The dense indumentum with its polyphenol content may replace the protective role of the epidermis in some young xeromorphic leaves

1996 ◽  
Vol 74 (3) ◽  
pp. 347-351 ◽  
Author(s):  
George Karabourniotis ◽  
Costas Fasseas
Keyword(s):  
Radiation Damage ◽  
Leaf Development ◽  
Olea Europaea ◽  
Quercus Ilex ◽  
Developmental Stages ◽  
Protective Role ◽  
Ultraviolet B ◽  
Young Leaves ◽  
Olea Europaéa

The bright, yellow-green, ammonia-induced fluorescence of polyphenol compounds contained in the nonglandular hairs and within the epidermis of Olea europaea and Quercus ilex leaves was age dependent. Epifluorescence microscopic examination of transverse sections of leaves from both species showed that abaxial and adaxial epidermal layers emitted the characteristic green-yellow bright fluorescence only in late developmental stages, when a considerable decrease of the trichome density had already occurred. At earlier developmental stages, only the dense and thick trichome layer emitted the bright green-yellow fluorescence. In addition, the trichomes of young leaves of Olea and Quercus resembled the glandular ones of other species morphologically and possibly functionally. These findings suggest that the protective role of the trichome against ultraviolet-B radiation damage and (or) other environmental factors is particularly significant during the early stages of leaf development and may be less important at later stages, when the protective role is taken over by the epidermis. Keywords: leaf hairs, phenolics, UV-B radiation damage, leaf development, Olea europaea L., Quercus ilex L.

Role of geranylgeranyl reductase gene in organ development and stress response in olive (Olea europaea) plants

2009 ◽  
Vol 36 (4) ◽  
pp. 370 ◽  
Author(s):  
Leonardo Bruno ◽  
Adriana Chiappetta ◽  
Innocenzo Muzzalupo ◽  
Cinzia Gagliardi ◽  
Domenico Iaria ◽  
...  
Keyword(s):  
Stress Response ◽  
Olea Europaea ◽  
Developmental Stages ◽  
Cold Treatment ◽  
In Situ Hybridisation ◽  
Transit Peptide ◽  
Specific Cell ◽  
Reductase Gene ◽  
Olea Europaéa

The NADPH-dependent geranylgeranyl reductase gene (OeCHLP) was characterised in olive (Olea europaea L.). OeCHLP catalyses the formation of carbon double bonds in the phytolic side chain of chlorophyll, tocopherols and plastoquinones and, therefore, is involved in metabolic pathways related to plant productivity and stress response, besides to nutritional value of its products. The nuclear OeCHLP encodes a deduced product of 51 kDa, which harbours a transit peptide for cytoplasm-to-chloroplast transport and a nicotinamide binding domain. Two estimated identical copies of gene are harboured per haploid genome of the cv. ‘Carolea’ used in the present study. Levels and cytological pattern of OeCHLP transcription were investigated by quantitative RT–PCR and in situ hybridisation. In line with the presence of ubiquitous tocopherols and/or chlorophyll, OeCHLP transcripts were present in various organs of plants. In leaves and fruits at different developmental stages, OeCHLP was differentially expressed in relation to their morpho-physiological features. An early and transient enhancement of gene transcription was detected in leaves of different age exposed to cold treatment (4°C), as well as in fruits mechanically wounded. Moreover, OeCHLP transcripts locally increased in specific cell domains of fruits severely damaged by the pathogen Bactrocera olea. Combined, these data show that OeCHLP expression early responds to biotic and abiotic stressful factors. Levels of tocopherols also increased in leaves exposed to cold conditions and fruits severely damaged by pathogen. We suggest that gene activity under stress condition could be related to tocopherol action.

scholarly journals The Role of Polyphenoloxidase, Peroxidase, and β-Glucosidase in Phenolics Accumulation in Olea europaea L. Fruits under Different Water Regimes

2017 ◽  
Vol 8 ◽  
Author(s):  
Marco Cirilli ◽  
Giovanni Caruso ◽  
Clizia Gennai ◽  
Stefania Urbani ◽  
Eleonora Frioni ◽  
...  
Keyword(s):  
Olea Europaea ◽  
Water Regimes ◽  
Olea Europaea L ◽  
Olea Europaéa

scholarly journals Desarrollo de pellets a partir de tres especies leñosas bajo condiciones mediterráneas

2014 ◽  
Vol 20 (3) ◽  
pp. 97-111 ◽  
Author(s):  
Harald Fernández-Puratich ◽  
José Vicente Oliver-Vilanueva ◽  
Mireya Valiente ◽  
Salvador Verdú ◽  
Nuria Albert
Keyword(s):  
Olea Europaea ◽  
Citrus Sinensis ◽  
Quercus Ilex ◽  
Prunus Amygdalus ◽  
Para Determinar ◽  
Olea Europaéa

