Gas exchange in yellow passion fruit under irrigation water salinity and nitrogen fertilization

ABSTRACT The objective of this study was to evaluate the gas exchange of ‘Redondo Amarelo’ passion fruit seedlings under the mitigating action of nitrogen fertilization on the salinity of irrigation water. The experiment was carried out in a greenhouse of the Universidade Federal de Campina Grande (CCTA-UFCG), Campus of Pombal, PB, Brazil, The experimental design was in randomized blocks, split plots, comprising five irrigation water electrical conductivities (plot) (ECw) (0.3; 1.0; 1.7; 2.4 and 3.1 dS m-1) and five doses of nitrogen (subplot) (60; 80; 100; 120 and 140% of 300 mg of N dm-3), in five blocks. Plants were grown in pots (Citropote JKS®) with volume of 3.780 mL, filled with soil, bovine manure, wood shavings in a proportion of 2:1:0.5 (mass basis), respectively. Water with salinity levels was applied in the period from 40 to 85 days after sowing. The internal CO2 concentration, transpiration, stomatal conductance and photosynthesis were measured at 55 and 70 days after sowing. There was an attenuating effect of nitrogen doses at irrigation water electrical conductivities of 1.7 and 2.4 dS m-1 on photosynthesis at 55 DAS. Irrigation water salinity reduces most of the variables evaluated, especially at the highest level studied (3.1 dS m-1).

Methylphosphonate Degradation and Salt-Tolerance Genes of Two Novel Halophilic Marivita Metagenome-Assembled Genomes from Unrestored Solar Salterns

Aerobic bacteria that degrade methylphosphonates and produce methane as a byproduct have emerged as key players in marine carbon and phosphorus cycles. Here, we present two new draft genome sequences of the genus Marivita that were assembled from metagenomes from hypersaline former industrial salterns and compare them to five other Marivita reference genomes. Phylogenetic analyses suggest that both of these metagenome-assembled genomes (MAGs) represent new species in the genus. Average nucleotide identities to the closest taxon were <85%. The MAGs were assembled with SPAdes, binned with MetaBAT, and curated with scaffold extension and reassembly. Both genomes contained the phnCDEGHIJLMP suite of genes encoding the full C-P lyase pathway of methylphosphonate degradation and were significantly more abundant in two former industrial salterns than in nearby reference and restored wetlands, which have lower salinity levels and lower methane emissions than the salterns. These organisms contain a variety of compatible solute biosynthesis and transporter genes to cope with high salinity levels but harbor only slightly acidic proteomes (mean isoelectric point of 6.48).

Effects of salinity and plant-based diet or animal-plant combination diet on the performance and metabolic status of juvenile Nile tilapia

The purpose of this study was to evaluate the effects of salinity and plant-based diet or animal-plant combination diet on the performance and metabolic status of juvenile Nile tilapia (Oreochromis niloticus). The experimental design was completely randomized in a 4 × 2 factorial scheme with four replicates. The treatments were established by the combination of salinities of 0, 10, 20, and 30 g L-1 with an animal-plant combination diet (AP) or plant-based diet (P). The replicates were 60 L tanks with 12 fish per tank. Diets were provided for 32 days, and the fish were fed three times a day (8, 12, and 17 h) until apparent satiety. Daily feed intake (DFI) was measured, body weight (BW) was recorded at the beginning and end of the trial, and total length (TL) and standard length (SL) were measured at the end of the trial. Average daily gain (ADG), specific growth rate (SGR), feed conversion ratio (FCR), and survival rate were calculated. After the biometric measurements were made at the end of the trial, blood samples were collected to determine the plasma concentrations of total protein (TP), glucose, cholesterol, and triglycerides (TG). The fish were euthanized, and the hepatopancreas was collected and weighed; thereafter, the hepatosomatic index (HSI) was calculated. An interaction was detected between salinity and diet type for final BW, ADG, TL, and SL. These traits were not influenced by salinity when it was associated with the AP diet, but reduced linearly with salinity in the P diet. DFI and survival rate were independently affected by salinity: DFI reduced linearly with salinity levels and survival rate was higher at a salinity of 10 g L-1. HSI increased linearly with salinity levels and was lower in the P diet than in the AP diet. Salinity had a quadratic effect on plasma TP, and the maximum value for this metabolite (2.96 g dL-1) is attained at a salinity of 10.26 g L-1. There was an independent effect of diet on the plasma concentrations of cholesterol and TG, which were lower in the P diet than in the AP diet. The salinity of 10 g L-1 associated with diet composed of animal and plant ingredients led to a better performance, higher survival rate, and less stressful environmental conditions for juvenile Nile tilapia.

