Citrus black spot severity related to premature fruit drop in sweet orange orchards

Citrus black spot (CBS) may cause substantial yield loss in sweet orange orchards. Severity and distribution of CBS symptoms on fruit may be variable and not all affected fruit may fall. However, the relationship between CBS symptoms and yield loss has not yet been investigated. This study aimed to determine CBS characteristics associated with premature fruit drop. A set of fruit was removed from the tree to measure the detachment force and another set of dropped fruit was collected from Pera and Valencia sweet orange orchards in three municipalities in Sao Paulo state, Brazil. CBS severity, distance of the nearest lesion from the peduncle, and fruit peel colour were assessed in both fruit sets. CBS severity was consistently related with the force to remove fruit and hence associated to the premature fruit drop, irrespective of the cultivar and location. The segmented linear regression showed that the fruit detachment force was reduced abruptly, at a rate of 7% for every 1% increase in disease severity up to 4.2 ± 1.0% CBS severity and, above this breakpoint, the force decreased slightly at a rate of 1.5%. Taking into account all orchards, the proportion of dropped fruit with CBS severity higher than the breakpoint was approximately 90%. This study provides a better understanding of the relationship between CBS severity and premature fruit drop of sweet orange. CBS severity breakpoint may be used as a reference to anticipate harvest and reduce CBS-related yield loss in orchards intended for juice processing.     

Bile acids combined with fecal sterols: a multiple biomarker approach for deciphering fecal pollution using river sediments

Journal of Soils and Sediments - Fecal sterols (FSs) and bile acids (BAs) are biomarkers that can be used to track sewage pollution. These biomarkers offer an alternative to microbiological...     

Effect of Proofing Time and Wheat Flour Strength on Bleaching,Sensory Characteristics,and Volume of French Breads with Added Soybean Lipoxygenase

Soybean lipoxygenase addition in wheat bread doughs is widely used to improve the crumb color and rheology but little is known about the variability of the activity of lipoxygenase under diverse breadmaking conditions. Thus the objective of this study was to evaluate how soybean lipoxygenase can affect bleaching, volume, and sensory characteristics of French breads when proofing time and wheat flour strength varies. A 3-factor Box-Behnken design was used in this study containing one block and three independent variables or factors designated by exogenous lipoxygenase activity (x₁ = 0–71 unit/μg of protein), wheat flour deformation energy (x₂ = 231–258 × 10^–4 J), and proofing time (x₃ = 2–6 hr). Breads were randomly prepared and all assays were repeated three times. Specific volume (from 5.8 ± 0.4 to 9.9 ± 0.4 cm³/g), sensory quality (from 5.2 ± 0.8 to 8.3 ± 0.6), and yellow hue (from 12.6 ± 0.5 to 16.2 ± 0.3) significantly changed (P < 0.01) among the treatments. Specific volume of the breads increased with higher values of wheat flour strength and proofing time (ŷ_vs = 7.5 + 0.9 x₂ + 1.2 x₃ +0.5 x₂x₃). Sensory quality improved at higher values of wheat flour strength and shorter proofing time (ŷ_sq = 7.8 + 0.7 x₂ – 0.2 x₃ – 0.4 x₂² – 0.6x₃² + 0.5 x₂x₃), while lower and more desirable values of yellow hue were achieved at longer proofing time, higher activity of lipoxygenase, and using stronger wheat flours (ŷ_b = 13.7 – 1.2 x₁ – 0.5 x₂ – 0.2 x₃ + 1.0 x₁² – 0.3 x₁x₂). All regression models showed a good fitness to the experimental data (lack-of-fit P > 0.05) and the difference between predicted and observed values were also not significant (P < 0.05). Our results suggested that proofing time and wheat flour strength have a greater effect on volume and sensory quality of French breads than soybean lipoxygenase. However, the bleaching effect of this enzyme showed positive interaction with proofing time and wheat flour strength, suggesting its application even when strong wheat flours are used for the manufacture of French breads.     

