Both native and invasive bark beetles threaten exotic conifers within the spa towns in the Czech part of “The Great Spas of Europe”

Exotic coniferous trees in forests adjacent to spa towns and in parks within spa towns are increasingly being attacked by outbreak populations of native bark beetles in western Bohemia (Central Europe). In the 12 localities in western Czech Republic the current study, we detected a total of 19 native bark beetle species infesting more than 10 % of exotic tree species in the genera Abies, Picea, Pinus, and Pseudotsuga in 1 year. Several exotic tree species were identified as new hosts for native European bark beetles. We also identified three non-native bark beetles, including Phloeosinus aubei, a species that transmits the pathogens that cause cypress canker disease.The numbers of infested trees in the localities were not correlated with the distance from surrounding bark beetle outbreak sites in commercial forests, because all forests adjacent to spas and all forests in spa towns (i.e., “urban forests”) are close to commercial forests with infested trees. Infestations were greater in spa towns than in the forests adjacent to spa towns. We therefore assume that trees within spa towns will be further attacked due to the increasing abundance of native bark beetles.     

Climate change amplifies the interactions between wind and bark beetle disturbances in forest landscapes

Context

Growing evidence suggests that climate change could substantially alter forest disturbances. Interactions between individual disturbance agents are a major component of disturbance regimes, yet how interactions contribute to their climate sensitivity remains largely unknown.

Objectives

Here, our aim was to assess the climate sensitivity of disturbance interactions, focusing on wind and bark beetle disturbances.

Methods

We developed a process-based model of bark beetle disturbance, integrated into the dynamic forest landscape model iLand (already including a detailed model of wind disturbance). We evaluated the integrated model against observations from three wind events and a subsequent bark beetle outbreak, affecting 530.2 ha (3.8 %) of a mountain forest landscape in Austria between 2007 and 2014. Subsequently, we conducted a factorial experiment determining the effect of changes in climate variables on the area disturbed by wind and bark beetles separately and in combination.

Results

iLand was well able to reproduce observations with regard to area, temporal sequence, and spatial pattern of disturbance. The observed disturbance dynamics was strongly driven by interactions, with 64.3 % of the area disturbed attributed to interaction effects. A +4 °C warming increased the disturbed area by +264.7 % and the area-weighted mean patch size by +1794.3 %. Interactions were found to have a ten times higher sensitivity to temperature changes than main effects, considerably amplifying the climate sensitivity of the disturbance regime.

Conclusions

Disturbance interactions are a key component of the forest disturbance regime. Neglecting interaction effects can lead to a substantial underestimation of the climate change sensitivity of disturbance regimes.

     

Effects of pruning intensity on the biochemical status of shoot buds in three mango (Mangifera indica L.) cultivars planted at high density

Summary

Mango (Mangifera indica L.) trees grown at high density show a decline in flowering and fruiting after good fruiting years as a result of various factors. Annual pruning can restore production and productivity in such trees. Chlorophyll, total sugars (TS), total phenolics (TP), and proline contents as well as polyphenol oxidase (PPO) activities, were measured in the 2005–2006 and 2006–2007 seasons in shoot buds with a few leaves in three mango cultivars (‘Amrapali’, ‘Mallika’, and ‘Dashehari’). Trees were grown at high density in an orchard and the aforesaid parameters were measured 1 month after different degrees of pruning (Stage I) and after subsequent fruit bud differentiation (FBD; Stage II). Severely-pruned mango trees had the highest contents of chlorophyll a, while chlorophyll b and total chlorophyll contents were found to be highest in moderately-pruned trees. Lightly-pruned trees had the highest contents of reducing sugars (RS), whereas TS contents were highest in severely-pruned trees. The contents of RS and TS increased in shoot buds during the FBD stage. A moderate intensity of pruning significantly increased TP contents, while the lowest TP contents were recorded in non-pruned trees. ‘Off’-year shoots had higher TP contents than ‘on’-year shoots. Irrespective of pruning intensity, shoot buds of ‘Mallika’ trees had the highest PPO activities, with lower levels in ‘Amrapali’ and ‘Dashehari’ shoot buds. PPO activities were reduced at the FBD stage in ‘on’-year shoots. Severely-pruned trees had the highest PPO activities, while the lowest PPO activities were recorded in lightly-pruned trees. Shoot bud proline contents were found to be highest in non-pruned trees, and decreased with increasing pruning intensity. Thus moderate pruning can be adopted in high density orchards to obtain sustainable production with improved maintenance of canopy architecture.     

