An efficient genetic transformation system mediated by Rhizobium rhizogenes in fruit trees based on the transgenic hairy root to shoot conversion.

Genetic transformation is a critical tool for gene editing and genetic improvement of plants. Although many model plants and crops can be genetically manipulated, genetic transformation systems for fruit trees are either lacking or perform poorly. We used Rhizobium rhizogenes to transfer the target gene into the hairy roots of Malus domestica and Actinidia chinensis. Transgenic roots were generated within 3 weeks, with a transgenic efficiency of 78.8%. Root to shoot conversion of transgenic hairy roots was achieved within 11 weeks, with a regeneration efficiency of 3.3%. Finally, the regulatory genes involved in stem cell activity were used to improve shoot regeneration efficiency. MdWOX5 exhibited the most significant effects, as it led to an improved regeneration efficiency of 20.6% and a reduced regeneration time of 9 weeks. Phenotypes of the overexpression of RUBY system mediated red roots and overexpression of MdRGF5 mediated longer root hairs were observed within 3 weeks, suggesting that the method can be used to quickly screen genes that influence root phenotype scores through root performance, such as root colour, root hair, and lateral root. Obtaining whole plants of the RUBY system and MdRGF5 overexpression lines highlights the convenience of this technology for studying gene functions in whole plants. Overall, we developed an optimized method to improve the transformation efficiency and stability of transformants in fruit trees.

Diversity of Lasiodiplodia Species Associated with Canker and Dieback in Fruit Trees in the Henan and Shandong Provinces of China.

Lasiodiplodia is a widely distributed genus that is associated with a variety of diseases in many plant species, especially fruit trees. In this study, a disease survey of fruit trees growing in 12 orchards located in the Henan and Shandong provinces of China was conducted between 2020 and 2022. The symptoms observed included stem canker, branch dieback, and gummosis. Phylogenetic analyses of internal transcribed spacer, tub2, tef1, and rpb2 sequence data combined with morphological characteristics revealed that the 19 isolates collected during the survey belonged to five documented Lasiodiplodia species, namely, Lasiodiplodia citricola, L. chiangraiensis, L. huangyanensis, L. pseudotheobromae, and L. theobromae, and two previously undescribed species, L. xinyangensis and L. ziziphi. In addition, the survey identified three novel host-pathogen interactions: L. chiangraiensis on loquat, L. citricola on apple, and L. huangyanensis on grapevine. Furthermore, the detailed phylogenic analysis indicated that four previously described Lasiodiplodia species were genetically very closely related that they would be better classified as synonyms rather than distinct species, so L. paraphysoides and L. nanpingensis should be considered synonyms of L. citricola, L. fujianensis should be a synonym of L. iraniensis, and L. henanica should be a synonym of L. huangyanensis. Pathogenicity tests confirmed that representative isolates of the two novel species and three new host-pathogen interactions identified in the current study were pathogenic to their original hosts, thereby fulfilling Koch's postulates. Similarly, all of the isolates were found to be pathogenic on four alternative hosts, although a high degree of variation in virulence was observed.

Advancements in Reference Gene Selection for Fruit Trees: A Comprehensive Review.

Real-time quantitative polymerase chain reaction (qRT-PCR) has been widely used in gene expression analyses due to its advantages of sensitivity, accuracy and high throughput. The stability of internal reference genes has progressively emerged as a major factor affecting the precision of qRT-PCR results. However, the stability of the expression of the reference genes needs to be determined further in different cells or organs, physiological and experimental conditions. Methods for evaluating these candidate internal reference genes have also evolved from simple single software evaluation to more reliable and accurate internal reference gene evaluation by combining different software tools in a comprehensive analysis. This study intends to provide a definitive reference for upcoming research that will be conducted on fruit trees. The primary focus of this review is to summarize the research progress in recent years regarding the selection and stability analysis of candidate reference genes for different fruit trees.

