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Olga M Grant - One of the best experts on this subject based on the ideXlab platform.
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genetic diversity of Cistus albidus in south east spain does not relate to mesoclimate
Functional Plant Biology, 2006Co-Authors: Olga M Grant, T Mcneilly, Lynton D IncollAbstract:Patterns of variation at selected isozyme loci were examined in populations of Cistus albidus L. in south-east Spain, from areas differing in precipitation and temperature, to determine whether population divergence has occurred. Total genetic diversity was high, with a high percentage of the variation being found between populations. Genetic variation between populations did not relate to climate. Populations exposed to severe summer drought did not show lower genetic diversity than populations from more benign climates. Little genetic variation was found between populations that showed variation in ecophysiological and growth responses in situ and under controlled conditions. Cluster analyses showed different patterns of between-population distances with respect to genetic, physiological and morphological data, and none of these patterns corresponded to that for between-site environmental variation.
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variation in growth responses to availability of water in Cistus albidus populations from different habitats
Functional Plant Biology, 2005Co-Authors: Olga M Grant, Lynton D Incoll, T McneillyAbstract:Seeds of Cistus albidus L. plants from three populations that are exposed to differing temperature and precipitation in Almeria province of south-east Spain, were collected and grown together in a factorial experiment with two irrigation treatments. The aim was to determine whether populations from different habitats differed when exposed to common conditions, or differed in the plasticity of their response to availability of water. Significant differences in growth of branches and in leaf dimensions were found between treatments, indicating phenotypic plasticity. There was also significant variation between populations in growth of branches and leaf dimensions, with a population from a location that is intermediate in terms of precipitation and temperature showing the greatest growth of branches and production of leaves under the well-watered treatment. This population is from a semi-arid climate, where precipitation is unpredictable, and selection may have occurred to favour rapid growth when water is available. This population had the narrowest leaves under both treatments, and the lowest leaf mass in the well-watered treatment. It also maintained the same mass per leaf under the two treatments, whereas the others showed an increased mass of leaves with increased availability of water. Thus, populations differed both in their manner of allocating resources and their response to availability of water.
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photochemical efficiency is an important component of ecophysiological variation of Cistus albidus between habitats in south east spain
Functional Plant Biology, 2005Co-Authors: Olga M Grant, Lynton D IncollAbstract:The ecophysiology of Cistus albidus L. plants in a variety of habitats in south-east Spain was measured in situ over the course of a year, to determine whether physiological variation occurs between populations growing in sites exposed to differing temperature and precipitation. Not all the observed variation could be explained by differing contemporary meteorological conditions. In particular, plants at the driest site maintained much higher photochemical efficiency through the summer and autumn than plants at the other sites, and also showed higher stomatal conductance after the autumn rains. Principal component analysis identified photochemical efficiency as the greatest source of variation between populations. Such variation may represent the result of differing selection in populations that have been exposed to different prevailing conditions of mean temperature, precipitation or atmospheric humidity, for long periods of time.
Josep Penuelas - One of the best experts on this subject based on the ideXlab platform.
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annual and seasonal changes in foliar terpene content and emission rates in Cistus albidus l submitted to soil drought in prades forest catalonia ne spain
Acta Physiologiae Plantarum, 2010Co-Authors: Joan Llusia, Josep Penuelas, Roma Ogaya, Giorgio A AlessioAbstract:We measured the gas exchange and foliar terpene concentrations and terpene emission rates of Cistus albidus throughout the seasons of two annual periods (2003 and 2005) of contrasting precipitations (900 vs. 500 mm) and in response to experimental drought in a Mediterranean forest of southern Catalonia. C. albidus showed a typical seasonal oscillation of photosynthetic rates and stomatal conductance. Maximum photosynthetic activity appeared in the spring of the first year of the study and minimum ones in both summers. Net photosynthetic rates and stomatal conductance tended to decrease with drought treatment. In the first year, Cistus albidus presented maximum values of stored terpenes in autumn and winter and minimum values in spring and summer. Average concentrations in the first year were 154 and 96 μg g−1 dry matter (d.m.) for control and drought, respectively. Average concentrations in the second year were higher, 339 and 263 μg g−1 (d.m.) for control and drought, respectively. The most abundant terpene was zingiberene, followed by aromadendrene, germacrene, (−)-α-cedrene, and sesquiphellandrene. The drought treatment tended to decrease terpene content, but not significantly. Considering all the treatments together, total terpene emissions ranged between practically 0 (spring 2003) to 9 μg g−1 (d.m.) h−1 (winter 2003). In the second year, total terpene emission rates decreased 39% in control plants, and 29% in drought plants. Significant seasonal differences in emission rates were found. Total emission rates tended to be higher in the drought treatment, especially in spring and autumn. These results help for a better understanding of the behavior of plant volatiles in Mediterranean conditions interannualy and seasonally, an issue of great interest for forest flammability and atmospheric chemistry.
