Mediation of rapid electrical, metabolic, transpirational, and photosynthetic changes by factors released from wounds. II. Mediation of the variation potential by Ricca's factor

1976 ◽  
Vol 54 (23) ◽  
pp. 2651-2661 ◽  
Author(s):  
Jerome W. Van Sambeek ◽  
Barbara G. Pickard ◽  
Corinne E. Ulbright
Keyword(s):  
Plant Extract ◽  
Leaf Tissue ◽  
Variation Potential ◽  
Active Factor ◽  
Threshold Response ◽  
Transpiration Stream ◽  
Low Concentrations ◽  
The Given

An extract of Lycopersicon leaf tissue applied to the base of an excised Lycopersicon leaf causes a variation potential to spread through the leaf. This spread of an electrical wave is closely dependent on the spread of the extract via the transpiration stream, and the amplitude of the variation potential depends on the concentration of extract applied. Extract from 5–10 mg fresh leaves diluted to 1 ml elicits threshold response, and saturation is accomplished with a concentration about 40 times greater. Evidently, the active factor or factors are effective at very low concentrations. A variety of substances cause electrical disturbances when applied to the excised leaf, but plant extract is the only tested material which under the given conditions desensitizes the leaf to an application of saturating extract 5 min after the initial application.The active factor or set of factors has been extracted from plants in several families and appears to be closely related to the substance implicated by Ricca in 1916 in trauma-induced closure of Mimosa leaves. In recognition of this early discovery, the material is at present called Ricca's factor.

Mediation of rapid electrical, metabolic, transpirational, and photosynthetic changes by factors released from wounds. I. Variation potentials and putative action potentials in intact plants

1976 ◽  
Vol 54 (23) ◽  
pp. 2642-2650 ◽  
Author(s):  
Jerome W. Van Sambeek ◽  
Barbara G. Pickard
Keyword(s):  
Action Potentials ◽  
Chemical Substance ◽  
Variation Potential ◽  
Transpiration Stream ◽  
Single Leaf ◽  
Intact Plants

Damaging representative plants from five angiosperm families by heating or crushing a small portion of a single leaf results in an electrical change which may spread throughout the shoot. In Mimosa, similar changes have previously been identified as variation potentials.Except in one of the five plants, a variation potential is often accompanied by brief fluctuations which may propagate either basipetally or acropetally and which have many of the properties of action potentials.The spread of a variation potential as described in Mimosa is due to the concommitant spread of a chemical substance in the transpiration stream. In this paper, it is shown that the spread of the purported variation potential is compatible with movement of material in the transpiration stream. In the next paper causation by a substance or group of substances, at present called Ricca's factor, is demonstrated.

scholarly journals POSSIBILITIES FOR INTER- AND INTRACELLULAR TRANSLOCATION OF SOME ICOSAHEDRAL PLANT VIRUSES

1969 ◽  
Vol 40 (3) ◽  
pp. 814-823 ◽  
Author(s):  
G. A. de Zoeten ◽  
G. Gaard
Keyword(s):  
Leaf Tissue ◽  
Plant Viruses ◽  
Infected Leaf ◽  
Mesophyll Cells ◽  
Low Concentrations ◽  
Infected Cells ◽  
Virus Research ◽  
High Concentrations ◽  
Pore Complexes ◽  
Intracellular Translocation

Southern bean mosaic virus (SBMV) and Tomato ringspot virus (TomRV) were compared with regard to possible ways of inter- and intracellular translocation. The pore complexes in the nuclear membranes of nuclei in leaf palisade and mesophyll cells of several plant species commonly used in plant virus research were studied. The pore structure resembled that earlier described. The diameter of the pores was great enough to allow icosahedral plant viruses between 25 and 30 mµ wide to move through. SBMV occurred in noncrystalline form in nuclei of infected cells. Although this virus forms paracrystalline structures when partially purified, no virus crystals were seen in the cytoplasm of cells containing high concentrations of SBMV. It was established that this virus could move through nuclear pores. TomRV was found in infected leaf tissue in low concentrations. This virus showed a tendency to crystallize even when present in low concentrations. TomRV was observed only in the cytoplasm, not in nuclei. This virus was present in plasmodesmata, indicating the possibility of cell to cell translocation of whole particles through these structures.

