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1.
Foods ; 12(5)2023 Feb 23.
Article in English | MEDLINE | ID: mdl-36900459

ABSTRACT

The possibility that nut intake may defend human health is an interesting point of view and has been investigated worldwide. Consequently, nuts are commonly promoted as healthy. In recent decades, the number of investigations proposing a correlation between nut consumption and a decrease in the risk of key chronic diseases has continued to increase. Nuts are a source of intake of fiber, and dietary fiber is associated with a reduced occurrence of obesity and cardiovascular diseases. Nuts likewise provide minerals and vitamins to the diet and supply phytochemicals that function as antioxidant, anti-inflammatory, and phytoestrogens agents and other protective mechanisms. Therefore, the main goal of this overview is to summarize current information and to describe the utmost new investigation concerning the health benefits of certain nuts.

2.
Foods ; 12(3)2023 Jan 26.
Article in English | MEDLINE | ID: mdl-36766071

ABSTRACT

Orchard net cover improves plant physiology, yield and fruit quality, pest and disease control, and anticipates fruit ripening. Moreover, this crop technology has been used to reduce natural cherry cracking (NCC). This is a serious physiological disorder that cracks the epidermis, the hypodermis, and the storage parenchyma layers of the fruit due to rainfall events near the harvest and it is related to low fruit osmotic potential and/or high fruit water permeability. This work aims to study the effect of orchard net cover on sweet cherry trees, cv. Early Bigi, in two harvesting years (2019 and 2021). The NCC, the induced cracking index (CI), and the cracking type incidence were determined. In addition, epicuticular and intra-cuticular wax content, biometric and physicochemical parameters were also evaluated. Net cover reduced the natural cracking index by 40%. High fruit weight values were observed in covered trees comparing to the control ones, with increases of 45% and 13%, in 2019 and 2021, respectively. A positive correlation was observed between CI and total soluble solids and a negative correlation between CI and wax content. Therefore, with forecasts of worsening heavy precipitation events near harvest, protecting cherry trees with nets will increase resistance to fruit cracking.

3.
Front Plant Sci ; 13: 999252, 2022.
Article in English | MEDLINE | ID: mdl-36275521

ABSTRACT

Arundo donax L. (Arundinoideae subfamily, Poaceae family) is a sub-tropical and temperate climate reed that grows in arid and semi-arid environmental conditions, from eastern China to the Mediterranean basin, suggesting potential adaptations at the epicuticular level. A thorough physical-chemical examination of the adaxial and abaxial surfaces of A. donax leaf was performed herein in an attempt to track such chemophenetic adaptations. This sort of approach is of the utmost importance for the current debate about the hypothetical invasiveness of this species in the Mediterranean basin versus its natural colonization along the Plio-Pleistocene period. We concluded that the leaf surfaces contain, apart from stomata, prickles, and long, thin trichomes, and silicon-rich tetralobate phytolits. Chemically, the dominating elements in the leaf ashes are oxygen and potassium; minor amounts of calcium, silicon, magnesium, phosphorous, sulphur, and chlorine were also detected. In both surfaces the epicuticular waxes (whose density is higher in the adaxial surface than in the abaxial surface) form randomly orientated platelets, with irregular shape and variable size, and aggregated rodlets with variable diameter around the stomata. In the case of green mature leaves, the dominating organic compounds of the epicuticular waxes of both surfaces are triterpenoids. Both surfaces feature identical hydrophobic behaviour, and exhibit the same total transmittance, total reflectance, and absorption of incident light. The above findings suggest easy growth of the plant, remarkable epidermic robustness of the leaf, and control of water loss. These chemophenetic characteristics and human influence support a neolithization process of this species along the Mediterranean basin.

