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Elastic properties of the growth-controlling outer cell walls of maize coleoptile epidermis

Lipchinsky, Andrei, Sharova, Elena I., Medvedev, Sergey S.
Acta physiologiae plantarum 2013 v.35 no.7 pp. 2183-2191
Zea mays, cell walls, coleoptiles, corn, mechanical stress, modulus of elasticity, polymers, seedlings, temperature
The effects of tensile stress and temperature on cell wall elasticity have been investigated in the outer cell walls of coleoptile epidermis of 4- and 6-day-old Zea mays L. seedlings. The change in tensile stress from 6 to 40 MPa caused the increase in cell wall elastic modulus from 0.4 to 3 GPa. Lowering the temperature from 30 to 4 A degrees C resulted in instantaneous and reversible cell wall elongation of 0.3-0.5 aEuro degrees. At a given temperature and stress level, the wall elastic modulus of 6-day-old seedlings tended to be 30 % higher than that of 4-day-old plants. The relationship between cell wall elasticity and mechanical stress indicated that the stress distribution within the cell wall is highly uneven. The analysis of the effect of temperature on cell wall elastic strain showed that structural differences between crystalline and amorphous load-bearing polymers were not the only cause of the uneven stress distribution. Based on the results obtained by Hejnowicz and Borowska-WykrA (TM) t (Planta 220:465-473, 2005), we suggested that the uneven stress distribution is partially related to the stress gradient between inner and outer layers of the cell wall.