THE EFFECT OF SODIUM DIMETHYLDITHIOCARBAMATE ON WATER UPTAKE, TRANSPIRATION, AND STOMATAL OPENING

1964 ◽  
Vol 42 (10) ◽  
pp. 1405-1410 ◽  
Author(s):  
G. D. Thorn ◽  
W. H. Minshall

Sodium dimethyldithiocarbamate, applied to the roots of tomato and bean plants, markedly decreases the rate of transpiration and prevents stomatal opening. The chemical also causes a large reduction in water movement associated with metabolic root pressure. The concentration of total amino acids moving out of the root system is reduced by as much as 50% of normal. Transpiration and stomatal opening of detached leaves from untreated plants are not affected appreciably by solutions of sodium dimethyldithiocarbamate.

2015 ◽  
Vol 45 (4) ◽  
pp. 459-468
Author(s):  
J. Czerski

An apparatus is described which allows continuous recording of water uptake by a plant. The elements of this apparatus serve at the same time for measurement of root pressure. The size of the recorded portion of uptaken water and of weeping sap excreted by the plant root can be regulated.


1979 ◽  
Vol 9 (3) ◽  
pp. 374-378 ◽  
Author(s):  
Richard E. Dickson

Xylem sap produced by root pressure and collected from topped cottonwood (Populusdeltoides Bartr.) contained sugars, organic acids, amino acids, protein, and inorganic nutrients. Amino acids and NO3N were present at the highest concentrations. Total amino acids in xylem sap ranged from 3 to 10 mol m−3 and NO3N ranged from 7 to 10 mol m−3. When lower leaves were photosynthetically labeled with 14CO2, activity was rapidly translocated to roots and recycled to shoots. Within 6 h after labeling leaves, xylem exudate contained between 1 and 2 × 106 disintegrations min−1 cm−3. Most of the activity (50 to 70%) was in the amino acid fraction. Although nine amino acids contained some activity, more than 90% of the 14C was found in five common transport and storage amino acids: asparagine, glutamine, serine, alanine, and γ-aminobutyric acid. Glutamine contained 60 to 70% of the activity in the amino acid fraction 2 h after topping. Sugars, translocated from lower leaves to roots via the ploem, are converted to amino acids in roots and then translocated to the developing shoot via the xylem.


2017 ◽  
Vol 68 (5) ◽  
pp. 1063-1069
Author(s):  
Cristina Simeanu ◽  
Daniel Simeanu ◽  
Anca Popa ◽  
Alexandru Usturoi ◽  
Dan Bodescu ◽  
...  

Polyodon spathula sturgeon breed is successfully reared in Romania in many fishery farms for meat production and it is capitalized on domestic market as consumption fish. In the current paper were studied a number of 1400 sturgeons from Polyodon spathula breed (1200 individuals of one summer - P.s.0+ and 200 individuals of fourth summers - P.s.3+). From this flock were weighted around 10%, for each age group, and for laboratory determinations were chosen 10 fishes for each age with the corporal mass close to the group mean. After analysing the fillets gathered from the studied fishes for establishing the chemical characteristics, nutritive and biological values of proteins were drawn some interesting conclusions. So, regarding chemical composition we notice that in the meat of analysed fishes water is in a rate of 75.41% at P.s.3+ and 78.37% for P.s.0+; proteins - between 18.08% for P.s.0+ and 19.89% for P.s.3+, values which place those fishes in the group of protein fishes; lipids - between 2.45% and 3.45%, values which situated those sturgeons in category of fishes with a low content in lipids; collagen � 3.83% at P.s.0+ and 4.14% at P.s.3+ which indicate low values for proteins of weak quality in the meat of those sturgeons. Study of nutritive value for the analysed fishes indicate the fact that fishes P.s.0+ have a mediocre nutritive value, having the ratio w/p of 4.33 while sturgeons P.s.3+ were placed in the 2nd category � fishes with a good nutritive value (rate w/p = 3.79). Energetic value of the studied fillets was 97.39 kcal/100 g for P.s.0+ and 114.31 kcal/100 g for P.s.3+, which enlightened an increase of nutritive value with aging, fact especially due to accumulation of adipose tissue. Study of proteins quality, through the presence of those 8 essential amino-acids in the meat of analysed fishes, show the fact that at sturgeons P.s.0+ proportion of essential amino-acids was 20.88% from total amino-acids, while at sturgeons P.s.3+ was 26.23%, fact which enlightened an increasing of proteins� biological value with fish aging. This fact was also shown by calculation of proteins� biological value through chemical methods (EAA index); calculated value for sturgeons P.s.0+ was a little bit lower (118.73) than the one calculated for sturgeons P.s.3+ (118.79).


