A complete regeneration protocol was developed for Prunus serotina Ehrh., an important hardwood species for timber and sawlog production in the central and eastern United States. Nodal sections were cultured on Murashige and Skoog (MS) medium supplemented with 4.44 μm 6-benzylaminopurine (BA), 0.49 μm indole-3-butyric acid (IBA), and 0.29 μm gibberellic acid (GA3). In vitro leaf explants of three genotypes were placed on woody plant medium (WPM) supplemented with 0, 2.27, 4.54, or 6.81 μm thidiazuron (TDZ) in combination with 0, 0.54, 1.07, or 5.37 μm naphthaleneacetic acid (NAA), and on WPM supplemented with 0, 4.44, 8.88, or 13.32 μm BA in combination with 0, 0.54, 1.07, or 5.37 μm NAA. Cultures were maintained either in continuous darkness for 5 weeks, or in the dark for 3 weeks and then transferred to a 16-hour photoperiod. TDZ and the genotype had a significant effect on the number of shoots regenerated. The maximum mean number of shoots regenerated per explant (5.05 ± 1.14) was obtained with 2.27 μm TDZ plus 0.54 μm NAA with the 3-week dark period then light treatment. The highest percent shoot regeneration (38.3) and mean number of shoots (4.13 ± 0.97) was obtained with 6.81 μm TDZ plus 1.07 μm NAA. The highest rooting (27%) of adventitious shoots and number of roots per shoot (2.3 ± 0.2) was obtained with 2.5 μm IBA when shoots were maintained for 7 days in the dark on rooting medium before transfer to a 16-hour photoperiod. The highest rooting (70%) of nodal explant-derived stock cultures and number of roots per shoot (2.7 ± 0.9) was also obtained with 2.5 μm IBA, but when shoots were maintained for 4 days in the dark before transfer to a 16-hour photoperiod. In total, 86% of the plantlets survived acclimatization to the greenhouse and 100% survival after overwintering in cold-storage.

The aim of this study was to evaluate the viability of using Landsat 8 spectral images to estimate water quality parameters and depth in El Guájaro Reservoir. On February and March 2015, two samplings were carried out in the reservoir, coinciding with the Landsat 8 images. Turbidity, dissolved oxygen, electrical conductivity, pH and depth were evaluated. Through multiple regression analysis between measured water quality parameters and the reflectance of the pixels corresponding to the sampling stations, statistical models with determination coefficients between 0.6249 and 0.9300 were generated. Results indicate that from a small number of measured parameters we can generate reliable models to estimate the spatial variation of turbidity, dissolved oxygen, pH and depth, as well the temporal variation of electrical conductivity, so models generated from Landsat 8 can be used as a tool to facilitate the environmental, economic and social management of the reservoir.

The temporary immersion bioreactor has been found to be an important tool for sugarcane micropropagation, allowing higher shoot formation rates and cost reduction. This research was conducted to demonstrate the agricultural value of temporary immersion bioreactor-derived sugarcane plants. The experiment was carried out for about 2 yr to study the field performance of these plants. Two control treatments were also evaluated representing the conventional forms of micro-and macropropagation. Growth of sugarcane stools, first ratoon and the use of micropropagated plants for macropropagation were recorded. Some botanical and chemical characteristics were evaluated. Differences among propagation systems were only found in the first 6 mo. of field growth, regarding the stem length and diameter. Such differences disappeared with the course of the experiment.

In this study, empirical models were generated to estimate water quality parameters, with the objective of showing the benefits of the satellite remote sensing application in the characterization of coastal waters. The study area was Playa Colorada Bay, located in the northwest of Mexico, in the eastern part of the Gulf of California. In two seasons of the year, on-site and laboratory characterizations were carried out to determine the spatial and temporal variation of phosphates (PO4), electrical conductivity (EC), total suspended solids (TSS), turbidity, and pH of water. Samplings were selected to match Landsat 8 satellite overpass in the study area. Radiometric and atmospheric corrections were applied to the images, prior to the generation of the models. The models were generated using the linear regression technique of successive steps; water quality parameters and their logarithms were used as dependent variables, and as independent variables were used corrected reflectance values of Landsat images. The results showed that the concentration of PO4 in the analyzed water samples were higher than those recommended in the Mexican ecological criteria of water quality, to protect the aquatic life of marine water in coastal areas. In autumn, PO4 was correlated with turbidity, T, pH, and TSS. The highest correlation coefficients were presented by TSS with PO4 (r = − 0.979) and pH (r = 0.958). The water quality models that were generated had coefficients of determination (R 2) in the range of 0.637 to 0.955 and show the viability of the application of Landsat 8 images in the characterization of water quality parameters in Playa Colorada Bay. Models allowed the estimation of the distribution of water quality parameters over the whole bay instead of only at the sampling stations, favoring a better understanding of their spatial distribution.

