龙牙花不同花器官的表皮形态

The Epidermal Morphology of the Flower of Erythrina corallodendron

花的光合作用与气孔密度密切相关,但关于在花生长过程中气孔密度如何改变尚未见报道。以龙牙花(Erythrina corallodendron)花为实验材料,将花的生长期分为6个阶段,采用光学显微镜对不同阶段的花萼、旗瓣、翼瓣、龙骨瓣、雌蕊托、子房、花柱、花丝和花药表皮的形态特征、表皮细胞密度、气孔密度、保卫细胞长度及宽度进行研究,并对其光合作用的能力进行测定。结果发现:除了翼瓣和花丝表皮以外,气孔均分布在花朵的其它器官表皮上,如花萼、旗瓣、龙骨瓣、雌蕊托、子房、花柱和花药。气孔复合体主要有无规则型、平列型以及辐射型,但不同花器官存在的气孔类型具有差异。在花萼、旗瓣、龙骨瓣、翼瓣以及花丝生长过程中表皮细胞密度逐步下降,表明其生长主要由表皮细胞扩大引起;大部分花器官如花萼、旗瓣、龙骨瓣、雌蕊托和子房表皮的气孔密度在其生长中后期趋于稳定,然而其保卫细胞长度和宽度的变化规律具有多样性。旗瓣不进行光合作用。

Flowers can undergo non-foliar photosynthesis,which is mainly affected by stomatal density.However,quantitative information on changes in stomatal density during flower development is still lacking.In the present study,Erythrina corallodendron flowers were classified into 6 developmental stages.The epidermal morphology,epidermal cell density,stomatal density,guard cell length and width of flowers were investigated at each stage by light microscopy.Photosynthesis of flower organs was also measured.Stomata were on the surface of sepal,vexilla,keel,anther,gynophore,ovary,and style but not wing or filaments.Flower organs showed anomocytic,paracytic,and actinocytic stomatal complexes.However,ontogenetic changes in stomatal complexes varied considerably among flower organs.Epidermal cell density on the surface of sepal,vexilla,keel,wing and filaments decreased with flower development,which suggests that the growth of sepal,vexilla,keel,wing and filaments were mainly due to cell expansion.Stomatal density of most flower organs,such as sepal,vexilla,keel,gynophore,and ovary,did not change markedly at later developmental stages.Changes in guard cell length and width varied considerably among different organs during flower development.Unlike the leaves,vexilla did not undergo photosynthesis.