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are phenolic compounds released from the mediterranean shrub Cistus albidus responsible for changes in n cycling in siliceous and calcareous soils
New Phytologist, 2004Co-Authors: Josep Penuelas, Eva Castells, D W ValentineAbstract:Summary • We studied the effects of Cistus albidus leaf leachates on nitrogen-cycling processes in two siliceous soils (granite and schist) and one calcareous soil. We compared those effects with gross N-transformation rates in soils sampled underneath Cistus. • Soils amended with leachates and soils sampled under Cistus had higher NH4+ immobilization and lower nitrification compared with control soils. Gross N mineralization increased under Cistus but decreased in soils amended with leachates. These effects were especially strong in granite soil. • To determine whether phenolic compounds were causing those effects, we incubated granite soils with leachate and a leachate fraction containing only nonphenolic compounds. Nonphenolic compounds increased NH4+ immobilization and decreased gross nitrification, while decreases in gross N mineralization were estimated to be caused by phenolic compounds. • Our results show that although phenolic compounds leached from green foliage changed gross N mineralization, their effects on net N rates were eclipsed by the changes produced by polar nonphenolic compounds such as carbohydrates. Plant nonphenolic compounds may drive N cycling under Cistus.
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Is there a feedback between N availability in siliceous and calcareous soils and Cistus albidus leaf chemical composition?
Oecologia, 2003Co-Authors: Eva Castells, Josep PenuelasAbstract:The effects of the Mediterranean shrub Cistus albidus on N cycling were studied in two siliceous (granitic-derived and schistic-derived) and one calcareous soil differentiated by their texture and acidity. We aimed to find out whether soils under C. albidus were affected by the release of C compounds from the canopy, and whether phenolic compound production in C. albidus changed depending on the soil N availability. Calcareous soils, with higher clay content and polyvalent cations, had a higher organic matter content but lower net N mineralization rates than siliceous soils, and C. albidus growing therein were characterized by lower foliar N and phenolic compound concentrations. Under C. albidus , all types of soils had higher phenolic compound concentrations and polyphenol oxidase activity. C. albidus presence and leachate addition decreased net N mineralization and increased soil respiration in siliceous soils, and these changes were related to a higher soil C/N ratio under the canopy. In calcareous soils, however, no significant effects of plant presence on N cycling were found. In the studied plant-soil system it is not likely that higher phenolic compound concentrations were selected during evolution to enhance nutrient conservation in soil because (1) higher phenolic compound concentrations were not associated with lower soil fertilities, (2) C compounds released from C. albidus accelerated N cycling by increasing N immobilization and no evidence was found for decreased gross N mineralization, and (3) soil organic N content was more related to soil chemical and physical properties than to the effects of the C. albidus canopy.
