Optimization of the Chromosome Production Technology of Gueldenstaedtia verna and Its Karyotype Analysis

The effects of different pretreatment methods and pretreatment time on the chromosome production were explored by using the conventional tabletting method with Gueldenstaedtia verna as the tested material, in order to optimize the chromosome production technology. And the chromosome karyotype analysis was carried out to provide the cytological basis for the classification of Gueldenstaedtia verna, the preservation & utilization of germplasm resources and its breeding. The results showed that: (1) When the pretreatment time was 3 h, the pretreatment effect of 0.1% colchicine solution was the best, while when the pretreatment time was 6 h, the pretreatment effect of 0.01% colchicine solution was the best. There were many division phases, the degree of chromosome condensation was suitable, the dispersion was better, and the morphology was clear. (2) The chromosome number of somatic cells of Gueldenstaedtia verna was 2n=2x=14, which was a diploid plant. The karyotype formula was K(2n)=2x=14=10m+4sm. The chromosomes with the metacentric chromosome (m) were the 1st, 2nd, 3rd, 4th and 7th pairs of chromosomes, and the chromosomes with the submetacentric chromosome (sm) were the 4th and 5th pairs of chromosomes. The composition of the relative length of chromosome was 2n=14=2L+8M2+4M1, the length ratio of chromosome was 1.30, and there were no chromosomes with the arm ratios greater than 2, which belonged to the ″1A″ type and was a symmetrical karyotype, indicating that the Gueldenstaedtia verna was a relatively original type in the evolution.