La biomasa leñosa como recurso energético varía según tres factores: 1) especie, 2) condiciones ambientales que influyen en su producción y 3) dispersión en el territorio. La estimación de la aptitud de este recurso es crucial para el desarrollo sustentable del sector agroforestal y, en concreto, de la cadena de valor bosque-industria-consumo. Tomando en cuenta esta situación, el objetivo de este documento consistió en determinar la aptitud de tres tipos arbóreos como biocombustible sólido. Una especie forestal (Quercus ilex), un cultivo energético (Paulownia spp.) y tres especies frutales Citrus sinensis (naranjo), Olea europaea (olivo) y Prunus amygdalus (almendro). Para alcanzar este objetivo, la investigación se centró en la caracterización física, química y energética de la biomasa leñosa de estas especies. Con base en un muestreo representativo, los resultados obtenidos sirvieron para determinar de forma cualitativa las aptitudes y limitaciones de estas especies como biocombustible sólido.Los principales resultados demuestran que la biomasa de cada especie estudiada es apta para su uso energético como biocombustible sólido, con la excepción de la madera de naranjo que presenta algunas limitaciones para la fabricación de pellets.

scholarly journals Evidence of Protective Role of Ultraviolet-B (UVB) Radiation in Reducing COVID-19 Deaths 

2020 ◽  
Author(s):  
Rahul Kalippurayil Moozhipurath ◽  
Lennart Kraft ◽  
Bernd Skiera
Keyword(s):  
Vitamin D ◽  
Growth Rates ◽  
Protective Role ◽  
Negative Association ◽  
Ultraviolet B ◽  
Cumulative Number ◽  
Uvb Radiation ◽  
Daily Growth ◽  
Percentage Points

Abstract Background. Prior studies indicate the protective role of Ultraviolet-B (UVB) radiation in human health, mediated by vitamin D synthesis. In this observational study, we empirically outline a negative association of UVB radiation as measured by ultraviolet index (UVI) with the number of COVID-19 deaths.Methods. We apply a fixed-effect log-linear regression model to a panel dataset of 152 countries over 108 days (n=6524). We use the cumulative number of COVID-19 deaths and case-fatality rate (CFR) as the main dependent variables and isolate UVI effect from potential confounding factors.Findings. After controlling for time-constant and time-varying factors, we find that a permanent unit increase in UVI is associated with a 1.2 percentage points decline in daily growth rates of cumulative COVID-19 deaths [p < 0.01] and a 1.0 percentage points decline in the CFR daily growth rate [p < 0.05]. These results represent a significant percentage reduction in terms of daily growth rates of cumulative COVID-19 deaths (-11.88%) and CFR (-38.46%).Interpretation. We find a significant negative association between UVI and COVID-19 deaths, indicating evidence of the protective role of UVB in mitigating COVID-19 deaths. If confirmed via clinical studies, then the possibility of mitigating COVID-19 deaths via sensible sunlight exposure or vitamin D intervention will be very attractive.

scholarly journals Mobilization of Boron in Olive Trees during Flowering and Fruit Development

HortScience ◽  
1994 ◽  
Vol 29 (6) ◽  
pp. 616-618 ◽  
Author(s):  
A. Delgado ◽  
M. Benlloch ◽  
R. Fernández-Escobar
Keyword(s):  
Fruit Development ◽  
Olea Europaea ◽  
Young Fruit ◽  
Low Degree ◽  
Young Leaves ◽  
Olive Trees ◽  
High Degree ◽  
Olea Europaéa

Change in B content of olive (Olea europaea L.) leaves during anthesis reveals the appearance of a potent B sink. This phenomenon was more marked in young leaves of bearing trees with a high degree of flowering than in nonbearing trees with a low degree of flowering. Applying B to the leaves at the time of anthesis increased the B concentrations in leaf blades, petioles, bark of the bearing shoot, and flowers and fruit 3 days after treatment. The results suggest that B is mobilized from young leaves during anthesis to supply the requirements of flowers and young fruit.

scholarly journals Evidence of protective role of Ultraviolet-B (UVB) radiation in reducing COVID-19 deaths

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Rahul Kalippurayil Moozhipurath ◽  
Lennart Kraft ◽  
Bernd Skiera
Keyword(s):  
Vitamin D ◽  
Growth Rates ◽  
Protective Role ◽  
Negative Association ◽  
Ultraviolet B ◽  
Cumulative Number ◽  
Uvb Radiation ◽  
Daily Growth ◽  
Percentage Points