Extraction, Characterization and Rheological Behavior of Tamarind Gum Under High Salinity

The objective of this work was to obtain tamarind gum from Tamarindus indica L. seeds, which are waste from the food industry. Tamarind gum was extracted by two methods and the highest yield achieved was 32.6% w/w, containing 69.25% w/w of organic matter, which was composed mostly of the nonionic polysaccharide xyloglucan. The greatest molar mass of the tamarind gum was Mw=7.16 x 105 g/mol with polydispersity index (PI) of 1.7. Evaluation of the rheological behavior of tamarind gum samples were carried out in two brines (total dissolved solids values of 29,711 mg/L and 68,317 mg/L, containing divalent ions) that simulated petroleum reservoir salinity levels, with different temperatures (25, 60 and 80°C). The rheological curves indicated high salt resistance of the gum samples. Under a shear rate of 7.3 s-1 the highest viscosity values found were approximately 86, 41 and 50 cP with at concentration of 5,000 ppm and temperatures of 25, 60 and 80ºC, respectively.

Detection of fecal coliforms and SARS-CoV-2 RNA in sewage and recreational waters in the Ecuadorian Coast: a call for improving water quality regulation

Wastewater surveillance represents an alternative approach for the diagnosis and early detection of infectious agents of public health importance. This study aimed to evaluate SARS-CoV-2 and other quality markers in oxidation lagoons, estuarine areas and seawater at Guayas and Santa Elena in Ecuador. Sample collections were conducted twice at 42 coastal sites and 2 oxidation lagoons during dry and rainy seasons (2020-2021). Physico-chemical and microbiological parameters were evaluated to determine organic pollution. Quantitative reverse transcription PCR was conducted to detect SARS-CoV-2. Results showed high levels of Escherichia coli and low dissolved oxygen concentrations. SARS-CoV-2 was detected in sea-waters and estuaries with salinity levels between 34.2-36.4 PSU and 28.8 degrees celsius -31.3 degrees celsius. High amounts of fecal coliforms were detected and correlated with the SARS-CoV-2 shedding. We recommend to decentralized autonomous governments in developing countries such as Ecuador to implement corrective actions and establish medium-term mechanisms to minimize a potential contamination route.

Biochemical changes in Conocarpus species under saline soils of Lal Suhanra National Park, Bahawalpur

In Pakistan, arid and semi-arid areas are more prone to limited rainfall, extensive evapo-transpiration and higher temperatures. For better understandings of current situation, a field experiment was carried out to study the morphological characteristics, biochemical responses and ionic composition of Conocarpus species (Conocarpus erectus and Conocarpus lancifolius) under saline soil conditions in Lal Suhanra National Park, Bahawalpur during 2019-21. Three sites one at normal soil (S.I) and two at different salinity levels (Medium and High Salinity) were observed in order to assess their effect on plant growth and other parameters. The data regarding physiological and biochemical parameters were recorded. Conocarpus lancifolius and Conocarpus erectus has maximum (233) mmol m-2sec-1 and (162) mmol m-2sec-1 stomatal conductance respectively. Maximum transpiration rate (4.57 MMOL M-2S-1) was observed at site-I in case of C. lancifolius, while maximum transpiration rate in case of C. erectus was (2.94 MMOL M-2S-1) at site-I. At control level, maximum photosynthetic rate was measured as (8.76 µmol m-2sec-1) in C. lancifolius and (5.59 µmol m-2sec-1) in case of C. erectus. Conocarpus species; Conocarpus lancifolius and Conocarpus erectus has maximum SOD (13.29 and 19.62) and CAT (16.48 and 42.05), and POD (14.81 and 8.81 U/mg protein) respectively. Maximum values of Na+K+ ratio in leaves (3.08), shoots (5.98) and roots (9.84) were detected at site-I in C. lancifolius. Based on statistically analyzed data, it is revealed that Conocarpus lancifolius can tolerate better salt stress as compared to Conocarpus erectus. Both species of Conocarpus can tolerate salinity up to 40 dSm-1 but growth of Conocarpus erectus is affected more as compared to Conocarpus lancifolius.

