Fructan metabolism in wheat in alternating warm and cold temperatures

• Published in: Plant physiology (Bethesda) Vol. 93; no. 3; pp. 902 - 906
• Main Authors: Jeong, B.R. (Purdue University, West Lafayette, IN), Housley, T.L
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Physiologists 01-07-1990
• Subjects: ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; Barley; Biological and medical sciences; CARBOHIDRATOS; Carbohydrate metabolism; COMPOSICION; COMPOSITION; Enzymes; FEUILLE; FRIO; FROID; Fructans; FRUCTOFURANOSIDASA; FRUCTOFURANOSIDASE; FRUCTOSA; FRUCTOSE; Fundamental and applied biological sciences. Psychology; GLUCIDE; HIDROLASAS; HOJAS; HYDROLASE; Leaf blade; Leaf sheaths; Leaves; Metabolism; METABOLISME DES GLUCIDES; METABOLISMO DE CARBOHIDRATOS; OBSCURIDAD; OBSCURITE; Photosynthesis, respiration. Anabolism, catabolism; Plant physiology and development; Plants; Seedlings; Stems; SUCROSA; SUCROSE; TEMPERATURA; TEMPERATURE; TRANSFERASAS; TRANSFERASE; TRITICUM AESTIVUM; Monocotyledones; Temperature; Temperature effect; β-D-Fructofuranosidase; Plant leaf; Metabolism; Cereal crop; Sucrose 1F-fructosyltransferase; Enzymatic activity; Gramineae; Angiospermae; Spermatophyta; Catabolism; Biological accumulation; Polysaccharide; Triticum aestivum
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.93.3.902

The objective of this research was to develop a system in which the direction of fructan metabolism could be controlled. Three-week-old wheat seedlings (Triticum aestivum L. cv Caldwell) grown at 25 degrees C were transferred to cold temperature (10 degrees C) to induce fructan synthesis and then were transferred to continuous darkness at 25 degrees C after defoliation and fructan degradation monitored. The total fructan content increased significantly 1 day after transferring from 25 degrees C to 10 degrees C in both leaf blades and the remainder of the shoot tissue, 90% of which was leaf sheath tissue. Leaf sheaths contained higher concentrations of fructan and greater portions of high molecular weight fructan than did leaf blades. Fructan content in leaf sheaths declined rapidly and was gone completely within 48 hours following transfer to 25 degrees C in darkness. In leaf blades the invertase activity fluctuated during cold treatment. The activity of sucrose: sucrose fructosyl transferase increased markedly during cold treatment, while fructan hydrolase activity decreased slightly. In leaf sheaths, however, the activity of invertase decreased rapidly upon transfer to cold temperature and remained low. Trends in sucrose: sucrose fructosyl transferase and hydrolase activity in shealths were the same as those of leaf blades. Sheath invertase and hydrolase activity increased when plants were transferred back to darkness at 25 degrees C, while sucrose: sucrose fructosyl transferase activity decreased. These results indicate that changing leaf sheath temperture can be utilized to control the direction of fructan metabolism and thus provide a system in which the synthesis or degradation of fructan can be examined