831 results on '"Transpiration stream"'
Search Results
2. Mechanism of Antibiotics Uptake in Plants
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El Gemayel, Lara J., Bashour, Isam I., Hashmi, Muhammad Zaffar, Series Editor, and Strezov, Vladimir, Series Editor
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- 2020
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3. Modelling the Fate of Chemicals in Plants
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Ciffroy, Philippe, Tanaka, Taku, Barceló, Damià, Editor-in-chief, Kostianoy, Andrey G., Editor-in-chief, Hutzinger, Otto, Founded by, Ciffroy, Philippe, editor, Tediosi, Alice, editor, and Capri, Ettore, editor
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- 2018
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4. Regulation of Leaf Traits in Canopy Gradients
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Pons, Thijs L., Govindjee, Series editor, Sharkey, Thomas D., Series editor, Hikosaka, Kouki, editor, Niinemets, Ülo, editor, and Anten, Niels P.R., editor
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- 2016
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5. Zinc uptake and distribution in ivy (Hedera helix L.) leaves
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Miroslav Horník, Jana Marešová, Jozef Augustín, and Martin Pipíška
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biology ,Health, Toxicology and Mutagenesis ,chemistry.chemical_element ,Zinc ,biology.organism_classification ,Analytical Chemistry ,Horticulture ,Nutrient ,Hedera helix ,chemistry ,Transpiration stream ,Zinc uptake ,Food Science ,Biotechnology - Abstract
Detached leaves of ivy (Hedera helix L.) were used as a model for the study of zinc uptake and transport in vascular plants. By the uptake via the surface of fully immersed leaves in 25 % Hoagland nutrient media (HM) spiked with 65ZnCl2 (50 μmol/dm3 ZnCl2), concentration in leaves 4.98 μg Zn/g (dry wt.), i. e. 2.6 μg Zn/dm2 leaf area after 7d exposition were obtained. By the uptake via immersed stalks of not immersed (transpiring) leaves concentrations up to 370 μg Zn/g (dry wt.) were obtained. When Zn enters into detached leaves via the surface of immersed leaf blades, zinc is uniformly distributed in leaf blades and leaf stalks. When zinc enters detached leaves via immersed stalks of non-immersed transpiring leaves, only small part of zinc is transported to leaf blades and the prevailing part remains in leaf stalks. Stalks act as a trap, able to prevent other leaf tissues against inhibitory effects of high Zn concentrations. Mineral nutrient salts in solutions mobilize Zn trapped in leaf stalks and facilitate Zn transport by transpiration stream to leaf blades, what means that Zn in stalks is bound in ion-exchageable forms.
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- 2021
6. Flooding-Driven Emissions from Trees
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Kreuzwieser, Jürgen, Rennenberg, Heinz, Niinemets, Ülo, editor, and Monson, Russell K., editor
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- 2013
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7. Monitoring for Phytoremediation of Groundwater Contamination
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Landmeyer, James E. and Landmeyer, James E.
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- 2012
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8. Hydraulics of Vascular Water Transport
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Sperry, John S. and Wojtaszek, Przemyslaw, editor
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- 2011
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9. Trichloroacetic Acid in the Forest Ecosystem
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Matucha, Miroslav, Schröder, Peter, Schröder, Peter, editor, and Collins, Christopher D., editor
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- 2011
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10. Uptake of Organic Contaminants from Soil into Vegetables and Fruits
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Trapp, Stefan, Legind, Charlotte N., and Swartjes, Frank A., editor
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- 2011
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11. Root Oxygen Deprivation and Leaf Biochemistry in Trees
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Arru, Laura, Fornaciari, Silvia, Mancuso, Stefano, editor, and Shabala, Sergey, editor
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- 2010
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12. Oxygen Transport in the Sapwood of Trees
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Mugnai, Sergio, Mancuso, Stefano, Mancuso, Stefano, editor, and Shabala, Sergey, editor
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- 2010
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13. Human Exposure Assessment for Food – One Equation for all Crops is not Enough
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Trapp, Stefan, Kulhanek, Ales, Mackova, Martina, editor, Dowling, David, editor, and Macek, Thomas, editor
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- 2006
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14. Phytoremediation of Volatile Organic Compounds
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Burken, Joel G., Ma, Xingmao, Mackova, Martina, editor, Dowling, David, editor, and Macek, Thomas, editor
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- 2006
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15. Environmental Factors Influence Plant Vascular System and Water Regulation
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Mirwais M. Qaderi, Ashley B. Martel, and Sage L. Dixon
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climate change ,drought stress ,elevated carbon dioxide ,environmental factors ,higher temperature ,plants ,transpiration stream ,vascular cambium ,Botany ,QK1-989 - Abstract
Developmental initiation of plant vascular tissue, including xylem and phloem, from the vascular cambium depends on environmental factors, such as temperature and precipitation. Proper formation of vascular tissue is critical for the transpiration stream, along with photosynthesis as a whole. While effects of individual environmental factors on the transpiration stream are well studied, interactive effects of multiple stress factors are underrepresented. As expected, climate change will result in plants experiencing multiple co-occurring environmental stress factors, which require further studies. Also, the effects of the main climate change components (carbon dioxide, temperature, and drought) on vascular cambium are not well understood. This review aims at synthesizing current knowledge regarding the effects of the main climate change components on the initiation and differentiation of vascular cambium, the transpiration stream, and photosynthesis. We predict that combined environmental factors will result in increased diameter and density of xylem vessels or tracheids in the absence of water stress. However, drought may decrease the density of xylem vessels or tracheids. All interactive combinations are expected to increase vascular cell wall thickness, and therefore increase carbon allocation to these tissues. A comprehensive study of the effects of multiple environmental factors on plant vascular tissue and water regulation should help us understand plant responses to climate change.
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- 2019
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16. Pathology of the Xylem
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Tyree, Melvin T., Zimmermann, M. H., Timell, T. E., editor, Tyree, Melvin T., and Zimmermann, M. H.
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- 2002
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17. Can hydraulic design explain patterns of leaf water isotopic enrichment in <scp> C 3 </scp> plants?
