The Induction Of Autotetraploid Of Siraitia Grosvenorii Via Tissue Culture

In this study, the seedlings and the tube plants of Siraitia grosvenorii were treated with colchicine to induce autotetraploid via tissue culture. The results showed that the effect of colchicine on S. grosvenorii was getting chimaera. The plants were regenerated by the technique of cutting apical buds and inducing multiple shoots, and then autotetraploid were separated. Colchicine was used dipping on growing point of seedlings for four times at concentrations of 0.1%, 0.2 %, 0.4 %, respectively. It was found that the treatment of 0.2% or 0.4% concentration for four times were better than that of 0.1%, resulting in 55% and 75% induction rate, respectively. Colchicine mixed with 0.3% agar promoted inducing autotetraploid. The results showed that the seedlings were treated with 0.1% colchicine mixed with 0.3% agar, resulting in 60% of variants. The desirable way was to treat the seedling growing point with 0.2% colchicine mixed with 0.3% agar for four times or 0.4% for two times, which induced 80% and 90% of variants, respectively.The shoot tips detached from the seedlings and tube plants were cultured for three days, and then were treated by colchicine with concentration of 100mg/L, 300mg/L, 500mg/L for 3, 5, 7 or 10 days, respectively. The results showed that the desirable concentration for inducing autotetraploid of seedlings shoot tips were treated with 100mg/L for 10 days, or 300mg/L for 7 days, or 500mg/L for 3 days and 5 days, respectively, which induction rates were from 80% to 100%. When the shoot tips detached from tube plants were treated with colchicine added into medium, and then were cultured directly, the induction rate was zero. In order to increase the induction rate, the shoot tips were cutting into 0.5-1.2 mm after treated with colchicines, and then were induced multiple shoots. When the regeneration buds grow up, the diploid plants were cutting for 1-3 times in order to promote the variation buts growing. The results indicated that the desirable way for inducing autotetraploid of shoot tip detached from tube plants was treated with 300mg/L for 10 days, 500mg/L for 7 days or 10 days, respectively, which induction rate was 60%, 66.7% and 73.3%, respectively. The leaf tissues of chimaera were cultured on the MS medium added different concentration plant hormones. The medium containing 6-BA5.0mg/L+NAA0.1mg/L was desirable for inducing adventitious buds. The differentiation rate of adventitious buds was up to 100%. The tetraploids separated from regeneration plants were complete polyploid.When tube plants of autotetraploid were subcultured on medium supplemented with 6-BA0.3-0.5mg/L and NAA0.02mg/L, their propagation coefficient were 3.0 in a month. Morphological and anatomical studies showed that the stem of autotetraploid was shorter and thicker than that of diploid. The leaf was wider and thicker than that of diploid. The leaf base was close. The color of leaf was much deeper. The hair of leaf was larger and longer. The results also showed that the size of stoma and guard cells were larger than that of diploid. The number of chloroplasts in a stomatal guard cell obviously increased with the chromosome sets added. The characters of morphology and anatomy could be as an index of tube plant of autotetraploid identification.Some morphological characters and breeding habit between the autotetraploid and diploid of S. grosvenorii were compared in this study. The results indicated that some organs of autoteraploid were larger compared with the diploid plants. The twig was stronger and the hair of young leaf was thicker. The leaf was wider and thicker. The leaf base was close. The leaf was bottle-green. The petal and ovary became bigger obviously. But the plant growth and development of autotetraploid was slower, so the time climbing the shelf was later and the branch stem was less than that of diploid plants. The flowering phase of autotetraploid plants was later. Some male flowers were sterile and the setting rate of female plants decreased obviously. The fruits became less and shorter a...