马来西亚部分豆科植物的花粉形态及其研究意义

Pollen morphological investigation on some Leguminosae species from Malaysia and its research significance

豆科(Leguminosae)植物是东南亚热带雨林中重要的乔木成分之一,其花粉形态分类对于精确重建植物群落具有重要的古生态学意义。本研究使用光学显微镜和扫描电子显微镜(SEM)对广布于马来西亚26种豆科植物花粉(隶属21属)进行了形态观察与描述。结果表明:花粉形态包括三孔、三孔合沟、三孔沟、九孔沟和多合体(16合)花粉等类型,其中,三孔沟型最为常见,占比65%;花粉形状以近球形居多,还有长球形和扁球形;花粉最大的为Albizzia(89.8μm×98.7μm),最小的为Ormosia bancana(18.1μm×19.2μm),花粉极轴长度在25~50μm占比77%;外壁纹饰以网状为主(53.8%),另外也有瘤状和光滑类型;根据SEM观察结果和已发表的豆科花粉形态资料,通过三孔沟型花粉不同体积、纹饰、孔的形状等特征可以比较好地将豆科花粉鉴定到属一级水平;各亚科[云实亚科(Caesalpinioideae)、含羞草亚科(Mimosoideae)、蝶形花亚科(Papilionoideae)]花粉有明显的形态差异。通过对花粉类型的母体植物生长环境的归纳,讨论了其对于不同植被群落的指示意义,为利用花粉化石记录重建古植被、古环境及气候演化提供依据。

Many Leguminosae species are important tree components in the tropical rainforests of Southeast Asia,the pollen types of which are of great significance for accurate reconstruction of past plant communities.Here,we used light microscopy(LM)and scanning electron microscopy(SEM)to observe and describe pollen morphology of 26 legume species from 21 genera,which are widely distributed in Malaysia.The morphological characteristics of these pollens are diverse,including triporate,syncolporate,tricolporate,9-colporate,and Polyad.Tricolporate type was the most common one(65%).The pollen shape was mainly spheroidal,others were prolate subprolate and oblate spheroid.The largest size of pollen was observed in Albizzia(89.8μm×98.7μm)and the smallest one was the Ormosia bancana(18.1μm×19.2μm).The pollens with polar axis length in the range of 25-50μm accounted for 77%of the total.Exine ornamentation was mainly reticulate(53.8%),but also included verrucate and psilate.Based on SEM observation and evidence in the literature,Leguminosae pollen can be better identified to genus level according to the different characteristics of the size,orientation and aperture of tricolporate type pollen.We found significant morphological differences among subfamilies(Caesalpinioideae,Mimosoideae,and Papilionoideae).With reference to the habitats of parent plants,we discussed their implication to indicate different plant communities and provided reference for the reconstruction of palaeovegetation,palaeoenvironment and palaeoclimate based on fossil pollen data.