177,294 research outputs found
LIGHT QUALITY MANAGEMENT IN FRUIT ORCHARDS: PHYSIOLOGICAL AND TECHNOLOGICAL ASPECTS
No full textLight quality (sunlight spectrum) management promises to provide a new
technological alternative to sustainable production in horticultural
crops. However, little information exists about physiological and
technological aspects on light quality management in fruit crops.
Sunlight composition changes widely in orchard canopies, inducing
different plant responses in fruit trees mediated by phytochrome (PHY)
and cryptochrome (CRY) activity. High proportion of far-red (FR) in
relation to red (R) light increases shoot elongation, while blue (B)
light induces shoot dwarfing. Red and ultraviolet (UV) light increases
fruit skin anthocyanin synthesis, while FR light shows a negative
effect. Red and B light can also alter leaf morpho-physiological traits
in fruit trees, such palisade thickness, stomatal aperture, and
chlorophyll content. Besides improvement of photosynthetically active
radiation (PAR) availability, the use of reflective films improves UV
and R light proportion, with positive effects on PHY mediated-responses
(fruit color, fruit weight, shoot growth), as reported in apple ( Malus
domestica Borkh.), peach ( Prunus persica [L.] Batsch), and sweet
cherry ( Prunus avium [L.] L.). Colored nets widely alter spectral
light composition with effects on plant growth, yield, and quality in
apple, kiwifruit ( Actinidia deliciosa [A. Chev.] C.F. Liang &
A.R. Ferguson), peach, and blueberry ( Vaccinium corymbosum L.)
orchards. Mechanisms of colored nets seem to be associated to
photosynthetic and morphogenetic process regulated by PAR availability,
R/B light proportion, and CRY activity. Alteration of light quality
affects significantly fruit tree plant responses and could be a useful
tool for sustainable (e.g. lower use of chemicals and labor-practices)
management of yield and quality in modern orchards
Has a “Chemical Magic” Opened up New Prospects for Glaucoma?
No full textChemical modification of the prototype CB1R ago-PAM, GAT211, yielded new CB1R allosteric modulators
(−)-(S,R)-13 and (+)-(R,S)-14, which showed significant bias for CB1R signaling pathways, as supported by docking studies.
Compound 14 efficiently lowered elevated intraocular pressure when it is due to an increase in endocannabinoid tone. This article
may open new avenues to meet the therapeutic needs presented by glaucoma
Red and blue netting alters leaf morphological and physiological characteristics in apple trees
No full textThere is little information about the role of red and blue light on leaf morphology and physiology in fruit trees, and more studies have been developed in herbaceous plants grown under controlled light conditions. The objective of this research was to evaluate the effect of red and blue screens on morpho-anatomy and gas exchange in apple leaves grown under ambient sunlight conditions. Apple trees cv. Fuji were covered by 40% red and blue nets, leaving trees with 20% white net as control. Light relations (photosynthetic photon flux density, PPFD; red to far-red light ratio, R/FR and blue to red light ratio, B/R), morpho-anatomical features of the leaf (palisade to spongy mesophyll ratio, P/S, and stomata density, SD) and leaf gas exchange (net photosynthesis rate, An; stomatal conductance, gs; transpiration rate, E; and intrinsic water use efficiency, IWUE) were evaluated. Red and blue nets reduced 27% PPFD, reducing by 20% SD and 25% P/S compared to control, but without negative effects on An and gs . Blue net increased gs 21%, leading to the highest E and lowest IWUE by increment of B/R light proportion. These findings demonstrate the potential use of red and blue nets for differential modulation of apple leaf gas exchange through sunlight management under field conditions
EXPLORING THE POTENTIAL USE OF PHOTO-SELECTIVE NETS FOR FRUIT GROWTH REGULATION IN APPLE
No full textThe effect of shading (i.e. reduction of sunlight availability) on fruit growth physiology has been widely studied in apple
(Malus domestica Borkh.), but little knowledge exist about fruit growth responses to changes in the light spectrum. The
aim of the present research was to study the effect of use of colored nets with differential sunlight transmission in the
blue (B, 400-500 nm), red (R, 600-700 nm) and far-red (FR, 700-800 nm) spectra on apple fruit growth and physiological
associated responses. Three year old ‘Fuji’ apple trees were covered with 40% photo-selective blue and red shade nets, 40%
neutral grey shade net, and 20% neutral white net as control. Red and blue net reduced in the same proportion (27%) the
photosynthetically active radiation with respect to control. However, blue net increased by 30% and reduced by 10% the
B:R and R:FR the light relations, respectively. Maximal fruit growth rate under blue and grey nets was 15-20% greater than
control. Fruit weight under blue net was 17% greater than control, but no significant differences in fruit weight were found
among red net and control. Leaf photosynthesis and total leaf area under blue net were 28% and 30% higher than control,
respectively; with ensuing positive effect on tree net C assimilation rate and total dry matter production. Results suggest that
shifting the B, R, and FR light composition with photo-selective nets could be a useful tool to manipulate the photosynthetic
and morphogenetic process regulating the carbohydrate availability for apple fruit growth
WHOLE CANOPY GAS EXCHANGES AND LIGHT INTERCEPTION OF THREE PEACH TRAINING SYSTEMS