Assessing temperature-based adaptation limits to climate change of temperate perennial fruit crops.

Temperate perennial fruit and nut trees play varying roles in world food diversity-providing edible oils and micronutrient, energy, and protein dense foods. In addition, perennials reuse significant amounts of biomass each year providing a unique resilience. But they also have a unique sensitivity to seasonal temperatures, requiring a period of dormancy for successful growing season production. This paper takes a global view of five temperate tree fruit crops-apples, cherries, almonds, olives, and grapes-and assesses the effects of future temperature changes on thermal suitability. It uses climate data from five earth system models for two CMIP6 climate scenarios and temperature-related indices of stress to indicate potential future areas where crops cannot be grown and highlight potential new suitable regions. The loss of currently suitable areas and new additions in new locations varies by scenario. In the southern hemisphere (SH), end-century (2081-2100) suitable areas under the SSP 5-8.5 scenario decline by more than 40% compared to a recent historical period (1991-2010). In the northern hemisphere (NH) suitability increases by 20% to almost 60%. With SSP1-2.6, however, the changes are much smaller with SH area declining by about 25% and NH increasing by about 10%. The results suggest substantial restructuring of global production for these crops. Essentially, climate change shifts temperature-suitable locations toward higher latitudes. In the SH, most of the historically suitable areas were already at the southern end of the landmass limiting opportunities for adaptation. If breeding efforts can bring chilling requirements for the major cultivars closer to that currently seen in some cultivars, suitable areas at the end of the century are greater, but higher summer temperatures offset the extent. The high value of fruit crops provides adaptation opportunities such as cultivar selection, canopy cooling using sprinklers, shade netting, and precision irrigation.

Moniliella zaluziensis sp. nov., a black yeast related to fruit trees of the Rosaceae family.

Our previous studies focused on the diversity of yeasts related to the aboveground parts of fruit trees, as well as the soil adjacent to these trees, located in the south-west of Slovakia. During these studies, we isolated two Moniliella strains: CCY 11-1-1T from the blossoms of a peach tree (Prunus persica) and CCY 11-1-2 from the soil adjacent to a pear tree (Pyrus communis), both found in the Malé Záluzie locality. The sequences of the D1/D2 domain of the large subunit (LSU) rRNA gene and the internal transcribed spacer (ITS) region were identical in both strains. They differed only by two nucleotide substitutions in the segment of the gene of translation elongation factor one alpha (TEF-1α). Phylogenetic analysis demonstrated that strains CCY 11-1-1T and CCY 11-1-2 formed a separate species in the clade of insect-associated members of the genus Moniliella. The strains differed from the closest species Moniliella oedocephalis by 23 nucleotide substitutions and 12 indels in the D1/D2 domain, more than 6 % in the ITS region (31 nt and 25 indels) and by 44 nt in the segment of TEF-1α. Therefore, these two strains are recognized as belonging to a novel species, for which we have proposed the name Moniliella zaluziensis sp. nov., derived from the locality of their origin, Malé Záluzie. The type strain of M. zaluziensis sp. nov. is CCY 11-1-1T.

Lasiodiplodia regiae sp. nov.: A New Species Causing Canker and Dieback of Fruit Trees in China.

Canker and dieback are serious fungal diseases of woody plants that can cause huge economic losses to orchards. The purpose of this study was to classify and assess the pathogenicity of fungal species associated with canker and dieback on fruit trees growing in Henan Province, China. In total, 150 isolates of Botryosphaeriaceae were obtained from six different fruit trees exhibiting typical symptoms of stem canker, branch dieback, and gummosis. Morphological examinations and phylogenetic analysis of ITS, tef1, tub2, and rpb2 revealed two Botryosphaeriaceae species, which are Botryosphaeria dothidea and a novel species, Lasiodiplodia regiae, respectively. Using Koch's postulates, we confirmed that the different isolates of L. regiae can cause disease in their original hosts. The pathogenicity tests showed that L. regiae can cause canker, dieback, and gummosis symptoms in four different hosts, indicating a relatively wider host range. Moreover, 10 L. regiae isolates exhibited similar symptoms but different levels of virulence on shoots of peach trees under field conditions. This study demonstrated that L. regiae was a new causal agent of canker and dieback of six fruit tree species, which could be a serious risk to the orchard industry in China. Furthermore, the findings provide a foundation for further epidemiological studies and the development of management strategies.

