A correlation analysis of Light Microscopy and X-ray MicroCT imaging methods applied to archaeological plant remains' morphological attributes visualization.

In this work, several attributes of the internal morphology of drupaceous fruits found in the archaeological site Monte Castelo (Rondonia, Brazil) are analyzed by means of two different imaging methods. The aim is to explore similarities and differences in the visualization and analytical properties of the images obtained via High Resolution Light Microscopy and X-ray micro-computed tomography (X-ray MicroCT) methods. Both provide data about the three-layered pericarp (exo-, meso- and endocarp) of the studied exemplars, defined by cell differentiation, vascularisation, cellular contents, presence of sclerenchyma cells and secretory cavities. However, it is possible to identify a series of differences between the information that can be obtained through each of the methods. These variations are related to the definition of contours and fine details of some characteristics, their spatial distribution, size attributes, optical properties and material preservation. The results obtained from both imaging methods are complementary, contributing to a more exhaustive morphological study of the plant remains. X-ray MicroCT in phase-contrast mode represents a suitable non-destructive analytic technique when sample preservation is required.

Influence of auto-exhaust pollution on trichome micromorphology of Olea europea L. leaves.

This study aimed to determine the influence of auto-exhaust pollution on trichome structure of Olea europea L. leaves. For this purpose, olive leaves were collected from two areas one of which is urban and the other is rural. Leaf surface sections in leaves were obtained to examine the influence of auto-exhaust pollution on trichome structure of olive. Width-length thicknesses in peltate trichome were measured using a micrometric ocular. To investigate the density and the percentages of damaged-nondamaged peltate trichomes among the groups, the upper epidermis of leaves was photographed with SEM. According to the results, the values of width and length thicknesses of peltate trichome were lower in urban area when compared to rural site. The density and percentages of nondamaged peltate structure were lower in urban area whereas damaged peltate structures were increased. Auto-exhaust pollution decreased the amount of nondamaged peltate trichome structure and caused damaged peltate structures in olive leaves. The plant can be more sensitive to drought because of decreased amount of peltate trichomes and also increased damaged peltate trichome structures in urban area.

A 3D study of the relationship between leaf vein structure and mechanical function.

We investigate the structures and mechanical properties of leaf midribs of Ficus microcarpa and Prunus dulcis, which deposit calcium oxalate crystals, and of Olea europaea midribs which contain no mineral deposits, but do contain lignified fibers. The midrib mechanical performance contributes to the leaf's ability to maintain a flat conformation for light harvesting and to efficiently reconfigure to reduce wind drag. We use a novel approach involving 3D visualization of the vein structure during mechanical load. This involves the use of customized mechanical loading devices that fit inside a microCT chamber. We show that the elastic, compression and torsional moduli of the midribs of leaves from the 3 species examined vary significantly. We also observed different modes of fracture and buckling of the leaves during compression. We assess the contributions of the calcium oxalate crystals to the mechanical and fracture properties. In F. microcarpa midrib linear arrays of calcium oxalate crystals contribute to resisting the bending, in contrast to P. dulcis leaves, where the calcium oxalate crystals do not resist bending. In both F. microcarpa and P. dulcis isolated calcium oxalate crystals enable high torsional compliance. The integrated microCT - mechanical testing approach could be used to investigate the structure-mechanics relationships in other complex biological samples. STATEMENT OF SIGNIFICANCE: Leaves need to maintain a flat conformation for light harvesting, but they also need to efficiently reconfigure to reduce wind drag. The leaf central vein (midrib) is a key structural component for leaf mechanicss. 3D visualization of the vein structure under mechanical loads showed that veins can be stiffened by reinforcement units composed of calcium oxalates crystals and lignin. The stiffening units can influence the bending and fracture properties of the midribs, and can contribute to determine if buckling will occur during folding. Mineral stiffening elements could be a widespread strategy to reinforce leaf veins and other biological structures. This structural-mechanical approach could be used to study other complex biological samples.

High-resolution imagery acquired from an unmanned platform to estimate biophysical and geometrical parameters of olive trees under different irrigation regimes.