The limitations of the constant load and self-paced exercise models of exercise physiology

2012 ◽  
Vol 8 (1) ◽  
pp. 3-9 ◽  
Author(s):  
F.E. Marino
Keyword(s):  
Biological System ◽  
Exercise Physiology ◽  
Constant Load ◽  
Physical Work ◽  
Biological Variability ◽  
Sensory Cues ◽  
Fully Integrated ◽  
Threshold Response ◽  
The Given ◽  
Constant Load Exercise

The fundamental tenets of exercise physiology are to describe energy transformations during physical work and make predictions about physical performance during different conditions. Historically, the most popular method to observe such responses during exercise has been the constant load or fixed intensity protocol based largely on the assumption that there is a threshold response of the organism under given conditions. However, constant load exercise does not fully allow for randomness or variability as the biological system is overridden by a predetermined externally imposed load which cannot be altered. Conversely, in self-regulated (paced) exercise there is almost an immediate reduction in power output and muscle recruitment upon commencing exercise. This observation suggests the existence of a neural inhibitory command processes. This difference in regulation demonstrates the inherent importance of variability in the biological system; for in tightly controlled energy expenditure, as is the case during constant load exercise, sensory cues cannot be fully integrated to provide a more appropriate response to the given task. The collective evidence from conventional constant load versus self-regulated exercise studies suggest that energy transformations are indeed different so that the inherent biological variability accounts for the different results achieved by the two experimental paradigms.

scholarly journals Provocation of life functions at a unicellular eukaryote level by extremely low doses of mammalian hormones: Evidences of hormesis

2019 ◽  
pp. 1-5
Author(s):  
György Csaba
Keyword(s):  
Endocrine System ◽  
Unicellular Eukaryote ◽  
Low Doses ◽  
Concentration Effects ◽  
Low Concentrations ◽  
High Concentrations ◽  
Membrane Components ◽  
The Given ◽  
Linear Concentration

Hormones, characteristic to higher ranked animals, are synthesized, stored, and secreted by unicellular eukaryote animals. The unicells also have receptors for recognizing these materials and transmit the message into the cells for provoking response. The hormones are effective in very low concentrations (down to 10–21 M) and opposite effects of lower and higher concentrations can be observed. However, sometimes linear concentration effects can be found, which means that hormesis exists, nevertheless uncertain, as it is in the phase of formation (evolutionary experimentation). Hormesis, by transformation (fixation) of cytoplasmic receptor-like membrane components to receptors in the presence of the given hormone, likely helps the development of unicellular endocrine character and by this the evolution of endocrine system. The effect by extremely low concentrations of hormones had been forced by the watery way of unicellular life, which could establish the physiological concentrations of hormones in the blood of higher ranked animals. This means that hormetic low doses are the normal, effective concentrations and the high concentrations are artificial, consequently could be dangerous.

Two measures of leaf capacitance: insights into the water transport pathway and hydraulic conductance in leaves

2011 ◽  
Vol 38 (2) ◽  
pp. 118 ◽  
Author(s):  
Chris J. Blackman ◽  
Tim J. Brodribb
Keyword(s):  
Water Transport ◽  
Lignin Content ◽  
Leaf Tissue ◽  
Dry Weight ◽  
Hydraulic Conductance ◽  
Leaf Water ◽  
Transport Pathway ◽  
Transpiration Stream ◽  
Two Measures ◽  
Key Indicators

The efficiency and stress tolerance of leaf water transport are key indicators of plant function, but our ability to assess these processes is constrained by gaps in our understanding of the water transport pathway in leaves. A major challenge is to understand how different pools of water in leaves are connected to the transpiration stream and, hence, determine leaf capacitance (Cleaf) to short- and medium-term fluctuations in transpiration. Here, we examine variation across an anatomically and phylogenetically diverse group of woody angiosperms in two measures of Cleaf assumed to represent bulk-leaf capacitance (Cbulk) and the capacitance of leaf tissues that influence dynamic changes in leaf hydration (Cdyn). Among species, Cbulk was significantly correlated with leaf mass per unit area, whereas Cdyn was independently related to leaf lignin content (%) and the saturated mass of leaf water per unit dry weight. Dynamic and steady-state measurements of leaf hydraulic conductance (Kleaf) agreed if Cdyn was used rather than Cbulk, suggesting that the leaf tissue in some species is hydraulically compartmentalised and that only a proportion of total leaf water is hydraulically well connected to the transpiration stream. These results indicate that leaf rehydration kinetics can accurately measure Kleaf with knowledge of the capacitance of the hydraulic pathway.

