塞威氏苹果花粉形态研究及其演化的探索

STUDIES ON THE POLLEN MORPHOLOGY OF MALUS SIEVERSII(LED)ROEM AND THE EXPLORATION F ITS EVOLUTION

塞威氏苹果花粉圆球形、近长球形或长球形。３沟，萌发孔３个环列于３沟中央，孔沟属Ｎ＿３Ｐ＿４Ｃ＿５型。外壁条穴纹饰或条穴附属物纹饰。花粉的大小与其Ｐ／Ｅ值成正相关。伊犁地区塞威氏苹果（新疆野苹果）花粉的Ｐ／Ｅ值较中亚地区本种花粉的Ｐ／Ｅ值为大。前者较后者原始。初步认为，中亚的塞威氏苹果的自然分布区应是后生分布区。

The pollen of Malus Sieversii(Led.)Roem shapes spheroidal,subprolate or prolate,with 3-colpi and 3-zonotreme in the middle of the colpi.The colp-orate belongs to N_3P_4C_5 type,exine striate-favolate pattem or striate-favolate-subsidiary pattem. The polar value and P/E value of the pollen grains presnts positlve correlation. From the view-point of the svstematical development, the pollen grain in the west part of Xinjiang,China,is more primitive than that in the region of the Central Middle Asia(i.e. in the former Soviet Union). As the P/E value of the M. Sieversii(Led.)Roem pollen grain from Xinjiang is larger than that of the Central Middle Asia,so we believe that the region of the Central Middle Asia should not be a primitive geographical distribution area of M. Sieversii(Led.)Roem,but a meta-geographical distribution region.