Hepatic ultrasonography in three breeds of healthy calves: Nellore,Curraleiro Pe-duro and Pantaneiro

An ultrasonography was performed in 21 healthy male calves of Nellore (n = 8), Curraleiro Pe-duro (n = 7) and Pantaneiro (n = 6) breeds, between 8 and 12 months, with the objective to display information about size, position and ultrasonographic parenchymal patterns of the liver, in addition to the topography of the gallbladder, right kidney and major vessels. The measurements used were dorsal margin distance (DMD) and ventral margin distance (VMD) of the liver, viewable extension (VE) of the liver, the caudal vena cava (CVC), width (CVCW) and depth (CVCD) and the portal vein (PV), width (PVW) and depth (PVD). The measures DMD, VMD and VE were similar, and the organ’s longest visible extension was in 11th ICS. CVC was more frequently observed in the 11th and 10th ICS, despite being visible from the 12th to the 9th ICS in Nellore and still 8th ICS in Curraleiro Pe-duro and Pantaneiro. CVCD was lower in the 10th and 9th ICS in Nellore. The PV presented higher observation frequency in the 10th ICS. The measures PVD and PVW were higher in Nellore in the 11th, 10th and 9th ICS. To our knowledge, this report is the first to document ultrasonographic findings in three healthy calves. Considering the three breeds, the results show no differences in the ultrasonographic features as regard to the measurements and visualization of the position, size and vasculature of the liver and there was no additional information about the topography of the gallbladder and the right kidney.     

Influence of forest cover and mesohabitat types on functional and taxonomic diversity of fish communities in Neotropical lowland streams

Abstract – In this study, we investigated how taxonomic and functional diversity of fish communities is influenced by forest cover and mesohabitat types in Neotropical lowland streams. We sampled fish fauna of 126 five‐metre‐long mesohabitats using an electrofishing unit in forested (n = 3) and deforested (n = 3) streams in the upper Paraná River basin, south‐eastern Brazil. According to velocity and depth, three mesohabitat types have been considered: riffles (shallow and fast‐flowing habitat), pools (deep and slow‐flowing habitat) and runs (intermediate depth and velocity). Seven functional traits and 27 trait categories related to ecological, behavioural and life‐history aspects of fish were considered. Our results indicate that forest cover and mesohabitat type influence fish communities in different ways. Whereas deforestation affects communities primarily through changes in diversity (functional and taxonomic), mesohabitat types determine changes in the functional composition. The increased diversity in deforested mesohabitats is driven by a decrease in species turnover among habitat patches within streams. This can be attributed to new feeding opportunities and microhabitat availabilities in deforested streams so favours the occurrence of species having a particular set of traits, indicating a strong habitat–trait relationship.     

Deficiency in silicon uptake affects cytological, physiological, and biochemical events in the rice--Bipolaris oryzae interaction

This study investigated how a defect in the active uptake of silicon (Si) affects rice resistance to brown spot. Plants from a rice mutant (low silicon 1 [lsi1]) and its wild-type counterpart (cv. Oochikara), growing in hydroponic culture with (+Si; 2 mM) or without (-Si) Si, were inoculated with Bipolaris oryzae. Si concentration in leaf tissue of cv. Oochikara and the lsi1 mutant increased by 381 and 263%, respectively, for the +Si treatment compared with the -Si treatment. The incubation period was 6 h longer in the presence of Si. The area under brown spot progress curve for plants from cv. Oochikara and the lsi1 mutant was reduced 81 and 50%, respectively, in the presence of Si. The reduced number of brown epidermal cells on leaves from cv. Oochikara and the lsi1 mutant supplied with Si contributed to the lower lipid peroxidation and electrolyte leakage. The concentration of total soluble phenolics in cv. Oochikara supplied with Si (values of 4.2 to 15.4 μg g(-1) fresh weight) was greater compared with plants not supplied with Si (values of 1.9 to 11.5 μg g(-1) fresh weight). The concentration of lignin was also important to the resistance of cv. Oochikara and the lsi1 mutant. Polyphenoloxidase activity did not contribute to the resistance of cv. Oochikara and the lsi1 mutant to brown spot, regardless of Si supply. Peroxidase and chitinase activities were higher in cv. Oochikara and the lsi1 mutant supplied with Si. These results bring novel evidence of the involvement of Si in a more complex defense mechanism than simply the formation of a physical barrier to avoid or delay fungal penetration.     

