid ‘Jonagold Wilmuta’ subjected to progressive drought. Leaf water potential was chosen to be the primary indicator of water stress in tested plants. Time courses of measured biochemical parameters showed that mild drought did not significantly affect the chosen stress indicators. Moderate drought increased the concentrations of ascorbic acid, total GSH, β-carotene, zeaxanthin and -tocopherol, indicating the adaptation to oxidative stress in apple trees. Moderate drought also increased concentration of soluble carbohydrates, mostly due to increased sorbitol concentration. Severe drought negatively affected vitality of apple trees, and caused a decrease in sorbitol concentration. Severe drought also caused decreases in ascorbic acid, total GSH, β-carotene, -tocopherol and chlorophyll concentrations, which, together with the increase in oxidised GSH concentration, indicated severe damage due to oxidative stress. Severe drought increased free amino acid concentration, which was probably the result of increased proteolysis. Zeaxanthin concentration remained high even in leaves of apple trees subjected to severe drought stress. The results were similar for both tested apple cultivars.     

Simple equations to estimate light interception by isolated trees from canopy structure features: assessment with three-dimensional digitized apple trees

* Simple models of light interception are useful to identify the key structural parameters involved in light capture. We developed such models for isolated trees and tested them with virtual experiments. Light interception was decomposed into the projection of the crown envelope and the crown porosity. The latter was related to tree structure parameters. * Virtual experiments were conducted with three-dimensional (3-D) digitized apple trees grown in Lebanon and Switzerland, with different cultivars and training. The digitized trees allowed actual values of canopy structure (total leaf area, crown volume, foliage inclination angle, variance of leaf area density) and light interception properties (projected leaf area, silhouette to total area ratio, porosity, dispersion parameters) to be computed, and relationships between structure and interception variables to be derived. * The projected envelope area was related to crown volume with a power function of exponent 2/3. Crown porosity was a negative exponential function of mean optical density, that is, the ratio between total leaf area and the projected envelope area. The leaf dispersion parameter was a negative linear function of the relative variance of leaf area density in the crown volume. * The resulting models were expressed as two single equations. After calibration, model outputs were very close to values computed from the 3-D digitized databases.     

Characterization of three new S-alleles and development of an S-allele-specific PCR system for rapidly identifying the S-genotype in apple cultivars

Apple (Malus domestica Borkh), a member of the Rosaceae, shows gametophytic self-incompatibility (GSI) controlled by polymorphic S-alleles. Identifying the S-genotypes of apple cultivars can be applied on correct assignment of apple cultivars to cross-compatibility groups, which is important for the efficient production of apple fruit. This study characterized three new S-alleles (designated S ₄₄ , S ₄₅ , and S ₄₆ ) in apple and developed an efficient analysis method that can be used to characterize S-genotypes by utilizing allele-specific polymerase chain reaction rapidly. Nineteen allele-specific primers were selectively designed to identify different alleles. Using this method, S-genotypes of 157 apple cultivars were identified.     

苹果优质生产的景适气象因子和气候区划

通过对我国不同生态气候区富士、乔纳金、新红星果实品质的调查分析,应用多元统计分析、线性规划和计算机技术,提出了影响不同苹果品质因素的主要气象因子及最适气象因子的取值和优化方案．系统聚类分析表明,黄土高原和甘肃陇东是我国富士、乔纳金和新红星的最优栽培气候区,渤海湾地区是富士、乔纳金的优质栽培气候区,西南高地局部小气候是新红星的最适生态区．同时,阐明了不同气候区苹果优质生产的有利条件和限制因子。     

Three-dimensional structure of the surface protein layer (MW layer) of Bacillus brevis 47

The three-dimensional (3D) structure of one surface protein layer from Bacillus brevis 47, the middle wall (MW) layer, has been reconstructed from tilted-view electron micrographs after correlation averaging to a resolution of 2 nm. The MW layer has p6 symmetry with a center-to-center spacing of 18.3 nm and a minimum thickness of 5.5 nm. The reconstruction reveals a distinct domain structure: the heavier domain of six monomers jointly forms a massive core centered at the sixfold symmetry axis, and lighter domains interconnect adjacent unit cells. In addition, the larger domains collectively form a pore by making contact with each other towards the inner surface, while the smaller domains establish a second connectivity towards the outer surface of the S layer. The MW layer of B. brevis resembles the S layer of Acetogenium kivui in various aspects: they have very similar lattice parameters and highly reminiscent 3D structures; the pores penetrate through the whole core and appear to determine the porosity of the S layers.     

Agrobacterium-mediated transformation of apple (Malus x domestica Borkh.): an assessment of factors affecting regeneration of transgenic plants