The long-term influence of past land use on the Walker Branch forest

Forest structure and composition influence patterns of insect outbreaks and can be explained on the Walker Branch watershed by past land use (timber harvest and agriculture), soils, aspect, and slope. In particular, pine bark beetles caused large losses of pine on sites that had been used for agriculture, on Fullerton silt loam soils, and on north-to-northeast and east-to-southeast exposures. Hickory bark beetles had a high impact on hickory biomass on Bodine soil areas that were forested in 1935 and sloped greater than 11%. Thus, prior land use can have an indirect effect on future disturbances.Because forest disturbances can affect nutrient distribution, land use can also indirectly affect nutrient availability. For example, locations of hickory bark beetle outbreaks experience a large flux of calcium from dead wood to soil because hickory accumulates large amounts of calcium in woody tissue. The research demonstrates a link between past land use, insect outbreaks, and calcium cycling.     

Local habitat characteristics have a stronger effect than the surrounding urban landscape on beetle communities on green roofs

Green roofs are a promising tool to return nature to cities and mitigate biodiversity loss brought about by urbanization. Yet, we lack basic information on how green roofs contribute to biodiversity and how their placement in the urban landscape affects different taxa and community composition. We studied the effects of local and landscape variables on beetle communities on green roofs. We expected that both local roof characteristics and urban landscape composition shape communities, but that their relative importance depends on species characteristics. Using pitfall traps, we collected beetles during two consecutive years from 17 green roofs in Basel, Switzerland. We evaluated the contribution of six local and six landscape variables to beetle community structure and to the responses of individual species. Communities on the roofs consisted of mobile and open dry-habitat species, with both local and landscape variables playing a role in structuring these communities. At the individual species level, local roof variables were more important than characteristics of the surrounding urban landscape. The most influential factors affecting the abundances of beetle species were vegetation, described as forb and grass cover (mainly positive), and roof age (mainly negative). Therefore, we suggest that the careful planning of green roofs with diverse vegetation is essential to increase their value as habitat for beetles. In addition, while beetle communities on green roofs can be diverse regardless of their placement in the urban landscape, the lack of wingless species indicates the need to increase the connectivity of green roofs to ground level habitats.     

The importance of host characteristics and canopy openness for pest management in urban forests

Urban forests are important for the health of cities. These forests face high anthropogenic pressure, including demands on their multi-functional role. Therefore, the impact of pests-induced disturbances may be greater for urban forests than forests outside of cities. Monitoring of pests in their native environment is an important tool for the management of urban forests. To better understand how pest population density is affected by the forest environment, we used the Oak bark beetle, Scolytus intricatus, as a model organism. The study was carried out in 2014–2015 in the urban forests of Pardubice City, Czech Republic. Pest population density was studied at three levels: branch, tree and patch. The increasing branch diameter was identified as an important variable with a threshold of 70 mm for entrance holes and 45 mm for emergence holes. Increasing host tree diameter at breast height with a threshold of 46.8 cm was statistically significant at the tree level in terms of the number of entrance holes. Increasing spring canopy openness was identified as an important variable at the patch level with a threshold of 50.78% and had a decreasing trend for the number of reared adults and their total body size. Big oak trees with thick branches under closed spring canopy are the most susceptible to attack by S. intricatus. Based on our findings, we propose that the maintenance of mature oaks under open canopies is important for urban forest management. Avoiding mixed plantings of oaks and conifers should promote these open canopies and lead to multiple advantages regarding oak silviculture.     

Disturbance propagation by bark beetles as an episodic landscape phenomenon

Landscapes are the resultant of ecological processes and events operating on many different space-time scales. Large scale disturbance is recognized as a major influence on landscape patterns, but the impact of small scale events is often overlooked. We develop an hierarchical framework to relate lightning and bark beetle population dynamics to the southern pine forest landscape using the concepts of disturbance propagation and amplification. The low level lightning disturbance can be propagated to the landscape level when weather and forest stand structure facilitate bark beetle epidemics. We identify epidemics as biotically-driven episodes that alter landscape structure. The concept of the landscape as the spatial dimension of these episodes is represented in a conceptual model linking insect-host and landscape mosaic interactions.     

