Effects of Root Zone Volume on the Growth of the Main and Latreal Shoot in Gypsophila paniculate L.,Dianthus caryophllus L.and Dendranthema grandiflora Kitamura.

The effect of root zone volume on the growth of main and lateral shoot were studied for Gypsophila paniclulate L.,Dianthus caryophyllus L.and Dendranthema grandiflora Kitamura.Cell trays of four cell sizes(cell volume;6,12,21,63cm3)were used.One cutting was planted in each cell,and after rooting the experiments were srarted.At the same time twelve cuttings of each species rooted in 12cm3 cell were transplanted into wooden containers(38880cm3)for control.Ten days after the start of the experiments,half of the plants were pinched to investigate the growth of lateral shoots.In all the three spieces,the stem length was significantly increased with the increasing root zone volume.In Gypsophila this effect was observed after only 10 days,as compared with after 20 days in Dianthus and Dendranthema. The leaf area was highest for plants grown in the wooden container(control).Growing in small cells significiantly reduced the shoot and root dry weight.However,the root zone volume had little effect on the root :shoot ratio.The total number of lateral shoots,node number and total fresh weight were significantly increased with increases in root zone volume.In Dendranthema the lateral shoots had a srong tendency to elongate from almost all nedes even in the smallest root zone volume of 6cm3.In Gypsophila and Dianthus,the number of lateral shoots increased significantly with increases in the root zone volume.The strongest effect of root zone volume on main and lateral shoot growth was observed in Gypsophila.The results showed that in all the species,a root zone volume of 12~21cm3 was optimal for transplant production using cell trays.