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 Yuping Li;Karl J.Niklas;Johan Gielis;Ülo Niinemets;Julian Schrader;Rong Wang;Peijian Shi

作者机构：College of HorticultureJinling Institute of TechnologyNanjing 210038People’s Republic of China Bamboo Research InstituteNanjing Forestry UniversityNanjing 210037People’s Republic of China Plant Biology SectionSchool of Integrative Plant ScienceCornell UniversityIthacaNY 14853USA Department of Biosciences EngineeringUniversity of AntwerpB-2020 AntwerpBelgium Institute of Agricultural and Environmental SciencesEstonian University of Life Sciences51006 TartuEstonia Estonian Academy of Sciences10130 TallinnEstonia Department of Biological SciencesMacquarie UniversitySydneyNSW 2109Australia BiodiversityMacroecology and BiogeographyUniversity of Göttingen37077 GöttingenGermany 

出 版 物：《Journal of Forestry Research》 (林业研究（英文版）)

年 卷 期：2022年第33卷第4期

页      面：1341-1348页

核心收录：

学科分类：0710[理学-生物学] 071001[理学-植物学] 0830[工学-环境科学与工程（可授工学、理学、农学学位）] 0907[农学-林学] 07[理学] 0829[工学-林业工程] 0901[农学-作物学] 

主　　题：Bilateral symmetry Leaf ellipticalness index Leaf laminae Leaf roundness index Magnoliaceae 

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 of0.05 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 were2,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.