The experiments were conducted in a fully-productive olive orchard (cv. Frantoio) at the experimental farm of University of Pisa at Venturina (Italy) in 2015 to assess the ability of an unmanned aerial vehicle (UAV) equipped with RGB-NIR cameras to estimate leaf area index (LAI), tree height, canopy diameter and canopy volume of olive trees that were either irrigated or rainfed. Irrigated trees received water 4-5 days a week (1348 m3 ha-1), whereas the rainfed ones received a single irrigation of 19 m3 ha-1 to relieve the extreme stress. The flight altitude was 70 m above ground level (AGL), except for one flight (50 m AGL). The Normalized Difference Vegetation Index (NDVI) was calculated by means of the map algebra technique. Canopy volume, canopy height and diameter were obtained from the digital surface model (DSM) obtained through automatic aerial triangulation, bundle block adjustment and camera calibration methods. The NDVI estimated on the day of the year (DOY) 130 was linearly correlated with both LAI and leaf chlorophyll measured on the same date (R2 = 0.78 and 0.80, respectively). The correlation between the on ground measured canopy volumes and the ones by the UAV-RGB camera techniques yielded an R2 of 0.71-0.86. The monthly canopy volume increment estimated from UAV surveys between (DOY) 130 and 244 was highly correlated with the daily water stress integral of rainfed trees (R2 = 0.99). The effect of water stress on the seasonal pattern of canopy growth was detected by these techniques in correspondence of the maximum level of stress experienced by the rainfed trees. The highest level of accuracy (RMSE = 0.16 m) in canopy height estimation was obtained when the flight altitude was 50 m AGL, yielding an R2 value of 0.87 and an almost 1:1 ratio of measured versus estimated canopy height.

Ethephon induced oxidative stress in the olive leaf abscission zone enables development of a selective abscission compound.

BACKGROUND: Table olives (Olea europaea L.), despite their widespread production, are still harvested manually. The low efficiency of manual harvesting and the rising costs of labor have reduced the profitability of this crop. A selective abscission treatment, inducing abscission of fruits but not leaves, is crucial for the adoption of mechanical harvesting of table olives. In the present work we studied the anatomical and molecular differences between the three abscission zones (AZs) of olive fruits and leaves. RESULTS: The fruit abscission zone 3 (FAZ3), located between the fruit and the pedicel, was found to be the active AZ in mature fruits and is sensitive to ethephon, whereas FAZ2, between the pedicel and the rachis, is the flower active AZ as well as functioning as the most ethephon induced fruit AZ. We found anatomical differences between the leaf AZ (LAZ) and the two FAZs. Unlike the FAZs, the LAZ is characterized by small cells with less pectin compared to neighboring cells. In an attempt to differentiate between the fruit and leaf AZs, we examined the effect of treating olive-bearing trees with ethephon, an ethylene-releasing compound, with or without antioxidants, on the detachment force (DF) of fruits and leaves 5 days after the treatment. Ethephon treatment enhanced pectinase activity and reduced DF in all the three olive AZs. A transcriptomic analysis of the three olive AZs after ethephon treatment revealed induction of several genes encoding for hormones (ethylene, auxin and ABA), as well as for several cell wall degrading enzymes. However, up-regulation of cellulase genes was found only in the LAZ. Many genes involved in oxidative stress were induced by the ethephon treatment in the LAZ alone. In addition, we found that reactive oxygen species (ROS) mediated abscission in response to ethephon only in leaves. Thus, adding antioxidants such as ascorbic acid or butyric acid to the ethephon inhibited leaf abscission but enhanced fruit abscission. CONCLUSION: Our findings suggest that treating olive-bearing trees with a combination of ethephon and antioxidants reduces the detachment force (DF) of fruit without weakening that of the leaves. Hence, this selective abscission treatment may be used in turn to promote mechanized harvest of olives.

Unusual positional effects on flower sex in an andromonoecious tree: Resource competition, architectural constraints, or inhibition by the apical flower?