4.
Foods ; 11(5)2022 Feb 23.
Article in English | MEDLINE | ID: mdl-35267278

ABSTRACT

The probability that fruit ingestion may protect human health is an intriguing vision and has been studied around the world. Therefore, fruits are universally promoted as healthy. Over the past few decades, the number of studies proposing a relationship between fruit intake and reduced risk of major chronic diseases has continued to grow. Fruits supply dietary fiber, and fiber intake is linked to a lower incidence of cardiovascular disease and obesity. Fruits also supply vitamins and minerals to the diet and are sources of phytochemicals that function as phytoestrogens, antioxidant and anti-inflammatory agents, and other protective mechanisms. So, this review aims to summarize recent knowledge and describe the most recent research regarding the health benefits of some selected red fruits.

5.
Foods ; 10(10)2021 Sep 29.
Article in English | MEDLINE | ID: mdl-34681365

ABSTRACT

The cherry rootstock influences the performance of the scion cultivar. It has an effect on cherry fruit quality, tree growth, yield and yield efficiency and floral and foliar nutrition. In this work, the influence of Saint Lucie 64 and Maxma 60 rootstocks on the fruit quality traits of cv. Early Bigi was evaluated. For this, several parameters, namely fruit weight (FW) and size (FS), soluble solids content (SSC), pH, titratable acidity (TA), flesh firmness (FF), epidermis rupture force (ERF), color and sensory profile, were assessed. Results showed that the fruits from trees on Saint Lucie 64 presented higher FF and ERF values and, consequently, better texture. On the other hand, fruits from trees on Maxma 60 showed sweeter cherries (higher SSC). Moreover, these trees presented the darkest cherries (lower values of L*, a*, b*, C* and hue°) and the highest SSC. Therefore, although the trees on Saint Lucie 64 produced firmer cherries, it was those with the Maxma 60 rootstock that produced sweeter and darker fruits. In conclusion, both scion-rootstock combinations proved to be good options for the region of Resende.

6.
Plant Physiol Biochem ; 166: 887-901, 2021 Sep.
Article in English | MEDLINE | ID: mdl-34243016

ABSTRACT

Copper (Cu) is an essential micronutrient for plants, but when present in excess, it induces toxicity. In this study, cuttings of four wine-producing varieties of Vitis vinifera L. were used: 'Tinta Barroca', 'Tinto Cão', 'Malvasia Fina' and 'Viosinho'. The grapevine cuttings were distributed by hydroponic solutions enriched with different Cu concentrations (1, 10, 25 and 50 µM) plus control. At the end of the experiment, the root growth was evaluated, and individual roots were collected, fixed, and used for histological sections and chromosome spreads preparation. The higher Cu concentrations induced toxicity and inhibited root growth. However, the grapevine varieties responded with the thickening of the root exodermis and endodermis. In the chromosome spreads, normal and abnormal interphase and mitotic cells were observed in all varieties and treatments. The increase of Cu concentration decreased the nucleolar activity, as seen by reducing the nucleolar number and area. It increased the frequency of interphase cells with anomalies (ICA), but it did not influence total soluble protein concentration. The augment of Cu concentration also decreased the mitotic index (MI) and increased the percentage of dividing cells with anomalies (DCA). Different types of chromosomal anomalies in all mitotic phases, treatments and varieties were found. Overall, the white wine varieties, 'Malvasia Fina' and 'Viosinho', appeared to be more tolerant to the Cu-induced stress because they showed higher root growth and mean MI and lower mean DCA than the red wine varieties.


Subject(s)
Vitis , Wine , Copper/toxicity , Hydroponics , Mitotic Index , Plant Roots
7.
Foods ; 10(3)2021 Mar 13.
Article in English | MEDLINE | ID: mdl-33805668

