Rita Baraldi - Academia.edu (original) (raw)
Papers by Rita Baraldi
New Phytologist, 2003
Tansley likened New Phytologist in his first editorial to an organism at the mercy of natural sel... more Tansley likened New Phytologist in his first editorial to an organism at the mercy of natural selection–'... if it is well adapted to fill its place in the scheme of things, it survives. If not, it inevitably goes under and disappears'(see Lewis & Ingram, 2002). What state is New Phytologist in at the beginning of 2004? Are the professional scientists who comprise this organisation delivering a suitable service to their peers, one that appears fit to survive? The New Phytologist Trust is an independent charity, a not-for-profit organisation much like a ...
Trees-structure and Function, 1999
Prunus persica plants were grown under prolonged exposure to different light treatments to determ... more Prunus persica plants were grown under prolonged exposure to different light treatments to determine the interaction between the blue light (BL) receptor and phytochrome and/or an independent BL response in the photoregulation of shoot and leaf development. Different light conditions were established in growth chambers by changing both the state of phytochrome and the BL photon flux density (PFD) at constant photosynthetically active radiation (PAR). Furthermore, to evaluate the independent action of the BL photoreceptor, increasing amounts of BL photons were added to the light emitted by low-pressure sodium (LPS) lamps without altering irradiance and phytochrome photoequilibrium. Applying the principle of equivalent light action, the observed blue inhibition of shoot elongation, leaf expansion and thickness were clearly related to a specific BL receptor because the state of phytochrome for each treatment was nearly identical. Increasing amounts of blue photons to light emitted from LPS lamps decreased shoot elongation, whereas leaf expansion was negatively affected only at the highest blue level, suggesting a specific fluence dependence response to BL for each organ and tissue. The BL effect was evident in reducing the thickness of all the leaf tissues except for the upper epidermis, which became thicker. This could be the result of an adaptation to protect the underlying photosynthetic apparatus. Other morphological and anatomical responses to the action of the BL receptor were greatly altered when the state of phytochrome changed in the plant tissues.
Annals of Botany, 2008
Aims The clone EMB-2 of the interspecific hybrid Helianthus annuus  H. tuberosus provides an int... more Aims The clone EMB-2 of the interspecific hybrid Helianthus annuus  H. tuberosus provides an interesting system to study molecular and physiological aspects of somatic embryogenesis. Namely, in addition to non-epiphyllous (NEP) leaves that expand normally, EMB-2 produces epiphyllous (EP) leaves bearing embryos on the adaxial surface. This clone was used to investigate if the ectopic expression of H. annuus LEAFY COTYLEDON1-LIKE (Ha-L1L) gene and auxin activity are correlated with the establishment of embryogenic competence. † Methods Ha-L1L expression was evaluated by semi-quantitative RT-PCR and in situ hybridization. The endogenous level and spatial distribution of free indole-3-acetic acid (IAA) were estimated by a capillary gas chromatography -mass spectrometry-selected ion monitoring method and an immuno-cytochemical approach. † Key Results Ectopic expression of Ha-L1L was detected in specific cell domains of the adaxial epidermis of EP leaves prior to the development of ectopic embryos. Ha-L1L was expressed rapidly when NEP leaves were induced to regenerate somatic embryos by in vitro culture. Differences in auxin distribution pattern rather than in absolute level were observed between EP and A-2 leaves. More precisely, a strong IAA immuno-signal was detected in single cells or in small groups of cells along the epidermis of EP leaves and accompanied the early stages of embryo development. Changes in auxin level and distribution were observed in NEP leaves induced to regenerate by in vitro culture. Exogenous auxin treatments lightly influenced Ha-L1L transcript levels in spite of an enhancement of the regeneration frequency. † Conclusions In EP leaves, Ha-L1L activity marks the putative founder cells of ectopic embryos. Although the ectopic expression of Ha-L1L seems to be not directly mediated by auxin levels per se, it was demonstrated that localized Ha-L1L expression and IAA accumulation in leaf epidermis domains represent early events of somatic embryogenesis displayed by the epiphyllous EMB-2 clone.
Scientia Horticulturae, 2010
... The total IAA content decreased of approximately 50% in transformed rolC3 plants compared to ... more ... The total IAA content decreased of approximately 50% in transformed rolC3 plants compared to control ones. A similar reduction occurred in the apex of pRi T-DNA-transformed tobacco plants, with a consequent attenuation of the basipetal auxin gradient (Prinsen et al., 1994). ...
