Preliminary image-based appraisal of starch in one-year-old grapevine shoots

Determination of starch concentration in grapevine woody tissues is pivotal to optimize some vineyard management techniques. Analytical assays represent the most reliable approach but nevertheless they are time-consuming. This study reports preliminary results on using imaging to estimate starch concentration in woody tissues stained with the Lugol's solution indicator in Vitis vinifera L.. One-year-old shoots (cv 'Primitivo') were sampled in winter time and forced to sprout inducing a starch depletion. The measured starch ranged from approx. 0.1 to 14.4 % (DW). Parallel image-based and analytical starch concentrations data (n=42) revealed that R (red), G (green) and B (blue) color channels were highly predictive across three phenological stages (r =-0.92), rising the imaging technique proposed as a promising tool to estimate the starch content

Phenotyping Key Fruit Quality Traits in Olive Using RGB Images and Back Propagation Neural Networks

To predict oil and phenol concentrations in olive fruit, the combination of back propagation neural networks (BPNNs) and contact-less plant phenotyping techniques was employed to retrieve RGB image-based digital proxies of oil and phenol concentrations. Fruits of cultivars (×3) differing in ripening time were sampled (∼10-day interval, ×2 years), pictured and analyzed for phenol and oil concentrations. Prior to this, fruit samples were pictured and images were segmented to extract the red (R), green (G), and blue (B) mean pixel values that were rearranged in 35 RGB-based colorimetric indexes. Three BPNNs were designed using as input variables (a) the original 35 RGB indexes, (b) the scores of principal components after a principal component analysis (PCA) pre-processing of those indexes, and (c) a reduced number (28) of the RGB indexes achieved after a sparse PCA. The results show that the predictions reached the highest mean R2 values ranging from 0.87 to 0.95 (oil) and from 0.81 to 0.90 (phenols) across the BPNNs. In addition to the R2, other performance metrics were calculated (root mean squared error and mean absolute error) and combined into a general performance indicator (GPI). The resulting rank of the GPI suggests that a BPNN with a specific topology might be designed for cultivars grouped according to their ripening period. The present study documented that an RGB-based image phenotyping can effectively predict key quality traits in olive fruit supporting the developing olive sector within a digital agriculture domain

Glutamate and substance P coexist in primary afferent terminals in the superficial laminae of spinal cord.

By light microscopic immunocytochemistry it has been previously shown that approximately equal to 70% of the neurons in rat dorsal root ganglia are labeled with an antiserum for glutamate conjugated to hemocyanin; the smaller among these neurons are also positive for substance P. By using a postembedding ImmunoGold method and electron microscopy, it is shown here that synaptic terminals in the superficial laminae of the spinal cord of rats selectively stain for the same glutamate antiserum. Immunolabeling is in small dome-shaped and in large scalloped synaptic terminals. Scalloped terminals are of two types. One type consists of dark terminals with many agranular vesicles of different size and a few large granular vesicles; these are probably endings of unmyelinated and small myelinated primary afferent fibers. The other type consists of light terminals with small agranular vesicles homogeneous in size with neurofilaments and many mitochondria; these are probably endings of larger myelinated primary afferent fibers. By means of double-labeling electron microscopic immunocytochemistry with colloidal gold particles of two different sizes, it is also shown here that substance P is present in only the dark type of glutamate-labeled scalloped terminals. The primary afferent origin of the terminals labeled by the antisera for glutamate and for substance P is demonstrated by a triple-labeling strategy: immunocytochemistry for both antisera on sections from rats in which dorsal rhizotomy or dorsal root ganglion injection of horseradish peroxidase conjugated to wheat germ agglutinin was performed. It is proposed that glutamate is the neurotransmitter in primary afferents mediating input from different peripheral receptor classes, including nociceptors. Effects of glutamate and substance P on spinal dorsal horn neurons may result from co-release of these two mediators from the same dorsal root afferent terminal

