1,720,976 research outputs found
Multiple linear regression and linear mixed models identify novel traits of salinity tolerance in Olea europaea L
No full text: Olive can be considered as moderately tolerant to salinity, with marked differences among cultivars. In the present study, two olive cultivars with different salt tolerance, 'Leccino' (sensitive) and 'Frantoio' (tolerant), were treated with 120 mM of NaCl for 30 days. We measured the expression of genes involved in the management of sodium in the leaves, such as NHX, SOS1 and H+ ATPase, and the concentration of Na+, K+, Mn2+, Mg2+ and Ca2+ in the roots, bark, xylem and leaves of the olive plants. The results were analyzed with multiple linear models and mixed models. Furthermore, we utilized the analysis of covariance to find significant relationships in our data. Both cultivars significantly reduced net photosynthesis and increased water-use efficiency after 30 days of treatment. Sodium accumulated significantly in the roots of both cultivars, and 'Leccino' plants were also able to translocate it to the leaves and the bark. The NHX and vacuolar ATPase subunit E genes were significantly overexpressed in both the cultivars treated with NaCl. The SOS1, ATPase11 and ATPase8 genes were overexpressed in 'Frantoio'. The covariance between gene expression and element concentrations data was analyzed to identify significant interactions between cultivars and treatments. Na+ accumulation in the roots of 'Frantoio' was positively related to the accumulation of K+, Mn2+, Mg2+ and Ca2+ in the xylem, bark and leaves. 'Frantoio' capability to mobilize elements, especially Ca2+, together with the overexpression of key genes for sodium management, could be crucial for salt tolerance
Root physiological and transcriptional response to single and combined S and Fe deficiency in durum wheat
No full textA number of connections and insights are emerging regarding the molecular and physiological basis of Fe and S interplay response of combined Fe and S starvation of durum wheat roots are here presented. Microarray analysis revealed that 128 transcripts were commonly modulated by both single and combined deficiencies, thus representing the “core” set of transcripts involved in the responses both to S and Fe shortage, whereas a total of 509 transcripts were modulated only by the simultaneous deficiency of S and Fe. Interestingly, among these latter, most of the genes of nitrate uptake and assimilation were down-regulated, while those involved into ammonium uptake were up-regulated as confirmed by the decrease in nitrate reductase enzyme activity. Transcripts playing a role into phosphate uptake were down-regulated in agreement with the observed lower P accumulation in roots. Combined deficiency mainly up-regulated transcripts involved with oxidative stress response although the related enzyme activities did not appear to differ significantly. Results allowed the identification of transcripts that are specific as well as those that are shared among single and combined deficiency responses, thus providing a starting point for detailed studies on candidate genes to improve the understanding of the molecular basis of nutrient acquisition
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
Effect of three safeners on sulfur assimilation and iron deficiency response in barley (Hordeum vulgare) plants
No full textBACKGROUND: Safeners are agrochemicals used in agriculture to protect crops from herbicide injuries. They act by stimulating herbicide metabolism. As graminaceous plants, to cope with iron (Fe) deficiency, activate sulfur (S) metabolism and release huge amounts of Fe-chelating compounds, or phytosiderophores (PSs), we investigated, in barley plants (Hordeum vulgare, L.) grown in Fe deficiency, the effects of three safeners on two enzymes of S assimilation, cysteine (Cys) and glutathione (GSH), and PS release. Finally, we monitored the root Fe content in plants treated with the most effective safener. RESULTS: Generally, all the safeners activated S metabolism and increased Cys and GSH contents. In addition, the safened plants excreted higher levels of PSs. Given that mefenpyr-diethyl (Mef) was the most effective in causing these effects, we assessed the Fe concentration inMef-treated barley and found higher Fe levels than those in untreated plants.
CONCLUSION: The three safeners, in different ways but specifically, activated S reductive metabolism and regulated Cys and GSH contents, PS release rate and Fe content (Mef-treated barley). The results of this research provide new indications of the biochemical and physiological mechanisms involved in the safening action
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Does Fe accumulation in durum wheat seeds benefit from improved whole-plant sulfur nutrition?
No full textSulphur (S) and iron (Fe) are an essential macro- and micronutrients for plant growth and development. A balanced supply of S and Fe for plants is of major importance since it has been demonstrated that plant capability to take up and accumulate Fe is strongly dependent on S availability in the growth medium and vice versa. In fact, that Fe deficiency adaptation requires the adjustment of S uptake and assimilation rate. Furthermore, it has been demonstrated that providing S above adequate concentrations may result in the improvement of Fe use efficiency in wheat plants and this S nutritional effect seems to be especially advantageous for plants grown under severe Fe limitation.
Aim of this study was to evaluate whether and to what extent the changes in S nutrition affect Fe accumulation into grains and whether grain Fe concentrations are significantly correlated with the concentration of Fe in the vegetative tissue.
This approach might represent an important tool to realize the improvement of the nutritional value of food crops by increasing Fe content (agronomic biofortification) through soil and crop management strategies which allow to may prevent Fe deficiency in crops without additional input of Fe fertilizers.
Durum wheat plants were grown on sand/perlite mixture with sufficient (1.2 mM) and high (2.5 mM) S supplies and with 10 or 80 M Fe-EDTA during the life cycle.
In particular, we will discuss the effect of S supply on plant growth parameters (fresh and dry weight and chlorophyll content) and on total S accumulation rate at both leaf and seed level. In addition, the relative changes of the leaf and seed ionome induced by different nutritional conditions were evaluated by using inductively coupled plasma-optical emission spectroscopy (ICP-OES). Finally, whole seeds and seed sections were subjected toinvestigated with micro-focused X-ray fluorescence (XRF) imaging to clarify the elemental distribution maps.of several elements, including S and Fe. Significant differences in the concentration and distribution of a number of elements could be observed according to the different treatments
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