1,721,072 research outputs found
The reproductive biology of the olive tree and its relationship to extreme environmental conditions
No full textThe olive fruit develops from the fertilized ovary of the olive flower, so fruit production is directly contingent upon flower formation (number and quality) and subsequent fertilization. In the olive tree, the flowers are born on inflorescences which differentiate from axillary buds formed the previous year along with new shoot and leaf growth. Following a period of winter dormancy in which they are still undifferentiated as reproductive structures, the axillary buds reinitiate growth and commence inflorescence differentiation, an extensive process which requires two to three months and includes the elongation and branching of the inflorescence axis and the formation of the individual flowers. Environmental limitations related to water availability and extreme temperatures may critically impact at different moments during this process, particularly in new areas of olive farming which vary from the strict Mediterranean climate where the olive tree originated and to which it is adapted. Specific cases which will be examined here are the effect of water deficits on inflorescence development, frost damage to floral buds, cold accumulation requirements for bud break, and high temperature effects on inflorescence development and fertilization.Peer Reviewe
Cellular processes of fruit tissues in response to water deficits
No full textResumen del trabajo presentado en el XIV International Plant Water Relations Symposium, celebrado en Madrid (España) del 03 al 05 de octubre de 2018.Fruit tissue response to water deficit is affected by the cellular development, differentiation, and growth of the different tissues which compose the fruit. This presentation explores that response in the mesocarp and endocarp cells of drupes, a fruit type widely present in commercial fruits. The mesocarp or fleshy part of the drupe pericarp is a tissue composed of parenchymatic cells in which division and expansion interact to produce expansive growth. The division-expansion interaction is also involved in the response to water. Water stress tends to reduce cell size rather than cell number, even when water status differences occur early in fruit growth when cell division is highly active. Mesocarp cell number reduction, though, which may not be visible until later fruit growth, is observed under more extreme deficits. Ultimately, division and expansion are both involved in the recuperation of waterstress-reduced mesocarp growth following re-watering. In contrast to the mesocarp, development of the endocarp, the innermost pericarp tissue, entails dense cell wall sclerification in addition to cell division and expansion. Water stress appears to prompt the initiation of sclerification, and by thus blocking the capacity for division and expansion drives the end of endocarp expansion. However while the onset of sclerification is earlier under water stress, full secondary cell wall deposition takes place much more slowly due to reduced production of the necessary photoasimilates, a secondary water-stress effect. In addition to deepening our understanding of fruit growth, the response of cellular development of the different fruit tissues to water stress provides new information for optimizing fruit growth by crop management practices
Calendar of olivebud differentiation and development
No full textTrabajo presentado en el Workshop Olive cultivar adaptation and climatic change, celebrado en Baeza el 2 y 3 de noviembre de 2017.N
Olive fruit cellular processes: implications for growth, quality and management
No full textResumen del trabajo presentado en la 6th International Conference on the Olive Tree and Olive Products, celebrada en Sevilla (España) del 15 al 19 de octubre de 2018.Fruit developmental depends on the cellular processes in the fruit tissues - cell division, expansion, and differentiation. Studies to better define and quantify these processes provide a more comprehensive view of their role, timing, interaction, and the factors which influence them, sometimes contrasting with traditional perceptions. While the highest rate and amount of mesocarp cell division is confirmed to occur immediately following bloom, increase in cell number continues throughout much of fruit development, although at a reduced rate. Cell number forms the basis of cultivar differences in fruit size, water status tends to impact cell size rather than number, and crop load, closely linked to substrate interactions, appears to affect cell number to a greater degree than cell size. Olive mesocarp oil metabolism may be less linked to cell division and expansion than previously hypothesized. Pit hardening entails the initiation and completion of individual cell sclerification, events which respond to different factors and vary among cells, and are coordinated with endocarp expansive growth. Endocarp sclerification is affected by both water and assimilate status, and appears to drive the end of endocarp expansion rather than vice versa. The developmental patterns of the different fruit tissues, and their associated substrate demands, provide new information for interpreting and thus optimizing olive fruit growth by crop management practices
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
- …