We have previously developed a protocol for efficient gene transfer and regeneration of transgenic calli following cocultivation of apple (cv. Jonagold) explants with Agrobacterium tumefaciens (De Bondt et al. 1994, Plant Cell Reports 13: 587–593). Now we report on the optimization of postcultivation conditions for efficient and reproducible regeneration of transgenic shoots from the apple cultivar Jonagold. Factors which were found to be essential for efficient shoot regeneration were the use of gelrite as a gelling agent and the use of the cytokinin-mimicing thidiazuron in the selective postcultivation medium. Improved transformation efficiencies were obtained by combining the hormones thidiazuron and zeatin and by using leaf explants from in vitro grown shoots not older than 4 weeks after multiplication. Attempts to use phosphinothricin acetyl transferase as a selectable marker were not successful. Using selection on kanamycin under optimal postcultivation conditions, about 2% of the leaf explants developed transgenic shoots or shoot clusters. The presence and expression of the transferred genes was verified by -glucuronidase assays and Southern analysis. The transformation procedure has also been succesfully applied to several other apple cultivars.Abbreviations BAP benzylaminopurine - CTAB hexadecyltrimethylammoniumbromide - Na₂EDTA ethylenediamine-tetra-acetate ferric-sodium salt - FeNaEDTA ethylenediamine-tetra-acetate ferric-sodium salt - GA₃ gibberellic acid 3 - GusA -glucuronidase - gusA -glucuronidase gene of Escherichia coli - IAA indole acetic acid - IBA indole butyric acid - 2iP N6-2-isopentenyl adenine - NAA naphthalene acetic acid - nptII neomycinphosphotransferase II gene - bar phosphinothricin acetyl transferase gene - PCR polymerase chain reaction - PPT phosphinothricin - STS silver thiosulphate - T-DNA transferred DNA - TDZ thidiazuron - X-Gluc 5-bromo-4-chloro-3-indolyl -D-glucuronide - Zea trans-Zeatin     

苹果叶片离体培养研究

用帝国、自由、富士、嘎拉、金冠、乔纳金、Ｊｏｎａｓｔｙ、红乔纳金、解放、皇家嘎拉１０个苹果品种的试管苗、切取叶块作离体培养试验。枝条的再生程序是：０．０５ｃｍ＾２大小的叶块,在再生培养基上,黑暗下培养两周时间,首先从叶切块基部的中脉处形成愈伤组织,然后是侧脉和其它部分陆续形成愈伤组织;经两击黑暗处理后,再在光照下培养约两周时间,就能从愈伤组织上开始生出枝条。再生能力的大小受品种基因型所左右,Ｊｏｎ     

Monochromatic synchrotron radiation muCT reveals disuse-mediated canal network rarefaction in cortical bone of growing rat tibiae.

The purpose of this study was to demonstrate the ability of computed microtomography based on monochromatic synchrotron radiation (SRmuCT) in microstructural analysis of cortical bone. Tibial diaphyses of growing rats (14 wk, n = 8) undergoing unilateral sciatic neurectomy 8 wk before study were imaged with spatial volume resolution of 5.83 x 5.83 x 5.83 microm3 by SRmuCT (20 keV) at the synchrotron radiation facility (SPring-8). Reconstructed image data were translated into local mineral densities by using a calibrated linear relationship between linear absorption coefficients and concentrations of homogeneous K2HPO4 solution. Pure bone three-dimensional images, produced by simple thresholding at a bone mineral density of 0.82 g/cm3, were analyzed for macro- and microscopic structural properties. In neurectomized hindlimbs, cortical canal network rarefaction as well as bone atrophy were found. The former was characterized by 30% smaller porosity, 11% smaller canal density in transverse section, and 38% smaller canal connectivity density than those in contralateral bone. On the other hand, no difference was found in bone mineral density between neurectomized and intact hindlimbs (1.37 vs. 1.36 g/cm3). In conclusion, SRmuCT is a promising method for the three-dimensional analysis of cortical microstructure and the degree of mineralization in small animals.     

A cellular solid model of the lamina cribrosa: mechanical dependence on morphology

The biomechanics of the optic nerve head (ONH) may underlie many of the potential mechanisms that initiate the characteristic vision loss associated with primary open angle glaucoma. Therefore, it is important to characterize the physiological levels of stress and strain in the ONH and how they may change in relation to material properties, geometry, and microstructure of the tissue. An idealized, analytical microstructural model of the ONH load bearing tissues was developed based on an octagonal cellular solid that matched the porosity and pore area of morphological data from the lamina cribrosa (LC). A complex variable method for plane stress was applied to relate the geometrically dependent macroscale loads in the sclera to the microstructure of the LC, and the effect of different geometric parameters, including scleral canal eccentricity and laminar and scleral thickness, was examined. The transmission of macroscale load in the LC to the laminar microstructure resulted in stress amplifications between 2.8 and 24.5xIOP. The most important determinants of the LC strain were those properties pertaining to the sclera and included Young's modulus, thickness, and scleral canal eccentricity. Much larger strains were developed perpendicular to the major axis of an elliptical canal than in a circular canal. Average strain levels as high as 5% were obtained for an increase in IOP from 15 to 50 mm Hg.     

Non destructive analysis of the wax layer of apple (Malus domestica Borkh.) by means of confocal laser scanning microscopy

Confocal laser scanning microscopy (CLSM) was used to non-destructively analyse the changes in the structure and thickness of the cuticle during storage of apples (Malus domestica Borkh.). Interpretation of the confocal images was performed by comparison with scanning electron microscopy and environmental scanning electron microscopy images. The natural reflectance of the wax and the auto-fluorescence of the underlying cells made it possible with CLSM to distinguish the wax from the underlying layers without any pretreatment of the fruit. The thickness of the consecutive layers (wax, cutin, cells) could be estimated from measurements of the reflection and fluorescence intensities as a function of the number of pixels. The mean wax-layer thickness measured in this way amounted to 2.58 microm, 3.41 microm or 4.14 microm for the cultivars Jonagold, Jonagored and Elstar, respectively. Changes in the wax structure and cells of the same important Belgian apple cultivars as mentioned above were monitored during nine months of storage in ultra low oxygen and after exposure to ambient conditions. The changes in the wax ultrastructure and cell morphology are likely related to water losses and specific protection of the apple cultivars against water losses during storage and shelf life.