Abstract
This report deals with the cuttings of Pinus strobus L. which is one of the most favorable exotic trees in northern Japan.
1) Materials and methods
The cuttings with top buds were collected from the middle and the lower branches of two mother trees, one of which is a 4-year-old and the other a 45-year-old. The cuttings were cut at 0.5cm below the bases of top buds. The cut surface was treated with IBA in talc powder, 10mg/g. Only tap water was used for the control in this experiment. These cuttings were planted in pots of Red-soil (tall origin) beds obtained from the Kamigamo Experimental Site of Kyoto University Forests on 6 April of 1959.
These pots were kept in a shadeless green house for 16 days; then they were taken outdoors. Once a day, the pots were sprinkled with tap water.
2) Experimental resulte
A) In the cuttings collected from the 4-year-old mother tree, the IBA treated cuttings showed 95% rooting and the untreated ones showed 100% rooting, but the cuttings from the 45-year-old tree showed the callus formation at the bottom of cut base. at 81 days after planting.
Among the cutting collected from the 45-year-old mother tree, the IBA treated cutting group showed 40% rooting after 137 days, 50% at 147 days, and 60% after 157 days respectively, but none of the untreated ones showed rooting.
B) The root formation was obseved at the cut base and another position near soil surface.
C) Cuttings from the 4-year-old tree rooted much more and earlier than those from the 45-year-old.
