الفهرس 
Stress and temperature stressOnly 14 pages are availabe for public view
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Abstract
ugar ca ne cells were grown in suspension cultures for 20 days at 15, 27,33 and 45 ”C to determine the optimum temperature for growth and sugar storage. Growth parameters, respiration, total nitrogen content in the medium, sugar cnentrations in the medium and cells, activity of sucrose-metabolising enzymes and sugar uptake were determined. The obtained results indicated that: (1) although the warm temperature (33 ”C) favoured the vegetative growth, 27 ”C being better for dry matter accumulation, (2) the respiration rate and sugar uptake increased with temperature, while total nitrogen and sugar concentrations in the medium decreased, (3) the’optimum temperature for sucrose accumulation being 27 ”C and 45 ”C was better than 15 ”C for sugar storage per flask, (4) sucrose metabolism by sugar cane storage cells being regulated by a cycle of simultaneous synthesis and degradation , which was more pronounced at 27, 33 and 45 ”C including four main phases (mobilisation phase, growth phase, sucrose accumulation phase and remobilisation phase) , whereas two phases (decline phase and increment phase) only were observed in cells grown at 15 ”C, (5) application of temperaure stress had resulted in a significant decrease in all enzyme levels, but the response was more pronounced in cells grown at 15 ”C than at 45 ”C, particularly with respect to sucrose-degrading enzymes, and (6) the optimal temperature for sucrose-degrading enzymes (invertases and sucrose synthase) appeared to be 33 ’C, while sucrosephosphate synthase induced its highest activity at 27 ”C. Sugar cane seeds Saccharum officinarum L. cv. H50-7209 were germinated for 20 days at 33 ”C. The produced plants were transferred to greenhouses and allowed to grow in vermiculite for 10 months under controlled environmental conditions. To make a comparative study to the effect of low and high temperature levels on growth, photosynthesis and sugar storage in sugar cane plant, three constant temperature levels were applied: (1) 27 ”C which considered as a control, (2) 15 ”C representing a chilling stress, and (3) 45 ”C which was applied as a heat stress.