Abstract Prior studies indicate the protective role of Ultraviolet-B (UVB) radiation in human health, mediated by vitamin D synthesis. In this observational study, we empirically outline a negative association of UVB radiation as measured by ultraviolet index (UVI) with the number of COVID-19 deaths. We apply a fixed-effect log-linear regression model to a panel dataset of 152 countries over 108 days (n = 6524). We use the cumulative number of COVID-19 deaths and case-fatality rate (CFR) as the main dependent variables and isolate the UVI effect from potential confounding factors. After controlling for time-constant and time-varying factors, we find that a permanent unit increase in UVI is associated with a 1.2 percentage points decline in daily growth rates of cumulative COVID-19 deaths [p < 0.01] and a 1.0 percentage points decline in the CFR daily growth rate [p < 0.05]. These results represent a significant percentage reduction in terms of daily growth rates of cumulative COVID-19 deaths (− 12%) and CFR (− 38%). We find a significant negative association between UVI and COVID-19 deaths, indicating evidence of the protective role of UVB in mitigating COVID-19 deaths. If confirmed via clinical studies, then the possibility of mitigating COVID-19 deaths via sensible sunlight exposure or vitamin D intervention would be very attractive.

Sorbitol Versus Sucrose as Photosynthesis and Translocation Products in Developing Apricot Leaves

1985 ◽  
Vol 12 (6) ◽  
pp. 657 ◽  
Author(s):  
RL Bieleski ◽  
RJ Redgwell
Keyword(s):  
Leaf Development ◽  
Main Product ◽  
Mature Leaf ◽  
Young Leaf ◽  
Mature Leaves ◽  
Specific Transport ◽  
Young Leaves

Very young apricot leaves behave like the young leaves of most plants; that is, [14C]sucrose is formed as the main product of 14CO2 photosynthesis, and also when the leaves are supplied with [14C]glucose. [14C]sorbitol is not produced, and is poorly metabolized when fed to the leaf. Expanding leaves behave differently: [14C]sorbitol and [14C]sucrose are formed in similar amounts from both 14CO2 and [14C]glucose; and when [14C]sorbitol is supplied, it is readily metabolized and utilized for growth. Mature leaves are different again. They form [14C]sorbitol as the main product from 14CO2 and from [14C]glucose, and they do not metabolize [14C]sorbitol at all. Thus during development, apricot leaves gain but then lose the ability to utilize sorbitol. They also gain and keep the ability to synthesize sorbitol. This suggests that different biochemical paths exist for sorbitol formation and utilization, and that these paths are differently developed in the various stages of leaf development. Although the very young leaves did not synthesize sorbitol from CO2 or glucose, they contained it as their major sugar. Translocation behaviour was therefore studied. Neither the very young leaves nor the expanding leaves export any photosynthate, but the mature leaf rapidly translocates carbohydrate, mainly in the form of sorbitol, to the younger leaves as well as the rest of the plant. [14C]sorbitol supplied to the mature leaf can be recovered in that form from the very young leaf on the same shoot. This further establishes the role of sorbitol in apricot as a specific transport carbohydrate.

Trichome density and its protective potential against ultraviolet-B radiation damage during leaf development

1995 ◽  
Vol 73 (3) ◽  
pp. 376-383 ◽  
Author(s):  
George Karabourniotis ◽  
Dimitris Kotsabassidis ◽  
Yiannis Manetas
Keyword(s):  
Radiation Damage ◽  
Leaf Development ◽  
Leaf Age ◽  
Ultraviolet B ◽  
Eriobotrya Japonica ◽  
Trichome Density ◽  
Cydonia Oblonga ◽  
Leaf Hairs ◽  
Ultraviolet B Radiation ◽  
Mature Leaves

Trichome density and the capacity of leaf hairs to protect underlying tissues against ultraviolet-B radiation damage were assessed during leaf development in three tree species. In all cases, trichome density and the relative quantities of ultraviolet radiation absorbing phenolic constituents (expressed on a leaf area basis) declined considerably with leaf age. In addition, the percent leaf dry mass invested in trichome decreased significantly. Reductions were greater on the adaxial leaf surface, leading to an almost glabrous upper epidermis in mature leaves. Internal (i.e., leaf total minus trichome) phenolics showed no significant changes with leaf age in Eriobotrya japonica and Cydonia oblonga. In Olea europaea, however, the concentration of internal phenolics was doubled in mature leaves. Ultraviolet-B radiation resulted in a reduction of photosystem II photochemical efficiency and extensive epidermal browning only in young, dehaired leaves. No such effects were observed in young, dehaired leaves in the absence of ultraviolet-B radiation or in normal young or mature ultraviolet-B-irradiated leaves. It is suggested that the dense trichomes often covering young leaves may, in addition to other functions, protect transiently the underlying cells against ultraviolet-B radiation damage during the time period required for the maturation of internal avoidance and (or) repairing mechanisms. Key words: Cydonia oblonga, Eriobotrya japonica, Olea europaea, leaf development, leaf hairs, phenolics, ultraviolet-B radiation damage.

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