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Xin Song, Graham D. Farquhar, Daniel McCallum, Kevin A. Simonin, D. Griffani, Margaret M. Barbour, Karen E. Loucos, Erin L Lockhart, and Arjina Shrestha
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0106 biological sciences ,0301 basic medicine ,Physiology ,Chemistry ,Transport pathways ,Soil science ,Plant Science ,Leaf water ,15. Life on land ,Vascular bundle ,01 natural sciences ,03 medical and health sciences ,030104 developmental biology ,Spongy tissue ,Transpiration stream ,Vascular tissue ,010606 plant biology & botany ,Transpiration - Abstract
H2 18 O enrichment develops when leaves transpire, but an accurate generalized mechanistic model has proven elusive. We hypothesized that leaf hydraulic architecture may affect the degree to which gradients in H2 18 O develop within leaves, influencing bulk leaf stable oxygen isotope enrichment (ΔL ) and the degree to which the Peclet effect is relevant in leaves. Leaf hydraulic design predicted the relevance of a Peclet effect to ΔL in 19 of the 21 species tested. Leaves with well-developed hydraulic connections between the vascular tissue and the epidermal cells through bundle sheath extensions and clear distinctions between palisade and spongy mesophyll layers (while the mesophyll is hydraulically disconnected) may have velocities of the transpiration stream such that gradients in H2 18 O develop and are expressed in the mesophyll. In contrast, in leaves where the vascular tissue is hydraulically disconnected from the epidermal layers, or where all mesophyll cells are well connected to the transpiration stream, velocities within the liquid transport pathways may be low enough that gradients in H2 18 O are very small. Prior knowledge of leaf hydraulic design allows informed selection of the appropriate ΔL modelling framework.
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- 2020
18. Birds girdling activity on exotic tree species as a form of adaptive behavior?
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Tomaskova, Ivana, Bazant, Vaclav, Bleha, Roman, Vitamvas, Jan, Delzon, Sylvain, Stastny, Karel, and Vackar, Jiri
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MULTIPURPOSE trees ,SYMPATRIC speciation ,BIOLOGICAL classification ,GENETIC speciation ,BIRD watching - Abstract
Four tree species in the Kostelec n. Č. l. arboretum (Czech Republic) have been repeatedly damaged by Dendrocopos medius. The unique aspect of this otherwise common behavior called girdling consists in regularly visiting the same trees every spring, although there are more than 1.200 tree species within the arboretum. We monitored transpiration, leaf phenology and the chemical composition of the xylem sap of girdled and nongirdled trees. Spectral analysis revealed slightly higher amounts of sugars, especially saccharose, in Cladrastis Raf. as the most regularly girdled tree among other conditions, comparing girdled to non-girdled trees. Higher transpiration rates were not confirmed in connection with girdling-quite the opposite- Cladrastis Raf. as the most highly favored tree for girdling showed the lowest transpiration rates (in average 6 kg water per day within spring months) compared to other non-girdled trees. We presume that the birds do not choose a particular tree on the basis of any visible or chemical traits but they examine many trees within their territory. Afterwards they probably remember the position of trees whose xylem sap starts to flow early in the spring compared to other trees, as their transpiration stream is enriched with sweet organic substances that represent an advantage for the forthcoming nesting period. [ABSTRACT FROM AUTHOR]
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- 2017
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19. Effects of Transpiration, Carbon Dioxide and Ozone on the Content of Cadmium and Zinc in Spring Wheat Grain
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Pleijel, H., Danielsson, H., Gelang, J., Selldén, G., Yunus, Mohammad, editor, Singh, Nandita, editor, and de Kok, Luit J., editor
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- 2000
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20. Imperforate tracheary elements and vessels alleviate xylem tension under severe dehydration: insights from water release curves for excised twigs of three tree species
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Akiko Takenouchi, Naoko Miki, Kenji Fukuda, Makoto Watanabe, Hiroyuki Tobita, Haruhiko Taneda, Daisuke Kabeya, Shin-Taro Saiki, Kenichi Yazaki, Mayumi Y. Ogasa, Delphis F. Levia, and Michio Oguro
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0106 biological sciences ,capacitance ,Cercidiphyllum ,Cercidiphyllum japonicum ,Plant Science ,Abies firma ,Biology ,Quercus serrata ,010603 evolutionary biology ,01 natural sciences ,Trees ,cryo‐SEM ,Quercus ,Xylem ,Botany ,Genetics ,Humans ,Ecology, Evolution, Behavior and Systematics ,Research Articles ,Dehydration ,Water ,micro focus x‐ray CT ,water storage ,Interspecific competition ,biology.organism_classification ,Droughts ,Transpiration stream ,xylem structure ,Abies ,010606 plant biology & botany ,Woody plant ,Research Article - Abstract
Premise Water stored in the xylem of woody plants is important for supporting the transpiration stream under prolonged drought, yet the source of stored water within the xylem during drought remains unclear. Insights into xylem water utilization during drought will uncover the adaptation strategies of the test species to stress. Methods To fill the existing knowledge gap, we excised twigs of Abies firma (Japanese fir, conifer), Cercidiphyllum japonicum (katsura tree, diffuse-porous) and Quercus serrata (konara oak, ring-porous) to quantify interspecific variation of water transfer in xylem corresponding with increasing cumulative water release (CWR) using micro x-ray computed tomography and cryo-SEM. Results For all species studied, the main components of water storage within the operating range of water potential were not living cells but cavitation release and capillaries. Abies firma maintained water in the earlywood-like cells, for possible maintenance of the transpiration stream. Cercidiphyllum japonicum maintained water in its vessels over 200 kg m-3 of CWR, while Q. serrata lost most of its water in vessels with increasing CWR up to 100 kg m-3 . Cercidiphyllum japonicum exhibited a higher water storage capacity than Q. serrata. Under high CWR, narrow conduits stored xylem water in C. japonicum and imperforate tracheary elements in Q. serrata. Conclusions Among the species examined, increasing CWR appears to indicate differential utilization of stored water in relation to variation of xylem structure, thereby providing insight into the interspecific responses of tree species to drought.
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- 2020
21. Uptake by Plants
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Trapp, Stefan, Matthies, Michael, Trapp, Stefan, and Matthies, Michael
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- 1998
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22. Translocation, Leaf Distribution, and Nutritional Status of Manganese in Cucumber Plants as Affected by Foliar Application of Exogenous Amino Acids
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Eskandari Samane
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0106 biological sciences ,0301 basic medicine ,Chemistry ,fungi ,food and beverages ,Plant physiology ,Xylem ,Chromosomal translocation ,Plant Science ,01 natural sciences ,Apoplast ,Bioavailability ,03 medical and health sciences ,Horticulture ,030104 developmental biology ,Transpiration stream ,Phloem ,Agronomy and Crop Science ,010606 plant biology & botany ,Transpiration - Abstract
The present study was carried out to investigate the effect of exogenous amino acids (AAs) on leaf apoplastic retention and symplastic absorption, leaf distribution, translocation, and nutritional status of manganese (Mn) in cucumber plants. Results showed that application of AAs increased the symplastic to apoplastic Mn proportion in leaves of cucumber. Furthermore, a greater part of Mn applied with AAs accumulated in the internal area of newly growing leaves suggesting the transport of Mn mostly in the phloem in the presence of AAs. In contrast, Mn preferentially accumulated in the marginal area of treated leaves indicating the Mn movement in xylem according to the transpiration stream. The AAs used in the present study also increased the relative translocation of Mn from treated leaves to the upper leaves and roots. More time was needed for long-distance translocation of Mn from treated leaves to the upper leaves than that to the roots. Application of AAs mainly increased the transport of Mn in the phloem. The leaf PO (peroxidase) activity was the better marker to index the nutritional status of Mn than PPO (polyphenoloxidase) activity. In conclusion, exogenous AAs especially lysine (Lys) promoted the mobility and bioavailability of applied Mn as foliar spray.