PREMISE OF THE STUDY: Two, nonmutually exclusive, mechanisms-competition for resources and architectural constraints-have been proposed to explain the proximal to distal decline in flower size, mass, and/or femaleness in indeterminate, elongate inflorescences. Whether these mechanisms also explain unusual positional effects such as distal to proximal declines of floral performance in determinate inflorescences, is understudied. METHODS: We tested the relative influence of these mechanisms in the andromonoecious wild olive tree, where hermaphroditic flowers occur mainly on apical and the most proximal positions in determinate inflorescences. We experimentally increased the availability of resources for the inflorescences by removing half of the inflorescences per twig or reduced resource availability by removing leaves. We also removed the apical flower to test its inhibitory effect on subapical flowers. KEY RESULTS: The apical flower had the highest probability of being hermaphroditic. Further down, however, the probability of finding a hermaphroditic flower decreased from the base to the tip of the inflorescences. An experimental increase of resources increased the probability of finding hermaphroditic flowers at each position, and vice versa. Removal of the apical flower increased the probability of producing hermaphroditic flowers in proximal positions but not in subapical positions. CONCLUSIONS: These results indicate an interaction between resource competition and architectural constraints in influencing the arrangement of the hermaphroditic and male flowers within the inflorescences of the wild olive tree. Subapical flowers did not seem to be hormonally suppressed by apical flowers. The study of these unusual positional effects is needed for a general understanding about the functional implications of inflorescence architecture.

Correlations between morpho-anatomical changes and radial hydraulic conductivity in roots of olive trees under water deficit and rewatering.

The effects of prolonged drought were studied on olive (Olea europaea L.; drought-sensitive cultivar Biancolilla and drought-tolerant cultivar Coratina) to examine how morpho-anatomical modifications in roots impact on root radial hydraulic conductivity (Lpr). Two-year-old self-rooted plants were subjected to a gradual water depletion. The levels of drought stress were defined by pre-dawn leaf water potentials (Ψw) of -1.5, -3.5 and -6.5 MPa. After reaching the maximum level of drought, plants were rewatered for 23 days. Progressive drought stress, for both cultivars, caused a strong reduction in Lpr (from 1.2 to 1.3 × 10(-5) m MPa(-1) s(-1) in unstressed plants to 0.2-0.6 × 10(-5) m MPa(-1) s(-1) in plants at Ψw = -6.5 MPa), particularly evident in the more suberized (brown) roots, accompanied with decreases in stomatal conductance (gs). No significant differences in Lpr and gs between the two olive cultivars were observed. Epifluorescence microscopy and image analyses revealed a parallel increase of wall suberization that doubled in white stressed roots and tripled in brown ones when compared with unstressed plants. In drought-stressed plants, the number of suberized cellular layers from the endodermis towards the cortex increased from 1-2 to 6-7. Recovery in Lpr during rewatering was correlated to the physical disruption of hydrophobic barriers, while the time necessary to obtain new mature roots likely accounted for the observed delay in the complete recovery of gs. Radial hydraulic conductivity in olive roots was strongly influenced by soil and plant water availability and it was also modulated by structural root modifications, size, growth and anatomy. These findings could be important for maintaining an optimal water status in cultivated olive trees by scheduling efficient irrigation methods, saving irrigation water and obtaining yield of high quality.

Polyphenols benefits of olive leaf (Olea europaea L) to human health / Beneficios polifenoles hoja de olivo (Olea Europaea L) para la salud humana

Introduction: The phenolic compounds present in olive leaves (Olea europaea L.) confer benefits to the human health. Objectives: To review the scientific literature about the benefits of the polyphenols of olive leaves to human health. Method: Literature review in the LILACS-BIREME, SciELO and MEDLINE databases for publications in English, Portuguese and Spanish with the descriptors 'Olea europaea', 'olive leaves', 'olive leaf', 'olive leaves extracts', 'olive leaf extracts', 'phenolic compounds', 'polyphenols', 'oleuropein', 'chemical composition', and 'health'. There were identified 92 articles, but only 38 related to the objectives of the study and 9 articles cited in the works were included due to their relevance. Results and discussion: The phenolic compounds present in olive leaves, especially the oleuropein, are associated to antioxidant, antihypertensive, hypoglycemic, hypocholesterolemic and cardioprotective activity. Furthermore, studies associate the oleuropein to an anti-inflammatory effect in trauma of the bone marrow and as a support in the treatment of obesity (AU)

