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Embryological Studies in Polygonatum humile Fisch. ex Maxim


 Embryology of Polygonatum humile Fisch.ex Maxim.was studied in the present work.  The anther was found to be 4-sporangiate.  The tapetum,of which each cell contained two or many nuclei at the late stage,  was the Glandular type.  Metosis of the microspore mother cells was accompanied by successive cytokinesis,and resulted in isobilateral  and tetrahedral tetrads.  The mature pollen grains were of 2-celled type.  The ovary was  trilocular. The placentation was axile,but the sutures of carpels were not fully fused in the center of the ovary above the placentas.  The ovule was biteguminous,  crassinucellate and  anatropous.The micropyle was formed by the inner integument.The development of the  embryo sac was of the Allium type.Raphides were observed in the ovary wall and the outer
integument after fertilization.The development of the embryo was similar to the Asterad  type.The endosperm was of the Nuclear type.  The gigantic endosperm nucleus was formed  and not cellulated at the chalazal end. According to the data from the present and previous  works,the embryological characters of Polygonatum were described.The concept and circumscription of the tribe Polygonateae proposed by Dahlgren et al.(1985) were discussed  with the comparison of the embryological data in and out of the tribe.Meanwhile,the systematic relationships between the genera of the tribe were also discussed.


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