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- 2019
23. Absorption and distribution of boron in Arabidopsis thaliana
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Noguchi, Kyotaro, Fujiwara, Toru, Chino, Mitsuo, Matsunaga, Toshiro, Watanabe-Oda, Hisao, Bell, R. W., editor, and Rerkasem, B., editor
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- 1997
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24. Influence of Silicon on Biocontrol Strategies to Manage Biotic Stress for Crop Protection, Performance, and Improvement
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Rupesh Kumar Singh, Vishnu D. Rajput, Chang-Song Zhong, Yang-Rui Li, Zhong-Liang Chen, Xiu-Peng Song, Krishan Kumar Verma, Munna Singh, Dao-Jun Guo, Tatiana Minkina, Dan-Dan Tian, and Amin Nikpay
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physio-biochemical/molecular strategies ,Plant Science ,Review ,Biology ,chemistry.chemical_compound ,Nutrient ,biotic stress ,Plant defense against herbivory ,Ecology, Evolution, Behavior and Systematics ,Herbivore ,Ecology ,Agroforestry ,herbivory ,plants ,Jasmonic acid ,fungi ,Botany ,food and beverages ,silicon ,pathogens ,Biotic stress ,Pesticide ,Crop protection ,chemistry ,QK1-989 ,Transpiration stream - Abstract
Silicon (Si) has never been acknowledged as a vital nutrient though it confers a crucial role in a variety of plants. Si may usually be expressed more clearly in Si-accumulating plants subjected to biotic stress. It safeguards several plant species from disease. It is considered as a common element in the lithosphere of up to 30% of soils, with most minerals and rocks containing silicon, and is classified as a “significant non-essential” element for plants. Plant roots absorb Si, which is subsequently transferred to the aboveground parts through transpiration stream. The soluble Si in cytosol activates metabolic processes that create jasmonic acid and herbivore-induced organic compounds in plants to extend their defense against biotic stressors. The soluble Si in the plant tissues also attracts natural predators and parasitoids during pest infestation to boost biological control, and it acts as a natural insect repellent. However, so far scientists, policymakers, and farmers have paid little attention to its usage as a pesticide. The recent developments in the era of genomics and metabolomics have opened a new window of knowledge in designing molecular strategies integrated with the role of Si in stress mitigation in plants. Accordingly, the present review summarizes the current status of Si-mediated plant defense against insect, fungal, and bacterial attacks. It was noted that the Si-application quenches biotic stress on a long-term basis, which could be beneficial for ecologically integrated strategy instead of using pesticides in the near future for crop improvement and to enhance productivity.
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- 2021
25. Molecular Biology and Biochemistry of Hm1, a Maize Gene for Fungal Resistance
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Meeley, R. B., Walton, J. D., Bliss, F. A., editor, Nester, Eugene W., editor, and Verma, Desh Pal S., editor
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- 1993
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26. ABA and the Control of Growth and Physiology of Stressed Plants
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Davies, W. J., Trejo, C. L., Palmer, S. J., Jackson, Michael B., editor, and Black, Colin R., editor
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- 1993
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27. Uptake of Organic Contaminants by Plants
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Mc Farlane, Craig and Travis, Curtis C., editor
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- 1991
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28. Current Studies on Human Exposure to Chemicals with Emphasis on the Plant Route
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Paterson, Sally, Mackay, Donald, and Travis, Curtis C., editor
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- 1991
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29. Plant Uptake of Organic Pollutants
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Bell, R. M., Failey, R. A., Cairns, J., Jr, editor, Harrison, R. M., editor, and Jones, K. C., editor
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- 1991
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30. The Effect of H2O2 on the Photosynthetic Biochemistry of Pisum sativum
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Ford, L., Pammenter, N. W., Amory, A. M., Cresswell, C. F., and Baltscheffsky, M., editor
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- 1990
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31. Measurement of the in Vivo Rate of Indole-3-Acetic Acid Turnover
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Nonhebel, H. M., Cooney, T. P., Pharis, Richard P., editor, and Rood, Stewart B., editor
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- 1990
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32. Xylem-Translocated Cytokinin: Metabolism and Function
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Letham, D. S., Parker, C. W., Zhang, R., Singh, S., Upadhyaya, M. N., Dart, P. J., Palni, L. M. S., Pharis, Richard P., editor, and Rood, Stewart B., editor
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- 1990
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33. Formation of root silica aggregates in sorghum is an active process of the endodermis
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Janina Kneipp, Victor M. R. Zancajo, Rivka Elbaum, and Milan Soukup
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0106 biological sciences ,0301 basic medicine ,Physiology ,lignin ,Plant Science ,Plant Roots ,01 natural sciences ,Ferulic acid ,Cell wall ,03 medical and health sciences ,chemistry.chemical_compound ,Cell Wall ,Lignin ,Silicic acid ,Sorghum ,AcademicSubjects/SCI01210 ,root endodermis ,food and beverages ,respiratory system ,Silicon Dioxide ,Research Papers ,SEM–EDX ,030104 developmental biology ,chemistry ,Polymerization ,Seedlings ,silica ,Transpiration stream ,Biophysics ,Endodermis ,Sorghum bicolor (L.) Moench ,010606 plant biology & botany ,Coniferyl alcohol - Abstract
Silica, a mineral reducing the digestibility of grass tissues, is assumed to form spontaneously in planta. We overturn this model, showing that silica deposition occurs during lignification and demands metabolic energy., Silica deposition in plants is a common phenomenon that correlates with plant tolerance to various stresses. Deposition occurs mostly in cell walls, but its mechanism is unclear. Here we show that metabolic processes control the formation of silica aggregates in roots of sorghum (Sorghum bicolor L.), a model plant for silicification. Silica formation was followed in intact roots and root segments of seedlings. Root segments were treated to enhance or suppress cell wall biosynthesis. The composition of endodermal cell walls was analysed by Raman microspectroscopy, scanning electron microscopy and energy-dispersive X-ray analysis. Our results were compared with in vitro reactions simulating lignin and silica polymerization. Silica aggregates formed only in live endodermal cells that were metabolically active. Silicic acid was deposited in vitro as silica onto freshly polymerized coniferyl alcohol, simulating G-lignin, but not onto coniferyl alcohol or ferulic acid monomers. Our results show that root silica aggregates form under tight regulation by endodermal cells, independently of the transpiration stream. We raise the hypothesis that the location and extent of silicification are primed by the chemistry and structure of polymerizing lignin as it cross-links to the wall.
