Stomata development and plant signaling peptides

Plant signaling peptides. Cysteine-rich peptides –

Ostrowski M., Kowalczyk S. (2015)

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Postepy Biochemii. 61(1): 79-92 – PMID: 26281357 –

https://europepmc.org/article/med/26281357

Abstract 

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Recent bioinformatic and genetic analyses of several model plant genomes have revealed the existence of a highly abundant group of signaling peptides that are defined as cysteine-rich peptides (CRPs). CRPs are usually in size between 50 and 90 amino acid residues, they are positively charged, and they contain 4-16 cysteine residues that are important for the correct conformational folding.

Despite the structural differences among CRP classes, members from each class have striking similarities in their molecular properties and function.

The present review presents the recent progress in research on signaling peptides from several families including: EPF/EPFL, SP11/SCR, PrsS, RALF, LURE, and some other peptides belonging to CRP group.

There is convincing evidence indicating multiple roles for these CRPs as signaling molecules during the plant life cycle, ranging from stomata development and patterning, self-incompatibility, pollen tube growth and guidance, reproductive processes, and nodule formation.

Stomata and improved aeration due to gas films

The mechanism of improved aeration due to gas films on leaves of submerged rice

Verboven P., Pedersen O., Ho Q. T., Nicolai B. M., Colmer T. D. (2014)

Pieter Verboven, Ole Pedersen, Quang Tri Ho, Bart M Nicolai, Timothy D Colmer,

Division BIOSYST-MeBioS, University of Leuven, Willem de Croylaan 42, 3001, Leuven, Belgium.

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Plant Cell Environ. 37(10):2433-2452 – doi: 10.1111/pce.12300 – Epub 2014 Mar 20 – PMID: 24548021 –

https://pubmed.ncbi.nlm.nih.gov/24548021/

Abstract

Some terrestrial wetland plants, such as rice, have super-hydrophobic leaf surfaces which retain a gas film when submerged. O2 movement through the diffusive boundary layer (DBL) of floodwater, gas film and stomata into leaf mesophyll was explored by means of a reaction-diffusion model that was solved in a three-dimensional leaf anatomy model.

The anatomy and dark respiration of leaves of rice (Oryza sativa L.) were measured and used to compute O2 fluxes and partial pressure of O2 (pO2 ) in the DBL, gas film and leaf when submerged. The effects of floodwater pO2 , DBL thickness, cuticle permeability, presence of gas film and stomatal opening were explored.

Under O2 -limiting conditions of the bulk water (pO2 < 10 kPa), the gas film significantly increases the O2 flux into submerged leaves regardless of whether stomata are fully or partly open. With a gas film, tissue pO2 substantially increases, even for the slightest stomatal opening, but not when stomata are completely closed. The effect of gas films increases with decreasing cuticle permeability. O2 flux and tissue pO2 decrease with increasing DBL thickness. The present modelling analysis provides a mechanistic understanding of how leaf gas films facilitate O2 entry into submerged plants.

Certain fractions of nanoparticles generated by the aerosol process could enter the leaf following the stomatal pathway

Nanoparticle synthesis and delivery by an aerosol route for watermelon plant foliar uptake

Wang W. N., Tarafdar J. C., Biswas P. (2013)

Wei-Ning Wang, Jagadish C. Tarafdar, Pratim Biswas,

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 J Nanopart Res 15: 1417 – https://doi.org/10.1007/s11051-013-1417-8 – 

https://link.springer.com/article/10.1007/s11051-013-1417-8#citeas

Abstract

An aerosol process was developed for synthesis and delivery of nanoparticles for living watermelon plant foliar uptake. This is an efficient technique capable of generating nanoparticles with controllable particle sizes and number concentrations.

Aerosolized nanoparticles were easily applied to leaf surfaces and enter the stomata via gas uptake, avoiding direct interaction with soil systems, eliminating potential ecological risks. The uptake and transport of nanoparticles inside the watermelon plants were investigated systematically by various techniques, such as elemental analysis by inductively coupled plasma mass spectrometry and plant anatomy by transmission electron microscopy.

The results revealed that certain fractions of nanoparticles (d _p  < 100 nm) generated by the aerosol process could enter the leaf following the stomatal pathway, then pass through the stem, and reach the root of the watermelon plants. The particle size and number concentration played an important role in nanoparticle translocation inside the plants. In addition, the nanoparticle application method, working environment, and leaf structure are also important factors to be considered for successful plant foliar uptake.