scholarly journals Data acquisition of triple quadrupole LC-MS for the citrinin determination

2017 ◽  
pp. 131-141
Author(s):  
Gorica Vukovic ◽  
Vojislava Bursic ◽  
Goran Aleksic ◽  
Slobodan Kuzmanovic ◽  
Magdalena Cara ◽  
...  
Keyword(s):  
Data Acquisition ◽  
Collision Cell ◽  
Triple Quadrupole ◽  
Best Response ◽  
Low Concentrations ◽  
Complex Sample ◽  
The Given

The analysis of citrinin is challenging because it needs to be detected in low concentrations in complex sample matrices. Before citrinin quantification, the data acquisition of LC-MS/MS must be performed, which includes the determination of ion monitoring reaction (SRM), finding fragmentation energies (Frag.) and collision cell energies (CE) for which the response of citrinin will be the highest for the given conditions. The best response of citrinin is obtained for Frag. of 66 V and CE of 17 and 29 V.

scholarly journals MOLECULAR DIAGNOSIS OF Guignardia citricarpa IN ASYMPTOMATIC SWEET ORANGE TISSUE

2017 ◽  
Vol 39 (4) ◽  
Author(s):  
FERNANDA DE SILLOS FAGANELLO ◽  
RENATO CARRER FILHO ◽  
VANESSA DUARTE DIAS ◽  
REGINA MELO SARTORI COELHO MORELLO ◽  
MARCOS GOMES DA CUNHA
Keyword(s):  
Real Time ◽  
Limit Of Detection ◽  
Black Spot ◽  
Leaf Tissue ◽  
Molecular Techniques ◽  
The European Union ◽  
Tissue Samples ◽  
Guignardia Citricarpa ◽  
Low Concentrations ◽  
Time Required

ABSTRACT Citrus black spot, a fungal disease caused by the quarantine fungus Guignardia citricarpa, restricts the exportation of fresh fruit to countries in the European Union. The occurrence of latent infections and the time required for diagnosis using conventional methods have brought about the need to validate fast, efficient and reproducible molecular techniques to detect the pathogen in asymptomatic tissue. As such, this study aims to detect G. citricarpa in the symptomatic fruit and asymptomatic leaf tissue of sweet oranges by conventional and real-time polymerase chain reaction (PCR). Specificity and limit of detection (LOD) were assessed in tissue samples of fruit lesions and asymptomatic leaves. Low concentrations of the fungus were found in asymptomatic leaves. Under these conditions, real-time PCR proved to be viable, reproducible and highly sensitive to detection of the pathogen.

scholarly journals Uptake of Trace Elements in Leaves of the Larrea Tridentata (DC.) Coville in Desert Washes of an Arid Environment

Environments ◽  
2019 ◽  
Vol 6 (6) ◽  
pp. 58
Author(s):  
Douglas B. Sims ◽  
Christopher J. Collumb ◽  
Amanda C. Hudson ◽  
Douglas J. Walton
Keyword(s):  
Trace Elements ◽  
Leaf Tissue ◽  
Arid Environment ◽  
Larrea Tridentata ◽  
Distribution Data ◽  
Plant Leaves ◽  
Creosote Bush ◽  
Low Concentrations ◽  
Leaf Tissues ◽  
Root Tissues

Trace elements (As, Cd, Cr, Pb, Ba, Fe, Al, Mn and Ba) were uptaken by the leaves of the creosote bush (Larrea tridentata (DC.) Coville) in Nelson, Nevada, although at low concentrations. Samples were collected up-gradient of the mine tailings, the tailings, and down gradient from the source to measure spatial distribution. Data show that trace elements (As, Ba, Cr, Hg, Se) enter L. tridentata through root tissues, migrating to leaf tissue, but at significantly lower levels than that of the source sediments. Metalloid (As and Se) concentrations in the leaf tissues ranged from non-detect to greater than 44 mg kg−1 As and non-detect to over 34 mg kg−1 Se. For trace metals, Hg ranged from non-detect to 0.14 mg kg−1; Ba from 1.74 to 4.12 mg kg−1; and Cr from non-detect to 6.18 mg kg−1 while Ag, Cd, and Pb were not detected in the plant leaves. When comparing the ratio of sediment metal concentration to plant metal concentrations, the Techatticup Wash contained the highest levels of trace elements in the leaves of the L. tridentata, followed by the Carnation Wash, with the Eagle Wash containing the lowest concentrations of trace elements.