Accumulation and Combined Effect of Salinity and Heavy Metals on Growth, Yield and Uptake of Green Pea Grown in Piped Hydroponics

This research is to study the accumulation and combined effect of three salinity levels (750, 1500 and 3750 ppm) and of heavy metals (3.26, 3.2, 2 ppm, 2, and 0.2 of Zn, Cu, Fe, Mn, and Mo, respectively) on growth, yield, and uptake of green pea plants grown in piped hydroponic. Due to freshwater shortages, the use of hydroponic growth system was encouraged and used. The experiment consists of planting green peas from seeds into a 6” PVC piped system. After 2.5 months of growing, the experiment was stopped and plants parts were separated and divided into pods, leaves, stems, and roots, Then, physical, and chemical measurements conducted on them. Results indicated that (1) Salt concentration above 1500 mg/l was detrimental on the growth of green pea, (2) the best growth, yield, and biomass weight were observed at salinity of 750 mg/l, (3) heavy metals had positive effect on stems and roots of plants, but declined effect plant growth in general, (4) lines with nutrient deficiency were deficient in growth too, (5) sodium increased in plant’s organs in response to increased salinity in the feed solution, (6) the largest concentration of copper and zinc were found at the roots of the highest salinity level lines (36.05 and 211.58 mg/kg dry plant, respectively), (7) the hydroponic system proved to be efficient and economical and therefore, it is recommended for use for Palestinian farmers, and (8) results obtained in this study agree with previously published research with extent differences.

The role of some chemical transactions in the germination of seeds of some salt-stressed pepper genotypes: دور بعض المعاملات الكيميائية في إنبات بذور بعض طرز الفليفلة الخاضعة للإجهاد الملحي

This research was carried out at Sweida Research Center/ General commission for Scientific Agricultural Research/ Syria during 2020. Seven pepper genotypes were used; five local varieties (10496, 10743, Aleppo pepper, thick sweet pepper and deer horn pepper) and two lines (129 and 110). This research aimed to determining the effect of seed priming treatments in enhancing the tolerance of pepper to salt stress during germination stage. Seeds were divided into four groups, the first group was treated with distilled water, the second with NaCl (50 mM), the third with poly ethylene glycol 6000 (PEG) (16.7 mM) and the fourth with sorbitol (250mM). Seeds were exposed after drying to several NaCl levels (0, 2, 4, 6 gl-1), in addition to untreated control for each genotype. Germination percentage, vigor and speed indicators were recorded. The research was conducted according to a completely random design, and data were analyzed by two way ANOVA at 0.01 significant level. In this research, studied genotypes showed different behavior according to the treatments and salinity levels. The results indicated that the treatments of PEG and sorbitol were superior for the studied indicators in most genotypes, especially at the low levels of salinity. In addition, the salinity and water treatments for most genotypes did not cause an increase in the values ​​of the studied indicators. Depending on these results, it is advisable to treat pepper seeds before sowing with sorbitol or PEG when the salinity level is low.

Survival and detection of bivalve transmissible neoplasia from the soft-shell clam Mya arenaria (MarBTN) in seawater

Many pathogens can cause cancer, but cancer itself does not normally act as an infectious agent. However, transmissible cancers have been found in a few cases in nature: in Tasmanian devils, dogs, and several bivalve species. The transmissible cancers in dogs and devils are known to spread through direct physical contact, but the exact route of transmission of bivalve transmissible neoplasia (BTN) has not yet been confirmed. It has been hypothesized that cancer cells could be released by diseased animals and spread through the water column to infect/engraft into other animals. To test the feasibility of this proposed mechanism of transmission, we tested the ability of BTN cells from the soft-shell clam (Mya arenaria BTN, or MarBTN) to survive in artificial seawater. We found that BTN cells are highly sensitive to salinity, with acute toxicity at salinity levels lower than those found in their environment. BTN cells also survive longer at lower temperatures, with >48% of cells surviving a week in seawater at temperatures from 4°C to 16°C, and 49% surviving for more than two weeks at 4°C. With one clam donor, living cells were observed for more than eight weeks at 4°C. We also used qPCR of environmental DNA (eDNA) to detect the presence of BTN-specific DNA in the environment. We observed release of BTN-specific DNA into the water of aquaria from tanks with highly BTN-positive clams, and we detected BTN-specific DNA in seawater samples collected from BTN-endemic areas, although the level detected was much lower. Overall, these data show that BTN cells can survive well in seawater, and they are released into the water by diseased animals, supporting the hypothesis that BTN is spread from animal-to-animal by cells through seawater.