木槿叶片结构的发育可塑性研究

对4个木槿种下类群叶片结构的发育可塑性进行了比较研究。(1)木槿 4 个种下类群的叶片在栅栏组织厚度、下表皮厚度、上表皮气孔密度、上下表皮气孔密度比,叶片厚度以及中脉维管组织等性状上均表现出较大的发育可塑性,这种可塑性对叶片适应植株光热综合因子的时空异质性具有重要意义。(2)木槿 4 个种下类群的同类型叶片在解剖学性状上的变异很小,即性状具有很大的稳定性。针对这一特点,对 4 个木槿种下类群一年生茎初生叶片结构的比较研究表明,紫花单瓣木槿和白花重瓣木槿之间的亲缘关系较近,雅致木槿和牡丹木槿亦存在较近的亲缘关系。研究结果支持将牡丹木槿和紫花单瓣木槿提升为亚种等级,并建议将白花重瓣木槿和雅致木槿分别看作紫花单瓣木槿和牡丹木槿的变型。

A study on developmental plasticity of leaf blades structure of Hibiscus syriacus

The developmental plasticity of anatomic characters of the leaf blades in 4 infraspecies of Hibiscus syriacus is studied.(1)In the process of ontogenesis in the 4 infraspecies of H.syriacus,developmental plasticity,which takes very important roles in adaptation to the spatial and time heterogeneity of habitat encountered by leaves,happened greatly in anatomic characters of the leaf blades,such as thickness of palisade tissue,lower epidermis,density of stoma in upper epidermis,stoma density ratio of upper epidermis and lower epidermis,thickness of leaves,and vascular tissue,etc. (2)According to the trait that there are little variation occurred in anatomic characters of the same type of leaf blades,or the anatomic characters are greatly stable,A comparative study on anatomic characters of the leaf blades in 4 infraspecies of H.syriacus is conducted. The results show that H.syriacus f.albus-plenus is closer to H.syriacus f.syriacus relationship in one hand,and in the other hand,H.syriacus f.elegantissimus is closer to H.syriacus f.paeoniflorus. These support the propose to regard H.syriacus f.paeoniflorus and H.syriacus f.syriacus as subspecies of H.syriacus,and suggest that H.syriacus f.albus-plenus and H.syriacus f.elegantissimus should be treated respectively as forma of H.syriacus Linn.subsp.syriacus and H.syriacus Linn.subsp.paeoniflorus(Gagnep.)G.R.Shi.