Nutrients ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 2009
Author(s):  
Joris H.J. van Sadelhoff ◽  
Linda P. Siziba ◽  
Lisa Buchenauer ◽  
Marko Mank ◽  
Selma P. Wiertsema ◽  
...  

Free amino acids (FAAs) are important regulators of key pathways necessary for growth, development, and immunity. Data on FAAs in human milk (HM) and their roles in infant development are limited. We investigated the levels of FAAs and total amino acids (TAA, i.e., the sum of conjugated amino acids and FAAs) in HM in relation to infant and maternal characteristics and immunological conditions. FAA and TAA levels in HM sampled at 6 weeks (n = 671) and 6 months (n = 441) of lactation were determined using high-performance liquid chromatography. Child growth was ascertained at 4–5 weeks and at 6–7 months of age. Child allergy and lower respiratory tract infections were assessed in the first years of life. Associations of amino acid (AA) levels in HM with child growth and health outcomes were determined by Spearman correlation and modified Poisson regression, respectively. Free glutamine, glutamate, and serine in 6-week HM positively correlated with infant weight gain in the first 4–5 weeks of age. Maternal pre-pregnancy weight and body mass index (BMI) were negatively correlated with free glutamine and asparagine in 6-week and 6-month HM and positively correlated with the sum of TAAs in 6-month HM, but significance was lost following confounder adjustment. Free glutamine was lower in 6-month HM of mothers with an allergy (either active or non-active). No consistent associations were found between FAAs in HM and child health outcomes. However, potential negative associations were observed between specific FAAs and the risk of food allergy. These results suggest that specific FAAs play a role in infant growth. Moreover, these findings warrant further investigations into the relation of FAAs in HM with infant health outcomes and maternal allergy.


1988 ◽  
Vol 15 (4) ◽  
pp. 557 ◽  
Author(s):  
MJ Canny ◽  
ME Mccully

Three methods of sampling xylem sap of maize roots were compared: sap bleeding from the stem cut just above the ground; sap bleeding from the cut tops of roots still undisturbed in the ground; and sap aspirated from excavated roots under reduced pressure. The bleeding saps were often unobtainable. When their composition was measured with time from cutting, the concentrations of the major solutes approximately doubled in 2 h. Aspirated sap was chosen as the most reliable sample of root xylem contents. Solute concentrations of the saps showed great variability between individual roots for all solutes, but on average the concentrations found (in �mol g-1 sap) were: total amino acids, 1.8; nitrate, 1.8; sugars (mainly sucrose), 5.4; total organic acids, 18.3. Individual amino acids also varied greatly between roots. Glutamine, aspartic acid and serine were generally most abundant. The principal organic acid found was malic, approximately 8 �mol g-1. From these analyses the ratios of carbon in the fractions (sugars : amino acids : organic acids) = (44 : 6 : 50). 14Carbon pulse fed to a leaf appeared in the root sap within 30 min, rose to a peak at 4-6 h, and declined slowly over a week. During all this time the neutral, cation and anion fractions were sensibly constant in the proportions 86 : 10 : 4. The 14C therefore did not move towards the equilibrium of 12C-compounds in the sap. It is argued that the results do not support a hypothesis of formation of amino carbon from recent assimilate and reduced nitrate in the roots and an export of this to the shoot in the transpiration stream.