Post-harvest micro-flora on major cultivars of Indian mangoes

This study examined the surface micro-flora on nine major mango varieties collected from nine states of India in three different harvesting stages (early, mid and late). Mango surface supported substantial microbial component, including various species of bacteria, filamentous fungi and yeasts. Total microbial population was in the range of 10⁵–10⁸ and was significantly different in different cultivars as well as harvesting stages. However, all the mango varieties invariably showed highest microbial population in third harvesting stage. Comparative microbial population of yeast, mold and bacteria showed significant variation in different mango varieties at the third harvesting stage except for Alphonso from Maharashtra and Karnataka. Microbial population on mango fruit surface was strongly influenced by climatic factor, stages of fruit development and varietal specificity.     

Assessment of genetic relatedness among mango cultivars of India using RAPD markers

Summary

DNA-based RAPD (Random Amplification of Polymorphic DNA) markers have been used extensively to study genetic relationships in a number of fruit crops. A wide genetic diversity exists in the mango fruit in India. Present day commercial cultivars originated mainly from this subcontinent. In this study, 18 commercial mango cultivars, traditionally grown in western, southern, northern and eastern parts of India, were selected to assess genetic relatedness. Total genomic DNA was extracted and subjected to RAPD analysis using 30 arbitrary 10-mer primers. Of these, 27 primers amplified mango genomic DNA. None of these primers produced unique band pattern for each cultivar. RAPD data were used to calculate a squared Euclidean distance matrix, and based on this cluster analysis was done using a minimum variance algorithm. Cluster analysis clearly showed two groups—the first consisting of western, northern and eastern mango cultivars and the second group consisting of southern cultivars. From the analysis of results, it appears the majority of mango cultivars originated from a local mango genepool and were domesticated later.     

Effect of Seed Coat Removal Treatments on Seed Germination and Seedling Attributes in Mango Varieties

A field experiment was carried out at the Indian Institute of Horticultural Research, Bengaluru during 2011–12 to study the effect of seed coat removal on seed germination and vigor of polyembryonic mango seedlings. In seed coat removal, the cultivar Muvandan recorded the maximum germination percent (85.4%), extent of polyembryony (2.76), and maximum number of leaves (10.3), whereas Bappakkai recorded maximum plant height (22.4 cm), stem girth (0.64 cm), leaf area (249.2 cm²), fresh weight (18.5 g) and dry weight (8.4 g), vigor index-I (1831.5 cm), and vigor index-II (685.7 g). With respect to treatments, seed coat removal was superior in all of the parameters, namely, initiation of germination (16.7 days), germination percent (78.3%), extent of polyembryony (2.50), plant height (19.5 cm), stem girth (0.62 cm), number of leaves per plant (8.7), leaf area (288.3 cm²), fresh weight (16.2 g) and dry weight (7.3 g), vigor index-I (1559.0 cm), and vigor index-II (581.8 g) compared to seed coat intact. There were no significant differences among the interactions of different treatments and cultivars.     

不同颜色粘虫板对葡萄园昆虫的诱集效应

为筛选出对葡萄害虫诱集效果好的粘虫板,选用黄色、蓝色、白色、紫色、绿色、红色、黑色和荧光色8种颜色的粘虫板对葡萄园内昆虫进行诱集试验。结果表明,共诱到昆虫7目18科22种,主要害虫有蓟马、蚜虫和叶蝉,其中蓟马数量占到昆虫总量的88.96%,天敌昆虫主要有寄生蜂、捕食性瓢虫、食蚜蝇和东亚小花蝽。紫板、蓝板和白板对蓟马的诱集效果强,黄板、荧光板和绿板次之,红板和黑板效果差;黄板对蚜虫诱集效果强,绿板和荧光板次之,黄板与其他色板之间差异显著;黄板、荧光板和绿板对叶蝉的诱集效果好,3种色板与蓝板之间差异不显著、与其他色板差异显著。白板、蓝板和黄板诱集到的天敌数量最多,占所有颜色粘虫板诱集天敌总量的69%左右。试验期间诱集到的昆虫益害比为0.036,各色板的益害比依次为黑色>荧光色>绿色>红色>黄色>白色>蓝色>紫色,其中紫板的益害比最低,仅为0.011。结合各色板的诱虫效果和益害比进行综合分析,建议选用紫板对蓟马进行诱杀,适时适量选择性使用黄板对蚜虫、叶蝉等进行诱杀。     

Effects of farmyard manure on soil organic carbon stock,the pattern of fertility build-up,and plant growth in ‘Mallika’ mango (Mangifera indica L.)

