Karyotype Studies On Three Common Species Of Ficus

Ficus L. which is belonging to Moraceae, includs 4 subgenus and about 1000 species, is a kind of trees possessing various ornamental value. At present, there are mang studies about Ficus L., which mainly centralized at figs-pollinators mutualism relation and biological feature of some fig trees. There are little of cytological studies about Ficus L.. Therefore, the chromosome karyotype of F. altissima, F. religiosa L. and F. microcarpa were investigated with the conventional pressing plate method, by which, I wish to provide some import refence to relationship researches, cross breeding, classification and identification etc. of Ficus L., lay a foundation of another studies of Ficus L.. The results showed:1,The seeds of F. altissima, F. religiosa L. and F. microcarpa are very small. The effects of conventional squash with different length of root-tip were studied. The reselts showed that the cells of meristematic zone were fewer after squashing when the length of root-tip were longer, which affacted on observation. The length of root-tip which were shotter made against operation. The suitable length of root-tip were 0.3-0.5cm.2,The stage of conventional squashing. The pretreatments of F. altissima, F. religiosa L. and F. microcarpa were unanimous basically. The best pretreatment method was mixture (0.05% colchicine and 0.002 mol·L-1 8-hydroxyquinoline by volume ratio 1:1) with lower temperature at 4℃for 24h. But the differences of three pretreatments of F. religiosa L. were not significant, what is the other two pretreatments(0.05% colchicine with lower temperature at 4℃for 24h and 0.002 mol·L-1 8-hydroxyquinoline with lower temperature at 4℃for 24h) were relatively suitable for F. religiosa L.. The root-tips were fixed with Camoy solution for 18-24 h in the dark. The differences of dissociation methods of three plants were significant. The best dissociation method of F. religiosa L. was 1 mol·L-1HCl with 60℃lasted 1-2 min. The best dissociation method of F. altissima was 1 mol·L-1HC1 with 60℃lasted about 1 min. The best dissociation method of F. altissima was 1 mol·L-1HCl with 60℃lasted 2-3 min. The stained with modified Carbol fuchsin solution. 3,The number of chromosome of F. altissima, F. religiosa L. and F. microcarpa are 2n=30.4,The karyotype formulae of F. altissima was 2n=2x=30=22m(2SAT)+6sm+2T, the average length of chromosome was 2.80μm, belonging to "2C" type. Its index of Asymmetric was 61.54%. The karyotype formulae of F. religiosa L. was 2n=2x=30=24m(2SAT)+6sm, the average length of chromosome was 3.30μm, belonging to "1B" type. Its index of Asymmetric was 60.28%. The karyotype formulae of F. microcarpa was 2n=2x=30=28m(2SAT)+2sm, the average length of chromosome was 3.44μm, belonging to "1B" type. Its index of Asymmetric was 58.16%. The chromosome of three plants were belonging to miniature or medium type chromosome, and all of them included a pair of satellite chromosomes. F. altissima is significantly different from F. religiosa L. and F. microcarpa in karyotype, but the differences between F. religiosa L. and F. microcarpa is not significant.5,The order of asymmetry index of F. altissima, F. religiosa L. and F. microcarpa is F. microcarpa<F. religiosa L.<F. altissima. F. altissima has a distant relationship to F. religiosa L.and F. microcarpa, F. religiosa L.has a near relationship to F. microcarpa. It is showed that F. religiosa L.and F. microcarpa may order than F. altissima.