1,720,962 research outputs found
Il ricino, la pianta e la coltura. Possibilità di adattamento e di conveniente introduzione nel nostro Paese
No full textThe disbudding (nipping) x genotype interaction demonstrates different perennial habits in castor-oil plant (Ricinus communis L.).
No full textIn castor-oil plant the perennial habit contrasts with the combine harvester. A hypothetical non-branching annual castor plant is based on the stop of the meristem activity in the axillary buds and/or in the cambium. To investigate the relationship between the cambial activity and the axillary bud outgrowth, an experiment on the axillary bud excision was carried out in the field with 64 inbred lines. The stems of treated plants were disbudded, while, as control, the same number of plants was untreated. At the harvest of the first raceme, the treated plants had obviously only the main stem whereas the control plants resulted normally branched. The disbudding treatment heavily affected the stem diameter and interacted with the genotypes. The seed production and the 1000-seed weight were significantly affected by the disbudding treatment. This research, aimed at solving a cultivation problem, can also contribute to better know the semelparity in plants
Reduced Growth and Nitrogen Uptake During Waterlogging at Tillering Permanently Affect Yield Components in Late Sown Oats
Get PDFIn Mediterranean Europe, winter cereals can experience soil waterlogging starting from crop establishment up to stem elongation and, in late sowings, this stress is combined with temperatures favorable to plant metabolism. Oats response to waterlogging has been rarely investigated, but these species seems to recover better than other cereals. In a 2-year experiment, Avena sativa and Avena byzantina were sown at the end of winter in pots placed outdoors. At the two-tiller stage, plants were exposed to waterlogging for periods ranging from 0 to 35 days. The dry weight and the N-concentration of shoots and roots were determined on waterlogged plants and drained controls at the start and the end of each waterlogging period, and at maturity. At maturity, the grain yield and its components were determined. To relate oat response to its specific morphological and developmental traits, results were compared to the published results in wheat and barley. Both oat species suffered severe damage during waterlogging: the uptake of nitrogen and the N-concentration of shoots were reduced after 7 days, tiller initiation and root growth after 14 days, and shoot growth after 21 days. All plants survived waterlogging, and the relative growth rates of roots and shoots and the net uptake rate of nitrogen were resumed during recovery. Nevertheless, at maturity, the straw and root biomass were markedly lower with all waterlogging durations, and grain yield decreased by 42% up to approximately 81% following an asymptotic equation. The most affected yield components were the number of panicles per plant and the number of kernels per panicle, but their relative sensitivity changed according to waterlogging duration. The slight increase in tiller fertility in response to short waterlogging and the small and irregular decrease in the number of kernels per spikelet suggest that the two oats could recover the initiation and size of inflorescences better than other winter cereals. Despite this, waterlogging in spring was highly detrimental to these oats because of severe damage under waterlogging and because of the inability to initiate new tillers and adequately resume root growth during recovery, once plants had achieved the phase of stem elongation
Accumulation and Remobilization of Dry Matter and Nitrogen in Oats As Affected By Genotype and Nitrogen Fertilization
No full textOptimized Nitrogen (N) management strategies are needed to maximize oat (Avena spp) production.
In Mediterranean conditions, warm temperatures and water scarcity occurring during grain filling reduce photosynthesis rate, limiting the contribution of current assimilates to grain filling. In these conditions, remobilization of pre-anthesis reserves becomes particularly important and Nitrogen (N) grains of cereals is derived largely from remobilization from vegetative tissue.
To determine whether genotypic differences in dry matter and nitrogen assimilation exist and are consistent across N fertilization, this study reports on comparisons of a diverse set of oat genotypes grown with different N rates in Central Italy.
Field experiments were carried out in two consecutive years and in both years, experimental treatments consisted of five oat genotype and three N rates. The oat genotypes were: Avena sativa L., cv. Genziana (Bulban/Weibull 17578//Moore/Angelica, year of release 2002), Avena byzantina Koch, cv. Argentina (line no. 109 from an Argentinian population, year of release 1969), line 54 (Argentina/Genziana), dwarf line 27 (Argentina/Tropicale), and naked line (Penncomp40/Argentina/Argentina//Manoire). The N rates were: 0, 80 and 160 kg N ha-1.
Plants were sampled at two harvesting stages: heading (Zadocks stage 59) and physiological maturity (Zadocks stage 92). The post-heading dry matter (DM) and N accumulation were calculated as the difference between DM and N content of the aerial plant part at physiological maturity and at heading. Then, remobilization on DM and N (DMR and NR) during grain filling were calculated as:
- DMR = DM of the aerial plant part at heading - (DM of leaves + culms + chaff at maturity);
- NR = N content of the aerial plant part at heading - (N content of leaves + culms + chaff at maturity).
Oat species displayed different differences in remobilization and NHI values depending on N fertilization rate
Le caratteristiche dei fagioli della Lucchesia. Caratterizazione morfologica, agronomica e prove di campo
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Variations on the Author
Get PDF“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
Get PDFWe 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
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