Potentiation of soybean resistance against Phakopsora pachyrhizi infection using phosphite combined with free amino acids

Considering the importance of Asian soybean rust (ASR), caused by Phakopsora pachyrhizi, in the decrease in soybean yield, this study investigated the potential of using phosphite combined with l -α-free amino acids (referred to as induced resistance [IR] stimulus hereafter) to boost defence responses of soybean plants against P. pachyrhizi infection. Plants were sprayed with water (control), acibenzolar-S-methyl (ASM) or IR stimulus and noninoculated or inoculated with P. pachyrhizi. Urediniospore germination was not affected by the IR stimulus in vitro. Reduced ASR severity, lower malondialdehyde concentration and less colonization of leaf tissues by P. pachyrhizi (lower TEF-1α expression from 1 to 15 days after inoculation [dai]) occurred for IR stimulus-sprayed plants. The pattern of gene expression for IR stimulus-sprayed and infected plants was strikingly similar but sometimes more remarkable than that in ASM-sprayed and infected plants. Higher production of phenolics and lignin along with stronger up-regulation of PAL1.3 (5 and 10 dai), PAL2.2 (3 dai), PAL3.1 (1, 3 and 5 dai), ICS1 (5 dai), CHIA1 (1, 5 and 10 dai), CHI1B1 (5 dai), PR-1A (5 and 10 dai), NR1-2 (5 and 10 dai) and INR-2 (5 and 10 dai) for IR stimulus-sprayed plants increased their resistance against ASR. In addition, IR stimulus-sprayed and infected plants showed less impairment of the photosynthetic apparatus and maintained high concentrations of chlorophyll a + b and carotenoids. These findings highlight the potential of using this IR stimulus for developing a well-tuned and effective defensive strategy in soybean plants against P. pachyrhizi infection.     

Unravelling the complex habitat use of the white mullet,Mugil curema,in several coastal environments from Neotropical Pacific and Atlantic waters

1. The white mullet, Mugil curema, is a widely distributed euryhaline species, the migratory behaviour of which is poorly understood. The objective of this work was to study the large-scale habitat use of this species for the first time. Several environments were considered, such as euryhaline and hypersaline lagoons, the sea, and a river, distributed in the Central Pacific (Mexico) and Atlantic (Gulf of Mexico, Caribbean Sea-Venezuela, and north-eastern Brazil).
2. Otolith core-to-edge Sr/Ca ratios of 163 fish, determined by laser ablation inductively coupled plasma mass spectrometry, were used to study the salinity-habitat migration history of the fish. Fish from Mexico (Tamiahua Lagoon, n = 4; Alvarado Lagoon, n = 2), Venezuela (n = 1), and Brazil (n = 12) (11.1% of the total) showed high Sr/Ca values at early life stages and were classified as marine estuarine opportunists. Two specimens (from Alvarado Lagoon and Balsas River, Mexico) showed Sr/Ca values consistently below the high salinity guide value (salinity < 33.5). For the rest of the fish (87.1%), the Sr/Ca ratio suggested a displacement from the estuary towards the sea or hypersaline environments, and so these fish were classified as estuarine migrants.
3. A change-point analysis identified six individuals with a single stable otolith Sr/Ca signature through ontogeny (three from Brazil, one from Venezuela, and two from Tamiahua Lagoon, Mexico), suggesting limited displacement between environments with different salinities. The rest of the individuals showed between two and 10 changes in stable Sr/Ca signatures (mean = 4.07 ± 1.85). The highest number of changes in Sr/Ca ratio (4.87 ± 1.1) was found in fish from Laguna Madre (Mexico) and the lowest was found in fish from Brazil (3.27 ± 1.70) (H = 19.8, p = 0.002).
4. Otolith Sr/Ca time series suggest that the migratory estuarine pattern is the most common throughout the study area. This work highlights that the sustainable use of M. curema depends on the conservation of estuaries and the corridors between them and other environments such as lagoons, rivers, mangroves and the sea.