Effect of salinity on the physiology of peanut variety 73-33 (Arachis hypogaea L.)

Peanut (Arachis hypogaea, L.) is an annual papilionaceous oilseed legume cultivated on nearly 25 million hectares in tropical and temperate zones due to its remarkable plasticity to temperature and water requirements. In Senegal, peanut is produced in rural areas where they are the main source of agricultural income. Variety 73-33 is cultivated in the river valley and the groundnut basin is subject to the influence of salinization affecting four of Senegal's ecogeographic zones. Studies conducted with randomized full-block experimental set-up in the laboratory and under semi-controlled greenhouse conditions have shown the effect of different concentrations of NaCl on the peanut variety 73-33: 0mM; 25mM; 50mM; 100mM; 200mM; 300mM; 400mM; 500mM for germination and 0mM; 25mM; 50mM; 100mM for growth growth and chlorophyll production. The parameters which were measured are: the germination rate (ten days after sowing), the number of nodules, the number of gynophores, the dry biomass and the production of chlorophyll at twenty, forty and seventy-five days after sowing. Germination is significantly negatively affected from 400mM. Twenty days after sowing there is a significant difference between the control and the other treatments for the production of chlorophyll a (Chla) only. Forty days after sowing, the production of chlorophyll a and total chlorophyll shows a very highly significant difference between all the treatments. The dry biomass only shows a significant difference from 100mM. Seventy-five days after sowing, the dry biomass and the number of gynophores are significantly reduced by the salinity from 25mM.

Potential of a mixed culture of microalgae for accumulation of beta-carotene under different stress conditions

Beta-carotene, a pigment found in plants, is mainly produced by microalgae. Nevertheless, this production has only been investigated in pure cultures. Beta-carotene production through mixed culture eliminates the costly procedure of sterilization and contamination prevention needed for pure cultures. In this study, for the first time, the growth, beta-carotene, and chlorophyll production of a mixed culture of microalgae from Caspian Sea was investiagted under different stress conditions. At the condition of tripled light intensity and nitrogen starvation, beta-carotene content increased from 18.03 to 43.8 and 46.5 mol beta-carotene g−1 protein, respectively. However, the salinity of 4 mol L−1 caused the beta-carotene content to fall to zero. The blank sample reached a constant value of 23 mol beta-carotene g−1protein. The comparable results with the specific monoculture species exhibit the high potential of a mixed culture of microalgae for beta-carotene production without need of the high sterilization cost. Nevertheless, more research is needed for where it can be a good substitute for pure culture.

Silicon mitigates nutritional stress in quinoa (Chenopodium quinoa Willd.)

Nutritional deficiency is common in several regions of quinoa cultivation. Silicon (Si) can attenuate the stress caused by nutritional deficiency, but studies on the effects of Si supply on quinoa plants are still scarce. Given this scenario, our objective was to evaluate the symptoms in terms of tissue, physiological and nutritional effects of quinoa plants submitted to nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) deficiencies under Si presence. The experiment consisted of a factorial scheme 6 × 2, using a complete solution (CS), -N, -P, -K, -Ca, -Mg combined with absence and presence of Si (1.5 mmol L−1). Symptomatic, physiological, nutritional and evaluation vegetative were performed in quinoa crop. The deficiencies of N, P, K, Ca and Mg in quinoa cultivation caused visual symptoms characteristic of the deficiency caused by respective nutrients, hence decreasing the plant dry mass. However, Si supply attenuated the deficiency effects by preserving the photosynthetic apparatus, increasing the chlorophyll production, increasing the membrane integrity, and decreasing the electrolyte leakage. Thus, the Si supply attenuated the visual effects provided by deficiency of all nutrients, but stood out for N and Ca, because it reflected in a higher dry mass production. This occurred because, the Si promoted higher synthesis and protection of chlorophylls, and lower electrolyte leakage under Ca restriction, as well as decreased electrolyte leakage under N restriction.

Wavelength-dependent effects of artificial light at night on phytoplankton growth and community structure

Artificial light at night (ALAN) is a disruptive form of pollution, impacting physiological and behavioural processes that may scale up to population and community levels. Evidence from terrestrial habitats show that the severity and type of impact depend on the wavelength and intensity of ALAN; however, research on marine organisms is still limited. Here, we experimentally investigated the effect of different ALAN colours on marine primary producers. We tested the effect of green (525 nm), red (624 nm) and broad-spectrum white LED ALAN, compared to a dark control, on the green microalgae Tetraselmis suesica and a diatom assemblage. We show that green ALAN boosted chlorophyll production and abundance in T. suesica . All ALAN wavelengths affected assemblage biomass and diversity, with red and green ALAN having the strongest effects, leading to higher overall abundance and selective dominance of specific diatom species, some known to cause harmful algal blooms. Our findings show that green and red ALAN should be used with caution as alternative LED colours in coastal areas, where there might be a need to strike a balance between the effects of green and red light on marine primary producers with the benefit they appear to bring to other organisms.

