我国特有珍稀濒危植物银缕梅(Parrotia subaequalis)的花粉形态研究

采用光学显微镜和扫描电镜对产自安徽省大别山金缕梅科银缕梅(Parrotia subaequalis)的花粉进行了观察和研究。银缕梅花粉粒近球形或长球形,P/E(极轴/赤道轴)=1.27(1.14-1.32),赤道面观椭圆形,极面观圆三角形或三裂圆形,大小为37.3(32.0～41.0)×29.4(25.0～36.0)μm。具3沟,沟狭长,几达两极。花粉外壁厚2.0～2.4μm,外层与内层近等厚,柱状层基柱发达。外壁纹饰在光镜下为细网状,在扫描电镜下为粗网状纹饰,网脊上有刺瘤。现生银缕梅具有鲜明的生境和分布格局特点,本研究为利用地层中银缕梅化石花粉重建古环境、古气候等提供了现代孢粉学参考依据,也为研究金缕梅科的起源、演化和现代地理分布提供了科学依据。

POLLEN MORPHOLOGY OF AN ENDANGERED ENDEMIC SPECIES,PARROTIA SUBAEQUALIS

Pollen grains of Parrotia subaequalis from Huangwei Town,Yuexi County,Anhui Province are examined under LM and SEM.The result shows that under LM,the pollen grains are prolate sphesoidal and trilobate circular in polar view,with exine 2.0-2.4μm thick.The inner layer and the outer layer are nearly equal in thickness.Under SEM,pollen grains are nearly prolate or subprolate in equatorial view and trilobate circular in polar view with 3colpi.Pollen grains are small to medium in size,37.33×26.04μm in average.Its P/E is 1.44.The aperture is tricolpate,colpi long and narrow,extending close to the pole.Exine fine reticulate under LM and coarse under SEM,with spines on ridges of lumina.Shaniodendron subaequalis has unique characters of habitat and the modern distribution,which will then be especially helpful for the use of this pollen in reconstructing the palaeovegetation,palaeoclimate and palaeoenvironment.It also helps the study of the origin,evolution and modern geographical distribution of the family Hamamelidaceae.