Abies pinsapo closed stomata rapidly over a very narrow range of soil water availability and atmospheric dryness

Regulation of Water Use in the Southernmost European Fir (Abies pinsapo Boiss.) – Drought Avoidance Matters

Sánchez-Salguero Raúl, Ortíz C., Covelo F., Ochoa V., García-Ruíz R., Seco J. I., Carreira J. A., Merino J. A., Linares J. C. (2015)

Sánchez-Salguero Raúl, Cristina Ortíz Felisa Covelo Victoria Ochoa Roberto García-Ruíz, José Ignacio Seco, José Antonio Carreira, José Ángel Merino, Juan Carlos Linares.

¹ Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide. Ctra. Utrera km. 1, 41013 Sevilla, Spain

² Biodiversidad y Conservación, Universidad Rey Juan Carlos, c/Tulipán s/n, 28933 Móstoles (Madrid), Spain

³ Departamento de Biología Animal, Biología Vegetal y Ecología, Universidad de Jaén, Ed. B3, Paraje las Lagunillas s/n, 23071 Jaén, Spain

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Forests 6(6): 2241-2260 – https://doi.org/10.3390/f6062241 –

https://www.mdpi.com/1999-4907/6/6/2241

Abstract

The current scenario of global warming has resulted in considerable uncertainty regarding the capacity of forest trees to adapt to increasing drought. Detailed ecophysiological knowledge would provide a basis to forecast expected species dynamics in response to climate change.

Here, we compare the water balance (stomatal conductance, xylem water potential, needle osmotic adjustment) of Abies pinsapo, a relict drought-sensitive Mediterranean fir, along an altitudinal gradient. We related these variables to soil water and nutrient availability, air temperature, atmospheric water potential, and vapour pressure deficit during two consecutive years.

Our results indicate that A. pinsapo closed stomata rapidly over a very narrow range of soil water availability and atmospheric dryness. This isohydric response during water stress suggests that this relict conifer relied on the plant hormone abscisic acid to maintain closed stomata during sustained drought, instead of needle desiccation to passively drive stomatal closure, needle osmotic adjustment or a plastic response of the xylem to different levels of water availability.

Both the soil and foliar nutrient contents suggest that the studied populations are not limited by nutrient deficiencies, and drought was stronger in the warmer low-elevation areas

Oils are blocking the stomata and intercellular spaces and reduce the transpiration rate

Effects of oils on plants

Baker J. M. (1970)

Environ. Pollut.; (United Kingdom) 1 –

https://www.osti.gov/etdeweb/biblio/5809922

Abstract

Oils vary in their toxicity according to the content of low-boiling compounds, unsaturated compounds, aromatics, and acids. The higher the concentration of these constituents, the more toxic the oil. After penetrating into a plant, the oil may travel in the intercellular spaces and possibly also in the vascular system. Cell membranes are damaged by penetration of hydrocarbon molecules, leading to leakage of cell contents, and oil may enter the cells.

Oils reduce the transpiration rate, probably by blocking the stomata and intercellular spaces. This may also be the reason for the reduction of the photosynthesis which occurs, though there are other possible explanations of this – such as disruption of chloroplast membranes and inhibition caused by accumulation of end-products.

The effects of oils on respiration are variable, but an increase of respiration rate often occurs, possibly due to mitochondrial damage resulting in an uncoupling effect. Oils inhibit translocation probably by physical interference. The severity of the above effects depends on the constituents and amount of the oil, on the environmental conditions, and on the species of plant involved.

88 references, 3 tables

Rubiaceous type of stomata on both sides of the leaf in Basella

Pharmacognostical Standardization of Upodika– Basella alba L.: An Important Ayurvedic Antidiabetic Plant

Shantha T. R., Patchaimal P., Reddy M. P., Kumar R. K., Tewari D., Bharti V., Venkateshwarlu G., Mangal A. K., Padhi M. M., Dhiman K. S. (2022)

TR Shantha¹, P Patchaimal¹, M Prathapa Reddy¹, R Kishore Kumar¹, Devesh Tewari², Vandana Bharti², G Venkateshwarlu¹, AK Mangal², MM Padhi², KS Dhiman²,

¹ From the Regional Ayurveda Research Institute for Metabolic Disorders, Drug Standardization Research Unit, Jayanagar, Bengaluru, India

² Central Council for Research in Ayurvedic Sciences, Ministry of AYUSH, Government of , New Delhi, India

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Ancient Sci Life36: 35-41 – https://www.ancientscienceoflife.org/text.asp?2016/36/1/35/195411 –

https://www.ancientscienceoflife.org/article.asp?issn=0257-7941;year=2016;volume=36;issue=1;spage=35;epage=41;aulast=Shantha

Abstract

Objective: 

To establish the pharmacognostic standards for the correct identification and standardization of an important Antidiabetic plant described in Ayurveda. 