ABSTRACT

Sweet cherry (Prunus avium L.) is a fruit appreciated by consumers for its well-known physical and sensory characteristics and its health benefits. Being an extremely perishable fruit, it is important to know the unique attributes of the cultivars to develop cultivation or postharvest strategies that can enhance their quality. This study aimed to understand the influence of physicochemical characteristics of two sweet cherry cultivars, Burlat and Van, on the food quality perception. Several parameters (weight, dimensions, soluble solids content (SSC), pH, titratable acidity (TA), colour, and texture) were measured and correlated with sensory data. Results showed that cv. Van presented heavier and firmer fruits with high sugar content. In turn, cv. Burlat showed higher pH, lower TA, and presented redder and brightest fruits. The principal component analysis revealed an evident separation between cultivars. Van cherries stood out for their sensory parameters and were classified as more acidic, bitter, and astringent, and presented a firmer texture. Contrarily, Burlat cherries were distinguished as being more flavourful, succulent, sweeter, and more uniform in terms of visual and colour parameters. The results of the sensory analysis suggested that perceived quality does not always depend on and/or recognize the quality parameters inherent to the physicochemical characteristics of each cultivar.

8.
Foods ; 10(1)2021 Jan 06.
Article in English | MEDLINE | ID: mdl-33419090

ABSTRACT

Polyphenols, as well as volatile compounds responsible for aromatic features, play a critical role in the quality of vegetables and medicinal, and aromatic plants (MAPs). The research conducted in recent years has shown that these plants contain biologically active compounds, mainly polyphenols, that relate to the prevention of inflammatory processes, neurodegenerative diseases, cancers, and cardiovascular disorders as well as to antimicrobial, antioxidant, and antiparasitic properties. Throughout the years, many researchers have deeply studied polyphenols and volatile compounds in medicinal and aromatic plants, particularly those associated with consumer's choices or with their beneficial properties. In this context, the purpose of this review is to provide an overview of the presence of volatile and nonvolatile compounds in some of the most economically relevant and consumed vegetables and medicinal and aromatic plants, with an emphasis on bioactive polyphenols, polyphenols as prebiotics, and, also, the most important factors that affect the contents and profiles of the volatile and nonvolatile compounds responsible for the aromatic features of vegetables and MAPs. Additionally, the new challenges for science in terms of improving polyphenol composition and intensifying volatile compounds responsible for the positive characteristics of vegetables and medicinal and aromatic plants are reported.

9.
Plants (Basel) ; 9(11)2020 Nov 12.
Article in English | MEDLINE | ID: mdl-33198394

ABSTRACT

Fruit cracking is one of the main concerns in sweet cherry production and is caused by a heavy rainfall before and during the harvest. This physiological disorder leads to severe economic losses, which can be more or less effective depending on the cracked region of the fruit: in the cheeks (side cracks), in the stylar scar region, or in the stem cavity region. Sweet cherry cracking can be affected by several factors such as cultivar, growing conditions, rootstock, fruit size, flesh osmotic potential, cuticular characteristics of the skin, and stage of fruit development. In this sense, the objective of this work was to evaluate the cracking incidence in two sweet cherry cultivars (Early Bigi and Lapins grafted on "Saint Lucie 64" rootstock) and correlate the cracking index with other quality parameters. Fruits were harvested on 2 May (cv. Early Bigi) and on 27 May (cv. Lapins) 2019 at their commercial ripening stage. In the field, the total yield and the trunk cross-sectional area were determined for each tree in order to calculate the yield efficiency. In the laboratory, the cracking index was determined in 150 fruits without visual defects. In addition, fruit size and weight, wax content, flesh firmness, epidermis rupture force, total soluble solids, pH, titratable acidity, and maturity index of 30 fruits were also evaluated. In general, all the analyzed quality parameters were influenced by the cultivar, being that cv. Lapins presented larger, heavier, firmer, and sweeter fruits, with more acidity and higher maturation index. However, cv. Lapins also presented higher cracking index, which was positively correlated with all the parameters above-mentioned and negatively correlated with the wax content. In fact, cv. Early Bigi presented a high wax content and simultaneously a low cracking index. The stylar scar region cracks were the most prevalent in both cultivars. These results allowed us to conclude that, in the North Portugal region, the Lapins cherries presented better quality attributes than the Early Bigi cherries. However, the latter are still very valuable to the region due to its early ripening. Additionally, it was also possible to conclude that bigger, firmer, more mature, and with lower wax content cherries were more sensitive to cracking than the smaller fruits, soft-fleshed, less mature, and with higher wax content.