Bioreactor Co-Cultivation of High Lipid and Carotenoid Producing Yeast Rhodotorula kratochvilovae and Several Microalgae under Stress

The co-cultivation of red yeasts and microalgae works with the idea of the natural transport of gases. The microalgae produce oxygen, which stimulates yeast growth, while CO2 produced by yeast is beneficial for algae growth. Both microorganisms can then produce lipids. The present pilot study aimed to evaluate the ability of selected microalgae and carotenogenic yeast strains to grow and metabolize in co-culture. The effect of media composition on growth and metabolic activity of red yeast strains was assessed simultaneously with microalgae mixotrophy. Cultivation was transferred from small-scale co-cultivation in Erlenmeyer flasks to aerated bottles with different inoculation ratios and, finally, to a 3L bioreactor. Among red yeasts, the strain R. kratochvilovae CCY 20-2-26 was selected because of the highest biomass production on BBM medium. Glycerol is a more suitable carbon source in the BBM medium and urea was proposed as a compromise. From the tested microalgae, Desmodesmus sp. were found as the most suitable for co-cultivations with R. kratochvilovae. In all co-cultures, linear biomass growth was found (144 h), and the yield was in the range of 8.78–11.12 g/L of dry biomass. Lipids increased to a final value of 29.62–31.61%. The FA profile was quite stable with the UFA portion at about 80%. Around 1.98–2.49 mg/g CDW of carotenoids with torularhodine as the major pigment were produced, ubiquinone production reached 5.41–6.09 mg/g, and ergosterol yield was 6.69 mg/g. Chlorophyll production was very low at 2.11 mg/g. Pilot experiments have confirmed that carotenogenic yeasts and microalgae are capable of symbiotic co-existence with a positive impact om biomass growth and lipid metabolites yields.

Bioprospecting of Rhizosphere-Resident Fungi: Their Role and Importance in Sustainable Agriculture

Rhizosphere-resident fungi that are helpful to plants are generally termed as ‘plant growth promoting fungi’ (PGPF). These fungi are one of the chief sources of the biotic inducers known to give their host plants numerous advantages, and they play a vital role in sustainable agriculture. Today’s biggest challenge is to satisfy the rising demand for crop protection and crop yield without harming the natural ecosystem. Nowadays, PGPF has become an eco-friendly way to improve crop yield by enhancing seed germination, shoot and root growth, chlorophyll production, and fruit yield, etc., either directly or indirectly. The mode of action of these PGPF includes the solubilization and mineralization of the essential micro- and macronutrients needed by plants to regulate the balance for various plant processes. PGPF produce defense-related enzymes, defensive/volatile compounds, and phytohormones that control pathogenic microbes’ growth, thereby assisting the plants in facing various biotic and abiotic stresses. Therefore, this review presents a holistic view of PGPF as efficient natural biofertilizers to improve crop plants’ growth and resistance.

Ecophysiological response of Astronium fraxinifolium (Anacardiaceae) in degraded and non-degraded brazilian Cerrado

Plants native from Cerrado generally have peculiar characteristics that allow tolerating water and nutritional stress. Astronium fraxinifolium is a Anacardiaceae tree of from Brazilian Cerrado. The aim of this research was to characterize A. fraxinifolium leaves morphophysiologically, in order to recognize characteristics related to acclimatization of the species in different soil conditions. Two populations of A. fraxinifolium were sampled in different study areas, A1 (Degraded Soil) and A2 (“Undegraded Soil”). Nitrogen compounds, total carbohydrates, chlorophyll, nutritional content, stomatal density and gas exchanges were quantified, comparing the areas. A high number of stomata was observed on the abaxial surface of A. fraxinifolium leaves, with a higher density occurring in A1 individuals. The values of chlorophyll and boron content were significantly higher in A2 plants. It’s possible that the lowest concentration of boron in A1 plants is related to chlorophyll production. Regardinf the other analysis, there weren’t significant differences between the areas. The results show that this species undergoes changes in production of chlorophyll, but liquid photosynthesis isn’t impaired, considering the low chlorophyll content in A1 being compensated by the higher stomatal density. Thus, these changes may be the result of acclimating this species to different environmental conditions to which it’s exposed.

Pengaruh Jenis Media Kultur Terhadap Konsentrasi Biomassa Nannochloropsis sp.

This study aims was to determine the effect of media type on biomass concentration and chlorophyll content in Nannochloropsis sp. and determine the best type of media for the highest chlorophyll production in this microalgae. The variables observed were the optimum growth and harvest time for Nannochloropsis sp., biomass concentration, and chlorophyll content from biomass extraction. The results showed that the wet biomass concentration value of Nannochloropsis sp. is 10.98 g / L for Walne media, and 5.10 g / L for Guillard media. Chlorophyll content extracted from dry biomass in microalgae Nannochloropsis sp. with Walne culture media was higher than Guillard media with a total chlorophyll of 353.045 µg / mL. So that the best chlorophyll production is cultivation using Walne culture media.

Home climate and habitat drive ecotypic stress response differences in an invasive grass

Invasive plants and agricultural weeds are a ubiquitous and ever-expanding threat to biosecurity, biodiversity and ecosystem services. Many of these species are known to succeed through rapid adaptation to biotic and abiotic stress regimes, often in highly disturbed systems. Given the current state of evidence for selection of weedy genotypes via primary physiological stresses like drought, flooding, heat, cold and nutrient deficiency, we posit that adaptation to land management regimes which comprise suites of these stresses can also be expected. To establish this link, we tested adaptation to water and nutrient stresses in five non-agricultural and five agricultural populations of the invader Johnsongrass (Sorghum halepense) sampled across a broad range of climates in the USA. We subjected seedlings from each population to factorial drought and nutrient stresses in a common garden greenhouse experiment. Agricultural and non-agricultural ecotypes did not respond differently to experimentally applied stresses. However, non-agricultural populations from more drought-prone and nutrient-poor locations outperformed their agricultural counterparts in shoot allocation and chlorophyll production, respectively. We also found evidence for root allocation adaptation to hotter climates, in line with other C4 grasses, while greater adaptation to drought treatment was associated with soil organic carbon (SOC)-rich habitats. These findings imply that adaptation to land-use types can interact with other macrohabitat parameters, which will be fluctuating in a changing climate and resource-needy world. We see that invasive plants are poised to take on novel habitats within their introduced ranges, leading to complications in the prevention and management of their spread.