A New Small-Size Camera with Built-In Specific-Wavelength LED Lighting for Evaluating Chlorophyll Status of Fruit Trees.

To produce high-quality crops, not only excellent cultivation techniques but also accurate nutrient management techniques are important. In recent years, many nondestructive tools such as the chlorophyll meter "SPAD" and the leaf nitrogen meter "Agri Expert CCN" have been developed for measuring crop leaf chlorophyll and nitrogen contents. However, such devices are still relatively expensive for individual farmers. In this research, we developed a low-cost and small-size camera with built-in LEDs of several specific wavelengths for evaluating the nutrient status of fruit trees. A total of 2 camera prototypes were developed by integrating 3 independent LEDs of specific wavelengths (Camera 1: 950 nm, 660 nm and 560 nm; Camera 2: 950 nm, 660 nm and 727 nm) into the device. In addition, a simple software tool was developed to enable the camera to capture leaf images under different LED lighting conditions. Using the prototypes, we acquired images of apple leaves and investigated the possibility of using the images to estimate the leaf nutrient status indicator SPAD (chlorophyll) and CCN (nitrogen) values obtained using the above-mentioned standard tools. The results indicate that the Camera 1 prototype is superior to the Camera 2 prototype and can potentially be applied to the evaluation of nutrient status in apple leaves.

Antioxidants in Fruit Fractions of Mediterranean Ancient Pear Cultivars.

BACKGROUND: The genetic diversity of Sardinian pear germplasm has received limited attention regarding its chemical composition. Understanding this composition can aid in the setting up of resilient, extensive groves that offer multiple products and ecosystem services. This research aimed at investigating the antioxidant properties and phenolic compounds of ancient pear cultivars grown extensively in Sardinia (Italy); Methods: the cultivars Buttiru, Camusina, Spadona, and Coscia (as a reference) were compared. Fruit samples were manually peeled and cut. Their flesh, peel, core, and peduncle were frozen separately, lyophilized, and milled before being analysed; Results: The content of total phenolics (TotP), total flavonoids (TotF), condensed tannins (CT), and antioxidant capacity in each fruit part varied significantly among the cultivars. The TotP content was high in the peduncle (42.2-58.8 g GAE kg-1 DM) and low in flesh (6.4-17.7 g GAE kg-1 DM); Conclusions: the highest values of antioxidant capacity, TotP, NTP, TotF, and CT were found in the flesh of the cultivar Buttiru and in the peel of the cultivar Camusina. Chlorogenic acid was the major individual phenolic compound in peel, flesh and core, whereas arbutin was mostly present in the peduncle. Results can contribute to revise target exploitations of underutilized ancient pear cultivars.

Ecosystem functions of fruit woody species in an urban environment.

The objective of this work was to investigate the potential ecosystem services of 16 fruit trees to plan and manage more efficiently "Urban Forest," increasing also the resilience of cities to climate change. We evaluated the potential capacity of PM10 absorption, the storage of CO2 from the atmosphere, and the cooling of the environment through shading by the crown and through evapotranspiration. We observed that some species, such as Morus nigra, Juglans regia, Pyrus communis, and Cydonia oblonga, are able to store a higher quantity of CO2 than others over a period of 50 years, respectively, of 2.40 tons, 2.33 tons, 1.51 tons, and 0.96 tons. Ficus carica, Juglans regia, and Morus nigra were relevant for PM10 absorption, since they were able to absorb, referring to the year 2019, 146.4 gr/tree, 195.6 gr/tree, and 143.1 gr/tree, respectively. Results showed that these ecosystem functions depend principally on the morphological characteristics of the individuals: their height, DBH, expansion of their crowns, and characteristics of the foliage system.