Image-based sensing of salt stress in grapevine

Grapevine is among the most economically important crops suffering environmental constraints, including drought and salt stress. Although imaging is increasingly used to detect abiotic stress in agriculture, image-based phenotyping in grapevine still needs optimisation. This study presents the RGB-(red, green, blue)-based phenotyping of the early stage of salt stress response in potted grapevine (Aleatico/SO4) irrigated with saline water (100 mM NaCl) for 9 days in contrast with vines irrigated with fresh water. The response was measured using stomatal conductance (gs), net photosynthetic rate (A), transpiration (E), maximum potential photosynthetic efficiency (Fv/Fm), stem water potential (SWP) concurrently with RGB imaging via a robotised platform. The image-based phenotyping of salt-stressed vines employed two sets of measurements: (i) the pixel fraction of specific colour bands (Yellow, Green, Brown and Dark Green) and (ii) the mean pixel value of R, G and B and other RGB-based colorimetric indexes. Results show that the responses of gs, A, E, Fv/Fm were closely related to increasing soil electrical conductivity (EC) and that imaging could detect the EC threshold of approx. 4 dS m-1 causing a 60 % decrease in these physiological traits compared to the pre-stress level. The SWP declined to about -0.7 MPa at the end of the experiment. The change of the relative pixel fraction of Dark Green to increasing EC has been analysed within a dose-response context, showing that a decrease of 1 % of the Dark Green colour band corresponded to the 4 dS m-1 EC threshold. This study also examined the use of the mean pixel value of the R, G and B channels as proxies of EC along with new RGB-based indexes resulting from the rearrangement of original R, G and B mean pixel values. Results show the suitability of the mean pixel value of R and Coloration Index [(R-B)/R] to serve as predictors of EC (R2 >= 0.80)

Free and glycosylated green leaf volatiles, lipoxygenase and alcohol dehydrogenase in defoliated Nebbiolo grapes during postharvest dehydration

none7noBackground and Aims: Nebbiolo grapes are used to produce Sfursat wine, following partial dehydration. This research aimed to clarify the influence of fruit exposure to light and postharvest water loss on the concentration of green leaf volatiles (GLVs) and lipoxygenase (LOX) and alcohol dehydrogenase (ADH) activity of grapes. Methods and Results: Nebbiolo grapes from Control vines (no defoliation) (ND) and from vines defoliated at fruitset (DFS) or defoliated post-veraison (DPV) were harvested at about 23°Brix and dehydrated at 10 and 20°C, 60% RH and air flow of 1.5 m/s. Berries were sampled at 10 and 20% mass loss (ML). Significant differences in crop yield, bunch mass and berry mass were observed. As expected, the higher the dehydration temperature, the faster the dehydration process: 20% ML at 20°C occurred between 18 and 25 days, the shortest time corresponding to ND and the longest to DFS; at 10°C, the dehydration lasted between 27 and 32 days. At 10°C, the ADH activity was almost double that at 20°C, and in DFS was much higher than in other samples. At harvest, LOX did not show any difference among the samples, while at 10°C and 10% ML, the enzyme activity increased significantly and then declined at 20% ML, especially in defoliated samples. At harvest, the total free GLVs associated with the metabolism of lipid oxidation were 9434, 7212 and 11 656 μg/kg dry weight (DW) in ND, DFS and DPV samples, respectively; the total bound GLVs lipid-derived were 7599, 18 486 and 15 409 μg/kg DW in ND, DFS and DPV samples, respectively. During dehydration at 10°C, the ML induced ADH + LOX activity, especially in defoliated samples, but the bound GLVs, produced by defoliation, greatly decreased. Conclusions: Defoliation affected the response of Nebbiolo grapes to dehydration temperature: postharvest cold stress (10°C) and ML induced glycosylation of GLVs, alcohol formation (via ADH) and membrane oxidation (via LOX); a further stress effect was observed with leaf removal, regardless of the time of application. Significance of the Study: The timing of defoliation and postharvest dehydration temperature are significant factors to mitigate the postharvest stress response of Nebbiolo grapes.openPiombino P.; Genovese A.; Rustioni L.; Moio L.; Failla O.; Bellincontro A.; Mencarelli F.Piombino, P.; Genovese, A.; Rustioni, L.; Moio, L.; Failla, O.; Bellincontro, A.; Mencarelli, F