scholarly journals IN VIVO ACUTE AND SUB-ACUTE TOXICITY STUDY OF ROOT EXTRACT OF CARISSA SPINARUM LINN. IN SWISS ALBINO MICE

2019 ◽  
pp. 62-65
Author(s):  
SIBHATU GEBREHIWOT
Keyword(s):  
Body Weight ◽  
Acute Toxicity ◽  
Plant Extract ◽  
Crude Extract ◽  
Physical Parameters ◽  
Swiss Albino Mice ◽  
Experimental Animals ◽  
Crude Plant Extract ◽  
Albino Mice ◽  
The Given

Objective: The objective of the present research work had been done to evaluate the toxicity of crude extract of Carissa spinarum in Swiss albino mice. Methods: In studying the toxicity, the Organization for Economic Cooperation and Development (OECD) guidelines were used. Experimental animals (mice), five mice in each, were grouped into four groups; three experimental groups and one negative control. In studying the acute toxicity, 2000, 3000 up to 5000 mg/kg crude plant extract was given orally using standard intragastric oral gavages. For acute toxicity, a single dose was given and gross behavioral changes were recorded. In sub-acute oral toxicity test, Carissa spinarum crude extract was given to the mice by standard intragastric oral gavages at doses of 500, 750 and 1000 mg/kg body weight of hydro-methanolic extract and 200, 600 and 1000 mg/kg of body weight of chloroform extract in every single to 28 d and various hematological and physical parameters were recorded. Results: In acute toxicity, the given dose of the plant extract did not produce significant physical and behavior changes up to the dose of 5000 mg/kg extracts. In addition, no death was occurred in the given doses. In sub-acute toxicity studies of the hydro-methanolic and chloroform extracts, there was no recorded significant change (p>0.05) of hematological and physical parameters in the treated groups when compared to the control groups. Conclusion: from the present study it was revealed that the crude extract of the plant did not produce any significant toxicological effect in the experimental animals and this supports the use of the plant in folk medicines.

scholarly journals RELATIONSHIP OF IRON AND MANGANESE AVAILABILITY IN PEAT-BASED MEDIA TO THE OCCURRENCE OF A SPECIFIC PHYSIOLOGICAL DISORDER IN TAGETES ERECTA

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1109d-1109 ◽  
Author(s):  
Mary C. Halbrooks ◽  
Joseph P. Albano
Keyword(s):  
Leaf Tissue ◽  
Tagetes Erecta ◽  
Physiological Disorder ◽  
Iron Chelate ◽  
Low Concentrations ◽  
The Media ◽  
Manganese Availability ◽  
Relationship Of ◽  
Over Time ◽  
Iron And Manganese

A specific physiological disorder of the recently matured leaves of Tagetes erecta has been demonstrated to be associated with high levels of iron and manganese in affected tissues. In previous work by the authors, the disorder was inducible and increased in severity with increasing levels of iron DTPA supplied to plants grown in peat-based media, but was much less severe when iron DTPA treatments were applied to plants grown hydroponically. At low concentrations of iron DTPA in solution, the occurrence of the disorder was more closely correlated with increased levels of manganese in leaf tissue than iron, Objectives of this study were to determine the effects of iron chelate (DTPA) on occurrence of the disorder and the availability of iron and manganese in the media in the absence of added manganese. Iron DTPA (1, 5, 15, and 20 ppm) was supplied to two cultivars of Tagetes erecta, `Voyager' and `First Lady', grown in a commercial peat-based media product under controlled environmental conditions. Concentrations of iron and manganese in leachate samples taken weekly, and in symptom and non-symptom tissue at harvest, and the progression of the symptoms in leaf tissue over time. will be discussed.

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