ANALYTICAL REVIEW OF APPROACHES TO MATHEMATICAL MODELING OF INTERACTIONS OF OPTICAL RADIATION WITH PLANT TISSUES

Author(s):  
M.V. SUKHANOVA ◽  
2011 ◽  
Vol 11 (04) ◽  
pp. 713-734 ◽  
Author(s):  
VALKO PETROV ◽  
CHRISTOF AEGERTER

This paper presents both a general review on developmental biomechanics and a concrete proposition for the computation of a symmetry breaking instability of a model of biological development in terms of self-organization theory. The necessary biological and physical facts taken from the literature are described and discussed in the context of a unified statement of the problems for mathematical modeling of pattern formation. This is then applied to planar cell polarization (PCP) of the Drosophila wing. In this way, the process is modeled by an elastopolarization equation. In terms of this statement, the mechanical specificity (interaction with basal plate) of wing PCP is characterized. Some aspects of modeling somite formation as well as other developmental processes are also concerned.


Author(s):  
V. I. Pushkareva ◽  
S. A. Ermolaeva

Specific epidemiology of sapronotic (soil-borne) bacteria is characterized from the ecological point of view. The characteristic feature of soil-borne pathogens is an ability to exist autonomously in the environment. This analytical review is focused on crops as alternative hosts for a number of soil-borne pathogenic bacteria (Yersinia, Salmonella, Listeria, Escherichia etc). Published experimental results evidence capabilities of human and animal pathogens to colonize plant tissues. Novel approaches are discussed to minimize risks of infection spreading with crops. These approaches include an analysis of wild plant natural resistance to pathogenic bacteria and a construction of transgenic plant crops expressing antimicrobial peptides. Multiple studies are cited that established wild plants used in traditional medicine as a source for obtaining molecules effective against resistant pathogens. The review includes recent author results on activity of wild plant extracts against Listeria and toxin-producing Escherichia.


2021 ◽  
Vol 78 (3) ◽  
pp. 34-42
Author(s):  
A.V. Kovanov ◽  
◽  
D.V. Zhignovskaya ◽  
V.A. Tsvetkov ◽  
V.A. Pronin ◽  
...  

The paper deals with some aspects of mathematical modeling of a scroll compressor. Various approaches to modeling the working processes of machines of the volumetric compression principle, their applied value and priority of use are presented. An analytical review of the methods for calculating the leakage of a compressed medium, applied to a scroll compressor, taking into account the classification of slots, is carried out. Conclusions are made about the need to clarify the assumptions and improve this technique by taking into account the fact of the mobility of the walls of the gap, depending on the share of the influence of various factors on the leakage of the compressed medium. And also about the influence of this fact on the accuracy of calculations and the optimal choice of the operating mode of the compressor. Examples are given in which taking this condition into account in the transformed systems of equations will improve the accuracy in applied calculations of the working processes of spiral machines, when designing new samples.


Author(s):  
John S. Gardner ◽  
W. M. Hess

Powdery mildews are characterized by the appearance of spots or patches of a white to grayish, powdery, mildewy growth on plant tissues, entire leaves or other organs. Ervsiphe cichoracearum, the powdery mildew of cucurbits is among the most serious parasites, and the most common. The conidia are formed similar to the process described for Ervsiphe graminis by Cole and Samson. Theconidial chains mature basipetally from a short, conidiophore mother-cell at the base of the fertile hypha which arises holoblastically from the conidiophore. During early development it probably elongates by polar-tip growth like a vegetative hypha. A septum forms just above the conidiophore apex. Additional septa develop in acropetal succession. However, the conidia of E. cichoracearum are more doliform than condia from E. graminis. The purpose of these investigations was to use scanning electron microscopy (SEM) to demonstrate the nature of hyphal growth and conidial formation of E. cichoracearum on field-grown squash leaves.


Author(s):  
Y. R. Chen ◽  
Y. F. Huang ◽  
W. S. Chen

Acid phosphatases are widely distributed in different tisssues of various plants. Studies on subcellular localization of acid phosphatases show they might be present in cell wall, plasma lemma, mitochondria, plastid, vacuole and nucleus. However, their localization in rice cell varies with developmental stages of cells and plant tissues. In present study, acid phosphatases occurring in root cap are examined.Sliced root tips of ten-day-old rice(Oryza sativa) seedlings were fixed in 0.1M cacodylate buffer containing 2.5% glutaraldehyde for 2h, washed overnight in same buffer solution, incubated in Gomori's solution at 37° C for 90min, post-fixed in OsO4, dehydrated in ethanol series and finally embeded in Spurr's resin. Sections were doubly stained with uranyl acetate and lead citrate, and observed under Hitachi H-600 at 75 KV.


Author(s):  
R.E. Crang ◽  
M. Mueller ◽  
K. Zierold

Obtaining frozen-hydrated sections of plant tissues for electron microscopy and microanalysis has been considered difficult, if not impossible, due primarily to the considerable depth of effective freezing in the tissues which would be required. The greatest depth of vitreous freezing is generally considered to be only 15-20 μm in animal specimens. Plant cells are often much larger in diameter and, if several cells are required to be intact, ice crystal damage can be expected to be so severe as to prevent successful cryoultramicrotomy. The very nature of cell walls, intercellular air spaces, irregular topography, and large vacuoles often make it impractical to use immersion, metal-mirror, or jet freezing techniques for botanical material.However, it has been proposed that high-pressure freezing (HPF) may offer an alternative to the more conventional freezing techniques, inasmuch as non-cryoprotected specimens may be frozen in a vitreous, or near-vitreous state, to a radial depth of at least 0.5 mm.


Author(s):  
Janet H. Woodward ◽  
D. E. Akin

Silicon (Si) is distributed throughout plant tissues, but its role in forages has not been clarified. Although Si has been suggested as an antiquality factor which limits the digestibility of structural carbohydrates, other research indicates that its presence in plants does not affect digestibility. We employed x-ray microanalysis to evaluate Si as an antiquality factor at specific sites of two cultivars of bermuda grass (Cynodon dactvlon (L.) Pers.). “Coastal” and “Tifton-78” were chosen for this study because previous work in our lab has shown that, although these two grasses are similar ultrastructurally, they differ in in vitro dry matter digestibility and in percent composition of Si.Two millimeter leaf sections of Tifton-7 8 (Tift-7 8) and Coastal (CBG) were incubated for 72 hr in 2.5% (w/v) cellulase in 0.05 M sodium acetate buffer, pH 5.0. For controls, sections were incubated in the sodium acetate buffer or were not treated.


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