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comparative protective strategies of Cistus albidus and quercus ilex facing photoinhibitory winter conditions
Environmental and Experimental Botany, 2002Co-Authors: Graca Oliveira, Josep PenuelasAbstract:The role of structural photoprotection under photoinhibitory winter conditions was evaluated in two Mediterranean woody species: Cistus albidus (semideciduous) and Quercus ilex (evergreen). Shoots were manipulated in order to modify the light load naturally received by the leaves throughout the cold season, and monitored for changes in maximum photochemical efficiency of PSII, phenology, and leaf morphology. Naturally steep leaves of C. albidus were restrained to a horizontal position, and compared with control leaves (naturally horizontal, or steeply inclined). Fully exposed leaves of Q. ilex were artificially protected through partial shading, and compared with control leaves (not shaded). During the cold season, the most exposed (either naturally or artificially) leaves were always more photoinhibited (had lower maximal photochemical efficiency of PSII) than the photoprotected ones. The differences disappeared at the beginning of spring. Winter photoinhibition was not more pronounced in older than in younger leaves of C. albidus, indicating that inclination rather than age affected their photochemical efficiency. Leaf chlorophyll contents were not significantly affected by the manipulations. Leaf thickness decreased slightly in the least exposed shoots of the evergreen species, but no changes were detected in leaf morphological traits of the semideciduous one. The increased photoinhibitory pressure led only to slight and non-significant changes in phenology and growth.
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Seasonal patterns of non-terpenoid C6-C10 VOC emission from seven Mediterranean woody species.
Chemosphere, 2001Co-Authors: Josep Penuelas, Joan LlusiaAbstract:Abstract The seasonal pattern of non-terpenoid C 6 –C 10 VOC emission by seven Mediterranean woody species ( Bupleurum fruticosum , Cistus albidus , Pinus halepensis , Arbutus unedo , Erica arborea , Quercus coccifera , and Q. ilex ) was studied under field conditions. Branch chamber samples were sorbed on carbotrap and analyzed by thermal desorption in combination with GC–MS. These non-terpenoid C 6 –C 10 VOC emissions were large, almost of similar magnitude to those of terpenes. Overall, maximum values were recorded in spring and summer (up to 12 μg g −1 DM h −1 in Q. ilex ) and minimum values in autumn and winter (up to 5 μg g −1 DM h −1 in Q. ilex ). These C 6 –C 10 VOC emissions represented 2.82% of the photosynthetic C fixation in summer and 0.22% in winter. Some compounds such as 2-ethoxyethyl acetate were emitted by most species, others such as 3-hexen-1-ol, phenol or decanal were significantly emitted only by few species. The greatest diversity of emitted non-terpenoid C 6 –C 10 VOCs was observed in spring and in Q. ilex . Temperature seemed a strong driver of these seasonal changes but other species-specific and seasonal factors seem involved. These results indicate that C 6 –C 10 non-terpenoid VOCs contribute a rather significant fraction of the total biogenic VOC flux from these Mediterranean species, especially in spring and summer, and therefore should be considered in VOC emission inventories and in model predictions of tropospheric chemistry.
Lynton D Incoll - One of the best experts on this subject based on the ideXlab platform.
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genetic diversity of Cistus albidus in south east spain does not relate to mesoclimate
Functional Plant Biology, 2006Co-Authors: Olga M Grant, T Mcneilly, Lynton D IncollAbstract:Patterns of variation at selected isozyme loci were examined in populations of Cistus albidus L. in south-east Spain, from areas differing in precipitation and temperature, to determine whether population divergence has occurred. Total genetic diversity was high, with a high percentage of the variation being found between populations. Genetic variation between populations did not relate to climate. Populations exposed to severe summer drought did not show lower genetic diversity than populations from more benign climates. Little genetic variation was found between populations that showed variation in ecophysiological and growth responses in situ and under controlled conditions. Cluster analyses showed different patterns of between-population distances with respect to genetic, physiological and morphological data, and none of these patterns corresponded to that for between-site environmental variation.