10.
Foods ; 8(12)2019 Dec 05.
Article in English | MEDLINE | ID: mdl-31817355

ABSTRACT

Flavours and fragrances are especially important for the beverage and food industries. Biosynthesis or extraction are the two main ways to obtain these important compounds that have many different chemical structures. Consequently, the search for new compounds is challenging for academic and industrial investigation. This overview aims to present the current state of art of beverage fragrance biotechnology, including recent advances in sensory and sensor methodologies and statistical techniques for data analysis. An overview of all the recent findings in beverage and food fragrance biotechnology, including those obtained from natural sources by extraction processes (natural plants as an important source of flavours) or using enzymatic precursor (hydrolytic enzymes), and those obtained by de novo synthesis (microorganisms' respiration/fermentation of simple substrates such as glucose and sucrose), are reviewed. Recent advances have been made in what concerns "beverage fragrances construction" as also in their application products. Moreover, novel sensory and sensor methodologies, primarily used for fragrances quality evaluation, have been developed, as have statistical techniques for sensory and sensors data treatments, allowing a rapid and objective analysis.

11.
J Sci Food Agric ; 99(12): 5341-5349, 2019 Sep.
Article in English | MEDLINE | ID: mdl-31058322

ABSTRACT

BACKGROUND: The strawberry (Fragaria × ananassa Duch.) is, among small fruits, the most cultivated and commercialized in Portugal. Recent studies have evidenced the positive effect of plant growth-promoting bacteria (PGPB) inoculation on strawberry production and, at the same time, provided an alternative strategy to reduce the use of fertilizers. In this study the effects of root inoculation with three PGPB strains (Pedobacter sp. CC1, Bacillus safensis B106 and Bacillus subtilis B167A) on the physiology, growth, fruit production and quality of strawberry cv. Camarosa are presented. RESULTS: PGPB inoculation significantly accelerated crop maturation, with inoculated plants fruiting about 2 weeks earlier than non-inoculated plants. Inoculated plants with Pedobacter sp. CC1 and Bacillus safensis B106 influenced the gas exchange parameters of strawberry plants. The contents of total phenolics and flavonoids in strawberry leaves were found to be greater with Pedobacter sp. CC1, when compared with non-inoculated plants. Furthermore, plants inoculated with the same bacterial strain showed enhancement in the dimensions of fruits, especially fruit length, and shape as well as in the total soluble solids content (°Brix). CONCLUSIONS: The results showed that the PGPB Pedobacter sp. CC1 improved performance of strawberry plants, suggesting that it could be a potential biofertilizer for strawberry plant nutrition. © 2019 Society of Chemical Industry.


Subject(s)
Agricultural Inoculants/growth & development , Bacillus/physiology , Fragaria/growth & development , Fragaria/microbiology , Fruit/chemistry , Pedobacter/physiology , Fertilizers/analysis , Flavonoids/analysis , Flavonoids/metabolism , Fragaria/chemistry , Fragaria/metabolism , Fruit/growth & development , Fruit/metabolism , Phenols/analysis , Phenols/metabolism , Portugal
12.
J Plant Physiol ; 215: 100-109, 2017 Aug.
Article in English | MEDLINE | ID: mdl-28618258