Summary

A field experiment was conducted on mango (Mangifera indica L.) to study the effects of farmyard manure (FYM) on soil organic carbon (SOC) content and on the build-up of fertility over three growing seasons (2006–2007, 2007–2008, and 2008–2009) at Bhubaneswar, Orissa, India. Five treatments, including the application of FYM at 5.0 kg plant^–1, 7.5 kg plant^–1, or 10.0 kg plant^–1, the recommended dose of a chemical fertiliser (RDF; N:P:K=75:20:60), and a non-fertilised control, were evaluated in a randomised block design. The results indicated that SOC contents increased significantly in the FYM-treated plots. The highest SOC density (554 g m^–2) and stock (5.55 Mg ha^–1) were recorded in the treatment with FYM at 10 kg plant^–1. The rate of increase in SOC density was highest (193 g m^–2 year^–1) with FYM at 10 kg plant^–1, and lowest in the untreated control (15 g m^–2 year^–1). Regular addition of FYM had a positive effect on the build-up of soil fertility. However, the greatest increases in soil N, P, K contents were in the 7.5 kg plant^–1 FYM treatment (means = 319.9, 19.1, and 270.8 kg ha^–1 for N, P, K, respectively). Farmyard manure significantly influenced the growth parameters of mango trees over the three seasons. There was a positive and linear relationship between increasing rates of application of FYM and trunk cross-sectional area.     

Fruit Fly (Diptera: Tephritidae) Host Status and Relative Infestation of Selected Mango Cultivars in Three Agro Ecological Zones in Uganda

Despite their economic importance, there is paucity of knowledge on fruit fly host status in Uganda. Therefore, this study set out to profile the host range of the main fruit fly pests and determine the susceptibility of selected fruits and mango cultivars across three main mango agro ecological zones, which included: Western Medium High Altitude Farmlands (WMHF), Lake Victoria Crescent (LVC), and the Northern Moist Farmlands (NMF) in Uganda. A wide range of fruits was sampled across the three zones. These were incubated at the National Agricultural Research Laboratories following standard protocols. Emerging fruit fly species were identified using standard keys and counted. Among the sampled fruits, 633 (35.0%) individual fruits from 15 plant families were positive for fruit fly infestation. Bactrocera invadens dominated (76.3%) of the positive samples, while infestation by native species, such as Ceratitis capitata and Ceratitis cosyra, was negligible. Annonaceae, Solanaceae, Rutaceae, and Anacardiaceae plant families recorded significantly more host species, while the number of pest fruit flies (species richness) per plant species followed a similar trend: Solanaceae > Rutaceae > Anacardiaceae. There was significant (P < 0.0001) variability in infestation among mango fruit cultivars, both within and across zones. When all zones were pooled together, Tommy Atkins and Kent, and Keitt, Kate, and Biire were the least and most infested, respectively. In conclusion, fruit flies have a diverse range of commercial and non-commercial hosts in Uganda. Strategies for fruit fly pest eradication in the country should ensure elimination or management of alternative fruit hosts and integration of tolerant mango cultivars in fruit development programs.     

The scale of saproxylic beetles response to landscape structure depends on their habitat stability

Context

Forest management and disturbances cause habitat fragmentation for saproxylic species living on old-growth attributes. The degree of habitat spatiotemporal continuity required by these species is a key question for designing biodiversity-friendly forestry, and it strongly depends on species’ dispersal. The “stability–dispersal” model predicts that species using stable habitats should have lower dispersal abilities than species associated with ephemeral habitat and thus respond to habitat availability at smaller scales.

Objectives

We aimed at testing the stability–dispersal model by comparing the spatial scales at which saproxylic beetle guilds using substrates with contrasted stability (from stable to ephemeral: cavicolous, fungicolous, saproxylophagous and xylophagous guilds) are affected by landscape structure (i.e. habitat amount and aggregation).

Methods

We sampled saproxylic beetles using a spatially nested design (plots within landscape windows). We quantified habitat availability (tree cavities, polypores and deadwood) in 1-ha plots, 26-ha buffers around plots and 506-ha windows, and analyzed their effect on the abundance and diversity of associated guilds.

Results

The habitat amount within plots and buffers positively affected the abundance of the cavicolous and the fungicolous guilds whereas saproxylophagous and xylophagous did not respond at these scales. The habitat aggregation within windows only positively affected the saproxylophagous species richness within plots and also on the similarity in species composition among plots.

