|Budget Amount *help
¥4,600,000 (Direct Cost : ¥4,600,000)
Fiscal Year 1995 : ¥1,100,000 (Direct Cost : ¥1,100,000)
Fiscal Year 1994 : ¥1,700,000 (Direct Cost : ¥1,700,000)
Fiscal Year 1993 : ¥1,800,000 (Direct Cost : ¥1,800,000)
The auther reported on the karyologycal studies of Criptomeria japonica that is the most important tree species for afforestation in Japan. Those results indicated that the karyotype of diploid C.japonica (2n=22), was classified into 3 types by the composition of F chromosome.
Therefore, the karyotype in C.japonica of triploid is separated into 4 types by the composition of F chromosome, such as Type 0 to Type IV.In this time, we detected Type 0 (Hita No.1 etc.), Type 1 (kuga No.1 etc.) and Type II (Hita No.18 etc.) of triploid C.japonica.
Next, the clear fluorescent signals of 45S rRNA gene were detected at the NOR of J chromosomes of C.japonica using the probes prepared by direct-cloning and direct-labeling methods.
On karyomorphological analysis of some species in Cupressaceae trees were carried out, also.
The species of Taxodiaceae could be separated into fourgroups bases on karyomorphology. Group I species have a pair of chromosomes consisting of a large arm, a small, rounded short arm and a large satellite connected to the small arm by an unusual secondary constriction. Cryptomeria japonica, C.fortunei, Gryptostrobus pensilis, Taxodium distichum, T.ascendens, Sequoiadendron gigantium, Taiwania cryptomerioides and Metasequoia glyptostroboides are included in this group. Group II incudes species having chromosomes with unusual secondary constrictions connecting a small telomere to the short arm. Species in this group are Cunninghamia lanceolata and Sequoia sempervirens. Group III contained a single species Taxodium mucronatum and was distinguished from the other groups by having both Group I and Group II secondary constrictions present. Group IV species had pairs of chromosomes with secondary constrictions differing from Group I and Group II types. Species in this group consisted of Athrotaxis cupressoides, A.laxifolia and A.selaginoides. The number of chromosomes with secondary constriction was consistent with the maximum number of nucleoli per cellfor each group.