Introducción: Los compuestos fenólicos presentes en las hojas del olivo (olea europaea l.) conferir beneficios para la salud humana. Objetivos: Revisar la literatura científica sobre los beneficios de los polifenoles de hojas de olivo para la salud humana. Método: Revisión de la literatura en las bases de datos lilacs-bireme, scielo y medline para publicaciones en inglés, portugués y español con los descriptores 'olea europaea', 'hojas de olivo', 'hoja de olivo', 'hojas de olivo extractos', 'los extractos de hoja de olivo', 'compuestos fenólicos', 'polifenoles', 'oleuropeína', 'composición quí-mica', y 'salud'. Se identificaron 92 artículos, pero sólo 38 en relación con los objetivos del estudio y 9 artículos citados en las obras se incluyeron debido a su relevancia. Resultados y discusión: Los compuestos fenólicos presentes en las hojas del olivo, especialmente la oleuropeína, se asocian a antioxidante, antihipertensivo, hipoglucemiante, actividad hipocolesterolémico y cardioprotector. además, los estudios asocian la oleuropeína a un efecto anti-inflamatorio en trauma de la médula ósea y como soporte en el tratamiento de la obesidad (AU)

Testing accuracy of long-range ultrasonic sensors for olive tree canopy measurements.

Ultrasonic sensors are often used to adjust spray volume by allowing the calculation of the crown volume of tree crops. The special conditions of the olive tree require the use of long-range sensors, which are less accurate and faster than the most commonly used sensors. The main objectives of the study were to determine the suitability of the sensor in terms of sound cone determination, angle errors, crosstalk errors and field measurements. Different laboratory tests were performed to check the suitability of a commercial long-range ultrasonic sensor, as were the experimental determination of the sound cone diameter at several distances for several target materials, the determination of the influence of the angle of incidence of the sound wave on the target and distance on the accuracy of measurements for several materials and the determination of the importance of the errors due to interference between sensors for different sensor spacings and distances for two different materials. Furthermore, sensor accuracy was tested under real field conditions. The results show that the studied sensor is appropriate for olive trees because the sound cone is narrower for an olive tree than for the other studied materials, the olive tree canopy does not have a large influence on the sensor accuracy with respect to distance and angle, the interference errors are insignificant for high sensor spacings and the sensor's field distance measurements were deemed sufficiently accurate.

The standard centrifuge method accurately measures vulnerability curves of long-vesselled olive stems.

The standard centrifuge method has been frequently used to measure vulnerability to xylem cavitation. This method has recently been questioned. It was hypothesized that open vessels lead to exponential vulnerability curves, which were thought to be indicative of measurement artifact. We tested this hypothesis in stems of olive (Olea europea) because its long vessels were recently claimed to produce a centrifuge artifact. We evaluated three predictions that followed from the open vessel artifact hypothesis: shorter stems, with more open vessels, would be more vulnerable than longer stems; standard centrifuge-based curves would be more vulnerable than dehydration-based curves; and open vessels would cause an exponential shape of centrifuge-based curves. Experimental evidence did not support these predictions. Centrifuge curves did not vary when the proportion of open vessels was altered. Centrifuge and dehydration curves were similar. At highly negative xylem pressure, centrifuge-based curves slightly overestimated vulnerability compared to the dehydration curve. This divergence was eliminated by centrifuging each stem only once. The standard centrifuge method produced accurate curves of samples containing open vessels, supporting the validity of this technique and confirming its utility in understanding plant hydraulics. Seven recommendations for avoiding artefacts and standardizing vulnerability curve methodology are provided.

Canopy light heterogeneity drives leaf anatomical, eco-physiological, and photosynthetic changes in olive trees grown in a high-density plantation.