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variation in growth responses to availability of water in Cistus albidus populations from different habitats
Functional Plant Biology, 2005Co-Authors: Olga M Grant, Lynton D Incoll, T McneillyAbstract:Seeds of Cistus albidus L. plants from three populations that are exposed to differing temperature and precipitation in Almeria province of south-east Spain, were collected and grown together in a factorial experiment with two irrigation treatments. The aim was to determine whether populations from different habitats differed when exposed to common conditions, or differed in the plasticity of their response to availability of water. Significant differences in growth of branches and in leaf dimensions were found between treatments, indicating phenotypic plasticity. There was also significant variation between populations in growth of branches and leaf dimensions, with a population from a location that is intermediate in terms of precipitation and temperature showing the greatest growth of branches and production of leaves under the well-watered treatment. This population is from a semi-arid climate, where precipitation is unpredictable, and selection may have occurred to favour rapid growth when water is available. This population had the narrowest leaves under both treatments, and the lowest leaf mass in the well-watered treatment. It also maintained the same mass per leaf under the two treatments, whereas the others showed an increased mass of leaves with increased availability of water. Thus, populations differed both in their manner of allocating resources and their response to availability of water.
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photochemical efficiency is an important component of ecophysiological variation of Cistus albidus between habitats in south east spain
Functional Plant Biology, 2005Co-Authors: Olga M Grant, Lynton D IncollAbstract:The ecophysiology of Cistus albidus L. plants in a variety of habitats in south-east Spain was measured in situ over the course of a year, to determine whether physiological variation occurs between populations growing in sites exposed to differing temperature and precipitation. Not all the observed variation could be explained by differing contemporary meteorological conditions. In particular, plants at the driest site maintained much higher photochemical efficiency through the summer and autumn than plants at the other sites, and also showed higher stomatal conductance after the autumn rains. Principal component analysis identified photochemical efficiency as the greatest source of variation between populations. Such variation may represent the result of differing selection in populations that have been exposed to different prevailing conditions of mean temperature, precipitation or atmospheric humidity, for long periods of time.
Leonor Alegre - One of the best experts on this subject based on the ideXlab platform.
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marked differences in seed dormancy in two populations of the mediterranean shrub Cistus albidus l
Plant Ecology & Diversity, 2017Co-Authors: Laura Siles, Maren Muller, Jana Cela, Iker Hernandez, Leonor Alegre, Sergi MunneboschAbstract:Background: Population structure and dynamics in natural ecosystems can be affected by seed viability and dormancy. However, how the endogenous contents of phytohormones and vitamin E in seeds relative to the environment affect viability and dormancy is not yet fully understood.Aims: We studied seed viability and germination capacity in two populations of the Mediterranean shrub, Cistus albidus, exposed to contrasting environmental conditions.Methods: We measured seed viability and germination capacity and endogenous contents of abscisic acid (ABA), gibberellins and vitamin E in seeds collected from two populations, in two environmentally contrasting environments in north-eastern Spain.Results: Plants growing in the natural site produced seeds with lower germination percentage but similar viability, indicating higher seed dormancy. Enhanced seed dormancy was paralleled with higher contents of ABA and lower contents of gibberellins (GAs). Contents of tocopherols and tocotrienols were higher in seeds of the...
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Redox proteomics and physiological responses in Cistus albidus shrubs subjected to long-term summer drought followed by recovery
Planta, 2015Co-Authors: Ricard Brossa, Marta Pintó-marijuan, Rita Francisco, Marta López-carbonell, Maria Manuela Chaves, Leonor AlegreAbstract:Main conclusion The interaction between enzymatic and non-enzymatic antioxidants, endogenous levels of ABA and ABA-GE, the rapid recuperation of photosynthetic proteins under re-watering as well the high level of antioxidant proteins in previously drought-stressed plants under re-watering conditions, will contribute to drought resistance in plants subjected to a long-term drought stress under Mediterranean field conditions. This work provides an overview of the mechanisms of Cistus albidus acclimation to long-term summer drought followed by re-watering in Mediterranean field conditions. To better understand the molecular mechanisms of drought resistance in these plants, a proteomic study using 2-DE and MALDI-TOF/TOF MS/MS was performed on leaves from these shrubs. The analysis identified 57 differentially expressed proteins in water-stressed plants when contrasted to well watered. Water-stressed plants showed an increase, both qualitatively and quantitatively, in HSPs, and downregulation of photosynthesis and carbon metabolism enzymes. Under drought conditions, there was considerable upregulation of enzymes related to redox homeostasis, DHA reductase, Glyoxalase, SOD and isoflavone reductase. However, upregulation of catalase was not observed until after re-watering was carried out. Drought treatment caused an enhancement in antioxidant defense responses that can be modulated by ABA, and its catabolites, ABA-GE, as well as JA. Furthermore, quantification of protein carbonylation was shown to be a useful marker of the relationship between water and oxidative stress, and showed that there was only moderate oxidative stress in C. albidus plants subjected to water stress. After re-watering plants recovered although the levels of ABA-GE and antioxidant enzymes still remain higher than in well-watered plants. We expect that our results will provide new data on summer acclimation to drought stress in Mediterranean shrubs.
