Potassium Movement Within Plants and Its Importance in Assimilate Transport

Invertase (INV) may influence sugar levels and assimilate transport in strawberry fruit. Several groups, including our own, have only detected acid INV (optimum pH 4.6) in strawberry fruit, however, recently Hubbard et al. (Physiol. Plant. 82:191-196, 1991) reported the presence of a neutral INV (pH 7.5). Since dissimilar isolation protocols may have contributed to the different findings, we re-examined our work with developing `Brighton' strawberry using the extraction procedure of Hubbard et al. Neutral INV activity per gFW (pH 7.5-8.0) increased many fold as fruit developed from green to the red ripe stage. Acid INV activity decreased markedly from green-white to the red stage. In addition, when fruit extracts were precipitated with cold acetone, a pellet contained 60% of the acid INV activity, and a surface coagulation of protein contained 60% of the neutral INV activity. This allowed easy separation of these two enzymes. Extraction methodologies affect isolation of neutral INV activity from strawberry fruit.

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Carbon and Oxygen Isotopes in Trees: Tools to Study Assimilate Transport and Partitioning and to Assess Physiological Responses Towards the Environment

Progress in Botany 72 - Progress in Botany ◽

10.1007/978-3-642-13145-5_9 ◽

2010 ◽

pp. 227-248 ◽

Cited By ~ 3

Author(s):

Arthur Gessler

Keyword(s):

Oxygen Isotopes ◽

Physiological Responses ◽

Assimilate Transport ◽

Carbon And Oxygen Isotopes

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Physiological Basis for the Different Phloem Mobilities of Chlorsulfuron and Clopyralid

Weed Science ◽

10.1017/s0043174500056034 ◽

1990 ◽

Vol 38 (1) ◽

pp. 1-9 ◽

Cited By ~ 23

Author(s):

Malcolm D. Devine ◽

Hank D. Bestman ◽

William H. Vanden Born

Keyword(s):

Leaf Tissue ◽

Phloem Transport ◽

Assimilate Transport ◽

Herbicide Application ◽

Irreversible Binding ◽

Sensitive Species ◽

Physiological Basis ◽

Treated Leaf ◽

Phloem Translocation ◽

Leaf Disks

Foliar-applied clopyralid was translocated much more readily than chlorsulfuron in the phloem of Tartary buckwheat plants. This result was not due to greater penetration of clopyralid into the treated leaf or to greater retention of chlorsulfuron in the cuticle. Experiments with excised leaf disks indicated that chlorsulfuron was taken up more readily by the leaf tissue and accumulated in the tissue to a higher concentration than clopyralid. Both herbicides effluxed readily from the tissue after transfer to herbicide-free medium, indicating that the accumulation was not due to irreversible binding within the tissue. Chlorsulfuron (2.8 nmol) applied with14C-sucrose reduced14C export from the treated leaf. Chlorsulfuron also reduced export of14C following exposure of the treated leaf to14CO2at 6, 12, or 24 h after herbicide application. This effect of chlorsulfuron could be partially reversed by pretreating the plants with a combination of 1 mM valine, leucine, and isoleucine. In similar experiments clopyralid had no effect on assimilate transport. It is concluded that phloem translocation of chlorsulfuron in sensitive species is limited by a rapid, indirect effect on phloem transport that reduces both its own translocation and that of assimilate.

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Uptake, partitioning and utilization of carbon and nitrogen in the phloem bleeding tree, Tasmanian blue gum (Eucalyptus globulus)

Functional Plant Biology ◽

10.1071/pp99149 ◽

2000 ◽

Vol 27 (9) ◽

pp. 869

Author(s):

John S. Pate ◽

David J. Arthur

Keyword(s):