Holocene land and sea-trade routes explain complex patterns of pre-Columbian crop dispersion.

Pre-Columbian crop movement remains poorly understood, hampering a good interpretation of the domestication and diversification of Neotropical crops. To provide new insights into pre-Columbian crop movement, we applied spatial genetics to identify and compare dispersal routes of three American crops between Mesoamerica and the Andes, two important centres of pre-Columbian crop and cultural diversity. Our analysis included georeferenced simple-sequence repeats (SSR) marker datasets of 1852 genotypes of cherimoya (Annona cherimola Mill.), a perennial fruit crop that became underutilised in the Americas after the European conquest, 770 genotypes of maize (Zea mays L.) and 476 genotypes of common bean (Phaseolus vulgaris L.). Our findings show that humans brought cherimoya from Mesoamerica to present Peru through long-distance sea-trade routes across the Pacific Ocean at least 4700 yr bp, after more ancient dispersion of maize and other crops through the Mesoamerican isthmus over land and near-coastal waters. To our knowledge, this is the first evidence of pre-Columbian crop movement between Mesoamerica and the Andes across the Pacific Ocean providing new insights into pre-Columbian crop exchange in the Americas. We propose that cherimoya represents a wider group of perennial fruit crops dispersed by humans via sea-trade routes between Mesoamerica and the Andes across the Pacific Ocean.

Pesticide selectivity to the parasitoid Trichogramma pretiosum: A pattern 10-year database and its implications for Integrated Pest Management.

Trichogramma pretiosum is one of the main egg parasitoids used in the control of lepidopteran pests in Brazil. This natural enemy can be negatively affected by the use of insecticides, herbicides, and fungicides. The present work used a systematic review and meta-analysis to group information from multiple studies on the selectivity of pesticides (279 commercial products) in rice, corn, soybean, apple and peach crops for immature stages (egg-larva, pre-pupa, and pupa) and adult parasitoids. The selected studies used the International Organization for Biological and Integrated Control (IOBC) methodology with the same adaptations for T. pretiosum. The meta-analysis found that corn crops had the highest frequency of tests (2 0 7). The most frequently tested active ingredients (a.i.) were glyphosate, glyphosate isopropylamine salt, and sulfur at frequencies of 41, 32 and 24 tests, respectively. The pesticides registered for rice crops showed the greatest sublethal effects on T. pretiosum, with an approximately 47% reduction in parasitism (RP) or emergence (RE). The adult stage of the parasitoid showed greater sensitivity to the tested pesticides (65% RP), in comparison to the immature stages. In general, insecticides showed superior toxicity for all development stages of T. pretiosum, compared to herbicides and fungicides, regardless of the recommended dosage for the crop. The present study aggregates information related to selectivity for the four life stages of T. pretiosum, contributing significantly to the integration of biological control and chemical control in rice, corn, soybean, apple and peach crops in Brazil.

Biogenic volatile organic compound emissions from leaves and fruits of apple and peach trees during fruit development.

Biogenic volatile organic compounds (BVOCs) are widely involved in a variety of atmospheric chemical processes due to their high reactivity and species diversity. To date, however, research on BVOCs in agroecosystems, particularly fruit trees, remains scarce despite their large cultivation area and economic interest. BVOC emissions from different organs (leaf or fruit) of apple and peach trees were investigated throughout the stages of fruit development (FS, fruit swelling; FC, fruit coloration; FM, fruit maturity; and FP, fruit postharvest) using a proton-transfer-reaction mass spectrometer. Results indicated that methanol was the most abundant compound emitted by the leaf (apple tree leaf 492.5 ± 47.9 ng/(g·hr), peach tree leaf 938.8 ±  154.5 ng/(g·hr)), followed by acetic acid and green leaf volatiles. Beside the above three compounds, acetaldehyde had an important contribution to the emissions from the fruit. Overall, the total BVOCs (sum of eight compounds studied in this paper) emitted by both leaf and fruit gradually decreased along the fruit development, although the effect was significant only for the leaf. The leaf (2020.8 ±  258.8 ng/(g·hr)) was a stronger BVOC emitter than the fruit (146.0 ± 45.7 ng/(g·hr)) (P = 0.006), and there were no significant differences in total BVOC emission rates between apple and peach trees. These findings contribute to our understanding on BVOC emissions from different plant organs and provide important insights into the variation of BVOC emissions across different fruit developmental stages.