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the timing of methyl jasmonate hydrogen peroxide and ascorbate accumulation during water deficit and subsequent recovery in the mediterranean shrub Cistus albidus l
Environmental and Experimental Botany, 2010Co-Authors: Tana Jubanymari, Sergi Munnebosch, Els Prinsen, Leonor AlegreAbstract:Abstract Here we examined the contribution of methyl jasmonate (MeJA) to the acclimation of a Mediterranean shrub, Cistus albidus L., to water stress under natural climatic conditions. For this purpose, changes in MeJA, hydrogen peroxide (H 2 O 2 ), ascorbate (AA) and the maximum efficiency of PSII photochemistry ( F v / F m ratio) and lipid peroxidation were monitored in young leaves of two sets of plants: well-watered plants and plants exposed to water stress and then re-watered. We also estimated plant water relations and plant growth. MeJA accumulation in water-stressed plants showed a maximum increase after 11 weeks of water stress and a second increase after the re-watering, which was performed in week 17 of the experiment. Like MeJA, H 2 O 2 variations showed a biphasic time course, reaching the first peak under mild water stress and the second peak during plant recovery. H 2 O 2 accumulation was not associated with oxidative damage, and in addition to showing intact cell ultratructure, water-stressed plants showed lower lipid peroxidation than well-watered plants. Furthermore, the F v / F m ratio remained above 0.75 throughout the experiment in both sets of plants. AA concentrations began to increase at the beginning of water stress, before the increase in MeJA. AA reached a steady maximum, which was maintained during water stress, and returned to initial values when plants were re-watered. On the basis of these results, we conclude that MeJA, H 2 O 2 and AA are involved in the mechanisms of plant resistance to water stress as follows: MeJA arrests the growth of young leaves and AA prevents oxidative damage.
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hydrogen peroxide is involved in the acclimation of the mediterranean shrub Cistus albidus l to summer drought
Journal of Experimental Botany, 2008Co-Authors: Tana Jubanymari, Sergi Munnebosch, Marta Lopezcarbonell, Leonor AlegreAbstract:: This study evaluated the possible role of hydrogen peroxide (H(2)O(2)) in the acclimation of a Mediterranean shrub, Cistus albidus L., to summer drought growing under Mediterranean field conditions. For this purpose, changes in H(2)O(2) concentrations and localization throughout a year were analysed. H(2)O(2) changes in response to environmental conditions in parallel with changes in abscisic acid (ABA) and oxidative stress markers, together with lignin accumulation, xylem and sclerenchyma differentiation, and leaf area were also investigated. During the summer drought, leaf H(2)O(2) concentrations increased 11-fold, reaching values of 10 micromol g(-1) dry weight (DW). This increase occurred mainly in mesophyll cell walls, xylem vessels, and sclerenchyma cells in the differentiation stage. An increase in ABA levels preceded that of H(2)O(2), but both peaked at the same time in conditions of prolonged stress. C. albidus plants tolerated high concentrations of H(2)O(2) because of its localization in the apoplast of mesophyll cells, xylem vessels, and in differentiating sclerenchyma cells. The increase in ABA, and consequently of H(2)O(2), in plants subjected to drought stress might induce a 3.5-fold increase in ascorbic acid (AA), which maintained and even decreased its oxidative status, thus protecting plants from oxidative damage. After recovery from drought following late-summer and autumn rainfall, a decrease in ABA, H(2)O(2), and AA to their basal levels (approximately 60 pmol g(-1) DW, approximately 1 micromol g(-1) DW, and approximately 20 micromol g(-1) DW) was observed.