No full textCanopy photosynthesis (A(c)), transpiration (E-c) and light interception of three peach training systems, delayed vasette (DV), palmette (P), and Y-trellis (Y), were measured by a whole-canopy gas exchange open system, and a custom-built all-wave scanner-recorder, Whole-canopy assimilation rates peaked before midday in both DV and P, then A, started to decrease in the afternoon, even if light was not a limiting factor. Both canopies reached similar maximum E-c rates in late afternoon. On the contrary, A(c) of the east and west sides of the Y was nearly constant between 10:00 and 15:00 hours.In DV and P, the assimilation-transpiration ratio (ATR) decreased from early morning hours to a minimum in early afternoon, increasing thereafter. In the Y, ATR values were higher than in DV and P and, after the initial morning decrease, they remained stable until the end of the day. On a hectare base, light interception in DV and P was similar, while Y showed higher interception throughout the day. Whole-canopy photosynthesis was linearly related to the amount of light intercepted by the tree
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe 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
The effect of defruiting at different stages of fruit development on leaf photosynthesis of 'Golden Delicious' apple
No full textNet photosynthetic rates (A) of leaves on 11-year-old, field-grown apple trees (Malus domestica Borkh. cv. Golden Delicious) were measured after removal of fruits at four different stages of development. Defruiting decreased A by 21, 42, 27 and 7% when fruits were growing at 311, 293, 229 and 113 mg(DW) day(-1), respectively. Photosynthesis was inhibited more in the afternoon than in the morning, but it was not affected during the first 8 h after fruit removal. Inhibition of A was positively correlated with crop sink strength, but it was not correlated with fruit relative growth rate or crop load. Defruiting decreased A at saturating irradiances (PPFD > 1000 mu mol m(-2) s(-1)), but did not modify the apparent quantum yield of single leaves. These results suggest that the overall effect of defruiting on carbon fixation is negligible in dense canopies, but it may be significant in sparse canopies and in single shoots
Possible role of mannitol as an oxygen radical scavenger in olive.
No full textAlong with mannose and sucrose, olive produces large amounts of mannitol in
photosynthesizing leaves. Leaf mannitol shows large variation among olive genotypes
and Sicilian cultivars with different leaf mannitol content were used in our trials to see
whether mannitol may function as an additional non-enzymatic system to protect cells
from oxygen radicals and photosystem damage. In one experiment, entire shoots of
‘Passulunara’, ‘Castriciana’, ‘Nocellara del Belice’, and ‘Moresca’ olive trees were
taken to a greenhouse, and mature leaves were treated with paraquat solution, which
generates oxygen radicals in presence of light. After 48 hours leaves were sampled,
photographed and percent of necrosis was quantified by digital image analysis.
Mannitol content was determined in control non-treated leaves positioned in the same
node as the paraquat-treated ones. The same experiment was repeated using fieldgrown trees under full sun light. In both cases, a significant inverse relation was found
between leaf necrosis and mannitol content suggesting that mannitol may provide
some scavenging action on paraquat-generated oxygen radicals. In another experiment, leaf gas exchange and chlorophyll fluorescence were measured on field-grown
‘Castriciana’ (higher mannitol) and ‘Nocellara del Belice’ (lower mannitol) trees in the
morning, at noon, and in the afternoon to quantify partitioning of absorbed energy
among net photosynthesis (J
CO2), photoprotection by heat dissipation (non-photochemical quenching, J
NPQ) and by alternative electron transport and photorespiration
(J
NC), formation of reactive oxygen species (ROS) and heat re-emission inactive
photosystem (PSII). ‘Nocellara’ reported higher J
CO2 and J
NC than ‘Castriciana’,
whereas J
NPQ was similar in the two cultivars. Despite a greater amount of energy for
ROS formation, ‘Castriciana’ yielded a smaller percentage of inactive photosystems
compared to ‘Nocellara’. Also in this case mannitol may act as an additional oxygen
radical scavenger and explain the differences in photosystem inactivation between the
two olive cultivars
Hsp90 Inhibitors, part 2: combining ligand-based and structure-based approches for virtual screening application
No full textHsp90 continues to be an important target for pharmaceutical discovery. In this project, virtual screening (VS) for novel Hsp90 inhibitors was performed using a combination of Autodock and Surflex-Sim (LB) scoring functions with the predictive ability of 3-D QSAR models, previously generated with the 3-D QSAutogrid/R procedure. Extensive validation of both structurebased (SB) and ligand-based (LB), through realignments and cross-alignments,
allowed the definition of LB and SB alignment rules. The mixed LB/SB protocol was applied to virtually screen potential Hsp90 inhibitors from the NCI Diversity Set composed of 1785 compounds. A selected ensemble of 80 compounds were biologically tested. Among these molecules, preliminary data yielded four derivatives exhibiting IC50 values ranging between 18 and 63 μM as hits for a subsequent medicinal chemistry optimization procedure
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