Identification of Pseudomonas Isolates Associated With Bacterial Canker of Stone Fruit Trees in the Western Cape, South Africa.

Bacterial canker is a common bacterial disease of stone fruit trees. The causal agents responsible for the disease include several pathovars in Pseudomonas syringae sensu lato and newly described Pseudomonas species. Pseudomonad strains were isolated from symptomatic stone fruit trees, namely apricot, peach, and plum trees cultivated in spatially separated orchards in the Western Cape. A polyphasic approach was used to identify and characterize these strains. Using a multilocus sequence typing approach of four housekeeping loci, namely cts, gapA, gyrB, and rpoD, the pseudomonad strains were delineated into two phylogenetic groups within P. syringae sensu lato: P. syringae sensu stricto and Pseudomonas viridiflava. These results were further supported by LOPAT diagnostic assays and analysis of clades in the rep-PCR dendrogram. The pseudomonad strains were pathogenic on both apricot and plum seedlings, indicative of a lack of host specificity between Pseudomonas strains infecting Prunus spp. This is a first report of P. viridiflava isolated from plum trees showing symptoms of bacterial canker. P. viridiflava is considered to be an opportunistic pathogen that causes foliar diseases of vegetable crops, fruit trees, and aromatic herbs, and thus the isolation of pathogenic P. viridiflava from twigs of plum trees showing symptoms of bacterial canker suggests that this bacterial species is a potentially emerging stem canker pathogen of stone fruit trees in South Africa.

Diversity of yeasts in the soil adjacent to fruit trees of the Rosaceae family.

Yeasts are common constituents of different types of soil. Their diversity depends on the season, the type and depth of the soil, the plant species, and the locality. In this study, diversity of yeasts isolated from the soil adjacent to five fruit trees (apple, appricot, peach, pear, and plum) in two localities (in Slovakia) in four sampling periods was examined. Our results demonstrated differences in the species richness and evenness among the yeast populations, which inhabited the soil beneath individual fruit tree species in both localities. Altogether, 32 ascomycetous and 27 basidiomycetous yeast species were discovered. The highest species richness was found in the soil adjacent to the apricot trees. Galactomyces candidum, Metschnikowia pulcherrima, Hanseniaspora uvarum, Schwanniomyces capriottii, and Tausonia pullulans, as well as the genus Apiotrichum, were present in soil samples in all samplings. Two species of the genus Holtermanniella (H. festucosa and H. takashimae) were exclusively isolated during Sampling IV in April. Cyberlindnera spp., Clavispora reshetovae, S. capriottii, and Trichosporon asahii were found only in one of two localities. Ascomycetous yeasts were present more frequently than their basidiomycetous counterparts in the three samplings (one in June and two in October); they formed from 65.6% to 70.8% of the total yeast population, whereas basidiomycetous yeasts prevailed in the April sampling (61.2%).

Bud sprouting and floral induction and expression of FT in loquat [Eriobotrya japonica (Thunb.) Lindl.].