In the field, leaves may face very different light intensities within the tree canopy. Leaves usually respond with light-induced morphological and photosynthetic changes, in a phenomenon known as phenotypic plasticity. Canopy light distribution, leaf anatomy, gas exchange, chlorophyll fluorescence, and pigment composition were investigated in an olive (Olea europaea, cvs. Arbequina and Arbosana) orchard planted with a high-density system (1,250 trees ha(-1)). Sampling was made from three canopy zones: a lower canopy (<1 m), a central one (1-2 m), and an upper one (>2 m). Light interception decreased significantly in the lower canopy when compared to the central and top ones. Leaf angle increased and photosynthetic rates and non-photochemical quenching (NPQ) decreased significantly and progressively from the upper canopy to the central and the lower canopies. The largest leaf areas were found in the lower canopy, especially in the cultivar Arbequina. The palisade and spongy parenchyma were reduced in thickness in the lower canopy when compared to the upper one, in the former due to a decrease in the number of cell layers from three to two (clearly distinguishable in the light and fluorescence microscopy images). In both cultivars, the concentration of violaxanthin-cycle pigments and ß-carotene was higher in the upper than in the lower canopy. Furthermore, the de-epoxidized forms zeaxanthin and antheraxanthin increased significantly in those leaves from the upper canopy, in parallel to the NPQ increases. In conclusion, olive leaves react with morphological and photosynthetic changes to within-crown light gradients. These results strengthen the idea of olive trees as "modular organisms" that adjust the modules morphology and physiology in response to light intensity.

Observation of eight ancient olive trees (Olea europaea L.) growing in the Garden of Gethsemane.

For thousands of years, olive trees (Olea europaea L.) have been a significant presence and a symbol in the Garden of Gethsemane, a place located at the foot of the Mount of Olives, Jerusalem, remembered for the agony of Jesus Christ before his arrest. This investigation comprises the first morphological and genetic characterization of eight olive trees in the Garden of Gethsemane. Pomological traits, morphometric, and ultrastructural observations as well as SSR (Simple Sequence Repeat) analysis were performed to identify the olive trees. Statistical analyses were conducted to evaluate their morphological variability. The study revealed a low morphological variability and minimal dissimilarity among the olive trees. According to molecular analysis, these trees showed the same allelic profile at all microsatellite loci analyzed. Combining the results of the different analyses carried out in the frame of the present work, we could conclude that the eight olive trees of the Gethsemane Garden have been propagated from a single genotype.

Vulnerability to cavitation in Olea europaea current-year shoots: further evidence of an open-vessel artifact associated with centrifuge and air-injection techniques.

Different methods have been devised to analyze vulnerability to cavitation of plants. Although a good agreement between them is usually found, some discrepancies have been reported when measuring samples from long-vesseled species. The aim of this study was to evaluate possible artifacts derived from different methods and sample sizes. Current-year shoot segments of mature olive trees (Olea europaea), a long-vesseled species, were used to generate vulnerability curves (VCs) by bench dehydration, pressure collar and both static- and flow-centrifuge methods. For the latter, two different rotors were used to test possible effects of the rotor design on the curves. Indeed, high-resolution computed tomography (HRCT) images were used to evaluate the functional status of xylem at different water potentials. Measurements of native embolism were used to validate the methods used. The pressure collar and the two centrifugal methods showed greater vulnerability to cavitation than the dehydration method. The shift in vulnerability thresholds in centrifuge methods was more pronounced in shorter samples, supporting the open-vessel artifact hypothesis as a higher proportion of vessels were open in short samples. The two different rotor designs used for the flow-centrifuge method revealed similar vulnerability to cavitation. Only the bench dehydration or HRCT methods produced VCs that agreed with native levels of embolism and water potential values measured in the field.

Polyphenols benefits of olive leaf (Olea europaea L) to human health.

