caa a22 4500 397522045 CHVBK 20180308164635.0 cr unu---uuuuu 161202e199508 xx s 000 0 eng 10.1093/jxb/46.8.1045 doi (NATIONALLICENCE)oxford-10.1093/jxb/46.8.1045 Tissue 8 [Elektronische Daten] [Zygmunt Hejnowicz, Andreas Sievers] The longitudinal and transverse forces involved in tissue stresses (TSs) and the stresses themselves, were determined for the hypocotyl of Helianthus annuus L. using Poisson ratios and data from measurements of (i) the forces necessary to restretch the strips of outer tissue (OT) to their initial length in situ; (ii) the external compressive force and (iii) the external osmotic pressure required to prevent the extension of isolated inner tissue (IT) immersed in water or mannitol solutions. These three independent measurements gave a similar magnitude for the longitudinal forces (tensile in the OT, compressive in the IT), 0.37 N in the apical region. More than 80% of the tensile force is transmitted by the epidermis, resulting in a longitudinal TS three times higher than that due to turgor pressure in this layer. The longitudinal compressive TS in the IT amounts to approximately one-third of turgor pressure in this tissue. Transverse TSs in the OT and in the IT were calculated from the longitudinal forces. In the OT, the tensile, circumferential TS is one-fifth to one-sixth of that in the longitudinal direction. In the IT the compressive TS in the transverse direction amounts to nearly half of that in the longitudinal direction. © Oxford University Press Research Papers nationallicence Tissue stresses nationallicence sunflower hypocotyl nationallicence epidermis nationallicence Hejnowicz Zygmunt Botanisches Institut, Universitüt Bonn, Venusbergweg 22, D-53115 Bonn, Germany aut Sievers Andreas Botanisches Institut, Universitüt Bonn, Venusbergweg 22, D-53115 Bonn, Germany aut Journal of Experimental Botany Oxford University Press 46/8(1995-08), 1045-1053 0022-0957 46:8<1045 1995 46 exbotj https://doi.org/10.1093/jxb/46.8.1045 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1093/jxb/46.8.1045 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Hejnowicz Zygmunt Botanisches Institut, Universitüt Bonn, Venusbergweg 22, D-53115 Bonn, Germany aut NATIONALLICENCE 700 1- Sievers Andreas Botanisches Institut, Universitüt Bonn, Venusbergweg 22, D-53115 Bonn, Germany aut NATIONALLICENCE 773 0- Journal of Experimental Botany Oxford University Press 46/8(1995-08), 1045-1053 0022-0957 46:8<1045 1995 46 exbotj Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence SWISSBIB 397521162 BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford