An elliptical blade is not a true ellipse,but a superellipse–Evidence from two Michelia species  

作　　者：Yuping Li Karl JNiklas Johan Gielis Ülo Niinemets Julian Schrader Rong Wang Peijian Shi 

机构地区：[1]College of Horticulture,Jinling Institute of Technology,Nanjing 210038,People’s Republic of China [2]Bamboo Research Institute,Nanjing Forestry University,Nanjing 210037,People’s Republic of China [3]Plant Biology Section,School of Integrative Plant Science,Cornell University,Ithaca,NY 14853,USA [4]Department of Biosciences Engineering,University of Antwerp,B-2020 Antwerp,Belgium [5]Institute of Agricultural and Environmental Sciences,Estonian University of Life Sciences,51006 Tartu,Estonia [6]Estonian Academy of Sciences,10130 Tallinn,Estonia [7]Department of Biological Sciences,Macquarie University,Sydney,NSW 2109,Australia [8]Biodiversity,Macroecology and Biogeography,University of Göttingen,37077 Göttingen,Germany

出　　处：《Journal of Forestry Research》2022年第4期1341-1348,共8页林业研究（英文版）

摘　　要：The shape of leaf laminae exhibits considerable diversity and complexity that reflects adaptations to environmental factors such as ambient light and precipitation as well as phyletic legacy.Many leaves appear to be elliptical which may represent a‘default’developmental condition.However,whether their geometry truly conforms to the ellipse equation(EE),i.e.,(x/a)^(2)+(y/b)^(2)=1,remains conjectural.One alternative is described by the superellipse equation(SE),a generalized version of EE,i.e.,|x/a|^(n)+|y/b|^(n)=1.To test the efficacy of EE versus SE to describe leaf geometry,the leaf shapes of two Michelia species(i.e.,M.cavaleriei var.platypetala,and M.maudiae),were investigated using 60 leaves from each species.Analysis shows that the majority of leaves(118 out of 120)had adjusted root-mean-square errors of<0.05 for the nonlinear fitting of SE to leaf geometry,i.e.,the mean absolute deviation from the polar point to leaf marginal points was smaller than 5%of the radius of a hypothesized circle with its area equaling leaf area.The estimates of n for the two species were<2,indicating that all sampled leaves conformed to SE and not to EE.This study confirms the existence of SE in leaves,linking this to its potential functional advantages,particularly the possible influence of leaf shape on hydraulic conductance.

关 键 词：Bilateral symmetry Leaf ellipticalness index Leaf laminae Leaf roundness index MAGNOLIACEAE 

分 类 号：Q944.56[生物学—植物学]