scholarly journals Girdling effects on fruit set and quantum yield efficiency of PSII in two Citrus cultivars

2007 ◽  
Vol 27 (4) ◽  
pp. 527-535 ◽  
Author(s):  
F. Rivas ◽  
A. Gravina ◽  
M. Agusti
2020 ◽  
Vol 12 (24) ◽  
pp. 4053
Author(s):  
Tianyuan Zou ◽  
Jing Zhang

Chlorophyll fluorescence (ChlF) is a useful indicator of plant photosynthesis and stress conditions. ChlF spectra can be simulated with the Fluspect model, which is a radiative transfer model that simulates leaf reflectance, transmittance, and fluorescence; however, it has never been used or validated under natural conditions. In this paper, a new fluorescence quantum yield efficiency of photosystem (FQE) retrieval method based on the Fluspect model is proposed for use in simulating ChlF in two healthy varieties of soybeans grown under natural conditions. The parameters, Chlorophyll a + b content (Cab), carotenoid (Cca), dry matter content (Cdm), indicator of leaf water content (Cw) and leaf mesophyll structure (N) and the simulated fluorescence from the experiment were compared with the measured values to validate the model under natural conditions. The results show a good correlation (coefficient of determination R2 = 0.7–0.9) with the measured data at wavelengths of 650–880 nm. However, there is a large relative error (RE) that extends up to 150% at the peak of the fluorescence curve. To improve the accuracy of the simulation, an inversion code containing the emission efficiency parameters for photosystems I and II was added, which retrieves FQE I and II from the measured fluorescence spectra. The evaluation results for all wavelengths and two peaks demonstrated a significant reduction in the error at the peak of the curve by the Fluspect model with the FQE inversion code. This new method reduced the overestimation of fluorescence from 150% to 20% for the RE, and the R2 value was higher than 0.9 at the spectra peaks. Additionally, the original plant parameter information remained mostly unchanged upon the addition of the inversion code.


2013 ◽  
Vol 48 (1) ◽  
pp. 33-41 ◽  
Author(s):  
Milica Fotiric Aksic ◽  
Vera Rakonjac ◽  
Dragan Nikolic ◽  
Gordan Zec

The objective of this work was to evaluate variability in reproductive biology traits and the correlation between them in genotypes of 'Oblačinska' sour cherry (Prunus cerasus). High genetic diversity was found in the 41 evaluated genotypes, and significant differences were observed among them for all studied traits: flowering time, pollen germination, number of fruiting branches, production of flower and fruit, number of flowers per bud, fruit set, and limb yield efficiency. The number of fruiting branches significantly influenced the number of flower and fruit, fruit set, and yield efficiency. In addition to number of fruiting branches, yield efficiency was positively correlated with fruit set and production of flower and fruit. Results from principal component analysis suggested a reduction of the reproductive biology factors affecting yield to four main characters: number and structure of fruiting branches, flowering time, and pollen germination. Knowledge of the reproductive biology of the 'Oblačinska' genotypes can be used to select the appropriate ones to be grown or used as parents in breeding programs. In this sense, genotypes II/2, III/9, III/13, and III/14 have very good flower production and satisfactory pollen germination.


2019 ◽  
Vol 23 (07n08) ◽  
pp. 766-780 ◽  
Author(s):  
Madalina E. Grigore ◽  
Rodica-M. Ion ◽  
Lorena Iancu ◽  
Ramona M. Grigorescu

In this review we present an updated survey of the main synthesis methods of gold nanoparticles (AuNPs) in order to obtain various tailored nanosystems for biomedical imaging. The synthesis approach significantly impacts on the AuNPs properties such as surface chemistry, biocompatibility and cytotoxicity. In recent years, nanomedicine emphasized the development of functionalized AuNPs for biomedical imaging. AuNPs are a good option for used as delivery photosensitizer agents for PDT of cancer. For example, the complex formed from AuNPs functionalized with PEGylate porphyrins presents several advantages in the medical field such as a better use in photodynamic therapy because of high triplet states and singlet oxygen quantum yield efficiency of porphyrin molecules.


