1,720,978 research outputs found
Physiological responses of white clover clones to ozone in the 2000 ICP-Crops experiment
No full textThe Oxidative Paradox in Low Oxygen Stress in Plants
No full textReactive oxygen species (ROS) are part of aerobic environments, and variations in the availability of oxygen (O2) in the environment can lead to altered ROS levels. In plants, the O2 sensing machinery guides the molecular response to low O2, regulating a subset of genes involved in metabolic adaptations to hypoxia, including proteins involved in ROS homeostasis and acclimation. In addition, nitric oxide (NO) participates in signaling events that modulate the low O2 stress response. In this review, we summarize recent findings that highlight the roles of ROS and NO under environmentally or developmentally defined low O2 conditions. We conclude that ROS and NO are emerging regulators during low O2 signalling and key molecules in plant adaptation to flooding conditions
OZONE DISTRIBUTION IN CENTRAL ITALY AND ITS EFFECTS ON CROP PRODUCTIVITY
No full textThe focus of the present study was to assess the ozone levels in a typical area of the Mediterranean basin, viz. Tuscany (central Italy). Eighty-thousand hourly mean ozone concentrations were recorded by 10 automatic analysers in the districts of Florence, Pisa, Lucca and Prato, from May to September 1995 to 1997. The highest daily mean concentrations were reached in Florence, with a maximum hourly average of 197 ppb. In Lucca and Pisa, the peaks were close to 100 ppb. Data from Prato were much lower. Long-term critical levels for vegetation, as set by United Nations Economic Commission for Europe (UNECE), were constantly exceeded in Florence and Pisa, occasionally in Lucca, never in Prato. The results were used to fit exposure/yield response relationships proposed by UNECE and US National Crop Loss Assessment Network for some important crops. The estimated yield losses varied in Florence from 8% for corn and alfalfa to 27% for soybean, in Pisa from 5% for corn to 24% for soybean, in Lucca from 3% for corn to 17% for soybean. A preliminary economic estimate for corn, wheat, barley, soybean, tomato and alfalfa, calculated annual damage to be 4.6 M Euro in Florence, 0.5 M Euro in Lucca and 3 M Euro in Pisa. The picture must be regarded as only partial, as exposure/yield response relationships for important Italian crops (such as grapevine and vegetables) are not available
MAPPING OZONE CRITICAL LEVELS FOR VEGETATION IN CENTRAL ITALY
No full textWithin the framework of the UN-ECE Convention on Long-Range Trans-boundary Air Pollution, critical ozone levels for forest trees and crops have been determined. This paper shows the mapping results of short and long-term threshold exceedances in an area of Central Italy. Eighty-thousand hourly mean ozone concentrations were recorded and computed to evaluate the potential distribution of the pollutant in the area. The results suggest that the threshold is frequently exceeded in the summer, and this may be very critical for the plants' health
Turning earthworms into moonworms: Earthworms colonization of lunar regolith as a bioengineering approach supporting future crop growth in space
Full text linkThe earthworms beneficial effects on soils may be promising to improve lunar soil fertility,
enabling the use of local substrates for space farming. Herein, we investigated the effects of the
lunar regolith simulant (LHS-1) at different concentrations in cow manure mixtures on the survival
and fitness of Eisenia fetida. During 14 and 60-day experiments, although E. fetida showed an
increased mortality with LHS-1 alone, most of the population survived. More numerous tunnels
were observed when exposed to the higher concentrations of LHS-1 (poor in nutrients for
earthworms). This may be related to an increased mobility for food search. The cocoons production
was not affected by different substrate treatments, except for the highest concentration of
LHS-1. No effects of different LHS-1 concentrations on the amount of ingested substrate were
recorded. This study shows that E. fetida can potentially colonize lunar regolith representing a
future valuable biological tool for supporting crops growth on the Moon
Molecular analysis of a sunflower gene encoding an homologous of the B subunit of a CAAT binding factor
No full textA genomic DNA fragment containing the entire LEAFY COTYLEDON1-LIKE (HaL1L) gene was
obtained by the Chromosome walking technique and it was confirmed and elongated by the screening
of a sunflower genomic DNA BAC Library. HaL1L encodes a NF-YB of a CCAAT box-binding factor (NFY)
involved in the genus Helianthus in early stages of zygotic and somatic embryogenesis. In the HaL1L
5'-flanking region, elements peculiar to a putative TATA-box promoter and two "CG isles" were
identified. An investigation on the methylation status of the CG rich DNA regions showed that
differentially methylated cytosines were recognizable in DNA of embryos at the fifth day from
pollination in comparison to the leaf DNA. These data suggested epigenetic regulation of HaL1L
transcription carried out by methylation of cytosine residues during plant development. The
nucleotide sequences were also analyzed to individuate cis-regulatory elements involved in the HaL1L
regulation by other transcription factors (TFs). One of the most intriguing motifs is WUSATA. It
represent the target sequence for the TF WUSCHEL, which could be involved in the complex regulation
system controlling embryo development. Noteworthy, the presence of auxin (ARE) and abscisic acid
(ABRE) responsive motifs in the HaL1L promoter region suggested an hormonal involvement in the
expression control of this gene. Finally, a control at translational level by a temporary unavailability of
pre-synthesized HaL1L mRNA could be also supposed for the presence of a cytoplasmic
polyadenylation signal identified in the 3'-downstream region
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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