Pollen production in the Poaceae family

Total pollen production per inflorescence was studied in the most important species of the Poaceae family in the city of Córdoba in order to further our knowledge of the partial contribution of each species of this family to the total amount of pollen released into the atmosphere.

The contribution of grasses in a given area was estimated by counting the number of inflorescences in an area of one square meter. Four different representative areas of the city were selected. The number of pollen grains per anther and flowers per inflorescence was also estimated in order to obtain total pollen production per inflorescence.

Pollen production per inflorescence ranged from 14,500 to more than 22,000,000 pollen grains, the amount being clearly higher in the perennial species. Pollen production per square meter was higher in the mountains near the city and lower in areas of abandoned crops.

Only a few species are responsible for the majority of pollen produced. A phenological study is necessary in order to determine the temporal distribution of this pollen production and subsequent shedding.     

Pollen biology in four Mediterranean Quercus species

Potential pollen production, viability and germination were studied in the most important species of Quercus in the mountains of Córdoba to determine the contribution of each species to the total amount of airborne pollen. The results were compared over two consecutive years with different rainfall patterns. The viability of pollen grains was determined at anther opening, and during the pollination period, in order to determine potential pollination capacity. Results indicated that there were differences in the number of pollen grains produced by stamen in the four species. Equally, there were differences in the number of flowers among the species, being Q. suber the species with higher number of catkins groups and flowers per individual tree. Total pollen production per tree can be summarized in the following proportion: 1: 3: 3: 6 (Q. coccifera, Q. ilex ssp. ballota, Q. faginea and Q. suber). Potential pollen viability was estimated using the Fluorochromatic Reaction (FCR) and a germination assay. The results have shown that Quercus potential pollen viability is high and declines slowly with time. Q. coccifera was the species with the highest percentage of germination, with Q. suber being the lowest.     

Anthocyanins Double the Shelf Life of Tomatoes by Delaying Overripening and Reducing Susceptibility to Gray Mold

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Experimental set up for the irradiation of biological samples and nuclear track detectors with UV C

Aim

In this work we present a methodology to produce an “imprint” of cells cultivated on a polycarbonate detector by exposure of the detector to UV C radiation.

Background

The distribution and concentration of ¹⁰B atoms in tissue samples coming from BNCT (Boron Neutron Capture Therapy) protocols can be determined through the quantification and analysis of the tracks forming its autoradiography image on a nuclear track detector. The location of boron atoms in the cell structure could be known more accurately by the simultaneous observation of the nuclear tracks and the sample image on the detector.

Materials and Methods

A UV C irradiator was constructed. The irradiance was measured along the lamp direction and at different distances. Melanoma cells were cultured on polycarbonate foils, incubated with borophenylalanine, irradiated with thermal neutrons and exposed to UV C radiation. The samples were chemically attacked with a KOH solution.

Results

A uniform irradiation field was established to expose the detector foils to UV C light. Cells could be seeded on the polycarbonate surface. Both imprints from cells and nuclear tracks were obtained after chemical etching.

Conclusions

It is possible to yield cellular imprints in polycarbonate. The nuclear tracks were mostly present inside the cells, indicating a preferential boron uptake.     

Vertical Redistribution of Soil Organic Carbon Pools After Twenty Years of Nitrogen Addition in Two Temperate Coniferous Forests

Nitrogen (N) inputs from atmospheric deposition can increase soil organic carbon (SOC) storage in temperate and boreal forests, thereby mitigating the adverse effects of anthropogenic CO₂ emissions on global climate. However, direct evidence of N-induced SOC sequestration from low-dose, long-term N addition experiments (that is, addition of < 50 kg N ha⁻¹ y⁻¹ for > 10 years) is scarce worldwide and virtually absent for European temperate forests. Here, we examine how tree growth, fine roots, physicochemical soil properties as well as pools of SOC and soil total N responded to 20 years of regular, low-dose N addition in two European coniferous forests in Switzerland and Denmark. At the Swiss site, the addition of 22 kg N ha⁻¹ y⁻¹ (or 1.3 times throughfall deposition) stimulated tree growth, but decreased soil pH and exchangeable calcium. At the Danish site, the addition of 35 kg N ha⁻¹ y⁻¹ (1.5 times throughfall deposition) impaired tree growth, increased fine root biomass and led to an accumulation of N in several belowground pools. At both sites, elevated N inputs increased SOC pools in the moderately decomposed organic horizons, but decreased them in the mineral topsoil. Hence, long-term N addition led to a vertical redistribution of SOC pools, whereas overall SOC storage within 30 cm depth was unaffected. Our results imply that an N-induced shift of SOC from older, mineral-associated pools to younger, unprotected pools might foster the vulnerability of SOC in temperate coniferous forest soils.

     

Noemi Controls Production of Flavonoid Pigments and Fruit Acidity and Illustrates the Domestication Routes of Modern Citrus Varieties

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Endophytes from wild cereals protect wheat plants from drought by alteration of physiological responses of the plants to water stress

Endophytes contribute to plant performance, especially under harsh conditions. We therefore hypothesized that wild plants have retained beneficial endophytes that are less abundant or not present in related crop plants. To test this hypothesis, we selected two endophytes that were found in Sharon goatgrass, an ancestor of wheat, and tested their effect on bread wheat. Both endophytes infected wheat and improved sustainability and performance under water-limited conditions. To determine how the endophytes modify plant development, we measured parameters of plant growth and physiological status and performed a comparative metabolomics analysis. Endophyte-treated wheat plants had reduced levels of stress damage markers and reduced accumulation of stress-adaptation metabolites. Metabolomics profiling revealed significant differences in the response to water stress of endophyte-treated plants compared with untreated plants. Our results demonstrate the potential of endophytes from wild plants for improvement of related crops and show that the beneficial effects of two endophytes are associated with alteration of physiological responses to water-limited conditions.     

Precise Gene Editing Preserves Hematopoietic Stem Cell Function following Transient p53-Mediated DNA Damage Response

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