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Bulletin of Botanical Research ›› 1985, Vol. 5 ›› Issue (1): 113-126.

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THE DEVELOPMENT OF THE GAMETOPHYTES OF PINUS KORAIENSIS

Jin Chun-ying   

  1. Dpartment of Forestry North-Eastern Forestry Institute Harbin, Heilongjiang
  • Online:1985-03-15 Published:2016-06-13

Abstract: The period of pollination of Pinus koraiensis is from June 8 to 20. During June 25-30, pollen grains germinate on the nucella, forming pollen tubes. On August 4, reproductive cells in the pollen grain divide mitotically into the sterile cells and spermatogenous cell. Next year, on June 3, spermatoge-nous cells divide into two male gametes of unequal size. Then in the pollen graint tube, a long ribbon is formed, with starch grain at the first place, followed by the tube nucleus, the ste-rile cell, the big male gamete and the small male gamete. Functional megaspores of P. kolaiensis divide five times du-ring July 5 to September 23, producing 32 free nuclei, then go into dormancy. In the next spring, free nuclei divide again.At the end of May, cell walls of female gametophytes are for-med between free nuclei. At the sametime, the archegonium initial is formed at the microphyle end of the female gamete, develo-ping into 1-4 archegonia, mainly 3;archegonium single, cover-ed with a layer of Jacket cells. Neck cells are of 1-2 layers.altogether 4 cells. on June 4, central cells begin to divide, con-tinuing the division till June 10, forming ventral canal cell and egg cell. From June 11. fertilization begins at the upper middle part of the egg cell.