The Experts below are selected from a list of 249 Experts worldwide ranked by ideXlab platform
Hipolito Medrano - One of the best experts on this subject based on the ideXlab platform.
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effect of water stress on partitioning of 14c labelled Photosynthates in vitis vinifera
Functional Plant Biology, 2004Co-Authors: Josefina Bota, Oleg Stasyk, Jaume Flexas, Hipolito MedranoAbstract:The influence of fruits on export and distribution of Photosynthates was studied in Vitis vinifera L. cv. Tempranillo using 14C labelling. Also, the influence of water stress was analysed in fruiting and fruitless plants of Tempranillo and fruiting plants of cv. Alfonso Lavallee. In fruitless plants of Tempranillo, reserve organs (trunk, roots and lower shoot) represented 80% of total plant dry matter (DM), and imported up to 90% of the total 14C exported from the fed leaf. Therefore, the distribution pattern of Photosynthates in these plants reflected mainly the sink size. However, the presence of fruits in Tempranillo strongly stimulated 14C export and changed the distribution pattern of assimilates. Fruits imported up to 70–80% of the total 14C exported, while representing only 25% of the total plant DM. Therefore, the strength of fruits as carbon sinks was independent of sink size, and it is discussed on the basis of a water potential gradient theory. Water stress caused a significant reduction of leaf water potential, photosynthesis and stomatal conductance, but caused only a slight, non-significant, decrease of carbohydrate export from the fed leaves, and did not affect the distribution pattern of 14C except in some minor fractions in Tempranillo. The 14C distribution into different fruit components was also unaffected. In contrast, in Alfonso Lavallee water stress resulted in a highly significant reduction of export, and an altered photosynthate distribution pattern. These differences could be due to the lower water potential attained in stressed Alfonso Lavallee plants.
Taizo Hogetsu - One of the best experts on this subject based on the ideXlab platform.
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Pathway and sink activity for photosynthate translocation in Pisolithus extraradical mycelium of ectomycorrhizal Pinus thunbergii seedlings
Mycorrhiza, 2016Co-Authors: Munemasa Teramoto, Bingyun Wu, Taizo HogetsuAbstract:The purpose of this study was to identify the pathway and sink activity of photosynthate translocation in the extraradical mycelium (ERM) of a Pisolithus isolate. We labelled ectomycorrhizal (ECM) Pinus thunbergii seedlings with 14CO2 and followed 14C distribution within the ERM by autoradiography. 14C photosynthate translocation in the ERM resulted in 14C distribution in rhizomorphs throughout the ERM, with 14C accumulation at the front. When most radial mycelial connections between ECM root tips and the ERM front were cut, the whole allocation of 14C Photosynthates to the ERM was reduced. However, the overall pattern of 14C distribution in the ERM was maintained even in regions immediately above and below the cut, with no local 14C depletion or accumulation. We inferred from this result that every portion in the ERM has a significant sink activity and a definite sink capacity for Photosynthates and that Photosynthates detour the cut and reach throughout the ERM by translocation in every direction. Next, we prepared paired ECM seedlings, ERMs of which had been connected with each other by hyphal fusion, alongside, labelled the left seedling with 14CO2, and shaded none, one or both of them. 14C Photosynthates were acropetally and basipetally translocated from the left ERM to ECM root tips of the right seedling through rhizomorphs in the left and right ERMs, respectively. With the left seedling illuminated, 14C translocation from the left to the right ERM increased by shading the right seedling. This result suggests that reduced photosynthate transfer from the host to its ERM increased sink activity of the ERM.
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Spatiotemporal transfer of carbon-14-labelled photosynthate from ectomycorrhizal Pinus densiflora seedlings to extraradical mycelia
Mycorrhiza, 2002Co-Authors: Bingyun Wu, Kazuhide Nara, Taizo HogetsuAbstract:Seedlings of Pinus densiflora colonized by an unidentified ectomycorrhizal fungus (T01) were labelled photosynthetically with ^14C. Movement of ^14C-labelled Photosynthates within the underground part of the seedlings was investigated by temporal autoradiography using an imaging plate. Within 1 day, ^14C was transferred from the shoot to the underground part that included roots, mycorrhizae, and the extraradical mycelium; within 3 days, the ^14C in the underground part reached its maximum density. Mycorrhizae and actively growing root tips were large C sinks. Three days after ^14C labelling, counts of ^14C radioactivity in the underground part of the mycorrhizal seedlings were 2.6 times those of nonmycorrhizal seedlings. The mycorrhizae of mycorrhizal plants accumulated 5.2 times the ^14C counts in the short-root tips of nonmycorrhizal plants. ^14C counts in various areas of the extraradical mycelium demonstrated that all ^14C-photosynthate transfer from the host root to the extraradical mycelium occurred within 3 days after ^14C labelling, and that there was only a short lag of
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Mycorrhiza — diversity and impacts
Mycorrhiza, 2002Co-Authors: Bingyun Wu, Kazuhide Nara, Taizo HogetsuAbstract:Seedlings of Pinus densiflora colonized by an unidentified ectomycorrhizal fungus (T01) were labelled photosynthetically with ^14C. Movement of ^14C-labelled Photosynthates within the underground part of the seedlings was investigated by temporal autoradiography using an imaging plate. Within 1 day, ^14C was transferred from the shoot to the underground part that included roots, mycorrhizae, and the extraradical mycelium; within 3 days, the ^14C in the underground part reached its maximum density. Mycorrhizae and actively growing root tips were large C sinks. Three days after ^14C labelling, counts of ^14C radioactivity in the underground part of the mycorrhizal seedlings were 2.6 times those of nonmycorrhizal seedlings. The mycorrhizae of mycorrhizal plants accumulated 5.2 times the ^14C counts in the short-root tips of nonmycorrhizal plants. ^14C counts in various areas of the extraradical mycelium demonstrated that all ^14C-photosynthate transfer from the host root to the extraradical mycelium occurred within 3 days after ^14C labelling, and that there was only a short lag of
Josefina Bota - One of the best experts on this subject based on the ideXlab platform.