ABSTRACT

Pinus sylvestris L. (Scots pine) is the conifer with widest natural distribution area. Portugal constitutes its westernmost limit of distribution. Most of the Portuguese populations were planted but two autochthonous populations were recently ascribed to 'Serra do Gerês' (NW Portugal), and seem to be well adapted to the temperate climate. However, the ongoing climate changes may compromise their survival. With this study we intend to evaluate the anatomic-physiological and genetic responses of Scots pine from five European provenances ('Gerês', 'Puebla de Lillo', 'Montes Universales', Germany and Sweden) to three water availability regimes, in order to determine which one(s) present higher resistance to drought. Individuals from 'Gerês' presented the highest stability in photosynthetic reactions as well as the better photochemical and metabolic behaviours under drought (T3). Hence, the relative expression ratio of three water stress-responsive genes during drought was lower and gradual in 'Gerês', compared to all other provenances, followed by Germany. The results achieved in 'Gerês' and Germany provenances are very interesting since they reflected that the native populations of 'Gerês' along with the Portuguese Scots pine planted populations with a probable German provenance, have ability and high adaptive potential to respond to situations of water deficit. Moreover, the present genetic and physiological data demonstrated the urgent demand for the conservation of Portuguese Scots pine genetic resources as well as its use in plantation/afforestation of areas where the warming and drought has been affecting the survival of this species.


Subject(s)
Pinus sylvestris/physiology , Adaptation, Physiological/genetics , Adaptation, Physiological/physiology , Climate Change , Droughts , Photosynthesis/genetics , Photosynthesis/physiology , Pinus sylvestris/genetics , Real-Time Polymerase Chain Reaction
13.
Afr J Tradit Complement Altern Med ; 13(6): 130-134, 2016.
Article in English | MEDLINE | ID: mdl-28480369

ABSTRACT

BACKGROUND: In Europe, Acacia and Eucalyptus, originate large amounts of biomass, due to their need by industries and other biological control, that can be used to extract antimicrobial substances. MATERIALS AND METHODS: Foliar aqueous, ethanolic and methanolic extracts of Acacia baileyana (Cootamundra wattle), Acacia dealbata (silver wattle), Acacia melanoxylon (black wattle) and Eucalyptus nicholii (narrow-leaved black peppermint) were assessed for antimicrobial activity against Escherichia coli, Bacillus cereus, Candida albicans and Candida parapsilosis, using the disc diffusion method. RESULTS: Ethanolic extracts from A. baileyana and A. dealbata showed significant (P< 0.05) antimicrobial activity. Concerning the microbial species tested, differences were found in A. baileyana (P< 0.01) and E. nicholii (P< 0.0001) extracts. These two extracts were effective mostly against B. cereus, followed by C. parapsilosis. According to the antimicrobial activity classification, eucalypt and Cootamundra and silver wattles extracts (both water and ethanol) presented good efficacy against B. cereus, a food poisoning agent, and moderate efficacy against the remaining microorganisms. E. coli, a Gram negative, exhibited low sensibility to all foliar extracts. CONCLUSION: A. baileyana, E. nicholii and A. dealbata foliar biomass could be used to develop alternative substances in microbial control.


Subject(s)
Acacia/chemistry , Anti-Infective Agents/pharmacology , Ethanol/pharmacology , Eucalyptus/chemistry , Methanol/pharmacology , Plant Extracts/pharmacology , Bacillus cereus/drug effects , Candida/drug effects , Candida albicans/drug effects , Escherichia coli/drug effects , Microbial Sensitivity Tests/methods , Plant Extracts/chemistry
14.
ScientificWorldJournal ; 2012: 608954, 2012.
Article in English | MEDLINE | ID: mdl-22629161

ABSTRACT

UV-B radiation effects on nutrient concentrations in above-ground organs of maize were investigated at silking and maturity at different levels of applied nitrogen under field conditions. The experiment simulated a 20% stratospheric ozone depletion over Portugal. At silking, UV-B increased N, K, Ca, and Zn concentrations, whereas at maturity Ca, Mg, Zn, and Cu increased and N, P and Mn decreased in some plant organs. Generally, at maturity, N, Ca, Cu, and Mn were lower, while P, K, and Zn concentrations in stems and nitrogen-use efficiency (NUE) were higher in N-starved plants. UV-B and N effects on shoot dry biomass were more pronounced than on nutrient concentrations. Nutrient uptake decreased under high UV-B and increased with increasing N application, mainly at maturity harvest. Significant interactions UV-B x N were observed for NUE and for concentration and mass of some elements. For instance, under enhanced UV-B, N, Cu, Zn, and Mn concentrations decreased in leaves, except on N-stressed plants, whereas they were less affected by N nutrition. In order to minimize nutritional, economical, and environmental negative consequences, fertiliser recommendations based on element concentration or yield goals may need to be adjusted.