Conclusions

Beetle guilds specialized on more stable habitat were affected by landscape structure at smaller spatial scales, which corroborated the stability–dispersal model. In managed forests, the spatial grain of conservation efforts should therefore be adapted to the target habitat lifetime.

     

Effect of temperature on pollen germination and pollen tube growth of four cultivars of mango (Mangifera indica L.)

Summary

The effect of a constant (10, 15, 20 or 25°C) or a diurnal maximum/minimum (15/5, 20/10, 25/15 or 30/20°C) incubation temperature on in vitro pollen germination and pollen tube growth in the pistils of two poly-embryonic (‘Kensington’ and ‘Nam Dok Mai’), and two mono-embryonic (‘Irwin’ and ‘Sensation’) mango cultivars was studied. In in vitro experiments where pollen was incubated in a liquid germination medium for 24 h in darkness, little difference was found between pollen germination of mono- and poly-embryonic cultivars. Averaged over the four cultivars, 53.9% of pollen germinated at 10°C, this increased to 76.2% when the incubation temperature was increased to 15°C, thereafter up to 25°C the percentage germination remained stable but germination decreased slightly to 68.2% at 30°C. Similarly, there was no difference in percent germination between cultivars when pollen was incubated under diurnal temperature regimes. Mean pollen germination of all four cultivars was 52.3% at 15/5°C and pollen germination increased by 10% when the temperature was raised to 30/20°C. When self-pollinated flowers were incubated for 24 h on a semi-solid agar medium at 10°C, pollen tube growth of the four cultivars was retarded and no pollen tubes reached the ovaries. As the temperature was increased from 15 to 25°C, the mean number of pollen tubes in ovaries increased from 0.04 to 0.25. At 30°C, the mean number of pollen tubes that entered ovaries decreased to 0.04. After incubation under diurnal temperature regimes, the mean number of pollen tubes in ovaries of all four cultivars at 15/5°C was 0.23 and increased to 0.42 when the temperature increased to 30/20°C. At each incubation temperature, there were significant differences in pollen tube growth between cultivars, but there were no differences between the temperature response of pollen from mono- and poly-embryonic cultivars.     

Forest loss and matrix composition are the major drivers shaping dung beetle assemblages in a fragmented rainforest

Context

Identifying the drivers shaping biological assemblages in fragmented tropical landscapes is critical for designing effective conservation strategies. It is still unclear, however, whether tropical biodiversity is more strongly affected by forest loss, by its spatial configuration or by matrix composition across different spatial scales.

Objectives

Assessing the relative influence of forest patch and landscape attributes on dung beetle assemblages in the fragmented Lacandona rainforest, Mexico.

Methods

Using a multimodel inference approach we tested the relative impact of forest patch size and landscape forest cover (measures of forest amount at the patch and landscape scales, respectively), patch shape and isolation (forest configuration indices at the patch scale), forest fragmentation (forest configuration index at the landscape scale), and matrix composition on the diversity, abundance and biomass of dung beetles.

Results

Patch size, landscape forest cover and matrix composition were the best predictors of dung beetle assemblages. Species richness, beetle abundance, and biomass decreased in smaller patches surrounded by a lower percentage of forest cover, and in landscapes dominated by open-area matrices. Community evenness also increased under these conditions due to the loss of rare species.

Conclusions

Forest loss at the patch and landscape levels and matrix composition show a larger impact on dung beetles than forest spatial configuration. To preserve dung beetle assemblages, and their key functional roles in the ecosystem, conservation initiatives should prioritize a reduction in deforestation and an increase in the heterogeneity of the matrix surrounding forest remnants.

     

Habitat and food supply across multiple spatial scales influence the distribution and abundance of a nocturnal aerial insectivore

Context

Conservation research often focuses on individual threats at a single spatial scale, but population declines can result from multiple stressors occurring at different spatial scales. Analyses incorporating alternative hypotheses across spatial scales allow more robust evaluation of the ecological processes underlying population declines.

Objectives

Populations of many aerially insectivorous birds are declining, yet conservation efforts remain focused on habitat due to an absence of data on changes in prey availability. We evaluate the potential for prey and habitat availability at multiple spatial scales to influence a population of eastern whip-poor-wills (Antrostomus vociferous).

Methods

We assess relationships between landcover (topographical map and satellite imagery) and insect abundance (moths and beetles from blacklight traps), and whip-poor-will distribution and abundance within eastern Canada using Ontario breeding bird atlas data (1980s and 2000s), acoustic recordings (regional), and point counts (local).