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enhanced photo and antioxidative protection and hydrogen peroxide accumulation in drought stressed Cistus clusii and Cistus albidus plants
Tree Physiology, 2003Co-Authors: Sergi Munnebosch, Tana Jubanymari, Leonor AlegreAbstract:: Mechanisms of drought stress resistance were studied in Cistus clusii Dunal and Cistus albidus L., two native Mediterranean shrubs that can withstand severe summer drought. While water deficit, solar radiation and temperature increased from winter to summer in the field, C. clusii and C. albidus reduced leaf area, increased root mass per leaf area, and showed diurnal changes in stomatal conductance to minimize water loss. In both species, the consequent reductions in CO2 assimilation were accompanied by reduced efficiency of photosystem II photochemistry, and protection against stress was afforded by enhanced de-epoxidation of violaxanthin in the xanthophyll cycle and increases in alpha-tocopherol and beta-carotene. In addition, hydrogen peroxide (H2O2) accumulation was observed in mesophyll cell walls of both species during the first stages of drought, although no accumulation of H2O2 was observed in chloroplasts or other organelles during the study. Despite these common responses, C. albidus and C. clusii differed in the extent of photo- and antioxidative protection. In response to drought, C. clusii showed a higher de-epoxidation state of the xanthophyll cycle and higher alpha-tocopherol and beta-carotene concentrations than C. albidus. We conclude that several structural and biochemical mechanisms underlie stress resistance in C. clusii and C. albidus, and are indicative of the different degrees of stress resistance of these shrubs.
Sergi Munnebosch - One of the best experts on this subject based on the ideXlab platform.
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contrasting patterns of hormonal and photoprotective isoprenoids in response to stress in Cistus albidus during a mediterranean winter
Planta, 2019Co-Authors: Marina Perezllorca, Andrea Casadesus, Sergi Munnebosch, Maren MullerAbstract:Main conclusion Seasonal accumulation of hormonal and photoprotective isoprenoids, particularly α-tocopherol, carotenoids and abscisic acid, indicate their important role in protecting Cistus albidus plants from environmental stress during a Mediterranean winter. The high diurnal amounts of α-tocopherol and xanthophylls 3 h before maximum light intensity suggest a photoprotective response against the prevailing diurnal changes.
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leaf orientation as part of the leaf developmental program in the semi deciduous shrub Cistus albidus l diurnal positional and photoprotective effects during winter
Frontiers in Plant Science, 2019Co-Authors: Marina Perezllorca, Andrea Casadesus, Maren Muller, Sergi MunneboschAbstract:Mediterranean ecosystems harbor a very important part of Earth's biodiversity, and they are a conservation priority due to the effects of global change. Here, we examined the performance of the semi-deciduous shrub Cistus albidus under Mediterranean conditions during winter, including changes in leaf angle governed by diurnal, seasonal, and positional effects and their relationship with winter photoinhibition and photoprotection. We found marked diurnal variations in leaf angle during the day in autumn, which disappeared as the photoperiod shortened during winter due to a progressive decrease in the predawn leaf angle from November to January. During this period, auxin contents decreased, while those of melatonin increased, and the Fv/Fm ratio, chlorophyll, and tocopherol contents kept unaltered, thus indicating the absence of photoinhibitory damage. A marked decrease in the leaf angle toward the shoot apex occurred during winter, which was associated with slightly higher Fv/Fm ratios. An analysis of the inter-individual variability and sun orientation effects on leaf movements in a population growing in the Montserrat mountains revealed a very marked variability of 46.8% in the leaf angle, while Fv/Fm ratio showed a variation of 7.5% only. West orientation, which was associated with reduced leaf temperatures, but with no differences in the photosynthetic photon flux density, led to enhanced tocopherol contents, while leaf angle, Fv/Fm ratio, chlorophyll, auxin, and melatonin contents kept unaltered. It is concluded that (1) C. albidus has very effective and fine-regulated photoprotection mechanisms, including an adequate orientation of decussate leaves as part of the developmental program, (2) leaf angle is modulated on a diurnal and seasonal basis, thus contributing to prevent photoinhibition as a first line of defense, and (3) enhanced tocopherol contents help withstand combined high light with low temperature stress in C. albidus growing at high elevation.