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- 2019
34. Sodium interception by xylem parenchyma and chloride recirculation in phloem may augment exclusion in the salt tolerant Pistacia genus: context for salinity studies on tree crops
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Or Sperling, Aude Tixier, Blake L. Sanden, Louise Ferguson, S.R. Grattan, Maciej A. Zwieniecki, Jessie Godfrey, Plant Sciences Department, University of California [Davis] (UC Davis), University of California-University of California, University of California, Agroécologie [Dijon], Université de Bourgogne (UB)-Institut National de la Recherche Agronomique (INRA)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, Agricultural Research Organization, and Department of Land, Air and Water Resources
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Salinity ,abiotic stress ,Perennial plant ,Physiology ,[SDV]Life Sciences [q-bio] ,Sodium ,chemistry.chemical_element ,Context (language use) ,budding ,pistachio ,Plant Science ,Phloem ,Plant Roots ,Trees ,Xylem ,[SDV.BV]Life Sciences [q-bio]/Vegetal Biology ,stem ,Ions ,salt tolerance ,grafting ,Plant Leaves ,Horticulture ,xylem retrieval ,woody perennial ,chemistry ,[SDE]Environmental Sciences ,Pistacia ,Transpiration stream ,Rootstock - Abstract
Working in tandem with root exclusion, stems may provide salt-tolerant woody perennials with some additional capacity to restrict sodium (Na) and chloride (Cl) accumulation in leaves. The Pistacia genus, falling at the nexus of salt tolerance and human intervention, provided an ideal set of organisms for studying the influences of both variable root exclusion and potentially variable discontinuities at the bud union on stem processes. In three experiments covering a wide range of salt concentrations (0 to 150 mM NaCl) and tree ages (1, 2 and 10 years) as well as nine rootstock-scion combinations we show that proportional exclusion of both Na and Cl reached up to ~85% efficacy, but efficacy varied by both rootstock and budding treatment. Effective Na exclusion was augmented by significant retrieval of Na from the xylem sap, as evidenced by declines in the Na concentrations of both sap and wood tissue along the transpiration stream. However, while we observed little to no differences between the concentrations of the two ions in leaves, analogous declines in sap concentrations of Cl were not observed. We conclude that some parallel but separate mechanism must be acting on Cl to provide leaf protection from toxicity specific to this ion and suggest that this mechanism is recirculation of Cl in the phloem. The presented findings underline the importance of holistic assessments of salt tolerance in woody perennials. In particular, greater emphasis might be placed on the dynamics of salt sequestration in the significant storage volumes offered by the stems of woody perennials and on the potential for phloem discontinuity introduced with a bud/graft union.
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- 2019
35. Mechanisms for minimizing height‐related stomatal conductance declines in tall vines
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C. W. Huang, Ram Oren, Katre Kets, Jean-Christophe Domec, Menachem Moshelion, Danielle A. Way, Sari Palmroth, Henry Berghoff, Interactions Sol Plante Atmosphère (UMR ISPA), Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro), Nicholas School of the Environment, Duke University [Durham], Department of Biology, Western University, University of Jerusalem, Institute of Botany and Ecology, University of Tartu, Department of Biology [New Mexico], The University of New Mexico [Albuquerque], Department of Forest Sciences, and University of Alaska [Fairbanks] (UAF)
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0106 biological sciences ,0301 basic medicine ,Physiology ,Water flow ,LEAF-AREA ,[SDV]Life Sciences [q-bio] ,Plant Science ,KUDZU-VINE ,01 natural sciences ,hydraulic compensation ,CURRENT-YEAR SHOOTS ,Photosynthesis ,4112 Forestry ,long-distance transport ,Plant Stems ,Pueraria lobata ,biology ,Chemistry ,Kudzu ,hydraulic resistance ,Pueraria ,Horticulture ,[SDE]Environmental Sciences ,Transpiration stream ,Gravitation ,SAPWOOD AREA ,Stomatal conductance ,capacitance ,VULNERABILITY SEGMENTATION ,XYLEM HYDRAULIC CONDUCTIVITY ,Petiole (botany) ,03 medical and health sciences ,PUERARIA-LOBATA ,WATER TRANSPORT-PROPERTIES ,Water ,Biological Transport ,Plant Transpiration ,Carbon Dioxide ,15. Life on land ,biology.organism_classification ,VESSEL SIZE ,Plant Leaves ,Permanent wilting point ,030104 developmental biology ,Liana ,Plant Stomata ,electrical circuit analogy ,TREE HEIGHT ,lianas ,010606 plant biology & botany - Abstract
International audience; The ability to transport water through tall stems hydraulically limits stomatal conductance (gs), thereby constraining photosynthesis and growth. However, some plants are able to minimize this height‐related decrease in gs, regardless of path length. We hypothesized that kudzu (Pueraria lobata) prevents strong declines in gs with height through appreciable structural and hydraulic compensative alterations. We observed only a 12% decline in maximum gs along 15‐m‐long stems and were able to model this empirical trend. Increasing resistance with transport distance was not compensated by increasing sapwood‐to‐leaf‐area ratio. Compensating for increasing leaf area by adjusting the driving force would require water potential reaching −1.9 MPa, far below the wilting point (−1.2 MPa). The negative effect of stem length was compensated for by decreasing petiole hydraulic resistance and by increasing stem sapwood area and water storage, with capacitive discharge representing 8–12% of the water flux. In addition, large lateral (petiole, leaves) relative to axial hydraulic resistance helped improve water flow distribution to top leaves. These results indicate that gs of distal leaves can be similar to that of basal leaves, provided that resistance is highest in petioles, and sufficient amounts of water storage can be used to subsidize the transpiration stream.
- Published
- 2019
36. Seawater Desalination with Light Energy Incorporating Artificial Transpiration Stream Using Gas Injection Tube
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Kisho Tomita, Masaki Kikuchi, and Masahiro Fujiwara
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Flux (metallurgy) ,business.industry ,Seawater desalination ,Chemistry ,Transpiration stream ,Environmental engineering ,Xylem ,Tube (fluid conveyance) ,General Chemistry ,Solar energy ,business ,Groundwater ,Transpiration - Abstract
Transpiration is a function of plants to evaporate water from their leaf stomata, which enables plants to take up ground water from their roots to their leaves through the xylem. This water flux fu...
- Published
- 2019
37. Uptake and translocation of organophosphate flame retardants (OPFRs) by hydroponically grown wheat (Triticum aestivum L.)
