期刊名称:Proceedings of the National Academy of Sciences
印刷版ISSN:0027-8424
电子版ISSN:1091-6490
出版年度:1991
卷号:88
期号:6
页码:2241-2243
DOI:10.1073/pnas.88.6.2241
语种:English
出版社:The National Academy of Sciences of the United States of America
摘要:High-sensitivity differential scanning calorimetry has been used to study the phase transition of cell wall preparations of the elongating and mature regions of soybean hypocotyls and of celery epidermis and collenchyma strands. A step-like transition believed to be glass transition was observed in walls isolated from the elongating region of soybean hypocotyls at 52.9 degrees C. Addition of 1 mM CaCl2 to the cell wall preparation increased the transition temperature to 60.8 degrees C and greatly reduced the transition magnitude. In walls from the mature region, the transition was small and occurred at a higher temperature (60.1 degrees C). Addition of calcium to the mature region cell wall had little effect on the transition. Based on the known interactions between calcium and pectin, we propose that calcium affects the glass transition by binding to the polygalacturonate backbone of wall pectin, resulting in a more rigid wall with a smaller transition at a higher temperature. The mature region either has more calcium in the wall or has more methyl-esterified pectin, making it less responsive to added calcium.