Mechanism of the inhibition of phloem loading by sodium sulfite: Effect of the pollutant on respiration, photosynthesis and energy charge in the leaf tissues

The oxidant air pollutants, ozone and peroxyacetyl nitrate, are produced in the atmosphere through the interaction of light with nitrogen oxides and gaseous hydrocarbons. These oxidants are phytotoxicants and are known to deleteriously affect plant growth, physiology, and biochemistry. In many instances they induce changes which lead to the death of cells, tissues, organs, and frequently the entire plant. The most obvious damage and biochemical changes are generally observed with leaves.Electron microscopic examination of leaves from bean (Phaseolus vulgaris L.) tobacco (Nicotiana tabacum L.) and cotton (Gossipyum hirsutum L.) fumigated for .5 to 2 hours with 0.3 -1 ppm of the individual oxidants revealed that changes in the ultrastructure of the cells occurred in a sequential fashion with time following the fumigation period. Although occasional cells showed severe damage immediately after fumigation, the most obvious change was an enhanced clarity of the cell membranes.

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Portein-gold labelling of ultrathin sections of wheat spot mosaic-affected wheat plants

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100160959 ◽

1990 ◽

Vol 48 (3) ◽

pp. 680-681

Author(s):

K. S. Zaychuk ◽

M. H. Chen ◽

C. Hiruki

Keyword(s):

Osmium Tetroxide ◽

Rnase A ◽

Leaf Ultrastructure ◽

Double Membrane ◽

Young Root ◽

Leaf Tissues ◽

Membrane Bound ◽

Ultrathin Sections ◽

Gold Labelling ◽

Electron Dense Core

Wheat spot mosaic (WSpM), which frequently occurs with wheat streak mosaic virus was first reported in 1956 from Alberta. Singly isolated, WSpM causes chlorotic spots, chlorosis, stunting, and sometimes death of the wheat plants. The vector responsible for transmission is the eriophyid mite, Eriophyes tulipae Kiefer. The examination of leaf ultrastructure by electron microscopy has revealed double membrane bound bodies (DMBB’s) 0.1-0.2 μm in diameter. Dispersed fibrils within these bodies suggested the presence of nucleic acid. However, neither ribosomes characteristic of bacteria, mycoplasma and the psittacosis group of organisms nor an electron dense core characteristic of many viruses was commonly evident.In an attempt to determine if the DMBB’s contain nucleic acids, RNase A, DNase I, and lactoferrin protein were conjugated with 10 nm colloidal gold as previously described. Young root and leaf tissues from WSpM-affected wheat plants were fixed in glutaraldehyde, postfixed in osmium tetroxide,and embedded in Spurr’s resin.

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Mesophyll conductance: the leaf corridors for photosynthesis

Biochemical Society Transactions ◽

10.1042/bst20190312 ◽

2020 ◽

Vol 48 (2) ◽

pp. 429-439 ◽

Cited By ~ 3

Author(s):

Jorge Gago ◽

Danilo M. Daloso ◽

Marc Carriquí ◽

Miquel Nadal ◽

Melanie Morales ◽

...

Keyword(s):

Molecular Mechanisms ◽

Current Knowledge ◽

Main Role ◽

Mesophyll Conductance ◽

Future Studies ◽

Cell Structures ◽

Leaf Tissues ◽

Change Framework ◽

Chloroplast Stroma

Besides stomata, the photosynthetic CO2 pathway also involves the transport of CO2 from the sub-stomatal air spaces inside to the carboxylation sites in the chloroplast stroma, where Rubisco is located. This pathway is far to be a simple and direct way, formed by series of consecutive barriers that the CO2 should cross to be finally assimilated in photosynthesis, known as the mesophyll conductance (gm). Therefore, the gm reflects the pathway through different air, water and biophysical barriers within the leaf tissues and cell structures. Currently, it is known that gm can impose the same level of limitation (or even higher depending of the conditions) to photosynthesis than the wider known stomata or biochemistry. In this mini-review, we are focused on each of the gm determinants to summarize the current knowledge on the mechanisms driving gm from anatomical to metabolic and biochemical perspectives. Special attention deserve the latest studies demonstrating the importance of the molecular mechanisms driving anatomical traits as cell wall and the chloroplast surface exposed to the mesophyll airspaces (Sc/S) that significantly constrain gm. However, even considering these recent discoveries, still is poorly understood the mechanisms about signaling pathways linking the environment a/biotic stressors with gm responses. Thus, considering the main role of gm as a major driver of the CO2 availability at the carboxylation sites, future studies into these aspects will help us to understand photosynthesis responses in a global change framework.