Phytochemistry, 2001
Emission rates of monoterpenes released by apple (Malus domestica Borkh) and cherry (Prunus avium... more Emission rates of monoterpenes released by apple (Malus domestica Borkh) and cherry (Prunus avium L.) were estimated at different phenological stages. These measurements employed a dynamic flow-through Teflon chamber, sample collection onto cartridges filled with graphitized carbon and thermal desorption gas chromatography-mass spectrometry (GC-MS) for identification and quantification of the emitted volatiles. At full bloom the release of monoterpene hydrocarbons from cherry flowers was 1213 ng g(-1) dry weight (DW) h(-1), exceeding by approximately three-fold the emission rate of apple flowers (366 ng g(-1) DW h(-1)). Observed seasonal variations in biogenic volatile organic compound (VOC) emissions ranged over several order of magnitudes. At fruit-set and ripening stages, in fact, the hydrocarbon emission dramatically decreased reaching the lowest values at harvest time when leaves were fully mature (3-9 ng g(-1) DW h(-1)). Wide diversity in the composition of compounds from the species studied was also recorded. At blooming, linalool contributed significantly to the monoterpene emission from apple (94% of the emitted carbon) while alpha-pinene and camphene represented on average more than 60% of the total emitted volatiles from cherry flowers. Among the monoterpenes identified in flowers, alpha-pinene, camphene and limonene were also found in the foliage emission of both species. Fruit trees are relevant monoterpene emitters only at blooming and thus for a short period of the vegetative cycle. When leaves are fully developed, the carbon loss due to monoterpene emissions related to the photosynthetically carbon gain is negligible.
Plant Biosystems, 2002
A survey was conducted to identify plants emitting isoprenoids in the Beijing area which could po... more A survey was conducted to identify plants emitting isoprenoids in the Beijing area which could potentially contribute to smog episodes when combined with anthropogenic pollutants. The emission pattern was similar to that observed in the previously surveyed boreal ecosystems (Europe, North America). Most deciduous oaks are strong isoprene emitters; however, some of them do not emit isoprenoids and are therefore
Annals of Botany, 2006
Background and Aims Plant lateral organs such as leaves arise from a group of initial cells withi... more Background and Aims Plant lateral organs such as leaves arise from a group of initial cells within the flanks of the shoot apical meristem (SAM). Alterations in the initiation of lateral organs are often associated with changes in the dimension and arrangement of the SAM as well as with abnormal hormonal homeostasis. A mutation named stem fasciated (stf) that affects various aspects of plant development, including SAM shape and auxin level, was characterized in sunflower (Helianthus annuus).
Plant Cell and Environment, 2004
The long-term effect of elevated atmospheric CO 2 on isoprenoid emissions from adult trees of two... more The long-term effect of elevated atmospheric CO 2 on isoprenoid emissions from adult trees of two Mediterranean oak species (the monoterpene-emitting Quercus ilex L. and the isoprene-emitting Quercus pubescens Willd.) native to a high-CO 2 environment was investigated. During two consecutive years, isoprenoid emission was monitored both at branch level, measuring the actual emissions under natural conditions, and at leaf level, measuring the basal emissions under the standard conditions of 30 ∞ ∞ ∞ ∞ C and at light intensity of 1000 m m m m mol m ----2 s ----1
Photosynthetica, 2008
We analyzed the response of potted strawberry tree (Arbutus unedo L.) seedlings exposed to water ... more We analyzed the response of potted strawberry tree (Arbutus unedo L.) seedlings exposed to water stress by withholding water for 10 d (WS). Leaf water potential, net CO 2 assimilation, and stomatal conductance decreased with increasing water deficit. A 30 % reduction of chlorophyll (Chl) content in the antenna complexes was observed in WS-plants.
Plant Growth …, 1998
The characterization by capillary gas chromatography-mass spectrometry of the plant hormones indo... more The characterization by capillary gas chromatography-mass spectrometry of the plant hormones indole-3-acetic acid and the gibberellins GA 1 and GA 3 from chemically-defined cultures of Acetobacter diazotrophicus and Herbaspirillum seropedicae is reported. Both bacteria are endophytic in gramineae species where they promote growth and yield. Quantification was also done by selected ion monitoring with [17,17-2 H 2 ]-Gibberellin A 1 , [17,17-2 H 2 ]-Gibberellin A 3 and [ 13 C 6 ]-indole-3-acetic acid as internal standards. The results presented show the importance of studying phytohormonal production when the interrelationships between plants and microorganisms are analyzed and may help explain the beneficial effects of endophytic bacteria to the host plant, as has been demonstrated previously for Azospirillum spp.