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marked differences in seed dormancy in two populations of the mediterranean shrub Cistus albidus l
Plant Ecology & Diversity, 2017Co-Authors: Laura Siles, Maren Muller, Jana Cela, Iker Hernandez, Leonor Alegre, Sergi MunneboschAbstract:Background: Population structure and dynamics in natural ecosystems can be affected by seed viability and dormancy. However, how the endogenous contents of phytohormones and vitamin E in seeds relative to the environment affect viability and dormancy is not yet fully understood.Aims: We studied seed viability and germination capacity in two populations of the Mediterranean shrub, Cistus albidus, exposed to contrasting environmental conditions.Methods: We measured seed viability and germination capacity and endogenous contents of abscisic acid (ABA), gibberellins and vitamin E in seeds collected from two populations, in two environmentally contrasting environments in north-eastern Spain.Results: Plants growing in the natural site produced seeds with lower germination percentage but similar viability, indicating higher seed dormancy. Enhanced seed dormancy was paralleled with higher contents of ABA and lower contents of gibberellins (GAs). Contents of tocopherols and tocotrienols were higher in seeds of the...
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zeatin modulates flower bud development and tocopherol levels in Cistus albidus l plants as they age
Plant Biology, 2015Co-Authors: Iker Hernandez, Javier A Miret, K Van Der Kelen, Debbie Rombaut, F Van Breusegem, Sergi MunneboschAbstract:In a previous study we showed that Cistus albidus (L.) experiences an age-dependent decay in flower vigour correlated with a decline in trans-zeatin (tZ) levels. In the present study we aimed to establish a causal relationship between these two phenomena. Exogenous tZ applied to plants grown under semi-controlled conditions did not rescue flower vigour; however, it accelerated flower development, but only in younger individuals. Older plants showed lower tocopherol levels in flower buds, which were restored by exogenous tZ, suggesting that a loss of antioxidant defences may underlie the age-dependent decay in flower vigour. We conclude that declining tZ levels may not be directly responsible for the age-associated loss of floral vigour; that tZ modulates the speed of flower development as plants age; and that flower buds alter their sensitivity to tZ as plants age.
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perennially young seed production and quality in controlled and natural populations of Cistus albidus reveal compensatory mechanisms that prevent senescence in terms of seed yield and viability
Journal of Experimental Botany, 2014Co-Authors: Maren Muller, Laura Siles, Jana Cela, Sergi MunneboschAbstract:The question of whether or not perennial plants senesce at the organism level remains unresolved. The aim of this study was to unravel whether or not plant age can influence the production and composition of seeds. Flower and seed production was examined in 3-, 8-, and 13-year-old Cistus albidus plants growing in experimental plots corresponding to the F2, F1, and F0 generations of the same population. Furthermore, the phytohormone, fatty acid, and vitamin E content of the seeds was evaluated, and their viability was examined. Whether or not age-related differences in seed quality were observed in a natural population in the Montserrat Mountains (NE Spain) was also tested. The results indicate that under controlled conditions, the oldest plants not only produced fewer flowers, but also had higher rates of embryo abortion in mature seeds. However, germination capacity was not negatively affected by plant ageing. Seeds of the oldest plants contained significantly higher salicylic acid, jasmonic acid, and vitamin E levels compared with those from younger plants. Despite vigour (in terms of plant growth) being severely reduced due to harsh environmental conditions in the natural population, the oldest individuals produced seeds with no decline in viability. Seed biomass was instead positively correlated with seed viability. In conclusion, increased plant size may explain the loss of seed viability in the experimental field, but older smaller individuals in natural populations can escape senescence in terms of seed viability loss.