1994 ◽  
Vol 119 (6) ◽  
pp. 1303-1311 ◽  
Author(s):  
Richard E.C. Layne ◽  
Perry Y. Jui

Ten genetically diverse peach [Prunus persica (L.) Batsch] seedling rootstocks were studied for 10 years on Fox sand using `Redhaven' as the scion. The purpose of the experiment was to assess the performance of three Harrow Research Station (Ont.) hybrid selections (H7338013, H7338016, and H7338019) and two northern China introductions (`Chui Lum Tao' and `Tzim Pee Tao') against five commercial standards, two of which were selected in Canada (`Harrow Blood' and `Siberian C') and three in the United States (`Bailey', `Halford', and `Lovell'). Rootstock performance was assessed indirectly by measuring or subjectively rating various aspects of scion performance including annual trunk cross-sectional area (TCA); final tree height, spread, and TCA; bloom and fruit set intensity; yield and yield efficiency; canker (Leucostoma spp.) severity; defoliation rate; winter injury; cold hardiness of flower buds and shoot xylem; and tree survival. Rootstock effects on the above measurements and ratings were significant in some years and not in others. Year effects were always large and significant, while rootstock × year interactions were usually small and not significant. In the combined analyses over years, the largest rootstock effects were obtained for bloom, fruit set, and defoliation ratings and for TCA measurements. Three cumulative responses, including marketable yields, yield efficiency, and tree survival, were used for comparing the five experimental rootstocks with the five commercial standards and also for ranking the 10 rootstocks with respect to each other to assess their potential commercial value as peach rootstocks. `Chui Lum Tao', H7338013, and `Bailey' had the most commercial potential for southern Ontario because they typically promoted above average cumulative yield, yield efficiency, and tree survival. `Tzim Pee Tao', `Siberian C', and `Harrow Blood' were less valuable, with low cumulative marketable yields. `Halford' and `Lovell' were the least valuable, with the lowest tree survival (17%). Performance of H7338013 exceeded that of both parents (`Bailey' and `Siberian C'), H7338019 exceeded `Siberian C' but not `Bailey', while performance of H7338016 was inferior to both parents. Wider testing of the experimental rootstocks on different soil types and climatic zones is needed.


2017 ◽  
Vol 62 (2) ◽  
pp. 133-141
Author(s):  
Dragan Milatovic ◽  
Dejan Djurovic ◽  
Gordan Zec

Growth and productivity characteristics including: initial and final fruit set, yield per tree, trunk cross-sectional area, yield efficiency and fruit weight were studied in ten cultivars of Japanese plums in the Belgrade area for the period of three years (2013-2015). Initial fruit set ranged from 5.6 to 44.4%, and the final fruit set from 2.6 to 23.36%. The high yield per tree (over 10 kg) was obtained in cultivars ?Obilnaja? and ?Morettini 355?, whereas the low yield (under 5 kg) was obtained in cultivars ?Strival?, ?Black Amber?, ?Early Angeleno? and ?Autumn Giant?. The lowest vigor was observed in the cultivar ?Golden Plum?, and the highest in the cultivar ?Strival?. The majority of cultivars had a very large fruit (over 50 g). The yield was strongly positively correlated with initial and final fruit set (r = 0.84**; r = 0.92**, respectively). Fruit weight was moderately negatively correlated with initial and final fruit set (r = -0.67*; r = -0.63*, respectively).


HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 482D-482 ◽  
Author(s):  
David E. Davis ◽  
John A. Barden ◽  
Ross E. Byers

In 1997 and 1998, we determined the effects of defoliation on return bloom and fruit set following a light cropping year. In one study, `Braeburn' trees were hand-thinned to a crop density (CD) of 3 fruit/cm 2 trunk cross sectional area (TCSA) in late May 1997, and then either completely defoliated or half of the tree defoliated by hand on one of five dates between June and Sept. 1997. Compared to a nondefoliated control, both whole and half-tree defoliation on all dates reduced fruit count and yield efficiency (kilograms per square centimeter of TCSA) and affected fruit weight, starch, firmness, and soluble solids in 1997. In 1998, return bloom and fruit set were reduced by most 1997 defoliation treatments. Compared to other dates, defoliation on 3 July caused the greatest reduction in return bloom in both whole and half-defoliated trees. In another study, `Braeburn' trees were hand-thinned to a CD of 5 in late May 1998; complete defoliation by hand on 1, 15, or 29 July reduced return bloom and fruit set in 1999; the 1 July treatment resulted in zero return bloom. `Golden Delicious' and `York' trees were thinned to a CD of 3 in late May 1998 and were hand-defoliated on 21 July or 12 August by removing every other leaf or removing three of every four leaves over the entire tree. In 1999, return bloom and spur and lateral fruit set were reduced by all defoliation treatments. Fruit set was most reduced by the 12 Aug. treatment. Fruit set for `York' was lower than for `Golden Delicious' in all cases.


