国产葛属植物花粉形态的研究

POLLEN MORPHOLOGY IN GENUS PUERARIA DC. FROM CHINA

对国产葛属ＰｕｅｒａｒａｉＤＣ．７种１变种植物花粉的光学显微镜、扫描电镜以及２种１变种的透射电镜观察表明：花粉形态各具特征；表面纹饰类型包括穿孔状（一般直径小于网脊直径或稍等，孔穴中无或少颗粒）、细网纹（网眼直径约与网脊直径相等或略细，网眼内具颗粒）、粗网纹（网眼直径大于网脊直径、网眼内具成片的众多颗粒）；孔沟类型为具孔膜或孔盖，孔膜常成孔桥．上述结果，表明葛属植物７种１变种的花粉形态是有区别的，从覆盖层等形态结构可以推测其亲缘关系，亦可看到部分的演化．

The morphological characters such as size, shape, apertures, furrow, exinestratification, tectum pattern, etc. of pollen in seven species and one variety of the genusPueraria DC. (P. lobata, P. lobata var. Montana. P. thomsonii, P. alopecuroides, P. calycina,P. edulis, P. Peduncularis and P. phaseoloides) from China were studied under LM andSEM; two species and one variety of them were studied under TEM. The results are as follows.Under LM, the tricolporate of a single pollen grain is subspherical, spherical andwide elliptical in shape in equatorial view, and 3-lobed circular in polar view. The sizeof pollen grain is generally constant; the length of polar axis is 18-34μm, mostly25.5- 28.5μm.Under SEM, the oramantation of the pollen grain may be divided into three types: (Ⅰ)perforate type, the diameter of pollen grain is generally less then or nearly equal to that ofmurus, no or only a few granules are present in the lumina; (Ⅱ) fine reticulate type, the diameter of lumina is nearly equal to or slightly smaller than that of murus, and there aregranules in the lumina, (Ⅲ) coarse reticulate type, the diameter of most lumina is longerthan that of murus and with numerous granules in the lumina. The pore type are: (1) thepore with membrane or sometimes operculum; (2) pore membrane often appears as bridgecrossing the colpus.Under TEM, the pollen grain has complete exine with sexine (including tectum,columella, foot layer) and nexine. The sexine is thicker than nexine, the tectum is thick,the foot layer is extremely thin.The morphological characters are varied within subsection or between subsections. Vander Maesen put P. lobata complex (including P. lobata var. lobata, P. lobata var. montana,and P. lobata var. thomsonii), P. alopecuroides, P. calycina and P. edulis under the samesubsection. Chen Zhongyi considered the P. lobata var. thomsonii as a species.It is suggested that the evolutionary trend of the ornamantation of the pollen grain is fromsubpunctate type to fine reticulate, then to course reticulate type. It corresponds withFerguson's idea. According to the oramantation Pueraria lobata is a more primitive species,and P. lobata var. montana and P. alopecuroides are closely related to P. lobata; all of thembelong to perforate type. P. thomsonii and P. edulis belong to fine reteculate type, while P.calycina to coarse reteculate type and they seem to be more evolutionary species in thesubsection.P. peduncularis and P. phaseoloides have coarsely reticulate ornamantation; the aperturemembrane is generally indistinct and the equatorial colpus bridge is usually present. There aremuch differences from the subsection mentined above.