Influence of Female Cones on the Branch Growth of Pinus tabulaeformis

The research on the relationship between reproductive and vegetative growth of Pinus tabulaeformis was carried out in 1995 and 1997.Branches bearing two year old female cones initiated nearly same second growing buds,lateral shoots and female strobili as vegetative branches.Neither the number nor the weight of female cones influenced the length of second-growing buds.However,the growth of current terminal shoots was reduced on female cone-bearing branches,and the number of lateral latent buds was increased.There are significant differences in current terminal shoot length,total length of lateral shoots and second-growing terminal bud length among clones,whereas no significant differences in the number of second buds,lateral shoots and lateral latent buds.The direct path coefficients of total dry weight of parent branches and types of branches to current total dry weight are 1.234 2 and 0.440 0 respectively,their direct contributions to multiple decisive coefficients 0.786 0 and 0.349 6 respectively.Branch units with two year old female cones produced significantly more total dry weight in the current year than vegetative branch units.Branches bearing female cones allocated between 35% and 60% of the current year’s dry weight to two-year-old cones and between 0.1% and 1.5% was allocated to one-year-old female cones.Female cones therefore apparently do not reduce the photosynthetic potential of trees.However,female cones definitely reduced the nutrition of whole tree,which directly resulted in periodic yield of cones bearing on branches in seed orchard.In addition,proper sampling and the effect of growth of female cones on vegetative growth of trees were discussed.