caa a22 4500 469098805 CHVBK 20180323133039.0 cr unu---uuuuu 170328e19920701xx s 000 0 eng 10.1007/BF01875445 doi (NATIONALLICENCE)springer-10.1007/BF01875445 Niklas Karl Section of Plant Biology, Cornell University, 14853, Ithaca, NY, USA aut Petiole mechanics, light interception by Lamina, and "Economy in Design” [Elektronische Daten] [Karl Niklas] Summary: Computer simulations were used to assess the influence of palmate leaf morphology, decussate phyllotaxy, and the elastic moduli of petioles on the capacity of turgid and wilted twigs ofAesculus hippocastanum to intercept direct solar radiation. Leaf size, morphology, orientation, and the Young's and shear moduli (E and G) of petioles were measured and related to leaf position on 8 twigs whose cut ends were placed in water ("turgid” twigs) and 8 twigs dried for 8 h at room temperature ("wilted” twigs). Petioles mechanically behaved as elastic cantilevered beams; the loads required to shear petioles at their base from twigs were correlated with the cross-sectional areas of phyllopodia but not with petiole length or tissue volume. Empirically determined morphometric and biomechanical data were used to construct "average” turgid and wilted twigs. The diurnal capacity to intercept direct sunlight for each was simulated for vertically oriented twigs for 15 h of daylight, 40° N latitude. The daily integrated irradiance (DII) of the wilted twig was roughly 3% less than that of the otherwise comparable twig bearing turgid leaves. Simulations indicated that the orientation of turgid leaves did not maximize DII. More decumbent (wilted) petioles increased DII by as much as 4%. Reduction in the girth, E, or G of petioles, or an increase in petiole length or the surface area of laminae (with attending increase in laminae weight), increased petiolar deflections and DII. Thus, the mechanical design of petioles ofA. hippocastanum was found not to be "economical” in terms of investing biomass for maximum light interception. Springer-Verlag, 1992 Leaf orientation nationallicence Biomechanics nationallicence Light interception nationallicence Economy in design nationallicence Oecologia Springer-Verlag 90/4(1992-07-01), 518-526 0029-8549 90:4<518 1992 90 442 https://doi.org/10.1007/BF01875445 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01875445 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Niklas Karl Section of Plant Biology, Cornell University, 14853, Ithaca, NY, USA aut NATIONALLICENCE 773 0- Oecologia Springer-Verlag 90/4(1992-07-01), 518-526 0029-8549 90:4<518 1992 90 442 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer