Specific Mass Transfer and Sink-Controlled Phloem Translocation in Castor Bean

1984 ◽  
Vol 11 (6) ◽  
pp. 483 ◽  
Author(s):  
J Kallarackal ◽  
JA Milburn
Keyword(s):  
Mass Transfer ◽  
Sap Flow ◽  
Ricinus Communis ◽  
Turgor Pressure ◽  
Back Pressure ◽  
Limiting Factor ◽  
Specific Mass ◽  
Phloem Sap ◽  
Phloem Translocation ◽  
Sieve Tubes

The specific mass transfer (SMT) into the fruits of Ricinus communis was measured in three different systems: (1) the intact truss, (2) fruit-thinned truss (all but one fruit removed), and (3) exuding peduncle. We found that the SMT in an intact system accords well with values reported in previous studies. But in the single-fruit and exuding systems the values were 2 and 18 times higher than the intact system, respectively. The inability of a single fruit to achieve a much higher SMT value shows that the assimilate unloading is sink-controlled. The high SMT value of the exuding system demonstrates the capacity of the sieve tubes to transport large volumes of phloem sap when turgor pressure in the sieve tubes at the sink ceases to be a limiting factor. This can be contrasted with the single-fruit system where the sink probably exerts a 'back pressure' while the assimilate supply is unlimited. The twofold increase in SMT shown by a single-fruit system is probably caused by hormone-stimulated assimilate unloading. SMT values have been used also to calculate the velocity of sap flow in the sieve tubes.

Interactions between Source, Path and Sink in Determining Phloem Translocation Rate

1978 ◽  
Vol 5 (5) ◽  
pp. 665
Author(s):  
A Lang
Keyword(s):  
Hydrostatic Pressure ◽  
Sap Flow ◽  
Sieve Tube ◽  
Joint Control ◽  
Temperature Changes ◽  
Slightly Compressible ◽  
Steady Rate ◽  
Phloem Translocation ◽  
Sieve Tubes ◽  
The Individual

Treatments involving mild (5-10 Celsius degrees) temperature changes, spanning a range of mean temperatures, were imposed upon the source, path and sink regions of a translocating plant of Nymphoides geminata whilst the translocation rate was monitored. The temperature dependence (Q*10) of the rate of translocation was evaluated for each of these treatments. A new steady rate was achieved in only 3-5 min following a temperature change and was sustained for 2 h or more. Changes in rate were propagated down the sieve tubes at speeds more than ten times greater than those of sap flow, indicating that translocation involves the flow of a slightly compressible sap. The results suggest that translocation rate is normally under the joint control of source, path and sink regions of the plant. An attempt is made to assess their relative contributions to the overall control and this leads to the conclusion that, in this plant situation, the pathway predominates in controlling rate. It would seem that the individual rates of activity of source, path and sink regions are modulated by changes in the sieve tube sap concentration in their vicinity, these changes corresponding to, and being brought about rapidly by, changes in the hydrostatic pressure of this sap.

Functioning of Conducting Elements of Phloem and Xylem in the Stalk of the Developing Fruit of Lupinus albus L

1978 ◽  
Vol 5 (3) ◽  
pp. 321 ◽  
Author(s):  
JS Pate ◽  
J Kuo ◽  
PJ Hocking
Keyword(s):  
Mass Transfer ◽  
Dry Matter ◽  
Xylem Sap ◽  
Cross Sectional Area ◽  
White Lupin ◽  
Sectional Area ◽  
Weight Changes ◽  
Specific Mass ◽  
Cross Sectional ◽  
Sieve Tubes

