High-temperature Stress

High-temperature stress is very unfavorable for the optimal growth of plants. Almost 25% of the total arable land worldwide is affected by heat and drought stress. The annual mean air temperature of 23% of the Earths land surface is above 40 °C [97], and with the increasing concentration of greenhouse gases the Earth s surface temperature is expected to increase further by 1.2-5.8°C by 2100 ad http / www.epa.gov). This rise in ambient temperature would clearly create a warmer climate in most parts of the world. 

In general, cool-season crops are more sensitive to heat stress than are warm-sea-son annuals. In barley, a high temperature leads to a reduction in tiller number, a shortened duration of the tillering stage, abortion of spikelets, and a decline in sucrose synthase activity and starch deposi- 

Heat Shock Response and Heat Shock Proteins 

Besides HS, selective plant Hsps are induced in response to different abiotic stresses such as heavy-metal stress, water stress, wounding stress, salt stress, cold shock, and anoxia stress. Plants, in general, survive lethal temperature stress more efficiently after prior exposure to a mild stress as against a direct response to lethal stress. This phenomenon is termed acquired thermotolerance [103]. Hsp are believed to be important for the protection of cells against heat injury both in basal thermotolerance (i.e., thermotolerance shown without prior heat shock) as well as in acquired thermotolerance responses. 

Over the years, a large number of genes that encode Hsp (referred to as heat shock genes or hsp) have been isolated, sequenced, and cloned. This has been 

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Certain pre-boiler cupronickels, such as 70 30 alloy tubes, subjected to high temperature, stress, and stop-start operation may suffer oxygen corrosion-induced dealloying followed by exfoliation corrosion, in which oxidized sheets peel away from the solid metal. 

High temperature/stress and stop/start operation effects on 70 30 cupronickel tubes (as found in some FW heaters). A chain of cause and effect including Oxygen corrosion Dealloying Exfoliation corrosion... 

High temperature stress Low temperature stress High winds Global warming Increased UV-B radiation... 

Kramer, P.J. (1980). Drought stress and adaptation. In Adaptation of Plants to Water and High Temperature Stress, ed. N.C. Turner P.J. Kramer, pp. 6-20. New York Wiley. 

Herrero, M.P. Johnson, R.R. (1980). High temperature stress and pollen viability of maize. Crop Science, 20, 796-800. 

Commercial polymer with an overall CTFE-to-ethylene ratio of 1 1 contains ethylene blocks and CTFE blocks of less than 10 mol% each. The modified copolymers also produced commercially exhibit improved high-temperature stress cracking. Typically, the modified copolymers are less crystalline and have lower melting points.88 Modifying monomers are hexafluoroisobutylene (HFIB), perfluorohexylethylene, and perfluoropropylvinyl ether (PFPVE).89... 

Phenolic acids disruption of normal membrane functions provides a ready explanation as to why several environmental stresses appear to increase the sensitivity to phenolic allelochemicals. Both high temperature stress and moisture... 

Clauss, F. "An Examination of High Temperature Stress Rupture Correlating Parameters." Proce. ASTM, 60, 905, 1960. 

Hong, S.W., and Vierling, E., 2000, Mutants of Arabidopsis thaliana defective in the acquisition of tolerance to high temperature stress. Proc. Natl. Acad. Sci. U.S.A. 97(8) 4392-4397. 

Levitt, J. 1980. Responses of plants to environmental stresses. Vol. I. Chilling, freezing, and high temperature stresses. 2 Ed. Academic Press, New York... 

C. A composition in this two-phase field should have superior high-temperature mechanical properties. Greskovich [21] has synthesized ceramics in this phase field, and high-temperature stress rupture tests showed that they are the most stable silicon nitride ceramics among all of the other systems studied. 

The results Just discussed indicate that the degradation rate is definitely changing between the high temperature stressing, 130°C, and the low temperature stressing, 90°C. 

Table 10.4 Selective reports on production of high-temperature, stress-tolerant transgenic crops... 

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