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Hongxia Zhao, Ling Xu, Yan Wang, and Qingzhi Wang
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Health, Toxicology and Mutagenesis ,0211 other engineering and technologies ,Chromosomal translocation ,02 engineering and technology ,010501 environmental sciences ,Plant Roots ,01 natural sciences ,chemistry.chemical_compound ,Hydroponics ,Triticum ,Flame Retardants ,0105 earth and related environmental sciences ,021110 strategic, defence & security studies ,Chemistry ,Organophosphate ,Public Health, Environmental and Occupational Health ,Biological Transport ,General Medicine ,Pollution ,Organophosphates ,Plant Leaves ,Kinetics ,Phytoremediation ,Environmental chemistry ,Root uptake ,Transpiration stream ,Hydrophobic and Hydrophilic Interactions ,Water Pollutants, Chemical - Abstract
The increasing load of organophosphate flame retardants (OPFRs) has generated wide concerns about their potential residues in aquatic environments. The uptake and translocation of fourteen OPFRs by wheat (Triticum aestivum L.) were studied under hydroponic conditions. The results revealed that OPFRs were removed from hydroponic solution by wheat, and the removal processes followed first-order kinetics. After 10 days, the removal efficiencies were in a range of 57.9 ± 3.8%−63.8 ± 5.6%. The potential for translocation of these OPFRs from the roots to foliage was also assessed. OPFRs with relatively higher hydrophobicity were more likely taken up by roots, and OPFRs with lower hydrophobicity were more prone to be translocated. Root concentration factors (RCFs), transpiration stream concentration factors (TSCFs), and foliage/root concentration factors (FRCFs) were calculated. Furthermore, significant correlations were found between RCF, FRCF or TSCF values of OPFRs and log Kow (p
- Published
- 2019
38. Aberrant protein phosphatase 2C leads to abscisic acid insensitivity and high transpiration in parasitic Striga
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Hiroaki Samejima, Masanori Okamoto, Hijiri Fujioka, Hideyuki Suzuki, Masaharu Mizutani, and Yukihiro Sugimoto
- Subjects
0106 biological sciences ,0301 basic medicine ,Phosphatase ,Arabidopsis ,Striga ,Plant Science ,Biology ,Pyruvate dehydrogenase phosphatase ,01 natural sciences ,03 medical and health sciences ,chemistry.chemical_compound ,Catalytic Domain ,Botany ,Phosphoprotein Phosphatases ,Abscisic acid ,Sorghum ,Plant Proteins ,Transpiration ,Arabidopsis Proteins ,Host (biology) ,Plant Transpiration ,Plants, Genetically Modified ,biology.organism_classification ,Droughts ,Protein Phosphatase 2C ,030104 developmental biology ,chemistry ,Transpiration stream ,Abscisic Acid ,Signal Transduction ,010606 plant biology & botany - Abstract
Striga parasitizes major crops in arid regions, depriving the host crop of nutrients through the transpiration stream and causing vast agricultural damage. Here, we report on the mechanism underlying how Striga maintains high transpiration under drought conditions. We found that Striga did not respond to abscisic acid, the phytohormone responsible for controlling stomatal closure. Protein phosphatase 2C of Striga (ShPP2C1) is not regulated by abscisic acid receptors, and this feature is attributable to specific mutations in its amino acid sequence. Moreover, Arabidopsis transformed with ShPP2C1 showed an abscisic acid-insensitive phenotype, indicating that ShPP2C1 functions as a dominant negative regulator of abscisic acid signal transduction. These findings suggest that ShPP2C1 interrupts abscisic acid signalling in Striga, resulting in high transpiration and subsequent efficient absorption of host nutrients under drought conditions.
- Published
- 2019
39. Isotope ratio laser spectroscopy to disentangle xylem-transported from locally respired CO2 in stem CO2 efflux
- Author
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Roberto L. Salomón, Boeckx Pascal, Linus De Roo, Bodé Samuel, and Kathy Steppe
- Subjects
0106 biological sciences ,0301 basic medicine ,Physiology ,Diffusion ,Co2 efflux ,Plant Science ,Photosynthesis ,01 natural sciences ,Trees ,03 medical and health sciences ,chemistry.chemical_compound ,Isotopes ,Xylem ,Respiration ,Spectroscopy ,Water content ,Isotope ,Plant Stems ,Chemistry ,Spectrum Analysis ,Radiochemistry ,Botany ,Plant Transpiration ,Carbon Dioxide ,Populus ,030104 developmental biology ,visual_art ,Transpiration stream ,Carbon dioxide ,Biophysics ,visual_art.visual_art_medium ,Bark ,010606 plant biology & botany - Abstract
Respired CO2 in woody tissues radially diffuses to the atmosphere or it is transported upward with the transpiration stream, making the origin of CO2 in stem CO2 efflux (EA) uncertain, which may confound stem respiration (RS) estimates. An aqueous 13C-enriched solution was infused into stems of Populus tremula L. trees, and real-time measurements of 13C-CO2 and 12C-CO2 in EA were performed via Cavity Ring Down Laser Spectroscopy (CRDS). The contribution of locally respired CO2 (LCO2) and xylem-transported CO2 (TCO2) to EA was estimated from their different isotopic composition. Mean daily values of TCO2/EA ranged from 13% to 38%, evidencing the notable role that xylem CO2 transport plays in the assessment of stem respiration. Mean daily TCO2/EA did not differ between treatments of drought stress and light exclusion of woody tissues, but they showed different TCO2/EA dynamics on a sub-daily time scale. Sub-daily CO2 diffusion patterns were explained by a light-induced axial CO2 gradient ascribed to woody tissue photosynthesis, and the resistance to radial CO2 diffusion determined by bark water content. Here, we demonstrate the outstanding potential of CRDS paired with 13C-CO2 labelling to advance in the understanding of CO2 movement at the plant-atmosphere interface and the respiratory physiology in woody tissues.
- Published
- 2019
40. Uptake and accumulation of microplastics in an edible plant
- Author
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Qian Zhou, Yongming Luo, Chen Tu, Na Yin, and Lianzhen Li
- Subjects
Microplastics ,Multidisciplinary ,biology ,Chemistry ,010502 geochemistry & geophysics ,biology.organism_classification ,01 natural sciences ,Apoplast ,Cell wall ,Mucilage ,Transpiration stream ,Biophysics ,Root cap ,Central cylinder ,Vascular tissue ,0105 earth and related environmental sciences - Abstract
Microplastic (MP, 100 nm−5 mm) may present an attributable risk to ecosystem and human health, and its pollution has become a global environmental concern. Despite a wealth of information on the accumulation of MPs in aquatic species, there is no information on the uptake and accumulation of MPs by higher plants. Terrestrial edible plants are directly exposed to MPs when agricultural soil was applied with organic manure, sewage sludge as fertilizer or plastic mulching. In this paper, the uptake of two sizes of polystyrene (PS) microbeads (0.2 and 1.0 μm) and then their distribution and migration in an edible plant lettuce were firstly investigated based on laboratory experiments. We used fluorescent markers to track PS microbeads in plant tissues and found fluorescence to be a sensitive and reliable detection method. Sections from untreated control lettuce showed no autofluorescence. When roots were treated with fluorescently labeled PS microbeads, the microbeads could be identified by its fluorescence. Our main study investigated the uptake of 0.2 μm beads, as few luminescence signals were observed in lettuce roots for 1.0 μm beads in our experiment. We observed that 0.2 μm fluorescent microbeads were extracellularly trapped in the root cap mucilage (which is a highly hydrated polysaccharide) and a “dark green tip” (which was typical of lettuce roots exposed to label PS beads) was usually visible to the naked eye. Confocal images revealed that the PS luminescence signals were mainly located in the vascular system and on the cell walls of the cortex tissue of the roots, indicated that the beads passed through the intercellular space via the apoplastic transport system. Once inside the central cylinder, the 0.2 μm PS beads were transferred from the roots to the stems and leaves via the vascular system following the transpiration stream. We also observed that the PS beads adhered to one another and self-assembled systematically into “grape-like” and “(chain) string-like” clusters in the intercellular space of the root and stem vascular tissue of lettuce plant. In contrast to the root and stem, PS beads were dispersed in the leaf tissue. Here, for the first time we provide evidence of the adherence, uptake, accumulation, and translocation of submicrometer MPs within an edible plant. Our findings highlight the previously underappreciated human exposure pathway to MPs through the consumption of contaminated crops and emphasize the need for new management strategies to control the release of MPs waste products into the terrestrial environment. Ultimately, the potential impacts of low range sized MPs on food safety of crop plants and human health need to be urgently considered.