Subject(s)
Nitrogen/metabolism , Plant Components, Aerial/physiology , Plant Components, Aerial/radiation effects , Solar Energy , Ultraviolet Rays , Zea mays/physiology , Zea mays/radiation effects
15.
J Agric Food Chem ; 57(1): 265-73, 2009 Jan 14.
Article in English | MEDLINE | ID: mdl-19072054

ABSTRACT

The impact of elevated carbon dioxide concentration ([CO2]) on the quality of berries, must, and red wine (with special reference to volatile composition, phenolic content, and antioxidant activity) made from Touriga Franca, a native grape variety of Vitis vinifera L. for Port and Douro wine manufacturing grown in the Demarcated Region of Douro, was investigated during 2005 and 2006. Grapevines were grown either in open-top chambers (OTC) with ambient (365 +/- 10 ppm) or elevated (500 +/-16 ppm) [CO2] or in an outside plot. In general, the increase of [CO2] did not affect berry characteristics, especially the total anthocyan and tannin concentrations. However, the total anthocyan and polyphenol concentrations of the red wine were inhibited under elevated [CO2]. The antioxidant capacity of the wines was determined by DPPH, ABTS, and TBARS assays and, despite the low concentrations of phenolics, the elevated [CO2] did not significantly change the total antioxidant capacity of the red wines. Thirty-five volatile compounds belonging to seven chemical groups were identified: C6 alcohols, higher alcohols, esters, terpenols, carbonyl compounds, acids, volatile phenols, and C13 norisoprenoids. Generally, the same volatile compounds were present in all of the wines, but the relative levels varied among the treatments. The effect of elevated [CO2] was significant because it was detected as an increase in ethyl 2-methylbutyrate, isoamyl acetate, ethyl hexanoate, ethyl octanoate, butyric acid, and isovaleric acid concentrations and a decrease in ethyl acetate concentration when compared to wines produced in ambient [CO2] in 2005. In elevated [CO2], wines from 2006 had lower methionol, 1-octanol, and 4-ethylguaiacol and higher ethyl lactate and linalool concentrations. The increase in [CO2] did not significantly affect C6 alcohols, citronellol, carbonyl compounds, and beta-damascenone concentrations. This study showed that the predicted rise in [CO2] did not produce negative effects on the quality of grapes and red wine. Although some of the compounds were slightly affected, the red wine quality remained almost unaffected.


Subject(s)
Antioxidants/analysis , Carbon Dioxide/analysis , Flavonoids/analysis , Odorants/analysis , Phenols/analysis , Vitis/chemistry , Wine/analysis , Anthocyanins/analysis , Atmosphere/chemistry , Fruit/chemistry , Polyphenols , Vitis/drug effects , Volatile Organic Compounds/analysis
16.
Tree Physiol ; 26(1): 93-104, 2006 Jan.
Article in English | MEDLINE | ID: mdl-16203719