Materials and Methods: Standardization was carried out on the leaf and stem of Basella alba L. with the help of the macro-morphological, microscopic, physicochemical and qualitative phytochemical studies. 

Results: Several specific characters were identified viz. clustered calcium oxalate crystals in the cortex region, absence of trichomes, succulent, thick, mucilaginous, fibrous stem. Rubiaceous type of stomata on both sides of the leaf. Quantitative microscopy along with physicochemical and qualitative phytochemical analysis were also established. 

Conclusion: The pharmacognostic standards could serve as the reference for the proper identification of the Basella alba L. which is an important anti-diabetic plant described in Ayurveda.

ABA is acting in the shoot to close stomata in response to a decrease in plant water status : a challenge of this root-sourced ABA paradigm

Figure 1. Diagrammatic representations of (A) the classical ‘root-sourced’ model for ABA biosynthesis and transport (red) in a plant experiencing soil water limitation (adapted from Davies and Zhang¹²) and (B) a schematic synthesis of the findings from our two recent studies. We propose a new, ‘leaf-sourced’ model whereby soil water limitation reduces root water status and thus plant water potential (Ψ, blue). A decline in water potential in the roots provides an instantaneous signal through the internal water column in the xylem to the leaves, directly influencing leaf water status. A decline in leaf water status triggers foliar ABA biosynthesis which in turn closes stomata. Foliage-derived ABA is basipetally transported from the leaves to the roots where it promotes root growth under both well-watered and water-stressed conditions. The promotion of root growth by foliage-derived ABA feeds back on the soil water available to the plant. Root ABA biosynthesis is minimal, scarcely influencing shoot physiology.

Uprooting an abscisic acid paradigm: Shoots are the primary source

McAdam S. A., Manzi M., Ross J. J., Brodribb T. J., Gómez-Cadenas A. (2016)

Scott A M McAdam ¹, Matías Manzi ², John J Ross ¹, Timothy J Brodribb ¹, Aurelio Gómez-Cadenas ²

• ¹ School of Biological Sciences, University of Tasmania , Hobart , Australia.
• ² Ecofisiologia y Biotecnologia, Dept. Ciències Agraries i del Medi Natural, Universitat Jaume I. Castellón de la Plana , Spain.

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Uprooting an abscisic acid paradigm: Shoots are the primary source – Plant Signal Behav. 11(6): e1169359 – doi: 10.1080/15592324.2016.1169359 – Erratum in: Addendum to: McAdam SAM, Brodribb TJ, Ross JJ. (2016) – Shoot-derived abscisic acid promotes root growth – Plant, Cell and Environment 39: 652-659 – doi: 10.111/pce.12669 –

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Erratum in: Manzi M, Lado J, Rodrigo MJ, Zacarías L, Arbona V, Gómez-Cadenas A. (2015) – Root ABA accumulation in long-term water-stressed plants is sustained by hormone transport from aerial organs – Plant and Cell Physiology 56: 2457-2466 – PMID: 27031537; – PMCID: PMC4973758 – https://pubmed.ncbi.nlm.nih.gov/27031537/

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Abstract

In the past, a conventional wisdom has been that abscisic acid (ABA) is a xylem-transported hormone that is synthesized in the roots, while acting in the shoot to close stomata in response to a decrease in plant water status. Now, however, evidence from two studies, which we have conducted independently, challenges this root-sourced ABA paradigm. We show that foliage-derived ABA has a major influence over root development and that leaves are the predominant location for ABA biosynthesis during drought stress.

Wax tubules on the epistomatal rims of stomata

Epicuticular wax on stomata of damaged silver fir trees (Abies alba Mili.)

Bačić T., Krstin L., Roša J., Popović Z. (2005)

Tomislav Bačić, Ljiljana Krstin, Jadranka Roša, Željko Popović,

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Acta Societatis Botanicorum Poloniae 74(2) : – https://doi.org/10.5586/asbp.2005.021 –

https://pbsociety.org.pl/journals/index.php/asbp/article/view/572

Abstract

Condition of epistomatal wax on the abaxial surface of the current and previous-year needles of damaged silver fir trees (Abies alba Mill.), both from the polluted Risnjak and “clean” Donja Dobra sites in Gorski Kotar region, both influenced by pollutants coming from Europe, during two years, three times a year, were examined with Scanning Electron Microscope.