Eucalyptus Globulus ◽

Assimilate Transport ◽

Concentration Gradients ◽

Phloem Sap ◽

Empirical Modelling ◽

Carbon And Nitrogen ◽

C And N ◽

Four Levels ◽

Gains And Losses ◽

Growing Shoot

This paper originates from a presentation at the International Conference on Assimilate Transport and Partitioning, Newcastle, NSW, August 1999 An empirical modelling procedure was employed to follow uptake, transport and utilization of photo-assimilated carbon (C) and soil-derived nitrogen (N) over a 19-d period (November 1998) in 2-year-old plantation-grown trees of Eucalyptus globulus Labill. Models utilized data for gains and losses of C and N in dry matter (DM) of tree parts, CO2 exchanges and transpiration of foliage, respiratory losses of stems and roots, C:N weight ratios of xylem and phloem sap collected at different sites within the system, and phloem sap sugar concentration gradients along trunks and branches to indicate directions of assimilate flow. The model for C depicted the fate of exported fixed C from four levels of branches on the shoot system, cycling of 16% of the C supplied from shoot to root back to the shoot in xylem, major involvement of xylem-derived C in nourishment of rapidly growing branches, and a net daily respiratory output per tree equivalent to 39% of its net daytime photosynthetic gain in C by foliage. The model for N showed that upper growing shoot parts gained more N mobilized from lower branches than was being acquired from soil. It also indicated high rates of cycling of N through mature foliage, effective retention of xylem-derived N by growing branches and apices, and feedback of substantial amounts of phloem-exported N from lower branches into xylem moving further up the trunk. Transpiration loss per tree was equivalent to 272 mL g–1 DM accumulated. Data are discussed in relation to similarly executed C:N partitioning studies on herbaceous annual species.

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Bark Banding of Pinus radiata with Morphactin (IT3456): Influence on Trunk Anatomy Assimilate Transport and Growth

Physiologia Plantarum ◽

10.1111/j.1399-3054.1977.tb01884.x ◽

1977 ◽

Vol 39 (4) ◽

pp. 280-284 ◽

Cited By ~ 5

Author(s):

ROBERT P. DOSS ◽

PETER M. NEUMANN ◽

RALPH A. BACKHAUS ◽

ROY M. SACHS

Keyword(s):

Pinus Radiata ◽

Assimilate Transport

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Assimilate Transport in the Xylem Sap of Pedunculate Oak (Quercus robur) Saplings

Plant Biology ◽

10.1055/s-2001-12898 ◽

2001 ◽

Vol 3 (2) ◽

pp. 132-138 ◽

Cited By ~ 40

Author(s):

U. Heizmann ◽

J. Kreuzwieser ◽

J.-P. Schnitzler ◽

N. Brüggemann ◽

H. Rennenberg

Keyword(s):

Quercus Robur ◽

Xylem Sap ◽

Assimilate Transport ◽

Pedunculate Oak

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Tissue distribution of primary metabolism between epidermal, mesophyll and parenchymatous bundle sheath cells in barley leaves

Functional Plant Biology ◽

10.1071/pp99156 ◽

2000 ◽

Vol 27 (9) ◽

pp. 747 ◽

Cited By ~ 7

Author(s):

Olga A. Koroleva ◽

A. Deri Tomos ◽

John Farrar ◽

Peter Roberts ◽

Christopher J. Pollock

Keyword(s):

Single Cell ◽

Sucrose Solution ◽

Sucrose Concentration ◽

Cell Types ◽

Bundle Sheath ◽

Assimilate Transport ◽

Primary Metabolism ◽

Diurnal Changes ◽

Radioactive Label ◽

Different Cell Types

This paper originates from a presentation at the International Conference on Assimilate Transport and Partitioning, Newcastle, NSW, August 1999 In order to investigate the roles of different cell types, metabolite compartmentation in barley (Hordeum vulgare L.) leaf tissue was mapped at the single-cell level, using single-cell sampling and analysis (SiCSA) techniques. The partitioning of recently fixed photoassimilate was investigated for the first time at single-cell resolution, using BAMS (biological accelerator mass spectroscopy) for precise measurement of 14C in femtomole quantities. The data obtained by BAMS qualitatively reflect concentrations of sugars in different cell types measured by SiCSA. Calculation of 14C-specific activities showed that the radioactive label saturated the mesophyll and parenchymatous bundle sheath (PBS) pools within the 45-min labelling period. During the photoperiod, sucrose concentration increased to 200 mM in mesophyll cells. The concentration of malate also increased during the photoperiod in mesophyll and PBS cells. Epidermal cells contained very low concentrations of sugar but high concentrations of malate (120–180 mM) and did not show significant diurnal changes. Accumulation of sugars and fructan synthesis could be induced in mesophyll and PBS cells by reduced export of sugars from leaves or, alternatively, when sugars were supplied from excised leaf blade bases immersed in a sucrose solution in the dark. The epidermis accumulated additional malate in step with the accumulation of sugar by the mesophyll/PBS cells during the long-term reduction of export. Immunolocalisation of Rubisco and cytochrome oxidase proteins was used to analyse the distribution of enzymes of photoassimilation and respiration between functionally different cells in mature leaves of barley.

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