Results

Whip-poor-will occurrence in both atlas time periods was positively associated with forest area and fragmentation, but only a delayed effect of urban area explained reductions in detection. Contemporary regional whip-poor-will presence was positively related to moth abundance, and local whip-poor-will abundance was best predicted by area of open-canopy forest, anthropogenic linear disturbance density, and beetle abundance. Our finding that bird presence and abundance were associated with human activity and insect abundance across spatial scales suggests factors beyond habitat structure are likely driving population declines in whip-poor-wills and other aerial insectivores.

Conclusions

This study demonstrates the importance of examining multiple hypotheses, including seasonally and locally variable food availability, across a range of spatial scales to direct conservation efforts.

     

Saproxylic species are linked to the amount and isolation of dead wood across spatial scales in a beech forest

Context

Dead wood is a key habitat for saproxylic species, which are often used as indicators of habitat quality in forests. Understanding how the amount and spatial distribution of dead wood in the landscape affects saproxylic communities is therefore important for maintaining high forest biodiversity.

Objectives

We investigated effects of the amount and isolation of dead wood on the alpha and beta diversity of four saproxylic species groups, with a focus on how the spatial scale influences results.

Methods

We inventoried saproxylic beetles, wood-inhabiting fungi, and epixylic bryophytes and lichens on 62 plots in the Sihlwald forest reserve in Switzerland. We used GLMs to relate plot-level species richness to dead wood amount and isolation on spatial scales of 20–200 m radius. Further, we used GDMs to determine how dead wood amount and isolation affected beta diversity.

Results

A larger amount of dead wood increased beetle richness on all spatial scales, while isolation had no effect. For fungi, bryophytes and lichens this was only true on small spatial scales. On larger scales of our study, dead wood amount had no effect, while greater isolation decreased species richness. Further, we found no strong consistent patterns explaining beta diversity.

Conclusions

Our multi-taxon study shows that habitat amount and isolation can strongly differ in the spatial scale on which they influence local species richness. To generally support the species richness of different saproxylic groups, dead wood must primarily be available in large amounts but should also be evenly distributed because negative effects of isolation already showed at scales under 100 m.

     

Slowing the deterioration of mango fruit during cold storage by pre-storage application of oxalic acid

Summary

The effects of pre-storage application of oxalic acid (OA) on the incidence of decay and ripening in mango fruit, and its physiological effects on the peel and flesh of mango were investigated after mango fruit (Mangifera indica L. cv. Zill) were dipped in 5 mM OA for 10 min at 25ºC then stored at 14º ± 1ºC for 5 weeks. In addition, spore germination and mycelium growth of Colletotrichum gloeosporioides Penz. on potato dextrose agar (PDA) media containing different concentrations of OA were measured. Application of OA decreased the incidence of decay and delayed the ripening process in mango fruit during cold storage. However, there was no reduction in fruit quality, as judged by the soluble solids content (SSC) and titratable acidity (TA) of fruit ripened at 25ºC for 3 d, following 3 weeks of cold storage. Oxalic acid-treatment resulted in decreased lipoxygenase (LOX) activity and increased superoxide dismutase (SOD) activity in the peel, and increased ascorbate peroxidase (APX) activity in both the peel and the flesh, coincident with a decrease in reactive oxygen species (ROS).At or above 5 mM, OA with unaltered (natural) pH or after neutralisation, also inhibited C. gloeosporioides development in vitro. It is suggested that the physiological effects of OA, in decreasing LOX activity and enhancing defense against oxidation damage, contributed to delaying the ripening process in mango fruit during cold storage. Thus, pre-storage application of OA could be a promising method to suppress post-harvest deterioration and extend the shelf-life of refrigerated mango fruit, possibly due to a combination of its physiological effect in delaying the ripening process, coupled with an inhibition of the development of pathogens such as C. gloeosporioides.     

Graft union formation in mango (Mangifera indica L.)

Summary

Graft union formation in mango (Mangifera indica L.) was studied using light microscopy. The initial wound response was resin secretion which contributed mainly to the initial adhesion of the graft partners. Early callus formation occurred mainly from the rootstock with cells produced in definite rows, often in fan-like array. Parenchyma cells at the cortex, pith, xylem and phloem rays were all involved in callus formation. The establishment of the cambial bridge between the stock and scion was followed by the formation of a protective layer, the periderm across the callus edges.