In the course of time the wax tubules on the epistomatal rims of stomata in polluted, but also in “clean” needles surface, become fused and agglomerated rapidly to various extents of morphologically different types of amorphous wax crusts, primarily compact and particulate ones. This process begins very early, especially in polluted Risnjak site, and may be interpreted as a possible result of air pollution.

However, the recrystalization, or production of new tubules, also appears relatively quickly in mostly cases. Quantitative estimations indicate a very large total amount of amorphous wax crusts in the current-year needles, and a very high percentage of the same wax in previous-year needles.

Amorphous wax crusts cover stomatal pores, as well as the rims, disturbing the normal gas exchange. Statistically there is a signicant tendency of increase in wax degradation in the needles of the polluted site in comparison with those of the unpolluted one, but there is an insignificant wax degradation among the needles of damaged trees within each site.

These results confirmed most of the research done in our preliminary report.

The response of stomata to strobilurin fungicides is complex

Strobilurin fungicides induce changes in photosynthetic gas exchange that do not improve water use efficiency of plants grown under conditions of water stress

Nason M. A., Farrar J., Bartlett D. (2007)

Mark A. Nason, John Farrar, David Bartlett,

School of the Environment and Natural Resources, University of Wales, Bangor, Gwynedd, UK.

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Pest Manag Sci. 63(12): 1191-1200 – doi: 10.1002/ps.1443 – PMID: 17912684 –

https://pubmed.ncbi.nlm.nih.gov/17912684/

Abstract

The effects of five strobilurin (beta-methoxyacrylate) fungicides and one triazole fungicide on the physiological parameters of well-watered or water-stressed wheat (Triticum aestivum L.), barley (Hordeum vulgare L.) and soya (Glycine max Merr.) plants were compared.

Water use efficiency (WUE) (the ratio of rate of transpiration, E, to net rate of photosynthesis, A(n)) of well-watered wheat plants was improved slightly by strobilurin fungicides, but was reduced in water-stressed plants, so there is limited scope for using strobilurins to improve the water status of crops grown under conditions of drought.

The different strobilurin fungicides had similar effects on plant physiology but differed in persistence and potency. When applied to whole plants using a spray gun, they reduced the conductance of water through the epidermis (stomatal and cuticular transpiration), g(sw), of leaves.

Concomitantly, leaves of treated plants had a lower rate of transpiration, E, a lower intercellular carbon dioxide concentration, c(i), and a lower net rate of photosynthesis, A(n), compared with leaves of control plants or plants treated with the triazole. The mechanism for the photosynthetic effects is not known, but it is hypothesised that they are caused either by strobilurin fungicides acting directly on ATP production in guard cell mitochondria or by stomata responding to strobilurin-induced changes in mesophyll photosynthesis. The latter may be important since, for leaves of soya plants, the chlorophyll fluorescence parameter F(v)/F(m) (an indication of the potential quantum efficiency of PSII photochemistry) was reduced by strobilurin fungicides.

It is likely that the response of stomata to strobilurin fungicides is complex, and further research is required to elucidate the different biochemical pathways involved.

Stomata and the tolerance of plants to air pollutants

Tolerance of plants to air pollutants. Shokubutsu no taiki osen taisei

Kondo N., Saji H., (1992)

National Institute for Environmental Studies, Tsukuba (Japan)

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Energy Technology Data Exchange (ETDEWEB) 1992-11-10

Abstract

Attempts have been made to improve tolerance of plants to air pollutants by changing activities in detoxifying enzymes against toxic substances attributable to air pollutants, through gene manipulation. An air pollutant, absorbed in a plant through its stomata, produces toxic substances in the cells and damages the organism.

Detailed discussions were given on the following: Stoma opening action and reaction; injuries attributable to air pollutants and detoxifying metabolism systems; ethylene and toxic enzymes of secondary toxic substances in an organism; different detoxifying mechanisms and active enzymes; and activation of detoxifying enzymes using genes.

Pollution tolerance in plants is governed by inherent plant natures and environmental conditions. Plants that have two opposing functions of emerging damages from toxicity and preventing them with detoxifying capability are controlled with a complex and delicate balance. Changing pollution tolerance in plants may be possible by manipulating genes, but the importance is to elucidate what the tolerating enzymes are, and obtain their genes. Genes that could be used are very few in number. Expectations are placed on the future development. 122 refs., 4 figs.