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PremisePhloem tissue allows for sugar transport along the entirety of a plant and, thus, is one of the most important anatomical structures related to growth. It is thought that the sugar-conducting sieve tube may overwinter and that its cells persist multiple seasons in deciduous trees. One possible overwintering strategy is to build up callose on phloem sieve plates to temporarily cease their function. We tested the hypothesis that five deciduous tree species produce callose on their sieve plates on a seasonal basis.MethodsYoung shoots of five deciduous tree species were sampled periodically between April 2019 and February 2020 in Edmonton, Alberta, Canada. After enzymatic digestion of cytoplasmic constituents, cross sections were imaged using scanning electron microscopy to observe and quantify the level of callose deposition at monthly intervals, and sieve plate pore size was measured. Using a conductivity apparatus, we measured xylem native embolism during these sampling periods.ResultsContrary to past work on some of the same species, we found little evidence that sieve tubes overwinter by becoming occluded with callose. Instead, we found that most sieve plates remain open. Xylem embolism was minimal during the peak growing season, but increased over winter.ConclusionsMany species had been assumed to deposit callose on sieve plates over winter, though anatomical and phenological phloem data were sparse. Our data do not support this notion.

Copyright of Canadian Journal of Animal Science is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Animal Science is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Red-osier dogwood extracts (RDE) contain high levels of phenolic compounds which have been recognized as natural antioxidants. In this study, the potential of RDE to prevent cardiovascular diseases (CVDs) was evaluated using Caco-2 cells and a co-culture model of Caco-2 BBe1/EA.hy926 cells in Transwell® plates. The results showed that RDE supplementation significantly prevented interleukin-8 (IL-8) production and suppressed the gene expression of IL-8, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and cyclooxygenase 2 (COX-2) in the TNF-α inflamed Caco-2 cells. Meanwhile, the polyphenols (quercetin-3-glucoside, quercetin-glucuronide, rutin, quercetin-3-O-malonylglucoside, and kaempferol-glucoside) in the RDE were validated to be absorbed by Caco-2 BBe1 cells and transported to the basal chamber where EA.hy926 cells were located during 12 h incubation. The transported polyphenols were able to prevent IL-8 production and suppress the gene expression of proinflammatory mediators (TNF-α, ICAM-1, VCAM-1, and COX-2) in the TNF-α or oxidized low-density lipoprotein (ox-LDL) treated EA.hy926 cells. These novel findings demonstrated that phenolic compounds in RDE can be transported to the cardiovascular system by intestinal absorption and mitigate the inflammatory responses of vascular endothelial cells, indicating that RDE could be a natural resource of polyphenols to prevent inflammation cytokine or oxidized lipid-induced CVDs.

Red-osier dogwood, a native species of flowering plant in North America, has been reported to have anti-oxidative properties because of abundant phenolic compounds; this could be promising as a functional food or a feed additive. In the present study, an oxidative damage model using 1.0 mM hydrogen peroxide (H2O2) in Caco-2 cells was established to evaluate the antioxidative effects of red-osier dogwood extracts (RDE). The results showed that 1.0 mM H2O2 pre-exposure for 3 h significantly decreased cell viability, and increased interleukin 8 (IL-8) secretion and the intracellular reactive oxygen species (ROS) level. Caco-2 cells were treated with 100 µg/mL RDE for 24 h after pre-exposure to H2O2. It was found that the decreased cell viability caused by H2O2 was significantly restored by a subsequent 100 µg/mL RDE treatment. Furthermore, the IL-8 secretion and ROS level were significantly blocked by RDE, accompanied by the enhanced gene expression of hemeoxygenase-1 (HO-1), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px), and the enhanced protein expression of the nuclear factor (erythroid-derived 2)-like 2 (Nrf-2). Moreover, RDE improved barrier functions in Caco-2 cells. Using RDE reduced the diffusion of fluorescein isothiocyanate (FITC)-dextran and increased the transepithelial resistance (TEER) value. The relative mRNA level of tight junction claudin-1, claudin-3, and occludin was elevated by RDE. These extracts also repaired the integrity of zonula occludens-1 (ZO-1) damaged by H2O2 and increased the protein expressions of ZO-1 and claudin-3 in the H2O2-pretreated cells. These results illustrated that RDE reduced the ROS level and enhanced the barrier function in oxidative-damaged epithelial cells.