ABSTRACT

Water relations, leaf gas exchange, chlorophyll a fluorescence, light canopy transmittance, leaf photosynthetic pigments and metabolites and fruit quality indices of cherry cultivars 'Burlat', 'Summit' and 'Van' growing on five rootstocks with differing size-controlling potentials that decrease in the order: Prunus avium L. > CAB 11E > Maxma 14 > Gisela 5 > Edabriz, were studied during 2002 and 2003. Rootstock genotype affected all physiological parameters. Cherry cultivars grafted on invigorating rootstocks had higher values of midday stem water potential (Psi(MD)), net CO(2) assimilation rate (A), stomatal conductance (g(s)), intercellular CO(2) concentration (C(i)) and maximum photochemical efficiency of photosystem II (PSII) (F(v)/F(m)) than cultivars grafted on dwarfing rootstocks. The Psi(MD) was positively correlated with A, g(s) and C(i). Moreover, A was positively correlated with g(s), and the slopes of the linear regression increased from invigorating to dwarfing rootstocks, indicating a stronger regulation of photosynthesis by stomatal aperture in trees on dwarfing Edabriz and Gisela 5. The effect of rootstock genotype was also statistically significant for leaf photosynthetic pigments, whereas metabolite concentrations and fruit physicochemical characteristics were more dependent on cultivar genotype. Among cultivars, 'Burlat' leaves had the lowest concentrations of photosynthetic pigments, but were richest in total soluble sugars, starch and total phenols. Compared with the other cultivars, 'Summit' had heavier fruits, independent of the rootstock. 'Burlat' cherries were less firm and had lower concentrations of soluble sugars and a lower titratable acidity than 'Van' cherries. Nevertheless, 'Van' cherries had lower lightness, chroma and hue angle, representing redder and darker cherries, compared with 'Summit' fruits. In general, Psi(MD) was positively correlated with fruit mass and A was negatively correlated with lightness and chroma. These results demonstrate that: (1) water relations and photosynthesis of sweet cherry tree are mainly influenced by the rootstock genotype; (2) different physicochemical characteristics observed in cherries of the three cultivars suggest that regulation of fruit quality was mainly dependent on the cultivar genotype, although the different size-controlling rootstocks also had a significant effect.


Subject(s)
Fruit/physiology , Plant Roots/physiology , Prunus/physiology , Chlorophyll/metabolism , Chlorophyll A , Fluorescence , Fruit/standards , Gases/metabolism , Light , Photosynthesis/physiology , Pigments, Biological/metabolism , Plant Leaves/metabolism , Prunus/metabolism , Prunus/radiation effects , Water/metabolism
17.
Tree Physiol ; 24(2): 233-9, 2004 Feb.
Article in English | MEDLINE | ID: mdl-14676039

ABSTRACT

Leaf-level morphological and structural adaptations to reduce water loss were examined in five olive (Olea europaea L.) tree cultivars (Arbequina, Blanqueta, Cobrançosa, Manzanilla and Negrinha) growing under field conditions with low water availability. Leaf measurements included leaf tissue thickness, stomatal density, leaf area, leaf mass per unit area, density of leaf tissue, relative water content, succulence, water saturation deficit, water content at saturation and cuticular transpiration rate. We found considerable genotypic differences among the cultivars. Negrinha, Manzanilla and Cobrançosa had more morphological and structural leaf adaptations to protect against water loss than the other cultivars. Manzanilla and Negrinha enhanced their sclerophylly by building parenchyma tissues and increasing protective structures like the upper cuticle and both the upper and lower epidermis. Cobrançosa exhibited good protection against water loss through high density of foliar tissue and by thick cuticle and trichome layers. Compared with the Negrinha, Manzanilla and Cobrançosa cultivars, Arbequina leaves had a thinner trichome layer, implying that the leaves were less protected against water loss; however, the development of smaller leaves may reduce water loss at the whole-plant level. Among cultivars, Blanqueta had the largest leaves and some anatomical traits that may lead to high water loss, especially from the adaxial surface. The mechanisms employed by the cultivars to cope with summer stress are discussed at the morpho-structural level.


Subject(s)
Olea/physiology , Plant Leaves/physiology , Trees/physiology , Dehydration/physiopathology , Olea/anatomy & histology , Plant Leaves/anatomy & histology , Plant Transpiration/physiology , Trees/anatomy & histology
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