Tissue Culture And Karyotype Analysis Of Catha Edulis

Khat (Catha edulis) is a large,thornless,flowering evergreen shrub,having manyarticulate branches.Gatha edulis originated in Ethiopia,but now was widely cultivated as animportant economic crop in many countries, such as in Kenya, Uganda, Tanzania, Arabia,Congo, Zimbabwe, Zambia, South Africa,and so on.In this paper two parts has been included: one is about the tissue culture of Cathaedulis,another is the study on karyotype of Catha edulis.The stem segment with bud of Catha edulis were used as explants in study of tissueculture to establish a rapid and efficient technique system of engendering adventious buds.The explants were sterilized by C₂H₅OH for 10 seconds and then HgCl₂ for 8 min,NaClO for 10 min and the pollution frequency can be effectively decreased. In primary culture the best effective medium for inducing adventious buds is MS-B5+BA3.0mg/L+NAA0.25mg/L,for inducing callus is MS-B5 + BA 1.0 m g/L+2,4-D2.0mg/L.In subculture stage using the medium MS- B5 + BA 1.0 m g / L + NAA0.1mg/L,proliferation rate could reach about 5.3 after 30 days, increasing the level of BA could be benefical to the differentiation of bud,and the increasing NAA level could restrain the process of bud differentiation .In the study on karyotype of the Catha edulis, Using the regular method of studying chromosome,the number of chromosome and karyotype were studied with the bud-tip from the three Euonymus family plants(they are respective purple bud and green bud Catha edulis belonged to Catha edulis genus and the Euonymus japonicas L. belonged to Euonymus genus.The result showed that green bud Catha edulis normal diploid 2n=32, 6L+8M₂+8M₁+10S,karyotype formula was K(2n)=32 =11m (2SAT) +5sm which belong to"2B" type,the AS.K% was 61.48%. Purple bud Catha edulis normal diploid 2n=32, 4L+3M₂+3M₁+6S,karyotype formula was K(2n)=32 =11m (2SAT) +5sm which belong to"2B" type,the AS.K% was 60.844%. Euonymus japonicas L. normal diploid 2n=32, the relative length was 2n=32=3L +3M₂+7M₁+3S, karyotype formula was K(2n)=32=10m(2SAT) +6sm, AS.K% was 63.05%,,Besides,In the process of studying Catha edulis chromosome,some important steps...