Plant cell responses

Work on the OB has clearly demonstrated that plant cell response to stress, including hydrodynamic stress, is a more complex process than was originally anticipated. Moreover, it highlights a number of cellular processes which may define immediate system response and longer term performance prospects of plant cell suspensions. 

V. Gianinazzi-Pearson, Plant cell responses to arbuscular mycorrhizal fungi getting to the roots of the symbiosis. Plant Cell 70 1871 (1996). 

CHEMILUMINESCENT AND BIOLUMINESCENT ANALYSIS OF PLANT CELL RESPONSES TO REACTIVE OXYGEN SPECIES PRODUCED BY A NEW WATER CONDITIONING APPARATUS EQUIPPED WITH TITANIA-COATED PHOTO-CATALYTIC FIBERS... 

Chemiluminescent and Bioluminescent Analysis of Plant Cell Responses 29... 

The Possible Role of Protein Kinases in the Plant Cell Response to Phytohormones... 

Protein phosphorylation is a widespread phenomenon in plant cells and phosphorylated proteins and protein kinases have been detected in all compartments of plant cells [16]. These data support the investigation of the role of protein kinases in plant cell response to phytohormones. 

It is clear that the regulation of gene expression is involved not only in long-term plant cell response to phytohormones, but also in short-term responses [21]. Trewavas [23] was the first to suggest that phosphorylation of chromatin-associated protein may mediate the hormonal regulation of transcription in plant cells. 

Ryan, C.A., Bishop, P.D., Walker-Simmons, M., Brown, W. Graham, J. (1985). The role of pectic fragments of the plant cell wall in response to biological stresses. In Cellular and Molecular Biology of Plant Stress, ed. J.L. Key T. Kosuge, pp. 319-34. New York Alan R. Liss. 

Ben-Hayyim etal. (1987) demonstrated that cultured citrus cells selected for tolerance to NaCl were most tolerant to polyethylene glycol, followed by NaCl and then CaC. The exposure of the cells to any of these osmotic agents resulted in an increase in intracellular K. The authors concluded that K played a key role in the growth of cells exposed to salt. Other researchers have also suggested that K may play a significant role in the response of plant cells to salinity (Rains, 1972 Croughan, Stavarek Rains, 1978 ... 

Plant cells selected for tolerance to stress show varied responses to the imposed osmotic gradients. In adapted cells, tolerance to salinity or to water stress was not found to increase proportionately with increases in turgor (Handa et al., 1983 Binzel et al., 1985). It was suggested from these observations and from studies by Heyser Nabors (1981) that no relationship existed between turgor and growth and that stress adaptation may alter the relationship between turgor and cell expansion (see also Chapter 6). 

Osmotic adjustment by plant cells in response to an increasing saline environment can be mediated by an alteration in intracellular concentrations of both inorganic and organic ions (Wyn Jones, 1980,1984 Aspinall, 1986 Flowers Yeo, 1986 Grumet Hanson, 1986 Moftah Michel, 1987). 

A number of chapters in this volume (especially Chapters 5 and 6) provide a more thorough discussion of osmotic adjustment by intact plants and tissues in response to environmental stress and the role of osmotically active solutes in this response. The following section focuses on the role of organic osmotica in the response of plant cells to salt stress. Cultured plant cells offer the opportunity to evaluate the effect of both internally synthesised and externally administered organic osmotica. 

A frequently observed response of plant cells exposed to saline stress is the accumulation of proline. Two cell lines of tobacco, one resistant and the other sensitive to growth inhibition by NaCl, accumulated proline when exposed to 1.5% w/v NaCl in the growth media (Dix Pearce, 1981). The NaCl sensitive line accumulated proline more rapidly than did the resistant line, though the levels accumulated were not adequate to provide osmotic protection against salt stress. The authors suggested that proline accumulation may have a protective role other than osmoregulation and may be symptomatic of stress injury, the nature of which was not discussed. 

For plant cell suspensions cultivated in shake flasks, Huang et al. [45] used the energy dissipation rate as a correlating parameter for system response. Specific power input was calculated using the empirical correlation proposed by Sumino et al. [46] and subsequently employed in other applications [47,48] ... 

Fig. 11. Hypothetical model for the oxidative burst in plant cells, in response to mechanical stress. Based on [174] and [172]...

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