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effect of water stress on partitioning of 14c labelled Photosynthates in vitis vinifera
Functional Plant Biology, 2004Co-Authors: Josefina Bota, Oleg Stasyk, Jaume Flexas, Hipolito MedranoAbstract:The influence of fruits on export and distribution of Photosynthates was studied in Vitis vinifera L. cv. Tempranillo using 14C labelling. Also, the influence of water stress was analysed in fruiting and fruitless plants of Tempranillo and fruiting plants of cv. Alfonso Lavallee. In fruitless plants of Tempranillo, reserve organs (trunk, roots and lower shoot) represented 80% of total plant dry matter (DM), and imported up to 90% of the total 14C exported from the fed leaf. Therefore, the distribution pattern of Photosynthates in these plants reflected mainly the sink size. However, the presence of fruits in Tempranillo strongly stimulated 14C export and changed the distribution pattern of assimilates. Fruits imported up to 70–80% of the total 14C exported, while representing only 25% of the total plant DM. Therefore, the strength of fruits as carbon sinks was independent of sink size, and it is discussed on the basis of a water potential gradient theory. Water stress caused a significant reduction of leaf water potential, photosynthesis and stomatal conductance, but caused only a slight, non-significant, decrease of carbohydrate export from the fed leaves, and did not affect the distribution pattern of 14C except in some minor fractions in Tempranillo. The 14C distribution into different fruit components was also unaffected. In contrast, in Alfonso Lavallee water stress resulted in a highly significant reduction of export, and an altered photosynthate distribution pattern. These differences could be due to the lower water potential attained in stressed Alfonso Lavallee plants.
Larry Boersma - One of the best experts on this subject based on the ideXlab platform.
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Partition of Photosynthates between shoot and root in spring wheat (Triticum aestivum L.) as a function of soil water potential and root temperature
Plant and Soil, 1994Co-Authors: Xiaomeili Li, Yongsheng Feng, Larry BoersmaAbstract:Low soil water potential and low or high root temperatures are important stresses affecting carbon allocation in plants. This study examines the effects of these stresses on carbon allocation from the perspective of whole plant mass balance. Sixteen-day old spring wheat seedlings were placed in a growth room under precisely controlled root temperatures and soil water potentials. Five soil water potential treatments, from −0.03 MPa to −0.25 MPa, and six root temperature treatments, from 12 to 32°C were used. A mathematical model based on mass balance considerations was used, in combination with experimental measurements of rate of net photosynthesis, leaf area, and shoot/root dry masses to determine photosynthate allocation between shoot and root. Partitioning of Photosynthates to roots was the lowest at 22–27°C root temperature regardless soil water potential, and increased at both lower and higher root temperatures. Partitioning of Photosynthates to the roots increased with decreasing soil water potential. Under the most favourable conditions, i.e. at −0.03 MPa soil water potential and 27°C root temperature, the largest fraction, 57%, of Photosynthates was allocated to the shoots. Under the most stressed conditions, i.e. at −0.25 MPa soil water potential and 32°C root temperature, the largest fraction, more than 80%, of Photosynthates was allocated to roots.
Oleg Stasyk - One of the best experts on this subject based on the ideXlab platform.
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effect of water stress on partitioning of 14c labelled Photosynthates in vitis vinifera
Functional Plant Biology, 2004Co-Authors: Josefina Bota, Oleg Stasyk, Jaume Flexas, Hipolito MedranoAbstract:The influence of fruits on export and distribution of Photosynthates was studied in Vitis vinifera L. cv. Tempranillo using 14C labelling. Also, the influence of water stress was analysed in fruiting and fruitless plants of Tempranillo and fruiting plants of cv. Alfonso Lavallee. In fruitless plants of Tempranillo, reserve organs (trunk, roots and lower shoot) represented 80% of total plant dry matter (DM), and imported up to 90% of the total 14C exported from the fed leaf. Therefore, the distribution pattern of Photosynthates in these plants reflected mainly the sink size. However, the presence of fruits in Tempranillo strongly stimulated 14C export and changed the distribution pattern of assimilates. Fruits imported up to 70–80% of the total 14C exported, while representing only 25% of the total plant DM. Therefore, the strength of fruits as carbon sinks was independent of sink size, and it is discussed on the basis of a water potential gradient theory. Water stress caused a significant reduction of leaf water potential, photosynthesis and stomatal conductance, but caused only a slight, non-significant, decrease of carbohydrate export from the fed leaves, and did not affect the distribution pattern of 14C except in some minor fractions in Tempranillo. The 14C distribution into different fruit components was also unaffected. In contrast, in Alfonso Lavallee water stress resulted in a highly significant reduction of export, and an altered photosynthate distribution pattern. These differences could be due to the lower water potential attained in stressed Alfonso Lavallee plants.