- Published
- 2019
41. The influence of Brassica rapa var. perviridis growth conditions on the uptake and translocation of pesticides
- Author
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Nobuyasu Seike, Takashi Otani, Yutaka Motoki, and Sayuri Namiki
- Subjects
Fenobucarb ,Health, Toxicology and Mutagenesis ,04 agricultural and veterinary sciences ,010501 environmental sciences ,Pesticide ,01 natural sciences ,chemistry.chemical_compound ,Horticulture ,chemistry ,Insect Science ,Brassica rapa ,Soil water ,Transpiration stream ,040103 agronomy & agriculture ,0401 agriculture, forestry, and fisheries ,Procymidone ,Water content ,0105 earth and related environmental sciences ,Transpiration - Abstract
We cultivated Brassica rapa var. perviridis in soil mixed with four pesticides (fenobucarb, procymidone, flutolanil, and tolclofos-methyl) at different temperatures, day lengths, and soil water contents. We compared plants' uptake and translocation abilities of the pesticides as affected by growth conditions. The root concentration factor (RCF) of pesticides tended to increase with rising temperature; however, but the influence of temperature on the transpiration stream concentration factor (TSCF) differed for each pesticide. The RCFs and TSCFs of pesticides were high for short days. The soil water content had little or no effect on the uptake and translocation of pesticides. These results showed that it is necessary to consider growth conditions, especially the temperature and day length in plant uptake models for these pesticides.
- Published
- 2018
42. Apoplastic and symplastic pathways in the leaf of the grey mangrove Avicennia marina (Forsk.) Vierh
- Author
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W. G. Allaway and Melissa A. Fitzgerald
- Subjects
Epidermis (botany) ,biology ,Physiology ,food and beverages ,Xylem ,Symplast ,Plant Science ,biology.organism_classification ,Apoplast ,Avicennia marina ,Transpiration stream ,Botany ,Relative humidity ,Transpiration - Abstract
summary Pathways for water and salts were traced from the vein endings to their sites of exit in leaves of Avicennia marina (Forsk.) Vierh. Investigations were conducted to determine whether the water and solutes separate at any point in the transpiration stream, and to identify their subsequent pathways. Leaves were placed with their cut petioles in solution containing one of two fluorochromes chosen to trace the transpiration stream. The apoplastic tracer was B-hydroxypyrene-1, 3, 6-trisulphonic acid (PTS), and the symplastic tracer was riboflavin buffered to pH 6.8. Leaf pieces were freeze-substituted with special care to keep the specimens dry to prevent redistribution of the water-soluble fluorochromes. Stages of the technique were sensitive to atmospheric moisture, so sections were cut in a room dried to 30% relative humidity, and they were stored in a sealed box containing desiccant. Riboflavin was never seen in the apoplast, and was inside the abaxtal (lower) glands within 30 min indicating a low resistance pathway through the symplast to the gland. The veins terminate in heavily pitted xylem vessels, and at the ends of these pits, the junction between the vein ending and the apoplast of the surrounding mesophyll, were high concentrations of PTS indicating regions of separation of the fluorochrome from water – places where the water crosses from the apoplast to the symplast. PTS diffused slowly in cell walls (measured diffusivity: 4.7 × 10−10 cm2 s−1 reaching the abaxial epidermis after 8 h, which was sufficient time for four complete changes of leaf water. It was concluded that the transpiration stream, probably containing the salt destined for secretion, moved symplastically from the xylem vein endings.
- Published
- 2021
43. SALT TOLERANCE IN THE HALOPHYTE SUAEDA MARITIMA (L.) DUM.: THE EFFECT OF SALINITY ON THE CONCENTRATION OF SODIUM IN THE XYLEM
- Author
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Timothy J. Flowers and N. J. W. Clipson
- Subjects
biology ,Physiology ,Sodium ,Potassium ,fungi ,food and beverages ,Xylem ,chemistry.chemical_element ,Plant Science ,Suaeda ,biology.organism_classification ,Salinity ,Suaeda maritima ,chemistry ,Botany ,Transpiration stream ,Transpiration - Abstract
Rates of ion transport and transpiration were measured during the day and night in whole seedlings of Suaeda maritima growing over a range of salinities, in order to calculate concentrations of sodium and potassium in the xylem during these periods. Mean sodium concentration in the xylem was maximal at 56 mol m−3 Na with an external salinity of 200 mol m−3 NaCl. The sodium concentration in the xylem was greater in the dark than in the light at all external salinities investigated. Comparison of the external sodium with that in the xylem indicated that sodium was more strongly excluded from the transpiration stream as salinity increased. The mean concentration of potassium in the xylem declined as external NaCl concentration increased, although selectivity for potassium increased at higher salinities. Results are discussed in relation to osmotic adjustment in S. maritima.
