1,720,996 research outputs found
Tubular adenoma of choroid plexus: a case report.
No full textA case of choroid plexus neoplasm histologically composed of tubular structures lined by a layer of cuboidal epithelium is reported. The neoplasm was located in the fourth ventricle of a 26-year-old man. The intense positivity for antisera anti-vimentin, anti-cytokeratin, anti-EMA and anti-S100 protein exhibited by these cells was consistent with choroid plexus origin. The patient is alive and in good health 5 years after surgery. The lesion represents a benign choroid plexus neoplasm not previously reported. The name "tubular adenoma of choroid plexus" is suggested for this variant
Apricot flower bud dormancy: main morphological, anatomical and physiological features related to winter climate influence.
No full textThis review examines recent advances regarding flower bud dormancy in apricot, focusing on biological, anatomical,
and physiological processes which occur during the induction and depth of dormancy. In a scenario of global
climate change, the relationship between endodormancy and winter climate influence is discussed. Dormancy regulation
is a complex process necessary for plant survival and development. In fruit species, the knowledge of mechanisms controlling
dormancy and establishing its release appears crucial for successful yields. Specific studies have suggested that,
when the flower buds are apparently inactive, slow and gradual changes occur in the whorls: organogenesis, such as
microsporogenesis processes and vascular connections take place during the entire dormancy period. It has been indicated
that an asynchronism between biological (i.e. endodormancy release, microsporogenesis evolution), anatomical (i.e.
xylem vessel differentiation) and biochemical (i.e. changes in metabolic compounds and enzymes) events could represent
further causes determining an inconstant rate of blooming. Temperature is the main factor involved in dormancy triggering
and releasing. In the perspective of global warming, mild winter temperatures could greatly impact apricot ecological
cropping systems. Phenological process-based models are considered to be the best tool to study the climatic changes and
subsequent expected phenology variation (dormancy and flowering). A new model, calibrated and validated on apricot
cultivars, is proposed to predict the dormancy release date in a future scenario
Study on the morphological evolution of bud break in Vitis vinifera L.
No full textThe aims are to evaluate morpho-anatomical bud
development during dormancy and to compare the heat
requirement needed to start bud break in several grapevine
cultivars characterised by different geographic
origins. A detailed description is presented of the bud
growth stages of Vitis vinifera cultivars to contribute
to the standardisation of national and international
testing systems of fruit growing. Based on the general
BBCH-scale, the codes describe the first stages of budbreak
in several cultivars with different geographical
origins. Dormancy release was evaluated both under
natural and forcing conditions, appropriate method to
establish the budbreak of deciduous species. The cultivars
were characterised in relation to the achievement
of complete bud scale opening stage (03 of BBCH scale)
which is suggested to consider as an early and indicator
of budbreak.The aims are to evaluate morpho-anatomical bud
development during dormancy and to compare the heat
requirement needed to start bud break in several grapevine
cultivars characterised by different geographic
origins. A detailed description is presented of the bud
growth stages of Vitis vinifera cultivars to contribute
to the standardisation of national and international
testing systems of fruit growing. Based on the general
BBCH-scale, the codes describe the first stages of budbreak
in several cultivars with different geographical
origins. Dormancy release was evaluated both under
natural and forcing conditions, appropriate method to
establish the budbreak of deciduous species. The cultivars
were characterised in relation to the achievement
of complete bud scale opening stage (03 of BBCH scale)
which is suggested to consider as an early and indicator
of budbreak
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
Morpho-Anatomical Observations During Bud Break in Vitis vinifera L.
No full textThe widespread distribution of grapevine is due to their large genetic
variability, as well as the relative low chilling requirement of buds to overcome
winter dormancy (50-400 h at <7°C). Irregular bud break, reported when grapevine
does not satisfy its chilling requirement, can cause poor uniformity of fruit
development, while it has been shown that grapevine budbreak usually improves
with increased exposure to chilling temperatures. The Baggiolini phenological stages
(1952) were proposed for grapevine, characterised by simple descriptions of stages
between budburst and fruit set. Afterwards a more specific evaluation method was
realised by Eichhorn and Lorenz (1977) which proposed the BBCH system with
transitional stages. Among the dormant and ‘woolly’ bud, occur important small
changes corresponding to some sub-phases, that are not correctly studied and that
could be an early signal of dormancy bud breaking. The ‘greentip’ stage (07) is
generally considered indicative of ‘budbreak’, but it is difficult to identify precisely,
because its duration is very short. The aim of this study is to explore the first phases
of bud sprouting from a morphological point of view, to better define the
phenological bud changes and to find the sub-phase as a clear indicator of budbreak
under the climatic conditions of the Tuscan coastal area (Pisa, Italy-lat. 43,02N, long.