Fragile coastal areas suffer from human activities. Environmental quality is one of the most important aspects in a tourist destination of sun and sand. The quality of bathing water and sand became indicators in the worldwide competition of beach destinations. We studied the water and sand quality along the beach of Puerto Velero, in northern Colombia. Water and sand beach quality were monitored during thirteen months. This allowed identifying the most significant sources of pollution along the beach, and understanding the interrelationship between tourism and the effects on the environment. Linear correlations allow assessing the association between the number of visitors and the physicochemical and microbiological parameters. The number of visitors was directly correlated with the presence of grease and oils, both in water and sand, as well as with fecal coliforms in water. A relation between the suspended solids and the presence of fecal coliforms in water and sand was observed. This statistical approach allows understanding the origin of beach sand and swimming water pollution at tourist beaches.

Heavy metals have become a subject of special concern worldwide, mainly due to high persistence in the environment, toxicity, biogeochemical recycling and ecological risk. Therefore, the objective of this investigation was to analyze the spatial-temporal distribution of heavy metals in water and sediments to determine the environmental status of El Guájaro Reservoir, where such studies have not been developed. Two measurement campaigns (dry and wet period) were carried out and eight sampling stations were selected. A comparison of water and sediment quality parameters with existing national and international regulations was done. Also, heavy metal distribution maps were generated, and the geoaccumulation index was calculated to identify sources and sediments contamination level. Based on the obtained results, agriculture and mining activities are the main causes of the reservoir contamination. This metals levels could be a potential risk for the aquatic life and the populations that are supplied from this water body.

Interploidy crosses between diploid daylily (Hemerocallis) cultivars (2n = 22) and tetraploid cultivars (2n = 44) were performed via in vivo hybridization aiming to produce triploid hybrid germplasm (3n = 33). Plant growth regulator-free MS based medium containing 5 levels of sucrose-1, 2, 3, 4 or 5% was used to optimize the embryo rescue medium. It was determined that the medium supplemented with 3% sucrose gave highest rate of immature hybrid embryo rescue. Thirty-seven hypothetically triploid genotypes were subjected to verification of ploidy status by root tip chromosome counting and flow cytometry. Thirty-one of them were confirmed triploids. These genotypes were in vitro propagated, acclimatized to ex vitro conditions, and planted for future field performance evaluation and environmental testing. The newly developed triploid genotypes could open new horizons for further polyploidy breeding.

Nutrient inputs and biogeochemical cycles in estuaries are strongly influenced by river discharge and suspended particulate matter (SPM). We evaluated temporal differences in nutrient bioavailability and net ecosystem productivity (NEP) and analyzed the effect of SPM on nutrient availability and estuary NEP in the mouth of the Magdalena River, Colombia. In this study, we used the stratified Muddy LOICZ model. Calculated water residence times in the estuary were low (~0.9-2.1 days), as were proportions of dissolved nitrogen (DIN) and phosphorus (DIP) forms (~10-30%) in the total nutrient pool. Dissolved nutrient proportions displayed differences between seasons (transition period [June 2018] and wet [November 2018]), and between the upper and lower, density-stratified water layers. Nutrient adsorption and desorption, associated with SPM in the estuary, determined bioavailable nutrient concentrations. When SPM was incorporated in the Muddy LOICZ model, the output indicated that NEP in the estuary was positive, i.e. gross primary productivity exceeded community respiration (autotrophic), and that there was net retention of nitrogen and phosphorus in the estuary. Primary producers in the autotrophic ecosystem fix sufficient carbon to supply higher trophic levels. Prevalence of fine sediment with high organic matter (OM) content in the Magdalena River, along with turbulence that results in vertical water column mixing, suggest conditions conducive to flocculation. This investigation highlights the importance of the Magdalena River mouth in the transport and processing of sediments and nutrients being discharged to the Caribbean Sea.