- Published
- 2021
44. Influence of xylem vascular architecture on the translocation of phosphorus from nodal roots in a genotype of Trifolium repens during undisturbed growth
- Author
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M. J. M. Hay and N. R. Sackville Hamilton
- Subjects
biology ,Physiology ,Stolon ,Axillary bud ,Transpiration stream ,Botany ,Trifolium repens ,Xylem ,Plant Science ,biology.organism_classification ,NODAL ,Vascular bundle ,Transpiration - Abstract
Our objective was to establish whether the xylem vascular connections (architecture) of a genotype of Trifolium repens L. had implications for the intraplant allocation of recently assimilated phosphorus (P). One nodal root of each plan! was isolated and fed 32 P-labelled nutrient solution for 24 h. The fed root was either on the parent axis (11-12 nodes proximal CO the apex) or on a branch at the third or fourth node along the branch when counting from the junction with the parent stolon. Allocation patterns were obtained by dissecting plants and assaying each dissected component for 32 P. Under conditions of undisturbed growth in a controlled environment xylem architecture was found to have an important influence on the intraplant distribution of 32 P from nodal roots. Allocation patterns of 32 P were consistent with those predicted from knowledge of the xylem vascular architecture of the genotype and a predominantly acropetal direction of the transpiration stream. For instance, very little 32 P (< 1 % of exported 32 P from the fed root) was found in branches on the opposite side of the stolon to the fed root, and the strong acropetal direction of the transpiration stream resulted in little allocation of 32 P to leaves that had traces that arose from axial bundles at positions proximal to that of the fed root (the leaf subtending the fed root and the next distal leaf had low 32 P content), to all plant organs proximal to the fed root (< 6%) and to all other roots (
- Published
- 2021
45. In vivo manipulation of cuticular water permeance and its effect on stomatal response to air humidity
- Author
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Gerhard Kerstiens
- Subjects
Physiology ,Cuticle ,fungi ,Turgor pressure ,Plant Science ,Permeance ,Biology ,chemistry.chemical_compound ,chemistry ,Guard cell ,Botany ,Shoot ,Transpiration stream ,Abscisic acid ,Transpiration - Abstract
summary Cuticular water permeance was manipulated in Corylus avellana L., Hypericum androsaemum L. and Populus tremula L. by (1) long-term application of low doses of various systemic herbicides inhibiting biosynthesis of cuticular waxes, (2) very short-term application of organic solvents to the leaf surface, and (3) exposure to natural strong winds. Treatment effects were very variable, but increased the natural range of permeances by a factor of 10 or so in undamaged leaves. All species had hypostomatous leaves. Relative change of leaf conductance (g) in response to stepwise increases of leaf-to-air water vapour pressure difference (VPD) was measured for individual leaves (Corylus) or groups of leaves at the shoot or branch tip. Adaxial cuticular water permeance (P) was determined for the same leaves after measurement of the VPD-response. A proportional measure of relative change of g with VPD, d(log e.g)dVPD, was then plotted against P. No increase in the strength of the closing response to increasing VPD was found with increasing P, as would have been expected if water loss through the cuticle was involved in stomatal response to changes in VPD via a direct effect on guard cell turgor. By contrast, high P coincided, most clearly in Corylus, with a reduced strength of the stomatal closing response to increasing VPD, i.e. less negative d(logeg)dVPD. As the responses were non-linear, the value of d(logeg)dVPD changed with VPD. With rising VPD, all three species and a fourth one previously studied showed a decline in the value of [d(logeg)dVPD]/d(log P), reaching negative values in one species. This is interpreted in terms of two independent and antagonistic effects of increased cuticular water permeance on guard cell response to VPD, one acting by reducing the backpressure exerted on guard cells by the epidermis, and the other one possibly causing greater depression of guard cell turgor through delivery of more chemical messengers (such as abscisic acid) to the guard cells with the cuticular transpiration stream.
- Published
- 2021
46. Leaf Age-Dependent Effects of Boron Toxicity in Two Cucumis melo Varieties
- Author
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Sasan Aliniaeifard, Dimitrios Fanourakis, Georgios Tsaniklidis, Costas Delis, Anastasios Kotsiras, and Theocharis Chatzistathis
- Subjects
0106 biological sciences ,root growth ,Chromosomal translocation ,Photosynthetic pigment ,01 natural sciences ,lcsh:Agriculture ,03 medical and health sciences ,chemistry.chemical_compound ,030304 developmental biology ,Abiotic component ,0303 health sciences ,antioxidant defense ,biology ,lcsh:S ,Membrane transport ,shoot growth ,biology.organism_classification ,Horticulture ,chemistry ,B excess ,Shoot ,Toxicity ,Transpiration stream ,borate transporter ,Agronomy and Crop Science ,Cucumis ,010606 plant biology & botany - Abstract
Boron (B) is an essential nutrient for plant growth and development, exhibiting extremely narrow margins between deficiency and toxicity. B toxicity is devastating for productivity and apparent for a continuously increasing part of agricultural land, under the influence of on-going climate change. In this study, the effects of increased B supply (by using H3BO3) were addressed by examining critical physiological responses of young and mature leaves, which were devoid of toxicity symptoms, in two melon varieties (Armenian cucumbers, cantaloupes). B was primarily translocated through the transpiration stream, and secondarily via the active cell membrane transport system. The B distribution pattern was independent of leaf age, and remained rather unchanged under increased B supply. Armenian cucumbers, exhibiting higher leaf B levels, underwent an enhanced adverse impact on (root and shoot) growth, photosynthetic pigment content, cellular membrane integrity, and also exhibited attenuated antioxidant defense stimulation. Notably, and unlike other abiotic stressors, no evidence of B toxicity-induced systemic reaction was apparent. B toxicity greatly enhanced the transcription of the genes coding for borate influx and efflux channels, an effect that was mostly evident in mature leaves. In conclusion, shoot physiological responses to B toxicity are highly localized. Moreover, the obstruction of the diffusion and the B translocation to the aerial organs under increased B supply is genotype-dependent, governing plant physiological responses.
- Published
- 2021
47. Radial and axial water movement in adult trees recorded by stable isotope tracing
- Author
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Kerstin Treydte, Sebastian Pfautsch, Tomasz Wyszesany, and Marco M. Lehmann
- Subjects
0106 biological sciences ,Physiology ,Plant Biology & Botany ,Plant Science ,01 natural sciences ,0602 Ecology, 0607 Plant Biology, 0705 Forestry Sciences ,Eucalyptus tereticornis ,Trees ,03 medical and health sciences ,Isotopes ,Xylem ,Water Movements ,030304 developmental biology ,Ironbark ,Hydrology ,0303 health sciences ,Eucalyptus ,Water transport ,biology ,Plant Stems ,Stable isotope ratio ,Water ,15. Life on land ,biology.organism_classification ,visual_art ,Transpiration stream ,visual_art.visual_art_medium ,Environmental science ,Bark ,Eucalyptus sideroxylon ,010606 plant biology & botany - Abstract
The capacity of trees to release water from storage compartments into the transpiration stream can mitigate damage to hydraulic functioning. However, the location of these ‘transient’ water sources and also the pathways of water movement other than vertical through tree stems still remain poorly understood. We conducted an experiment on two tree species in a common garden in eastern Australia that naturally grow in regions of high (Eucalyptus tereticornis, ‘Red Gum’) and low (Eucalyptus sideroxylon, ‘Ironbark’) annual precipitation rates. Deuterium-enriched water (1350% label strength) was directly introduced into the transpiration stream of three trees per species for four consecutive days. Subsequently, the trees were felled, woody tissue samples were collected from different heights and azimuthal positions of the stems, and stable isotope ratios were determined on the water extracted from all samples. The presence/absence of the tracer along the radial and vertical stem axes in combination with xylem hydraulic properties inferred from sapflow, leaf and stem water potentials, wood moisture contents and anatomical sapwood characteristics elucidated species-specific patterns of short-term stem water storage and movement. The distribution of water isotopes at natural abundance among woody tissues indicated systematic differences with highest values of sapwood water and lower values in inner bark and heartwood. Presence of tracer in water of the inner bark highlighted the importance of this tissue as capacitor. Although injected at the northern side of stems, tracer was also discovered at the southern side, providing empirical evidence for circumferential flow in sapwood, particularly of Ironbark. Greater vertical water transport in Red Gum compared with more radial and circumferential water transport in Ironbark were associated with species-specific sapwood anatomy. Our study highlights the value of combining information from stable isotope tracers and wood anatomy to investigate patterns of water transport and storage of tall trees in situ.