Soil pH is a major factor affecting plant growth. Plant responses to pH conditions widely vary between different species of plants. However, the exact mechanisms of high pH tolerance of plants are largely unknown. In the present study, we compared the pH responses of paper birch ( Betula papyrifera) seedlings, a relatively sensitive species to high soil pH, with red-osier dogwood ( Cornus sericea), reported to be relatively tolerant of high pH conditions. We examined the hypotheses that tolerance of plants to high root zone pH is linked to effective control of root apoplastic pH to facilitate nutrient and water transport processes, In the study, we exposed paper birch and red-osier dogwood seedlings for six weeks to pH 5, 7 and 9 under controlled-environment conditions in hydroponic culture. Then, we measured biomass, gas exchange, root hydraulic conductivity, ferric chelate reductase (FCR) activity, xylem sap pH and the relative abundance of major elements in leaf protoplasts and apoplasts., The study sheds new light on the rarely studied high pH tolerance mechanisms in plants. We found that compared with paper birch, red-osier dogwood showed greater growth, higher gas exchange, and maintained higher root hydraulic conductivity as well as lower xylem sap pH under high pH conditions., The results suggest that the relatively high pH tolerance of dogwood is associated with greater water uptake ability and maintenance of low apoplastic pH. These traits may have a significant impact on the uptake of Fe and Mn by leaf cells. [ABSTRACT FROM AUTHOR]

Red-osier dogwood ( Cornus sericea L.) seedlings from three seed sources of different climatic conditions were treated hydroponically with 0-100 mM NaCl to compare their salinity tolerance. The control seedlings from the coldest location, Alberta (AB) had the lowest biomass and transpiration rate, as well as the highest photosynthetic water use efficiency. When exposed to 100 mM NaCl for 1 week, the seedlings from AB maintained a higher photosynthetic rate and stomatal conductance than the seedlings from the low precipitation location, British Columbia (BC), and the high precipitation location, New Brunswick (NB). After 2 weeks of treatment at this highest salt concentration, leaf injury occurred in the plants from all the locations suggesting that in spite of early differences, the seedlings from all locations may not be able to survive the salinity stress over time. In contrast, when plants were exposed to 50 mM NaCl, the seedlings from AB had low level of leaf injury, followed by the plants from BC compared with the NB seedlings. Furthermore, at this moderate salt concentration, the seedlings from NB (with the highest biomass for the control) had the lowest root relative growth rate and the highest leaf area; while the seedlings from AB and BC had the highest photosynthetic water use efficiency. The seedlings from AB were able to retain more K in the roots than the seedlings from NB, suggesting a higher level of salinity tolerance. Lower chloride content was observed in the leaves of the AB seedlings than in the BC seedlings. The results of this study show that when exposed to 50 mM NaCl, the seedlings from the cold (AB) and dry (BC) locations had higher salt tolerance than the seedlings from the milder climate (NB). These results suggest that cross tolerance may occur in red-osier dogwood; however, it varies depending on the level of salinity stress. [ABSTRACT FROM AUTHOR]

Background and Aims: Qualitative and quantitative studies of the pattern of invasive plant development is considered a key aspect in understanding invasiveness. An architectural analysis was therefore performed in order to understand the relationship between shoot architecture and invasiveness in red-osier dogwood, Cornus sericea (Cornaceae). [ABSTRACT FROM PUBLISHER]

A predominant 24-kD dehydrin-like protein was previously found to fluctuate seasonally within red-osier dogwood (Cornus sericea L.) stems. The current study attempted to determine what environmental cues triggered the accumulation of the 24-kD protein and to assess its potential role in winter survival. Controlled photoperiod and field studies confirmed that photoperiod regulates a reduction of stem water content (SWC), freeze-tolerance enhancement and accumulation of the 24-kD protein. Diverse climatic ecotypes, which are known to respond to different critical photoperiods, displayed differential reduction of SWC and accumulation of the 24-kD protein. A time-course study confirmed that prolonged exposure to short days is essential for SWC reduction, 24-kD protein accumulation, and freeze-tolerance enhancement. Water deficit induced 24-kD protein accumulation and enhanced freeze-tolerance under long-day conditions. In all instances, freeze-tolerance enhancement and 24-kD protein accumulation was preceded by a reduction of SWC. These results are consistent with the hypothesis that C. sericea responds to decreasing photoperiod, which triggers a reduction in SWC. Reduced SWC in turn may trigger the accumulation of the 24-kD protein and a parallel increase in freeze-tolerance. [ABSTRACT FROM PUBLISHER]

Cold-acclimated stems of red-osier dogwood (Cornus sericea L.) were sampled in midwinter and early spring and subjected to the following low temperature treatments: (a)0 → -40 → 0°C; (b)0 → -40 → -196 → 0°C; (c) 0 →-40 → -196 → -269 → -196 → 0°C:(d) 0 → -40 → -269→ -l96→0°C: (e) 0→ -196→ 0°C; (f) 0 → -269 → -196 → 0°C. The cortical parenchyma cells of the outer stem layers survived exposure to -269°C when pre-frozen to -40°C and either transferred directly to - 269°C or to - 196→C and then to -269°C (treatments c and d). Acclimated stems transferred to a greenhouse (22 °C) 2 weeks prior to the low temperature treatments deacclimated and were not able to survive freezing to - 10°C. Cortical cells of stem samples taken in March. near the time when dogwood naturally deacclimates, survived - 196°C (treatment b), but not -269°C (treatment c or d).Thus, the freezing tolerance of dogwood varies seasonally from near - 10°C to below -269°C. [ABSTRACT FROM AUTHOR]

