Comparative studies on phenotypic plasticity of two herbs, Changium smyrnioides and Anthriscus sylvestris

The endangered medicinal herb, Changium smyrnioides can only be found in deciduous forest gaps within the middle to northern subtropical broad-leaved evergreen forest zone of China. The considerable plasticity of its shoot and root structure helps it to capture light more effectively in winter and early spring, and to adapt to the soil moisture conditions in its narrow habitat. Another medicinal plant, Anthriscus sylvestris, is of similar economic importance but commonly distributed widely. In contrast to C. smyrnioides, it has low structural plasticity. It is also specialized to adapt to the moist and sunny environment, where habitat, such as the banks of creeks and rivers, is abundant.     

Comparative studies on phenotypic plasticity of two herbs, Changium smyrnioides and Anthriscus sylvestris

INTRODUCTION Changium smyrnioides Wolff, a monotypicspecies of family Umbellaceae, occurs only in anarrow zone in the middle to eastern part of theChangjiang (Yangtze) River Basin, China. As ahighly valued medicinal herb, the fleshy roots ofthis species are widely picked, and as its habitatsare being disturbed increasingly by land use, it hasbecome an endangered species (Qiu and Fu, 2001).Anthriscus sylvestris (L.) Hoffm belongs to thesame family; has similar morphology and life…     

谈新课程理念下数学课的反思教学

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利用哲学思想方法把握数学教学本质

数学与哲学有着密切的关系,用哲学中的辩证思想来分析数学中的思想方法,对我们深入了解数学的本质,特别是了解与掌握数学思想方法,提高解决数学问题的能力,是十分有益的。     

一道课本习题引发的探究

1原题再现 苏教版高中《数学4》（必修）第51页“探究与拓展”第19题为： 一铁棒欲通过如图1的直角走廊,试回答下列问题：     

明党参、峨参种群分布格局的比较研究

应用邻接格子法研究了濒危植物明党参(Changium smyrnioides Wolff)及伞形科另一种药用植物峨参(Anthuiscus sylvestris(L．)Hoffm．)不同生境的种群分布格局．明党参的格局规模在0．64m^2的区组上均为集群分布，在其余4个小组上分布格局存在差异；峨参在所研究的格局规模上均为集群分布，且在0．04m^2上集聚度最大．峨参个体密集度大，还有无性繁殖，因而在受到采挖时可以较快恢复；而明党参密集度低，生长时间长，更新速度慢，受到采挖和人类土地利用干扰后种群不易恢复，可能是其日益稀少和濒危的原因之一．