The present volume xylem structure and the ascent of sap by m h zimmermann very appropriately inaugurates the springer series in wood science an enterprise recently initiated in the belief that wood and related forest products at this time have attained a new importance as renewable resources available in vast quantities the scope of the series is intended to be wide and virtually all aspects of wood science and technology will be considered topics will include the structure of wood . The cohesion tension theory and new evidence are introduced in response to recent controversies over the mechanism of sap ascent in plants the physiology anatomy and biophysics of xylem dysfunction are discussed and new insights into hydraulic architecture are reviewed with special emphasis on physiological limits on maximum transpiration and how hydraulic architecture limits gas exchange carbon gain and growth of plants the text concludes with a description of xylem failure and . The cohesion tension theory and new evidence are introduced in response to recent controversies over the mechanism of sap ascent in plants the physiology anatomy and biophysics of xylem dysfunction are discussed and new insights into hydraulic architecture are reviewed with special emphasis on physiological limits on maximum transpiration and how hydraulic architecture limits gas exchange carbon gain and growth of plants the text concludes with a description of xylem failure and . Xylem sap contained the galactolipids di and mono galactosyldiacylglycerol dgdg and mgdg as well as all common plant phospholipids but only traces of sulfolipids with total lipid