Growth and Nutrition Developmemt of Seed and Cone of Masson Pine

The growth and nutrition development of seed/cone of masson pine werestudied systematically during four years from l990 to l993.The results were as follows :(l)The cones of masson pine need two years to ripen.Formation period of young cone wasthat year after pollinating(in the first ten-day of April),rapid growth period was from June(before fertilizing)to the second ten-day of September in the second year,and riping periodwas from the last ten-day of September to October;2)In the growth period of 2-year-oldcone,dry substance weight increased and water content decreased gradually.Both arrived atbalance point at the end of October,i.e. before the end of October the water weight surpassed the dry substance and while after the end of October the dry substance surpassed thewater;(3)During the development of one-year-old cone,the change of N,K and P contentis similar to each other,and the N content of 2-year-old cone decreased gradually to be similar to the K content.N and K content of seed are matched in July. Since then N content decreased tiil riping period and was similar to P content in the second ten-day of October;(4)During the procedure of embryo development,the change of volume and nutrition content ofseed/cone were the greatest in the stage of proembryo and young embryo and then tended tolevel off gradually.