Preliminary Research On Colchicine Induced Polyploidy And Abiotic Stress In Three Kiwifruit Cultivars

Kiwi is a perennial vine plant that is widely favored by consumers due to its unique flavor,flesh color,and high vitamin C,mineral,and dietary fiber content.Currently,there are about 54 species of kiwifruit plants in the world.Kiwifruit is dioecious,and male plants cannot bear fruit.The efficiency of cross breeding is low.Currently,most Actinidia chinensis in the industry have small fruit sizes,and chromosome doubling has been proven to produce better traits in fruit trees.In order to enrich the germplasm resources of Actinidia chinensis,this experiment selected three diploid varieties and strains of Actinidia chinensis,Yangshi Jinhong 50,Jinmi,and Hongyang’s preferred progeny strain ZPS-18.Firstly,the explants were cultured,and after obtaining the calli,three MS media with different hormone ratios were designed to select the most suitable media formula for the growth of the three types of Actinidia chinensis tissue culture seedlings,The calli of these three varieties were doubled with colchicine to induce individual lines.The polyploid plants were initially screened by morphological observation,and ploidy was identified by flow cytometry.Autotetraploid plants were obtained and domesticated and transplanted.At the same time,the changes in the contents of catalase(CAT),superoxide dismutase(SOD),peroxidase(POD),and malondialdehyde(MDA)in the leaves and stems of tissue cultured seedlings of Yangshi Jinhong 50 and its autotetraploid and diploid under salt stress,drought stress,and low temperature stress were analyzed,and the stress resistance mechanism of autotetraploid kiwifruit and its diploid ancestors was preliminarily explored in order to cultivate high-quality,high-yield New varieties of kiwifruit with resistance to stress,thereby enriching the germplasm resources of kiwifruit.The main research results are as follows:1.A rapid propagation system was established using the leaves of diploid Yangshi Jinhong 50,Jinmi,and Hongyang’s offspring ZPS-18 as explants.The best sterilization method for explants: 75% ethanol for 30 seconds,0.1% mercuric chloride for 4 minutes,and sterile water for 4 times;The medium for inducing callus was MS+ZT 1.0mg/L+2,4-D1.0mg/L;The optimal medium for adventitious bud proliferation was MS+6-BA3.0mg/L+ZT 2.0mg/L+IBA 0.1mg/L;The optimal rooting medium is 1/2MS+IBA 1mg/L,with a rooting rate of 85% and a transplant survival rate of 90%.2.Using colchicine solution to soak diploid callus meristems for autotetraploid induction.The results showed that soaking with 0.1% colchicine for 4 hours had the best induction efficiency,and the induction rate of Yangshi Jinhong 50 was 37% The induction rate of Jinmi was 24% The induction rate of ZPS-18 was 3%.3.In this preliminary comparative analysis of salt,drought and cold resistance in Yangshi Jinhong 50 autotetraploid and diploids,the activities of SOD,POD,CAT and MDA in leaves and stems under abiotic stress were measured.The results showed that the overall ROS activity in autotetraploid was higher than that in diploids under stress of adversity;Cell membranes were less damaged than diploid.Preliminary analysis concluded that autotetraploid are stronger than diploids in combating abiotic stress.