细蔓点地梅在豫西南的发现及其微形态特征和系统演化意义

Discovery of Androsace cuscutiformis(Primulaceae)in Southeast Henan, China and its micromorphological characteristics and systematic evolutionary significance

关键词:  河南, 细蔓点地梅, 新记录, 叶表皮, 花粉, 系统演化

Key words:  Henan, Androsace cuscutiformis, new record, leaf epidermis, pollen, systematic evolution

摘要:

该文报道了河南报春花科点地梅属1新记录种,即细蔓点地梅(Androsace cuscutiformis Franch.)。该种因其叶片显著分裂,裂片深达叶中部,具有典型匍匐茎而明显区别于该属在河南分布的其它种类,同时编制了河南点地梅属植物检索表,并对该种的叶表皮和花粉形态特征进行了观察和描述。结果表明:该种上下表皮细胞都为不规则多边形,垂周壁深波状,下叶表皮具有椭圆形气孔器,上下表皮都具有坑状雕刻的多细胞毛和球状蜡质,叶表皮形态特征和毛的类型可能为点地梅属系统分类和演化提供参考。花粉椭圆形,具三孔沟,沟较狭窄,花粉外壁具有坑状雕刻,未发现有萌发孔,该种是点地梅属裂叶组内最小的花粉粒。裂叶组因叶大、具长柄、叶缘有齿或深裂而明显区别于该属的其它组,该种与其近缘种腋花点地梅(A. axillaris)和掌叶点地梅(A. geraniifolia)间断分布的地理格局和特殊的繁殖方式表明该种很可能为点地梅属的原始类群在伏牛山、秦岭南坡及大巴山的孑遗植物。

Abstract:

Androsace cuscutiformis is reported as a newly recorded species of Primulaceae from Henan. A. cuscutiformis is different from the others species of Androsace in Henan Province with distinctly stolons filiform and lobed leaf blade in the middle. Identification key is provided for Androsace indigenous to Henan Province. The micromorphological characte-ristics of the leaf epidermis and pollen of A. cuscutiformis were observed and described by light microscope(LM)and scanning electron microscope(SEM). The results were as follows both the upper and lower epidermal cells were irregularly polygonal in shape with anticlinal walls sinuate, the lower epidermis had elliptic stomatal apparatus, both the upper and lower epidermis had multicellular hairs with pit sculpture and globular wax, leaf epidermis and types of hair may provide definite reference for the systematic classification and evolution in Androsace; the pollen was elliptic with tricolporate, colpi was narrow, the exine ornamentation of pollen was microechinate without endoaperture, A. cuscutiformis had the smallest pollen in the sect. Samuelia which are different from other groups in Androsace had broad blades, long petioles and dentate or lobed leaf blade. The disjunct distribution of A. cuscutiformis and its relative species A. axillaris and A. geraniifolia and special reproductive mode are likely to indicate that A. cuscutiformis is the relict plant of the primitive group of Androsace in the Funiu Mountain, the southern slope of Qinling Mountains and Daba Mountain.