New Phytologist, 2003
Tansley likened New Phytologist in his first editorial to an organism at the mercy of natural sel... more Tansley likened New Phytologist in his first editorial to an organism at the mercy of natural selection–'... if it is well adapted to fill its place in the scheme of things, it survives. If not, it inevitably goes under and disappears'(see Lewis & Ingram, 2002). What state is New Phytologist in at the beginning of 2004? Are the professional scientists who comprise this organisation delivering a suitable service to their peers, one that appears fit to survive? The New Phytologist Trust is an independent charity, a not-for-profit organisation much like a ...
Trees-structure and Function, 1999
Prunus persica plants were grown under prolonged exposure to different light treatments to determ... more Prunus persica plants were grown under prolonged exposure to different light treatments to determine the interaction between the blue light (BL) receptor and phytochrome and/or an independent BL response in the photoregulation of shoot and leaf development. Different light conditions were established in growth chambers by changing both the state of phytochrome and the BL photon flux density (PFD) at constant photosynthetically active radiation (PAR). Furthermore, to evaluate the independent action of the BL photoreceptor, increasing amounts of BL photons were added to the light emitted by low-pressure sodium (LPS) lamps without altering irradiance and phytochrome photoequilibrium. Applying the principle of equivalent light action, the observed blue inhibition of shoot elongation, leaf expansion and thickness were clearly related to a specific BL receptor because the state of phytochrome for each treatment was nearly identical. Increasing amounts of blue photons to light emitted from LPS lamps decreased shoot elongation, whereas leaf expansion was negatively affected only at the highest blue level, suggesting a specific fluence dependence response to BL for each organ and tissue. The BL effect was evident in reducing the thickness of all the leaf tissues except for the upper epidermis, which became thicker. This could be the result of an adaptation to protect the underlying photosynthetic apparatus. Other morphological and anatomical responses to the action of the BL receptor were greatly altered when the state of phytochrome changed in the plant tissues.
Annals of Botany, 2008
Aims The clone EMB-2 of the interspecific hybrid Helianthus annuus  H. tuberosus provides an int... more Aims The clone EMB-2 of the interspecific hybrid Helianthus annuus  H. tuberosus provides an interesting system to study molecular and physiological aspects of somatic embryogenesis. Namely, in addition to non-epiphyllous (NEP) leaves that expand normally, EMB-2 produces epiphyllous (EP) leaves bearing embryos on the adaxial surface. This clone was used to investigate if the ectopic expression of H. annuus LEAFY COTYLEDON1-LIKE (Ha-L1L) gene and auxin activity are correlated with the establishment of embryogenic competence. † Methods Ha-L1L expression was evaluated by semi-quantitative RT-PCR and in situ hybridization. The endogenous level and spatial distribution of free indole-3-acetic acid (IAA) were estimated by a capillary gas chromatography -mass spectrometry-selected ion monitoring method and an immuno-cytochemical approach. † Key Results Ectopic expression of Ha-L1L was detected in specific cell domains of the adaxial epidermis of EP leaves prior to the development of ectopic embryos. Ha-L1L was expressed rapidly when NEP leaves were induced to regenerate somatic embryos by in vitro culture. Differences in auxin distribution pattern rather than in absolute level were observed between EP and A-2 leaves. More precisely, a strong IAA immuno-signal was detected in single cells or in small groups of cells along the epidermis of EP leaves and accompanied the early stages of embryo development. Changes in auxin level and distribution were observed in NEP leaves induced to regenerate by in vitro culture. Exogenous auxin treatments lightly influenced Ha-L1L transcript levels in spite of an enhancement of the regeneration frequency. † Conclusions In EP leaves, Ha-L1L activity marks the putative founder cells of ectopic embryos. Although the ectopic expression of Ha-L1L seems to be not directly mediated by auxin levels per se, it was demonstrated that localized Ha-L1L expression and IAA accumulation in leaf epidermis domains represent early events of somatic embryogenesis displayed by the epiphyllous EMB-2 clone.
Scientia Horticulturae, 2010
... The total IAA content decreased of approximately 50% in transformed rolC3 plants compared to ... more ... The total IAA content decreased of approximately 50% in transformed rolC3 plants compared to control ones. A similar reduction occurred in the apex of pRi T-DNA-transformed tobacco plants, with a consequent attenuation of the basipetal auxin gradient (Prinsen et al., 1994). ...