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Phloem loading

AccessScience ◽

10.1036/1097-8542.900128 ◽

2015 ◽

Keyword(s):

Phloem Loading

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AN IMPROVED METHOD FOR INHIBITOR FREE NUCLEIC ACIDS FROM POLYPHENOL RICH LEAVES OF MUSA SPP

FLORA AND FAUNA ◽

10.33451/florafauna.v23i1pp25-36 ◽

2017 ◽

Vol 23 (1) ◽

Author(s):

N.NANDHA KUMAR ◽

K. SOURIANATHA SUNDARAM ◽

D. SUDHAKAR ◽

K.K. KUMAR

Keyword(s):

Polymerase Chain Reaction ◽

Quantitative Polymerase Chain Reaction ◽

Proteinase K ◽

Chain Reaction ◽

Banana Plant ◽

High Molecular Weight Dna ◽

Musa Spp ◽

Leaf Tissues ◽

Polymerase Chain

Excessive presence of polysaccharides, polyphenol and secondary metabolites in banana plant affects the quality of DNA and it leads to difficult in isolating good quality of DNA. An optimized modified CTAB protocol for the isolation of high quality and quantity of DNA obtained from banana leaf tissues has been developed. In this protocol a slight increased salt (NaCl) concentration (2.0M) was used in the extraction buffer. Polyvinylpyrrolidone (PVP) and Octanol were used for the removal of polyphenols and polymerase chain reaction (PCR) inhibitors. Proteins like various enzymes were degraded by Proteinase K and removed by centrifugation from plant extract during the isolation process resulting in pure genomic DNA, ready to use in downstream applications including PCR, quantitative polymerase chain reaction (qPCR), ligation, restriction and sequencing. This protocol yielded a high molecular weight DNA isolated from polyphenols rich leaves of Musa spp which was free from contamination and colour. The average yields of total DNA from leaf ranged from 917.4 to 1860.9 ng/ìL. This modified CTAB protocol reported here is less time consuming 4-5h, reproducible and can be used for a broad spectrum of plant species which have polyphenol and polysaccharide compounds.

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Quantum Calculation of Proton and Other Charge Transfer Steps in Voltage Sensing in the Kv1.2 Channel

10.26434/chemrxiv.8251073 ◽

2019 ◽

Author(s):

Alisher M Kariev ◽

Michael Green

Keyword(s):

Charge Transfer ◽

Energy Charge ◽

Quantum Calculation ◽

Quantum Calculations ◽

Gating Current ◽

Transmembrane Segment ◽

Voltage Sensing ◽

Standard Models ◽

Charge Displacement ◽

Voltage Sensing Domain

Quantum calculations on 976 atoms of the voltage sensing domain of the Kv1.2 channel, with protons in several positions, give energy, charge transfer, and other properties. Motion of the S4 transmembrane segment that accounts for gating current in standard models is shown not to occur; there is H+ transfer instead. The potential at which two proton positions cross in energy approximately corresponds to the gating potential for the channel. The charge displacement seems approximately correct for the gating current. Two mutations are accounted for (Y266F, R300cit, cit =citrulline). The primary conclusion is that voltage sensing depends on H+ transfer, not motion of arginine charges.

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Influence of Nemarioc-AL and Nemafric-BL phytonematicides on mineral nutrient elements in tomato leaf tissues under field conditions

Research on Crops ◽

10.31830/2348-7542.2019.085 ◽

2019 ◽

Vol 20 (3) ◽

Keyword(s):

Tomato Leaf ◽

Field Conditions ◽

Mineral Nutrient ◽

Nutrient Elements ◽

Leaf Tissues

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