Red-osier dogwood extracts (RDE) contain high levels of phenolic compounds which have been recognized as natural antioxidants. In this study, the potential of RDE to prevent cardiovascular diseases (CVDs) was evaluated using Caco-2 cells and a co-culture model of Caco-2 BBe1/EA.hy926 cells in Transwell® plates. The results showed that RDE supplementation significantly prevented interleukin-8 (IL-8) production and suppressed the gene expression of IL-8, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and cyclooxygenase 2 (COX-2) in the TNF-α inflamed Caco-2 cells. Meanwhile, the polyphenols (quercetin-3-glucoside, quercetin-glucuronide, rutin, quercetin-3-O-malonylglucoside, and kaempferol-glucoside) in the RDE were validated to be absorbed by Caco-2 BBe1 cells and transported to the basal chamber where EA.hy926 cells were located during 12 h incubation. The transported polyphenols were able to prevent IL-8 production and suppress the gene expression of proinflammatory mediators (TNF-α, ICAM-1, VCAM-1, and COX-2) in the TNF-α or oxidized low-density lipoprotein (ox-LDL) treated EA.hy926 cells. These novel findings demonstrated that phenolic compounds in RDE can be transported to the cardiovascular system by intestinal absorption and mitigate the inflammatory responses of vascular endothelial cells, indicating that RDE could be a natural resource of polyphenols to prevent inflammation cytokine or oxidized lipid-induced CVDs. [ABSTRACT FROM AUTHOR]

Red-osier dogwood, a native species of flowering plant in North America, has been reported to have anti-oxidative properties because of abundant phenolic compounds; this could be promising as a functional food or a feed additive. In the present study, an oxidative damage model using 1.0 mM hydrogen peroxide (H2O2) in Caco-2 cells was established to evaluate the antioxidative effects of red-osier dogwood extracts (RDE). The results showed that 1.0 mM H2O2 pre-exposure for 3 h significantly decreased cell viability, and increased interleukin 8 (IL-8) secretion and the intracellular reactive oxygen species (ROS) level. Caco-2 cells were treated with 100 µg/mL RDE for 24 h after pre-exposure to H2O2. It was found that the decreased cell viability caused by H2O2 was significantly restored by a subsequent 100 µg/mL RDE treatment. Furthermore, the IL-8 secretion and ROS level were significantly blocked by RDE, accompanied by the enhanced gene expression of hemeoxygenase-1 (HO-1), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px), and the enhanced protein expression of the nuclear factor (erythroid-derived 2)-like 2 (Nrf-2). Moreover, RDE improved barrier functions in Caco-2 cells. Using RDE reduced the diffusion of fluorescein isothiocyanate (FITC)-dextran and increased the transepithelial resistance (TEER) value. The relative mRNA level of tight junction claudin-1, claudin-3, and occludin was elevated by RDE. These extracts also repaired the integrity of zonula occludens-1 (ZO-1) damaged by H2O2 and increased the protein expressions of ZO-1 and claudin-3 in the H2O2-pretreated cells. These results illustrated that RDE reduced the ROS level and enhanced the barrier function in oxidative-damaged epithelial cells. [ABSTRACT FROM AUTHOR]

Red-osier dogwood, a native species of flowering plant in North America, has been reported to have anti-oxidative properties because of abundant phenolic compounds; this could be promising as a functional food or a feed additive. In the present study, an oxidative damage model using 1.0 mM hydrogen peroxide (H 2 O 2 ) in Caco-2 cells was established to evaluate the antioxidative effects of red-osier dogwood extracts (RDE). The results showed that 1.0 mM H 2 O 2 pre-exposure for 3 h significantly decreased cell viability, and increased interleukin 8 (IL-8) secretion and the intracellular reactive oxygen species (ROS) level. Caco-2 cells were treated with 100 µg/mL RDE for 24 h after pre-exposure to H 2 O 2 . It was found that the decreased cell viability caused by H 2 O 2 was significantly restored by a subsequent 100 µg/mL RDE treatment. Furthermore, the IL-8 secretion and ROS level were significantly blocked by RDE, accompanied by the enhanced gene expression of hemeoxygenase-1 (HO-1), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px), and the enhanced protein expression of the nuclear factor (erythroid-derived 2)-like 2 (Nrf-2). Moreover, RDE improved barrier functions in Caco-2 cells. Using RDE reduced the diffusion of fluorescein isothiocyanate (FITC)-dextran and increased the transepithelial resistance (TEER) value. The relative mRNA level of tight junction claudin-1, claudin-3, and occludin was elevated by RDE. These extracts also repaired the integrity of zonula occludens-1 (ZO-1) damaged by H 2 O 2 and increased the protein expressions of ZO-1 and claudin-3 in the H 2 O 2 -pretreated cells. These results illustrated that RDE reduced the ROS level and enhanced the barrier function in oxidative-damaged epithelial cells.