10,36E). Plant material of two diffused cultivars of Vitis vinifera: ‘Cabernet
Sauvignon’ and ‘Sangiovese’ were utilised. After accumulation of 1250 Chilling
Units (CU) dormancy breaking on two-node cuttings, by forcing method was
evaluated (18 days at 25°C, 60-70% relative humidity, 12/12-h photoperiod). Bud
opening evolution was marked by the phenological stages (BBCH scale) reached in
two day intervals under forcing and field conditions. Morpho-anatomical evolution
of bud tissue was studied on fresh material under stereomicroscope. Heat
requirement (GDH) was also calculated. The first stages of bud evolution were
distinguished in both genotypes which showed a different GDH requirement. In
relation to the morphological characteristics, stage 03 (bud scales opening) is
suggested as a suitable early indicator of bud break in Vitis viniferaThe widespread distribution of grapevine is due to their large genetic
variability, as well as the relative low chilling requirement of buds to overcome
winter dormancy (50-400 h at <7°C). Irregular bud break, reported when grapevine
does not satisfy its chilling requirement, can cause poor uniformity of fruit
development, while it has been shown that grapevine budbreak usually improves
with increased exposure to chilling temperatures. The Baggiolini phenological stages
(1952) were proposed for grapevine, characterised by simple descriptions of stages
between budburst and fruit set. Afterwards a more specific evaluation method was
realised by Eichhorn and Lorenz (1977) which proposed the BBCH system with
transitional stages. Among the dormant and ‘woolly’ bud, occur important small
changes corresponding to some sub-phases, that are not correctly studied and that
could be an early signal of dormancy bud breaking. The ‘greentip’ stage (07) is
generally considered indicative of ‘budbreak’, but it is difficult to identify precisely,
because its duration is very short. The aim of this study is to explore the first phases
of bud sprouting from a morphological point of view, to better define the
phenological bud changes and to find the sub-phase as a clear indicator of budbreak
under the climatic conditions of the Tuscan coastal area (Pisa, Italy-lat. 43,02N, long.
10,36E). Plant material of two diffused cultivars of Vitis vinifera: ‘Cabernet
Sauvignon’ and ‘Sangiovese’ were utilised. After accumulation of 1250 Chilling
Units (CU) dormancy breaking on two-node cuttings, by forcing method was
evaluated (18 days at 25°C, 60-70% relative humidity, 12/12-h photoperiod). Bud
opening evolution was marked by the phenological stages (BBCH scale) reached in
two day intervals under forcing and field conditions. Morpho-anatomical evolution
of bud tissue was studied on fresh material under stereomicroscope. Heat
requirement (GDH) was also calculated. The first stages of bud evolution were
distinguished in both genotypes which showed a different GDH requirement. In
relation to the morphological characteristics, stage 03 (bud scales opening) is
suggested as a suitable early indicator of bud break in Vitis vinifer
Fabbisogno in freddo e comparsa delle anomalie fiorali in genotipi di Prunus armeniaca L.
No full textGrowth, gas exchange and ionic relations of peach rootstocks under root zone salinity stress
No full textThe responses to increasing NaCl concentration in the root zone of two commercial rootstocks for peach, namely GF677 and Mr.S. 2/5, were evaluated. Four-month-old micropropagated plants were grown in hydroponics under greenhouse conditions and supplied daily with Hoagland solution with the addition of 0, 25, 50, and 100 mM NaCl, during a four-week period. Growth, gas exchange performances and ionic relations were evaluated. Ionic relations regarded both net ion fluxes and Na+ and Cl-concentrations in leaves of different age. Relative growth rates, that were significantly reduced at any external NaCl concentration, did not show clear genotypic differences. In contrast, both stomatal conductance (gs) and net CO2 assimilation rate (A) were decreased by NaCl to a greater extent in GF 677 than in Mr.S. 2/5. Salt-induced decreases in net CO2 assimilation rates were primarily due to stomatal limitations in both rootstocks. GF 677 showed a greater ability to limit the transport of Na+ (and Cl-) to the shoot and into the leaves, and this more efficient control of salt entry into the whole plant helped young leaves to be preserved from massive toxic ion accumulation. As a consequence, independent of rootstock responses in terms of growth and gas exchange performances, GF 677 appears more suitable than Mr.S. 2/5 for peach cultivation under mild soil salinity concentration
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