Study On The Biological Characteristics Of Colchicine-induced Polyploid Tea Chrysanthemums

Chrysanthemum is one of the top ten traditional famous flowers in China and one of the four cut flowers in the world.It has a long cultivation history and is widely used.Its cultivation area and yield are among the top in the world,and it has important ornamental and economic value.Tea chrysanthemum refers to a type of chrysanthemum that is suitable for drinking and has multiple effects such as dispersing wind,relieving heat,detoxifying and anti-inflammatory effects,and clearing the liver and brightening the eyes.With the improvement of people’s living standards,chrysanthemum culture has begun to popularize,and the application of tea chrysanthemum is gradually widespread,and the cultivation area is constantly increasing.Many tea chrysanthemums have problems such as shorter plant height,lower nutritional content,and weaker cold resistance.Therefore,it is important to cultivate tea chrysanthemums that grow more vigorously,have higher nutritional content,and have stronger resistance.Chromosome doubling is an important means of obtaining polyploid materials,and polyploid plants outperform diploid plants in phenotype expression.Numerous studies have shown that colchicine treatment of plant stem tips and other parts induces chromosome doubling,thereby breeding excellent varieties that meet people’s needs.Therefore,this experiment used the tea chrysanthemum variety‘Jinsihuangju’and the early flowering variety‘Qiyueju’,which currently have the largest cultivation area,as the test materials.The chrysanthemum stem tips were treated with concentrations of 0.05%,0.10%,0.15%,and 0.20%colchicine,respectively.After determining their chromosome doubling,the most suitable colchicine concentration for chromosome doubling of‘Jinsihuangju’and‘Qiyueju’was selected,Compare and analyze the morphological indicators,nutrient content,and cold resistance indicators of‘Jinsihuangju’and‘Qiyueju’with non doubled cuttings after doubling the optimal concentration.The main research findings are as follows:1.Colchicine treatment induced chromosome doubling in‘Jinsihuangju’and‘Qiyueju’,resulting in an increase in their stomata.Colchicine induced chromosome doubling in cells,and 0.10%concentration was the optimal colchicine treatment concentration.The length and width of stomata of the‘Jinsihuangju’leaf increased by 6.05%～9.32%and 4.22%～7.86%,respectively.The length and width of stomata in the leaves of‘Qiyueju’increased by 5.34%～8.43%and 4.02%～6.85%,respectively.2.Colchicine treatment promoted the growth and development of‘Jinsihuangju’and‘Qiyueju’.After colchicine treatment,the plant height of‘Jinsihuangju’and‘Qiyueju’increased respectively compared with the control.By 5.63%and 6.65%,stem diameter and leaf number increased significantly.This suggests that doubling chromosomes can make chrysanthemum plants more robust.3.Colchicine treatment increased the contents of total flavonoids,total amino acids and mineral elements in‘Jinsihuangju’and‘Qiyueju’.After colchicine treatment,compared with the control,the total flavonoid content of‘Jinsihuangju’and‘Qiyueju’Chrysanthemum doubled increased by 8.44%and 9.70%,and the total amino acid content increased by 5.25%and 7.51%,respectively.The mineral elements such as Ca²⁺,Mg²⁺,Fe²⁺and Zn²⁺of the two chrysanthemums also increased to some degree.These results indicated that the doubling of chromosome could increase the contents of total flavonoids,total amino acids and mineral elements of chrysanthemum,so that the quality of chrysanthemum was better and the nutrients were richer.4.Colchicine treatment increased the chlorophyll content of‘Jinsihuangju’and‘Qiyueju’.After being treated at-2℃for 9h,the chlorophyll content of the doubled‘Jinsihuangju’increased by 15.44%compared with the control group.After being treated at 0℃for 9h,the chlorophyll content of‘Qiyueju’increased by 10.52%compared with the control group.These results indicated that chromosome doubling could increase the chlorophyll content of chrysanthemum,utilize more light energy,increase the photosynthetic capacity of plants under the stress of adversity,and improve the cold resistance of chrysanthemum.5.Colchicine treatment increased the content of soluble sugar and soluble protein in‘Jinsihuangju’and‘Qiyueju’.After being treated at-2℃for 9h,the soluble sugar content and soluble protein content of the doubled‘Jinsihuangju’increased by 3.66%and 6.25%compared with the control group.After being treated at-2℃for 9h,the soluble sugar content and soluble protein content of the doubled‘Qiyueju’increased by 3.64%and 6.64%compared with the control group.These results indicated that chromosome doubling could increase the content of soluble sugar and soluble protein in chrysanthemum,and increase the concentration of plant cell fluid under the stress of adversity,so as to improve the cold tolerance of chrysanthemum.6.Colchicine treatment increased the SOD and POD activities of‘Jinsihuangju’and‘Qiyueju’.The doubled‘Jinsihuangju’was treated at 0℃for 9h,SOD activity increased by 8.05%and POD activity increased by 8.30%compared with control group.The doubled‘Qiyueju’was treated at 0℃for 9h,SOD activity increased by 12.09%and POD activity increased by14.71%compared with control group.These results indicated that chromosome doubling could increase SOD and POD activities of chrysanthemum,thus enhancing its cold toleranceIn short,0.10%concentration of colchicine treatment doubled the chromosomes of chrysanthemums,and the doubling chrysanthemum plants performed better in morphological indicators,nutrient content,cold resistance and other aspects,which was an ideal new germplasm for tea.