INTRODUCTION: The phenolic compounds present in olive leaves (Olea europaea L.) confer benefits to the human health. OBJECTIVES: To review the scientific literature about the benefits of the polyphenols of olive leaves to human health. METHOD: Literature review in the LILACS-BIREME, SciELO and MEDLINE databases for publications in English, Portuguese and Spanish with the descriptors "Olea europaea", "olive leaves", "olive leaf", "olive leaves extracts", "olive leaf extracts", "phenolic compounds", "polyphenols", "oleuropein", "chemical composition", and "health". There were identified 92 articles, but only 38 related to the objectives of the study and 9 articles cited in the works were included due to their relevance. RESULTS AND DISCUSSION: The phenolic compounds present in olive leaves, especially the oleuropein, are associated to antioxidant, antihypertensive, hypoglycemic, hypocholesterolemic and cardioprotective activity. Furthermore, studies associate the oleuropein to an anti-inflammatory effect in trauma of the bone marrow and as a support in the treatment of obesity.

Introducción: Los compuestos fenólicos presentes en las hojas del olivo (olea europaea l.) conferir beneficios para la salud humana. Objetivos: Revisar la literatura científica sobre los beneficios de los polifenoles de hojas de olivo para la salud humana. Método: Revisión de la literatura en las bases de datos lilacs-bireme, scielo y medline para publicaciones en inglés, portugués y español con los descriptores "olea europaea", "hojas de olivo", "hoja de olivo", "hojas de olivo extractos", "los extractos de hoja de olivo", "compuestos fenólicos", "polifenoles", "oleuropeína", "composición química", y "salud". Se identificaron 92 artículos, pero sólo 38 en relación con los objetivos del estudio y 9 artículos citados en las obras se incluyeron debido a su relevancia. Resultados y discusión: Los compuestos fenólicos presentes en las hojas del olivo, especialmente la oleuropeína, se asocian a antioxidante, antihipertensivo, hipoglucemiante, actividad hipocolesterolémico y cardioprotector. además, los estudios asocian la oleuropeína a un efecto anti-inflamatorio en trauma de la médula ósea y como soporte en el tratamiento de la obesidad.

Infrared machine vision system for the automatic detection of olive fruit quality.

External quality is an important factor in the extraction of olive oil and the marketing of olive fruits. The appearance and presence of external damage are factors that influence the quality of the oil extracted and the perception of consumers, determining the level of acceptance prior to purchase in the case of table olives. The aim of this paper is to report on artificial vision techniques developed for the online estimation of olive quality and to assess the effectiveness of these techniques in evaluating quality based on detecting external defects. This method of classifying olives according to the presence of defects is based on an infrared (IR) vision system. Images of defects were acquired using a digital monochrome camera with band-pass filters on near-infrared (NIR). The original images were processed using segmentation algorithms, edge detection and pixel value intensity to classify the whole fruit. The detection of the defect involved a pixel classification procedure based on nonparametric models of the healthy and defective areas of olives. Classification tests were performed on olives to assess the effectiveness of the proposed method. This research showed that the IR vision system is a useful technology for the automatic assessment of olives that has the potential for use in offline inspection and for online sorting for defects and the presence of surface damage, easily distinguishing those that do not meet minimum quality requirements.

Olive tree-ring problematic dating: a comparative analysis on Santorini (Greece).

Olive trees are a classic component of Mediterranean environments and some of them are known historically to be very old. In order to evaluate the possibility to use olive tree-rings for dendrochronology, we examined by various methods the reliability of olive tree-rings identification. Dendrochronological analyses of olive trees growing on the Aegean island Santorini (Greece) show that the determination of the number of tree-rings is impossible because of intra-annual wood density fluctuations, variability in tree-ring boundary structure, and restriction of its cambial activity to shifting sectors of the circumference, causing the tree-ring sequences along radii of the same cross section to differ.

Morphological traits and RAPD markers for characterization and identification of minor Spanish olive cultivars from the Extremadura region.

