Plant tissue section

Lauchli A, Schwander H. X-ray microanalyser study on the location of minerals in native plant tissue sections. Experientia 1966 22 503-505. 

Mass spectrometry imaging (MSI) circumvents these issues by combining MS with microscopy (5). Spatially resolved mass spectrometric experiments directly on the surface of tissue sections enable the reconstruction of images and therefore the localization of hundreds of molecules within their histological context without any labeling. MSI has therefore received considerable interest as an imaging technique for the ex vivo molecular interrogation of animal, human, or plant tissue sections (6). 

Various types of biocatalytic materials, such as isolated enzymes, bacterial cells, and intact mammalian and plant tissue sections, are available for the preparation of biocatalytic-based biosensors (3-7), An enzyme, or a group of enzymes, provides the required biocatalytic activity. For the bacterial cell and tissue based systems, the required enzyme is housed in these biocatalytic materials which can help stabilize the enzyme and prolong the biocatalytic activity. 

The occurrence of toxic compounds in plant tissues is not necessarily related to allelopathy. Allelopathy should be evidenced through experiments in which a toxic product is shown to be released from the putative aggressor, and arrives at the putative victim in functional concentrations under reasonably natural conditions (Inderjit and Callaway 2003). First of all, laboratory experiments dealing with allelopathy should demonstrate the release of a compound in the medium. Two methods to collect allelchemicals released by laboratory cultures of macrophyte or microalgae are described in Sections 5 and 6. 

Most research into in vitro foreign protein production has been undertaken using cell suspensions. However, other forms of plant tissue culture such as hairy roots and shooty teratomas have also been tested in a number of studies (Table 2.1). The characteristics of different types of plant tissue culture and their utility for large-scale foreign protein production are outlined in the following sections. 

All of the principles and ideas covered in the previous section may be translated directly to the use of microorganisms as tools in the production of compounds of plant biosynthetic or biodegradative importance. Just as one finds microbial systems to be of value in preparing metabolites in mammalian systems, it may be possible to use microbial transformations to prepare derivatives of alkaloids that might be found rarely or only in very small quantities in plants. In this way, abundant prototype alkaloids may be used as microbial transformation substrates to provide a range of metabolites. As in the mammalian case, metabolism studies using plant tissues, tissue cultures, or cell-free extracts may be conducted in parallel with microbial metabolic systems. Metabolites common to both would be prepared in quantity by relatively simple fermentation scale-up methods. 

In spite of the often constitutive activity of AGO in the majority of plant tissues, an increase in its activity may regulate ethylene production especially associated with ripening and senescence of leaves, fruits, and flowers (see Sections 5.04.2.3 and 5.04.4.2.3, and Figure 3). 

The detailed distribution of polysaccharides within cell walls can be determined by immunolabeling sections of plant tissues with appropriate antibodies (Knox, 2008). Such studies also show the distribution of polysaccharides in the middle lamella (Figure 3.5), which develops from the cell plate, formed at cell division, and is responsible for cell-cell adhesion. Cell comers (tri-cellular junctions) and the comers of the intercellular spaces can be regarded as extensions of the middle lamella. They are where stresses that tend to separate plant cells are concentrated and have been referred to as reinforcing zones (Jarvis et al., 2003). These zones and the middle lamella are rich in pectic polysaccharides, but contain no cellulose microfibrils (Jarvis et al., 2003). 

Dilute perchloric acid or trichloroacetic acid, or ethanol, is usually employed for extraction of the glycosyl esters of nucleoside pyrophosphates from biological materials.19 The high lability of these compounds in acidic media (see Section IV, p. 356) leads to unavoidable losses during extraction with acids. Extraction with ethanol can lead to difficulties, as ethanol may not completely inactivate pyrophosphatases present in the tissue the action of these enzymes may result in partial degradation of the nucleoside pyrophosphate derivatives. Such a situation has been encountered particularly with plant tissues.20... 

Bright field microscopy is suitable to observe stained bacteria, thick tissue sections, thin sections with condensed chromosomes, large protists or metazoans, living protists or metazoans, algae, and other microscopic plant material. 

The plant molecular systematist is confronted with three major practical issues when initiating a survey of land plants collection of plant tissue (location, type of tissue, quantity, preservation, transport, etc.), method of macromolecule extraction, and molecular technique used. These three factors are closely intertwined, and each can, and often does, have an influence on the others. The practical issues discussed in this chapter must therefore be considered in the broader context of issues relating to macromolecule isolation (see [12] in this volume) and the kind of molecular information to be obtained (see Section II in this volume). 

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