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Role of xyloglucan in gravitropic bending of azuki bean epicotyl
Author(s) -
Ikushima Toshimitsu,
Soga Kouichi,
Hoson Takayuki,
Shimmen Teruo
Publication year - 2008
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.2007.01047.x
Subject(s) - epicotyl , xyloglucan , gravitropism , cell wall , pectin , bending , extensibility , biophysics , hemicellulose , chemistry , materials science , botany , hypocotyl , composite material , biology , cellulose , biochemistry , arabidopsis , gene , mutant , computer science , operating system
The mechanism of the gravitropic bending was studied in azuki bean epicotyls. The cell wall extensibility of the lower side became higher than that of the upper side in the epicotyl bending upward. The contents of matrix polysaccharides of the cell wall (pectin and xyloglucan in hemicellulose‐II) in the lower side became smaller than those in the upper side. The molecular mass of xyloglucans in the lower side decreased. After an epicotyl was fixed to a metal rod to prevent the bending, gravistimulation was applied. Fundamentally the same results were obtained with respect to rheological and chemical characteristics of the cell wall as those of epicotyls showing gravitropic bending. The present results suggested that the initial gravitropic bending was caused by the increase in extensibility of the lower side and the decrease in extensibility of the upper side via the change of the cell wall matrix, especially xyloglucans.