A total of 91 wild olive accessions and 31 olive cultivars growing in the Extremadura region of central-western Spain were analyzed using morphological traits and RAPD markers. We focused on three main and 16 minor Spanish olive cultivars that are recognized as native or local to the Extremadura region. The five arbitrary 10-mer primers tested on the olive cultivars gave 67 polymorphic bands, representing 91% of the total amplification products. The number of bands per primer ranged from 9 to 18, whereas the number of polymorphic bands ranged from 8 to 17. All the cultivars could be identified by a combination of three primers (OPF-6, OPA-8, and OPK-16); four cultivar-specific markers were detected. The minor local "Jariego" and "Tempranillo" cultivars showed the most distal similarities. The resulting dendrogram, using the unweighted pair-group method with arithmetic mean clustering algorithm, depicted the pattern of relationships between the local Extremadura cultivars and the cultivars from geographically connected regions. This analysis showed a correlation between most of the minor local cultivars and the geographical origin; there was no apparent clustering according to morphological traits or fruit use of olive cultivars when these parameters were used as analysis criteria.

Morphological, histological and ultrastructural changes in the olive pistil during flowering.

Sexual reproduction is essential for the propagation of higher plants. From an agronomical point of view, this is a particularly key process because fertilization guarantees fruit formation in most cultivated fruit species. In the olive, however, in spite of its agricultural importance, little attention has been paid to the study of sexual reproduction. In order to investigate the cellular and molecular mechanisms that regulate pollen-pistil interactions in the olive during the progamic phase, it is essential to first have a good knowledge of the reproductive structures involved in such interactions. This study characterizes the anatomical and ultrastructural changes in the olive pistil, beginning from the young pistil developing within the bud until the time of petal loss and visible stigma senescence. We have correlated changes in the pistil with a series of defined floral developmental stages and determined that olive pistil structures cannot be considered completely mature and ready to be pollinated and fertilized until the onset of anthesis. Our results clearly show histological and ultrastructural variation during the diverse flowering events. We discuss whether the changes observed might influence or result from pollen-pistil interactions during the progamic phase.

Temporal matching among diurnal photosynthetic patterns within the crown of the evergreen sclerophyll Olea europaea L.

Trees are modular organisms that adjust their within-crown morphology and physiology in response to within-crown light gradients. However, whether within-plant variation represents a strategy for optimizing light absorption has not been formally tested. We investigated the arrangement of the photosynthetic surface throughout one day and its effects on the photosynthetic process, at the most exposed and most sheltered crown layers of a wild olive tree (Olea europaea L.). Similar measurements were made for cuttings taken from this individual and grown in a greenhouse at contrasted irradiance-levels (100 and 20% full sunlight). Diurnal variations in light interception, carbon fixation and carbohydrate accumulation in sun leaves were negatively correlated with those in shade leaves under field conditions when light intensity was not limiting. Despite genetic identity, these complementary patterns were not found in plants grown in the greenhouse. The temporal disparity among crown positions derived from specialization of the photosynthetic behaviour at different functional and spatial scales: architectural structure (crown level) and carbon budget (leaf level). Our results suggest that the profitability of producing a new module may not only respond to construction costs or light availability, but also rely on its spatio-temporal integration within the productive processes at the whole-crown level.

Spatial sap flow and xylem anatomical characteristics in olive trees under different irrigation regimes.

The compensation heat pulse (CHP) method is widely used to estimate sap flow and transpiration in conducting organs of woody plants. Previous studies have reported a natural azimuthal variability in sap flow, which could have practical implications in locating the CHP probes and integrating their output. Sap flow of several olive trees (Olea europaea L. cv. 'Arbequina') previously grown under different irrigation treatments were monitored by the CHP method, and their xylem anatomical characteristics were analyzed from wood samples taken at the same location in which the probes were installed. A significant azimuthal variability in the sap flow was found in a well-irrigated olive tree monitored by eight CHP probes. The azimuthal variability was well related to crown architecture, but poorly to azimuthal differences in the xylem anatomical characteristics. Well-irrigated and deficit-irrigated olive trees showed similar xylem anatomical characteristics, but they differed in xylem growth and in the ratio of nocturnal-to-diurnal sap flow (N/D index). The results of this work indicate that transpiration cannot be accurately estimated by the CHP method in olive trees if a small number of sensors are employed and that the N/D index could be used as a sensitive water status indicator.