2013 ◽  
Vol 1 (No. 3) ◽  
pp. 85-98
Author(s):  
Dohnal Michal ◽  
Dušek Jaromír ◽  
Vogel Tomáš ◽  
Herza Jiří

This paper focuses on numerical modelling of soil water movement in response to the root water uptake that is driven by transpiration. The flow of water in a lysimeter, installed at a grass covered hillslope site in a small headwater catchment, is analysed by means of numerical simulation. The lysimeter system provides a well defined control volume with boundary fluxes measured and soil water pressure continuously monitored. The evapotranspiration intensity is estimated by the Penman-Monteith method and compared with the measured lysimeter soil water loss and the simulated root water uptake. Variably saturated flow of water in the lysimeter is simulated using one-dimensional dual-permeability model based on the numerical solution of the Richards’ equation. The availability of water for the root water uptake is determined by the evaluation of the plant water stress function, integrated in the soil water flow model. Different lower boundary conditions are tested to compare the soil water dynamics inside and outside the lysimeter. Special attention is paid to the possible influence of the preferential flow effects on the lysimeter soil water balance. The adopted modelling approach provides a useful and flexible framework for numerical analysis of soil water dynamics in response to the plant transpiration.


1975 ◽  
Vol 85 (1) ◽  
pp. 93-101 ◽  
Author(s):  
D. G. Harrison ◽  
D. E. Beever ◽  
D. J. Thomson ◽  
D. F. Osbourn

SUMMARYThe effects of an altered rumen dilution rate (D) upon the molar proportions of volatile fatty acids (VFA) in rumen liquor, VFA production rate, microbial protein synthesis and carbohydrate digestion within the rumen were studied using adult wether sheep.Dilution rate and VFA proportions were unaltered by the infusion of up to 121 water/day into the rumen of sheep fed dried grass and concentrate (9:1). There was a small but significant (P< 0·05) increase in the rumen volume when the infusion rate was increased from 8 to 12 1/day.The intraruminal infusion of artificial saliva (41/day), or artificial saliva containing 4% or 8% w/v polyethylene glycol (PEG) caused a significant increase in D with an associated decline in the molar proportion of propionate (Pr) in the rumen liquor. A similar effect was obtained with the intraruminal infusion of 2·5% w/v sodium bicarbonate. The overall regression of Pr on D was highly significant: Pr = 32·5–82·1D;r= –0·99, P < 0·001.A diet of flaked maize: dried grass (6:4) was offered to three sheep each fitted with a rumen cannula and with a re-entrant cannula at the proximal duodenum. The intraruminal infusion (4 1/day) of artificial saliva containing 4% w/v PEG caused a significant (P< 0·01) increase in D and a significant (P< 0·01) depression in Pr in two animals. The dilution rate and Pr in the third animal were virtually unaltered by infusion. The regression of Pr on D for the three animals was highly significant: Pr = 34·8–136·8D; r = –0·98, P < 0·001. Each increase in D was associated with an increased flow of α-linked glucose polymer, total amino acids and total microbial amino acids into the small intestine and with an increased efficiency of microbial protein synthesis within the rumen.


1988 ◽  
Vol 42 (3) ◽  
pp. 273-285 ◽  
Author(s):  
Bohoussou Kouassi ◽  
Jacques Diopoh ◽  
Yves Leroy ◽  
Bernard Fournet

1972 ◽  
Vol 27 (3) ◽  
pp. 475-481 ◽  
Author(s):  
Z. Dvořák

1. The amounts of available cystine and tyrosine in the protein of different animal tissues showed a close correlation with the level of hydroxyproline, and may be estimated from hydroxyproline values by regression equations.2. Estimates of ‘chemical score’ have been calculated from the content of hydroxyproline determined in a series of samples for which net protein utilization (NPU) for rats had also been determined. Chemical scores calculated as percentages of the total ‘essential+semiessential’ amino acid content of each material correlated closely with NPU, whereas scores calculated as percentages of total amino acids did not. ‘Methionine+cystine’ were calculated to be first limiting amino acids in every sample.


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