AMPA Receptor Subunits Underlying Terminals of Fine-Caliber Primary Afferent Fibers

Postembedding immunogold electron microscopy was used to determine the relation of primary afferent terminals in superficial laminae of the spinal dorsal horn with AMPA receptor subunits. Immunogold particles coding for GluR1 and GluR2/3 were concentrated at synaptic sites, between 30 nm outside and 40 nm inside the postsynaptic membrane. Immunopositive synapses displayed round vesicles and asymmetric specializations, characteristic of terminals releasing excitatory neurotransmitters; symmetric synapses, characteristic of terminals releasing inhibitory amino acids, were immunonegative

Phenotyping under extreme weather conditions and microsatellite based genotyping of some Hungarian grape cultivars

Phenology is an indicator of plant response to the environment. In viticulture growth stages timing is important for site and cultivar selection, vineyard planning and cultural practices management. In the last years, autochthonous cultivars obtained an increased interest and, therefore, in this work we studied the phenological performances of Hungarian old varieties. The data recorded in 2012 were compared with the ones published 60 years ago. The examined genotypes were identified by SSR markers. Extremely high temperature and low precipitation occurred during the 2012 vintage. The uncommon weather conditions affected the length of the vegetation period less than expected. However, the time period between flowering and harvest decreased significantly. In general, minor varieties seem to be more sensitive to extreme conditions than international cultivars, according to their eno-carpological characteristics

Glutamate-positive neurons in the somatic sensory cortex of rats and monkeys

The morphology and laminar distribution of neurons labeled with an antiserum prepared against glutamic acid (Glu) conjugated to keyhole limpet hemocyanin have been studied in the somatic sensory cortex of rats and monkeys. In both species, the vast majority of immunostained neurons are pyramidal; some nonpyramidal neurons are also present. Positive neurons are observed in all cortical layers, although variations are found in the percentage of Glu-positive neurons in the different layers. In rats they are most numerous in layer V (36%), followed by layer II (33%), layer III (32%), and layer VI (29%). In layer IV, 13% of all neurons are positive. Immunoreactive neurons are very sparse in layer I. In monkeys, Glu-positive neurons represent 51% of all neurons in layer V, 49% in layer III, 40% in layers II and VI, and 19% in layer IV. No differences are evident in the laminar distribution of Glu-positive neurons among cytoarchitectonic areas 3a, 3b, 1, and 2. As in rats, Glu-positive neurons are very sparse in layer I. Since Glu and GABA metabolisms are closely related, double-labeling experiments were performed in which thin, adjacent paraffin sections were stained alternately with the anti-Glu serum and with an anti-GABA serum. The 2 populations are almost completely segregated, even though a small fraction of neurons (less than 5%) are labeled by the antisera against both antigens.(ABSTRACT TRUNCATED AT 250 WORDS

Influence of freezing and heating conditions on grape seed flavan-3-ol extractability, oxidation, and galloylation pattern

In cool-climate viticulture, the short growing season can influence grape seed maturation by reducing the apparent oxidation of flavan-3-ol monomers and associated increase in seed browning. A reduction in seed maturation increases the potential extraction of flavan-3-ol monomers into wine during maceration operations, heightening bitterness. Here, we carried out a 2 × 2 factorial experiment to test the ability of freezing and heating treatments to advance maturation (decrease flavan-3-ol, improve browning) of (Vitis vinifera L.) Pinot noir and Cabernet Sauvignon seeds over a 24-h incubation period. Only freezing significantly increased seed browning in both cultivars. Subsequent correlations with seed flavan-3-ol monomer concentrations suggest that freezing enhanced the oxidation of these compounds. Interestingly, natural ripening and freezing reduced galloylated flavan-3-ol monomers to a greater extent than non-galloylated ones. This study provides new information regarding the susceptibility of flavan-3-ol monomers to freezing and heating, and also suggests that freezing can advance the maturation the seeds of under-ripe red vinifera grapes