MAIN CONCLUSION: EjFT1 and EjFT2 genes were isolated and sequenced from leaves of loquat. EjFT1 is involved in bud sprouting and leaf development, and EjFT2 in floral bud induction. Loquat [Eriobotrya japonica (Thunb.) Lindl.] is an evergreen species belonging to the family Rosaceae, such as apple and pear, whose reproductive development, in contrast with these species, is a continuous process that is not interrupted by winter dormancy. Thus, the study of the mechanism of flowering in loquat has the potential to uncover the environmental and genetic networks that trigger flowering more accurately, contributing for a better understanding of the Rosaceae floral process. As a first step toward understanding the molecular mechanisms controlling flowering, extensive defoliation and defruiting assays, together with molecular studies of the key FLOWERING LOCUS T (FT) gene, were carried out. FT exhibited two peaks of expression in leaves, the first one in early to mid-May, the second one in mid-June. Two FT genes, EjFT1 and EjFT2, were isolated and sequenced and studied their expression. Expression of EjFT1 and EjFT2 peaks in mid-May, at bud sprouting. EjFT2 expression peaks again in mid-June, coinciding with the floral bud inductive period. Thus, when all leaves of the tree were continuously removed from early to late May vegetative apex differentiated into panicle, but when defoliation was performed from early to late June apex did not differentiate. On the other hand, fruit removal advanced EjFT1 expression in old leaves and the sooner the fruit detached, the sooner the bud sprouted. Accordingly, results strongly suggest that EjFT1 might be related to bud sprouting and leaf development, while EjFT2 might be involved in floral bud induction. An integrative model for FT functions in loquat is discussed.

Inverse PCR and Quantitative PCR as Alternative Methods to Southern Blotting Analysis to Assess Transgene Copy Number and Characterize the Integration Site in Transgenic Woody Plants.

One of the major unanswered questions with respect to the commercial use of genetic transformation in woody plants is the stability of the transgene expression over several decades within the same individual. Gene expression is strongly affected by the copy number which has been integrated into the plant genome and by the local DNA features close to the integration sites. Because woody plants cannot be subjected to selfing or backcrossing to modify the transgenic allelic structure without affecting the valuable traits of the cultivar, molecular characterization of the transformation event is therefore crucial. After assessing the transgene copy number of a set of apple transgenic clones with Southern blotting, we describe two alternative methods: the first is based on inverse PCR (i-PCR) and the second on the quantitative PCR (q-PCR). The methods produced comparable results with the exception of the data regarding a high copy number clone, but while the q-PCR-based system is rapid and easily adaptable to high throughput systems, the i-PCR-based method can provide information regarding the transformation event and the characteristics of the sequences flanking the transgenic construct.

Specific PCR and real-time PCR assays for detection and quantitation of 'Candidatus Phytoplasma phoenicium'.

Almond witches' broom (AlmWB) is a fast-spreading lethal disease of almond, peach and nectarine associated with 'Candidatus Phytoplasma phoenicium'. The development of PCR and quantitative real-time PCR (qPCR) assays for the sensitive and specific detection of the phytoplasma is of prime importance for early detection of 'Ca. P. phoenicium' and for epidemiological studies. The developed qPCR assay herein uses a TaqMan(®) probe labeled with Black Hole Quencher Plus. The specificity of the PCR and that of the qPCR detection protocols were tested on 17 phytoplasma isolates belonging to 11 phytoplasma 16S rRNA groups, on samples of almond, peach, nectarine, native plants and insects infected or uninfected with the phytoplasma. The developed assays showed high specificity against 'Ca. P. phoenicium' and no cross-reactivity against any other phytoplasma, plant or insect tested. The sensitivity of the developed PCR and qPCR assays was similar to the conventional nested PCR protocol using universal primers. The qPCR assay was further validated by quantitating AlmWB phytoplasma in different hosts, plant parts and potential insect vectors. The highest titers of 'Ca. P. phoenicium' were detected in the phloem tissues of stems and roots of almond and nectarine trees, where they averaged from 10(5) to 10(6) genomic units per nanogram of host DNA (GU/ng of DNA). The newly developed PCR and qPCR protocols are reliable, specific and sensitive methods that are easily applicable to high-throughput diagnosis of AlmWB in plants and insects and can be used for surveys of potential vectors and alternative hosts.