- Published
- 2021
48. Model-based analysis of the uptake of perfluoroalkyl acids (PFAAs) from soil into plants
- Author
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Gredelj, Andrea, Polesel, Fabio, Trapp, Stefan, Gredelj, Andrea, Polesel, Fabio, and Trapp, Stefan
- Abstract
Perfluoroalkyl acids (PFAAs) bioaccumulate in crops, with uptake being particularly high for short-chain PFAAs that are constantly transported with transpiration water to aerial plant parts. Due to their amphiphilic surfactant nature and ionized state at environmental pH, predicting the partitioning behavior of PFAAs is difficult and subject to considerable uncertainty, making experimental data highly desirable. Here, we applied a plant uptake model that combines advective flux with measured partition coefficients to reproduce the set of empirically derived plant uptake and soil-partitioning data for nine PFAAs in red chicory, in order to improve the mechanistic understanding and provide new insights into the complex uptake processes. We introduced a new parameter for retarded uptake (R) to explain the slow transfer of PFAA across biomembranes of the root epidermis, which has led to low transpiration stream concentration factors (TSCFs) presented in literature so far. We estimated R values for PFAAs using experimental data derived for red chicory and used the modified plant uptake model to simulate uptake of PFAA into other crops. Results show that this semi-empirical model predicted PFAAs transport to shoots and fruits with good accuracy based on experimental root to soil concentration factors (RCFdw) and soil to water partition coefficients (Kd) as well as estimated R values and plant-specific data for growth and transpiration. It can be concluded that the combination of rather low Kd with high RCFdw and the absence of any relevant loss are the reason for the observed excellent plant uptake of PFAAs.
- Published
- 2020
49. The contributions of apoplastic, symplastic and gas phase pathways for water transport outside the bundle sheath in leaves.
- Author
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BUCKLEY, THOMAS N.
- Subjects
- *
GAS phase reactions , *PLANT anatomy , *WATER transfer , *XYLEM , *STOMATA , *LIGHT absorption - Abstract
Water movement from the xylem to stomata is poorly understood. There is still no consensus about whether apoplastic or symplastic pathways are more important, and recent work suggests vapour diffusion may also play a role. The objective of this study was to estimate the proportions of hydraulic conductance outside the bundle sheath contributed by apoplastic, symplastic and gas phase pathways, using a novel analytical framework based on measurable anatomical and biophysical parameters. The calculations presented here suggest that apoplastic pathways provide the majority of conductance outside the bundle sheath under most conditions, whereas symplastic pathways contribute only a small proportion. The contributions of apoplastic and gas phase pathways vary depending on several critical but poorly known or highly variable parameters namely, the effective Poiseuille radius for apoplastic bulk flow, the thickness of cell walls and vertical temperature gradients within the leaf. The gas phase conductance should increase strongly as the leaf centre becomes warmer than the epidermis - providing up to 44% of vertical water transport for a temperature gradient of 0.2 K. These results may help to explain how leaf water transport is influenced by light absorption, temperature and differences in leaf anatomy among species. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
50. Investigating plant uptake of organic contaminants through transpiration stream concentration factor and neural network models
- Author
-
Majid Bagheri, Joel G. Burken, Nadège Oustriere, Honglan Shi, Matt A. Limmer, Xiaolong He, Wenyan Liu, Laboratoire de Génie Civil et Géo-Environnement (LGCgE) - ULR 4515 (LGCgE), Université d'Artois (UA)-Université de Lille-Ecole nationale supérieure Mines-Télécom Lille Douai (IMT Lille Douai), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-JUNIA (JUNIA), Université catholique de Lille (UCL)-Université catholique de Lille (UCL), JUNIA (JUNIA), and Université catholique de Lille (UCL)
- Subjects
Bisphenol A ,Environmental Engineering ,010504 meteorology & atmospheric sciences ,010501 environmental sciences ,Plant Roots ,Zea mays ,01 natural sciences ,DEET ,chemistry.chemical_compound ,Solanum lycopersicum ,Environmental Chemistry ,Lignin ,Centrifugation ,Cellulose ,Waste Management and Disposal ,Triticum ,0105 earth and related environmental sciences ,food and beverages ,Plant physiology ,Biological Transport ,Plant Transpiration ,Contamination ,Pollution ,chemistry ,Environmental chemistry ,Transpiration stream ,[SDE]Environmental Sciences ,Neural Networks, Computer - Abstract
Uptake of seven organic contaminants including bisphenol A, estriol, 2,4-dinitrotoluene, N,N-diethyl-meta-toluamide (DEET), carbamazepine, acetaminophen, and lincomycin by tomato (Solanum lycopersicum L.), corn (Zea mays L.), and wheat (Triticum aestivum L.) was measured. The plants were grown in a growth chamber under recommended conditions and dosed by these chemicals for 19 days. The plant samples (stem transpiration stream) and solution in the exposure media were taken to measure transpiration stream concentration factor (TSCF). The plant samples were analyzed by a freeze-thaw centrifugation technique followed by high performance liquid chromatography-tandem mass spectrometry detection. Measured average TSCF values were used to test a neural network (NN) model previously developed for predicting plant uptake based on physicochemical properties. The results indicated that moderately hydrophobic compounds including carbamazepine and lincomycin have average TSCF values of 0.43 and 0.79, respectively. The average uptake of DEET, estriol, acetaminophen, and bisphenol A was also measured as 0.34, 0.29, 0.22, and 0.1, respectively. The 2,4-dinitrotoluene was not detected in the stem transpiration stream and it was shown to degrade in the root zone. Based on these results together with plant physiology measurements, we concluded that physicochemical properties of the chemicals did predict uptake, however, the role of other factors should be considered in the prediction of TSCF. While NN model could predict TSCF based on physicochemical properties with acceptable accuracies (mean squared error less than 0.25), the results for 2,4-dinitrotoluene and other compounds confirm the needs for considering other parameters related to both chemicals (stability) and plant species (role of lipids, lignin, and cellulose).
- Published
- 2021
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