Phytochemistry, 2001
Emission rates of monoterpenes released by apple (Malus domestica Borkh) and cherry (Prunus avium... more Emission rates of monoterpenes released by apple (Malus domestica Borkh) and cherry (Prunus avium L.) were estimated at different phenological stages. These measurements employed a dynamic flow-through Teflon chamber, sample collection onto cartridges filled with graphitized carbon and thermal desorption gas chromatography-mass spectrometry (GC-MS) for identification and quantification of the emitted volatiles. At full bloom the release of monoterpene hydrocarbons from cherry flowers was 1213 ng g(-1) dry weight (DW) h(-1), exceeding by approximately three-fold the emission rate of apple flowers (366 ng g(-1) DW h(-1)). Observed seasonal variations in biogenic volatile organic compound (VOC) emissions ranged over several order of magnitudes. At fruit-set and ripening stages, in fact, the hydrocarbon emission dramatically decreased reaching the lowest values at harvest time when leaves were fully mature (3-9 ng g(-1) DW h(-1)). Wide diversity in the composition of compounds from the species studied was also recorded. At blooming, linalool contributed significantly to the monoterpene emission from apple (94% of the emitted carbon) while alpha-pinene and camphene represented on average more than 60% of the total emitted volatiles from cherry flowers. Among the monoterpenes identified in flowers, alpha-pinene, camphene and limonene were also found in the foliage emission of both species. Fruit trees are relevant monoterpene emitters only at blooming and thus for a short period of the vegetative cycle. When leaves are fully developed, the carbon loss due to monoterpene emissions related to the photosynthetically carbon gain is negligible.
Plant Biosystems, 2002
A survey was conducted to identify plants emitting isoprenoids in the Beijing area which could po... more A survey was conducted to identify plants emitting isoprenoids in the Beijing area which could potentially contribute to smog episodes when combined with anthropogenic pollutants. The emission pattern was similar to that observed in the previously surveyed boreal ecosystems (Europe, North America). Most deciduous oaks are strong isoprene emitters; however, some of them do not emit isoprenoids and are therefore
Annals of Botany, 2006
Background and Aims Plant lateral organs such as leaves arise from a group of initial cells withi... more Background and Aims Plant lateral organs such as leaves arise from a group of initial cells within the flanks of the shoot apical meristem (SAM). Alterations in the initiation of lateral organs are often associated with changes in the dimension and arrangement of the SAM as well as with abnormal hormonal homeostasis. A mutation named stem fasciated (stf) that affects various aspects of plant development, including SAM shape and auxin level, was characterized in sunflower (Helianthus annuus).
Plant Cell and Environment, 2004
The long-term effect of elevated atmospheric CO 2 on isoprenoid emissions from adult trees of two... more The long-term effect of elevated atmospheric CO 2 on isoprenoid emissions from adult trees of two Mediterranean oak species (the monoterpene-emitting Quercus ilex L. and the isoprene-emitting Quercus pubescens Willd.) native to a high-CO 2 environment was investigated. During two consecutive years, isoprenoid emission was monitored both at branch level, measuring the actual emissions under natural conditions, and at leaf level, measuring the basal emissions under the standard conditions of 30 ∞ ∞ ∞ ∞ C and at light intensity of 1000 m m m m mol m ----2 s ----1
Photosynthetica, 2008
We analyzed the response of potted strawberry tree (Arbutus unedo L.) seedlings exposed to water ... more We analyzed the response of potted strawberry tree (Arbutus unedo L.) seedlings exposed to water stress by withholding water for 10 d (WS). Leaf water potential, net CO 2 assimilation, and stomatal conductance decreased with increasing water deficit. A 30 % reduction of chlorophyll (Chl) content in the antenna complexes was observed in WS-plants.
Plant Growth …, 1998
The characterization by capillary gas chromatography-mass spectrometry of the plant hormones indo... more The characterization by capillary gas chromatography-mass spectrometry of the plant hormones indole-3-acetic acid and the gibberellins GA 1 and GA 3 from chemically-defined cultures of Acetobacter diazotrophicus and Herbaspirillum seropedicae is reported. Both bacteria are endophytic in gramineae species where they promote growth and yield. Quantification was also done by selected ion monitoring with [17,17-2 H 2 ]-Gibberellin A 1 , [17,17-2 H 2 ]-Gibberellin A 3 and [ 13 C 6 ]-indole-3-acetic acid as internal standards. The results presented show the importance of studying phytohormonal production when the interrelationships between plants and microorganisms are analyzed and may help explain the beneficial effects of endophytic bacteria to the host plant, as has been demonstrated previously for Azospirillum spp.