Transport of 1-aminocyclopropane-1-carboxylic acid (ACC) in the transpiration stream of tomato (Lycopersicon esculentum) in relation to foliar ethylene production and petiole epinasty

1998 ◽  
Vol 25 (4) ◽  
pp. 453 ◽  
Author(s):  
Mark A. Else ◽  
Michael B. Jackson

We investigated the concentration and delivery of 1-aminocyclopropane-1-carboxylic acid (ACC) in the transpiration stream of flooded and well-drained 1-month-old tomato plants (Lycopersicon esculentum Mill. cv. Ailsa Craig) over time in parallel with foliar ethylene production and petiole epinasty. ACC was measured by gas chromatography using a nitrogen–phosphorus detector. Before analysis, roots of freshly detopped plants were pressurised pneumatically to make xylem sap flow at rates similar to those of whole plant transpiration. Delivery of ACC from roots to shoots of well-drained plants was sufficient to support basal ethylene production in shoots of unstressed plants. Delivery from flooded, oxygen-deficient, roots increased after 6 h and coincided with the onset of epinastic leaf curvature. Further increases in ACC delivery and epinastic curvature occurred later in the photoperiod. After 24 h flooding, ACC delivery in xylem sap was 28 times more than in well-drained plants. This increased export of ACC from flooded roots was more than sufficient to account for the extra ethylene production in the shoots and coincided with ACC accumulation in the leaves. Removing the shoot before flooding did not reduce ACC export from oxygen-deficient roots indicating that the ACC originated in roots and not the shoot. Increased ethylene production in petioles of flooded plants lagged 18 h behind epinasty.

2002 ◽  
Vol 25 (7) ◽  
pp. 1407-1413 ◽  
Author(s):  
Seong Hee Lee ◽  
Gap Chae Chung ◽  
Baik Ho Cho ◽  
Ja Ock Guh ◽  
Sang Ryong Suh

1986 ◽  
Vol 32 (2) ◽  
pp. 325-328 ◽  
Author(s):  
V A Soo ◽  
R J Bergert ◽  
D G Deutsch

Abstract We describe a quantitative screen for hypnotic-sedative drugs in which we use capillary gas chromatography with a nitrogen-phosphorus detector (GC/NPD) as the primary method and capillary gas chromatography-mass spectrometry (GC-MS) for confirmation. GC retention times of the acid-extracted underivatized drugs were stable (CVs less than 1%), and the detector response varied linearly over a 20-fold concentration range with a mean correlation coefficient for 11 drugs of 0.989. The limits of detection were satisfactory (0.5 mg/L in a 0.5-mL serum sample and 1-microL injection volume), as were precision (average CV 5.2% within day, 6.4% between day). The complementary use of capillary GC-MS not only unambiguously confirms presumptive peaks identified by GC, but also prevents reports of false positives and identifies compounds not included in the quantitative GC screen that may be listed in the GC-MS library.


Agriculture ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 292
Author(s):  
Ilie Bodale ◽  
Gabriela Mihalache ◽  
Vladut Achiţei ◽  
Gabriel-Ciprian Teliban ◽  
Ana Cazacu ◽  
...  

Nutrient consumption by plants depends on the growth stage and environmental conditions. In general, plants take up species of elements at different speeds. We monitored and recorded the electrical charge flow through xylem sap of tomato plants (Brillante F1) using femto/picoammeter equipment (Keysight B2981A). This technique evaluates the nutrient uptake of tomato treated with the most common macronutrients (KNO3; KH2PO4; Ca(NO3)2; KCl) by monitoring the electrical conductivity for 24 h. The electrical conductivity of each treatment correlated with the plant growth and development stages. The results showed that the tomato plants had a high consumption of nutrients in the vegetative stage, while in other stages, they had a specific consumption, like phosphorus for bulb formation, potassium for increasing the number of flowers and water for the ripening of fruits. The quantitative evaluation of the ions absorbed by the plant was based on the magnitude and shape of the electrical conductivity curves. Our technique is an efficient method to determine nutrient consumption and is useful in predicting the deficiency of a certain element in tomato plants.


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.


IAWA Journal ◽  
2015 ◽  
Vol 36 (2) ◽  
pp. 138-151 ◽  
Author(s):  
Luíza Teixeira-Costa ◽  
Gregório Ceccantini

Parasitic plants are capable of causing a variety of effects to their hosts, including alterations in the process of wood formation. However, the majority of studies dealing with parasitic plant anatomy have focused on the host–parasite interface and the direct action of the haustorium, which is the organ responsible for attaching the parasite to the host. Considering this gap, we studied the anatomical and functional effects caused by a mistletoe species, Phoradendron crassifolium (Santalaceae), on the wood anatomy of the host tree Tapirira guianensis (Anacardiaceae). Both parasitized and non-parasitized branches were collected from host trees. Traditional wood anatomy procedures were employed, along with functionality experiments using the ascent of safranin solution through the xylem. Prior to the analysis, all sampled branches were divided in “upstream” and “downstream” portions, considering the direction of xylem sap flow inside the plant body. This design was chosen in order to avoid biased results derived from normal ontogeny-related wood anatomical and functional changes. Our results showed that infested wood expressed a higher density of embolized vessels, narrower vessel lumen diameter, higher vessel density, taller and wider rays, and fibers with thinner cell walls. All these responses were most conspicuous in the downstream sections of the parasitized branches. We propose that the wood anatomical and functional alterations were induced by the combination of water stress caused by water use by the parasite and consequent low turgor in differentiating cambial derivates; by unbalanced auxin/cytokinin concentrations originating at the infestation region due to phloem disruptions caused by the parasite’s penetration and action; and by higher than usual ethylene levels. Further analysis of hydraulic conductivity and hormonal changes in host branches are necessary to test this hypothesis.


Weed Science ◽  
1969 ◽  
Vol 17 (2) ◽  
pp. 197-201 ◽  
Author(s):  
Wm. Harold Minshall

An application of potassium nitrate or urea to the soil of detopped potted tomato plants [Lycopersicon esculentum Mill.] increased the rate of exudation from the stumps of the plants from 100 to over 300% and increased the concentration of 2-chloro-4-ethylamino-6-isopropylamino-s-triazine [atrazine] in this augmented exudate from 9 to 40%. Atrazine applied to the soil at 2:00 PM was detected in the stump exudate within 10 min and with an application of 3500 μg per pot it was approaching its maximum concentration by the end of 3 hr. The build-up in the concentration of atrazine in the exudate occurred at a faster rate in plants treated with potassium nitrate than in water control plants. Increasing the soil temperature from 10 to 30 C increased the rate of exudation and at each temperature an application of potassium nitrate or of urea increased the concentration of atrazine in the augmented exudate. In addition to atrazine, 2-chloro-4,6-bis(isopropylamino)-s-triazine [propazine], 2-methoxy-4,6-bis(isopropylamino)-s-triazine [prometone], and 2-methoxy-4-ethylamino-6-isopropylamino-s-triazine [atratone] were applied at 1750 and 3500 μg/pot. The concentration of these triazines in the exudate increased directly with their solubility in water. An application of urea increased the concentration of all four triazines in the exudate.


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