The economy of water and dry matter in fruits of white lupin (L. albus L.) was studied by measuring transpiration, CO2 exchange and weight changes over an 8-week growth period. These data were combined with analyses of upper stem tracheal (xylem) sap and fruit tip phloem sap to estimate rates of import of dry matter and water through xylem and phloem. Assuming unidirectional mass flow to operate, phloem carried 97 % of the dry matter and 27 % of the water entering the fruit, and xylem supplied the remainder of the water, 30 % of the minerals and 10 % of the amino compounds. The structure of fruit stalks of various age was examined by light microscopy. Cross-sectional areas occupied by different tissues were measured, and numbers and mean transverse areas of conducting elements estimated. Sieve tubes comprised 0.66-1.13% of the stalk's cross-sectional area, vessels plus tracheids 0.27 - 0.50%. Secondary xylem consisted mainly of fibres. Sieve tubes occupied 18 - 27% of the phloem cross-sectional area. The fully grown stalk showed approximately three times as many sieve tubes in transverse section as vessels plus tracheids. Transfer of dry matter and water through the fruit stalk was highest during the exponential phase of fruit growth. Peak specific mass transfer in sieve tubes was 3.95 g dry matter per square centimetre of sieve tube per hour, in tracheids plus vessels 0.28 g cm2 h-1. Maximum flow velocity in sieve tubes was 22 cm h-1, in tracheids plus vessels, 147 cm h-1. Values for specific mass transfer and flow velocities were several times less in stalks of very young or near-mature fruits.

Studies on the Feeding and Nutrition of Tuberolachnus Salignus (Gmelin) (Homoptera, Aphididae):

1957 ◽  
Vol 34 (3) ◽  
pp. 334-341
Author(s):  
T. E. MITTLER
Keyword(s):  
Host Plant ◽  
Sieve Tube ◽  
Normal Rate ◽  
Phloem Sap ◽  
Food Canal ◽  
Tuberolachnus Salignus ◽  
Normal Feeding ◽  
Sieve Tubes ◽  
Considerable Pressure ◽  
Salix Spp

1. A study has been made of the factors involved in the uptake of phloem sap by Tuberolachnus salignus (Gmelin) feeding on the stems of various Salix spp. 2. A method has been developed for maintaining the parthenogenetic viviparous forms of T. salignus in culture throughout the year. 3. It has been established that during normal feeding T. salignus have the tips of their stylets inserted into the phloem sieve-tubes of the host plant. 4. The phloem sieve-tube sap of intact and turgid willow stems is under considerable pressure. This pressure forces the sieve-tube mp up the stylet food canal of feeding aphids, and also causes the sieve-tube sap to exude for many hours from the cut end of embedded stylet bundles. 5. Intact and feeding T. salignus rely almost entirely on this pressure to maintain their normal rate of eieve-tube sap uptake. The aphids must, however, swallow actively in order to ingest.

scholarly journals CAPILLARY ELECTROPHORETIC ANALYSIS OF LOW-MOLECULAR-MASS OF CA SPECIES IN PHLOEM SAP OF Ricinus communis L.

2010 ◽  
Vol 6 (2) ◽  
pp. 181-185 ◽  
Author(s):  
Noor Fitri ◽  
Björn Thiele ◽  
Klaus Günther ◽  
Buchari Buchari
Keyword(s):  
Molecular Mass ◽  
Ricinus Communis ◽  
Ultra Violet ◽  
Electrophoretic Analysis ◽  
Active Species ◽  
Dihydrogen Phosphate ◽  
Hydrogen Phosphate ◽  
Phloem Sap ◽  
Ricinus Communis L ◽  
Capillary Electrophoretic

A capillary electrophoretic (CE) analysis with ultra-violet (UV) detection was performed for further separation of low-molecular-mass (LMM) calcium species in phloem sap of Ricinus communis L. Two different background electrolytes (BGE) were used for the separation; these are (1) hydrogen phosphate/dihydrogen phosphate buffer containing cetyltrimethylammonium bromide (CTAB) as an electro-osmotic flow (EOF) modifier, and (2) boric acid buffer containing CTAB. Various parameters affecting the analysis, including the composition and pH of the BGE were systematically studied. The sensitivity, resolution, baseline noise, migration time of the species peaks, and reproducibility of the method were evaluated under optimised condition. At least 13 UV-active species were optimally separated within about ten minutes. The optimised measurement condition was also achieved using 10 mM hydrogen phosphate/10 mM dihydrogen phosphate containing 0.5 mM CTAB at pH 8.0 as BGE, and by applying voltage of ‑20 kV and temperature of 14°C. Evidently, the analytical method was successfully used for the separation of LMM calcium species in phloem sap of R. communis L.   Keywords: capillary electrophoresis, calcium species, phloem sap, Ricinus communis