2016 ◽  
Vol 8 (4) ◽  
pp. 2081-2086
Author(s):  
G. A. Dar ◽  
F. A. Misger ◽  
Amit Kumar ◽  
J. A. Rather

Present experiment was carried out in a seven year old private plum orchard near SKUAST-Kashmir, Shalimar Campus, Srinagar during 2012 and 2013, to examine the response to nitrogenous fertilizer and boron on growth, fruit set and yield of plum var. Santa Rosa. Urea @ 500 g (N1), CaNO3 @ 1450 g (N2), N1 + 50 g boron (N3) and N2 + 50 g boron (N4) were applied at T1 = Full dose in spring, T2 = Full dose after harvest and T3 = 3/4 dose in spring and 1/4 dose after harvest. Observations were recorded on parameters viz. incremental tree girth, shoot extension growth, plant height, plant spread, leaf area, fruit set, fruit drop, yield, yield efficiency. All the growth parameters were high in treatment combination N1T1. Maximum fruit set (19.68 % and 20.90 %) was recorded in N3T2, yield (20.60 kg/tree and 22.88 kg/tree) was recorded in N4T2, yield efficiency (0.45 and 0.46 kg/cm2) was recorded in N4T2 and minimum fruit drop (4.25 % and 4.55 %) were recorded under the treatment combination N4T2 and N4T3, respectively in the both the years. Both sources of nitrogen and boron can be considered as best fertilizer in plum orchards for improving the growth, fruit set, fruit yield, yield efficiency.


HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 792D-793
Author(s):  
Richard Marini*

Six-year-old York/M.9 trees were used to evaluate combinations of chemicals for fruit thinning. In one experiment a factorial combination of 2 levels of carbaryl (0 or 600 mg·L-1) and 5 levels of 6-BA (0, 40, 80, 120, and 160 mg·L-1) were sprayed when fruit diam. averaged 10.5 mm. Carbaryl significantly reduced fruit set, number of fruit/tree, yield efficiency, and crop density, and increased fruit weight. The main effect of 6-BA did not significantly influence any response variable. Two variables were significantly influenced by the carbaryl × 6-BA interaction. In the absence of carbaryl, fruit set was reduced and fruit weight was increased by 6-BA at concentrations less than 160 mg·L-1, but the addition of 6-BA to carbaryl was no more effective than carbaryl alone. In a second experiment, a factorial combination of 2 levels of carbaryl (0 vs. 600 mg·L-1), 2 levels of NAA (0 vs. 5 mg·L-1), and 2 levels of ethephon (0 vs. 450 mg·L-1) were sprayed when fruit when fruit diam. averaged 10.5 mm. Carbaryl and NAA reduced fruit set by about 30%, but ethephon overthinned and reduced set by 65%. When the other materials were combined with ethephon, thinning was similar to ethephon alone. The combination of carbaryl and NAA was no more effective than either material alone. The lowest values for yield, yield efficiency, and numbers of fruit per tree were associated with the combination of ethephon plus NAA. Ethephon was the only material that increased fruit weight.


MRS Advances ◽  
2020 ◽  
Vol 5 (62) ◽  
pp. 3315-3325
Author(s):  
Viktoriia Savchuk ◽  
Arthur R. Knize ◽  
Pavlo Pinchuk ◽  
Anatoliy O. Pinchuk

AbstractWe present a systematic numerical analysis of the quantum yield of an electric dipole coupled to a plasmonic nanoparticle. We observe that the yield is highly dependent on the distance between the electric dipole and the nanoparticle, the size and permittivity of the nanoparticle, and the wavelength of the incident radiation. Our results indicate that enhancement of the quantum yield is only possible for electric dipoles coupled to a nanoparticle with a radius of 20 nm or larger. As the size of the nanoparticle is increased, emission enhancement occurs at wavelengths dependent on the coupling distance.


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