Host suitability analysis of the bark beetle Scolytus amygdali (Coleoptera: Curculionidae: Scolytinae).

Scolytus amygdali is a polyphagous insect pest that feeds on fruit trees and forest trees. Our study assessed the host preference and reproductive potential of S. amygdali on four tree species: almond (Prunus dulcis), apricot (Prunus armeniaca), peach (Prunus persica), and plum (Prunus domestica). Females of S. amygdali produced maternal galleries that were longer on peach than the other three trees, and female fecundity was highest on peach. Females with longer maternal galleries produced more eggs, indicating a positive correlation between maternal gallery length and female fertility. The under-bark development time of S. amygdali is significantly shorter on plum (45 days) and almond (56 days) than on apricot (65 days) and peach (64 days). Despite this longer development time on peach, our results still suggest that, of the four types of tree tested, peach is the most preferred host for S. amygdali.

Heavy metals in navel orange orchards of Xinfeng County and their transfer from soils to navel oranges.

This study investigated heavy metal concentrations in soils and navel oranges of Xinfeng County, a well-known navel orange producing area of China. The results showed that the average concentrations of lead (Pb), cadmium (Cd), chromium (Cr), arsenic (As) and mercury (Hg) in orchard soils all increased compared to the regional background values, especially for Cd, which increased by 422%. When compared to the Chinese Environmental Quality Standard for soil (GB15618-1995), Pb, Cr and Hg concentrations in all orchard soil samples were below the limit standards, but Cd concentrations in 24 soil samples (21%) and As concentrations in 8 soil samples (7%) exceeded the limit standards. However, concentrations of all heavy metals in navel orange pulps were within the National Food Safety Standard of China (GB 2762-2012). Dietary risk assessment also showed that the exposure to these five heavy metals by consumption of navel oranges could hardly pose adverse health effects on adults and children. Since the range and degree of soil Cd pollution was widest and the most severe of all, Cd was taken as an example to reveal the transfer characteristics of heavy metals in soil-navel orange system. Cd concentrations in different organs of navel orange trees decreased in the following order: root>leaf>peel>pulp. That navel oranges planted in the Cd contaminated soils were within the national food safety standard was mainly due to the low transfer factor for Cd from soil to pulp (TFpulp). Further studies showed that TFpulp was significantly negatively correlated with soil pH, organic carbon (OC) and cation exchange capacity (CEC). Based on these soil properties, a prediction equation for TFpulp was established, which indicated that the risk for Cd concentration of navel orange pulp exceeding the national food limit is generally low, when soil Cd concentration is below 7.30 mg/kg. If appropriate actions are taken to increase soil pH, OC and CEC, Cd concentrations in navel orange pulps could be further reduced.

Orchards for edible cities: cadmium and lead content in nuts, berries, pome and stone fruits harvested within the inner city neighbourhoods in Berlin, Germany.

Today's urban gardening focuses mainly on vegetable production and rarely includes fruit trees. Health effects of consuming urban crops are questioned due to high local pollution loads. Here, we determined cadmium and lead content in the edible parts of nuts, berries, pome, and stone fruits harvested from fruit trees and shrubs within inner city neighbourhoods of Berlin, Germany. We analysed how local settings at sampling sites shaped the trace metal content. We revealed significant differences in trace metal content depending on species, fruit type, local traffic, and parameters related to barriers between the sampling site and neighbouring roads. Higher overall traffic burden and proximity to roads increased whereas buildings or vegetation as barriers reduced trace metal content in the edible biomass. We demonstrate, that the consumption of non-vegetable fruits growing in inner city sites in Berlin does not pose a risk on human health as long as the fruits are thoroughly washed and it is provided that site pollutions and impacts are considered in garden concepts and guidelines.