Dynamics of xylem and phloem sap flow in an outdoor zelkova tree visualized by magnetic resonance imaging

2019 ◽  
Vol 40 (3) ◽  
pp. 290-304
Author(s):  
Yasuhiko Terada ◽  
Yusuke Horikawa ◽  
Akiyoshi Nagata ◽  
Katsumi Kose ◽  
Kenji Fukuda
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Cross Section ◽  
Sap Flow ◽  
Diurnal Changes ◽  
Flow Volume ◽  
Resonance Imaging ◽  
Flow Measurements ◽  
Phloem Sap ◽  
Xylem Flow

Abstract Xylem and phloem sap flows in an intact, young Japanese zelkova tree (Zelkova serrata (Thunb.) Makino) growing outdoors were measured using magnetic resonance imaging (MRI). Two propagator-based sequences were developed for q-space imaging: pulse field gradient (PFG) with spin echo (PFG-SE) and stimulated echo (PFG-STE), which were used for xylem and phloem flow measurements, respectively. The data evaluation methods were improved to image fast xylem flow and slow phloem flow. Measurements were taken every 2–3 h for several consecutive days in August 2016, and diurnal changes in xylem and phloem sap flows in a cross-section of the trunk were quantified at a resolution of 1 mm2. During the day, apparent xylem flow volume exhibited a typical diurnal pattern following a vapor pressure deficit. The velocity mapping of xylem sap flow across the trunk cross section revealed that the greatest flow volume was found in current-year earlywood that had differentiated in April–May. The combined xylem flow in the 1- and 2-year-old annual rings also contributed to one-third of total sap flow. In the phloem, downward sap flow did not exhibit diurnal changes. This novel application of MRI in visualization of xylem and phloem sap flow by MRI is a promising tool for in vivo study of water transport in mature trees.

Development of a regional specific crop coefficient (Kc) for castor (Ricinus communis L.) in Florida, USA by using the sap flow method

2015 ◽  
Vol 74 ◽  
pp. 465-471 ◽  
Author(s):  
David N. Campbell ◽  
Chae-In Na ◽  
Diane L. Rowland ◽  
Ronnie W. Schnell ◽  
Jason A. Ferrell ◽  
...  
Keyword(s):  
Sap Flow ◽  
Ricinus Communis ◽  
Crop Coefficient ◽  
Flow Method ◽  
Ricinus Communis L

Predicting the Hermeticity of Compression Seals in Microchannel Hemodialysers

2014 ◽  
Author(s):  
Brian K. Paul ◽  
Dustin K. Ward
Keyword(s):  
Mass Transfer ◽  
Patient Outcomes ◽  
End Stage Renal Disease ◽  
Limiting Factor ◽  
Home Hemodialysis ◽  
Kidney Dialysis ◽  
Medical Facilities ◽  
Stage Renal Disease ◽  
End Stage ◽  
The Cost

Most end stage renal disease patients receive kidney hemodialysis three to four times per week at central medical facilities. At-home kidney dialysis increases the convenience and frequency of hemodialysis treatments which has been shown to produce better patient outcomes. One limiting factor in realizing home hemodialysis treatments is the cost of the hemodialyser. Microchannel hemodialysers produced using compression sealing techniques show promise for reducing the size and cost of hemodialysers. Challenges include the use of a 25 μm thick elastoviscoplastic mass transfer membrane for gasketing. This paper provides a framework for predicting the hermeticity of these compression seals. The mechanical properties of a Gambro AN69ST membrane are determined and used to establish limits on the dimensional tolerances of the polycarbonate laminae containing sealing boss used to seal the hemodialyser. The resulting methods are applied to the fabrication of a hemodialysis device showing constraints on the scaling of this method to larger device sizes. The resulting hemodialysis device is used to perform urea mass transfer experiments without leakage.

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