Research On M₁Population Derived From EMS Treatment In Polygonum Capitatum Buch.-Ham.ex D.Don

Polygonum capitatum Buch.-Ham.ex.D.Don is a kind of perennial wild medical plants widely distribute in China, it is of high economic and ornamental value. By taking the local P.capitatum seed in Chongqing Beibei selected as the research material.The change of morphology,appearance performance, the physiological and biological index of the plant under different concentrations (Ck、0.2%、0.4%、0.6%、0.8%) and immersing times (12h、24h、36h、48h、72h) were observed and measured. Through the observation and assay of the rate of germination, seedling formation and the growth of the young seedlings of the M1generation which were germinated from the seeds mutation with different dosages.165mutants of morphology were selected from the M1generation, The main results were as follows:1.P.capitatum were treated with EMS of five concentrations(0%,0.2%,0.4%,0.6%,0.8%) and four treatment times (12h、24h、36h、48h、72h) resulted in0.6%EMS24h and0.8%EMS12h treatment were Semi Lethal Dose。The effect of the EMS mutation on the rate of germination and seedling showed that the relatively low dosage of the EMS could stimulate the germination to some extent while the high restrained it. Simultaneously,the speed of the germination was delayed with both the low and high dosage.2.The field screening of the mutants of the morphologies of1415seedlings of the M1generation were analyzed and165mutant plants were selected, the mutation frequency is37.5%. Only the lowest height of mutant was found for the plant height mutation. Both the forward and negative mutating directions were found of the length and morphological index of leaf while only the negative mutating Was found of the leaf area. The most forward mutation was found to be the average width of the plant, and the next is the height. Most of the mutants were found with the0.6%,0.8%treatment.(1) Plant height mutation:The effect of chemical mutation on the characteristics of the young seedling showed that the low dosage as0.2%could stimulate the growth while the high restrained it. The restraining effect was obvious on the plant height, With the increasing of the dosage of the mutation, the degree of restraining was enhanced. The average plant height is57.80cm, while the average for the mutant plant height is85.93cm, among them, the highest plant height of is112.92cm, the minimum is21.20cm,The result of influence of EMS on the height showed that:0.2%>CK>0.4%>0.6%>0.8%, while the height showed that:139cm、112.7cm、92.4cm、71.5cm and33.2cm;(2) Leaf mutation:Morphological variation of M1was mainly induced by mutagens which made the plant physiological process into disorder. In the M1generation received50leaf mutation strains, the mutation frequency is5.53%. Leaf mutation traits contained greenish leaf, wrinkled leaf, up—curly leaf, down-curly leaf, the area of contrast average leaf is8.971cm2, mutant leaf averaged area is11.456cm2, The result of influence of EMS on the area showed that:0.2%>0.8%>0.6%>0.4%> CK;(3) Anthocyanin content mutation:The average anthocyanin content is0.9115g/100g, while the average for the mutant plant anthocyanin content is0.6544g/100g, amongthem,the highest anthocyanin content is1.5775g/100g, the minimum anthocyanin content is0.2615g/100g;(4) Sterility mutations:EMS could advance P. capitatum growth duration and in M1generation,the average weight of seeds are1.0905g,while the mean weight of the mutant plants’are0.8266g.3.Research on filter oriented drought—tolerant mutantation showed that0.4%concentration of EMS got the best result at drought—tolerant mutantation; the formation rate of P. capitatum redued by increase processing concentrations.Cultivated by directional filter plant got significantly improve their drought tolerance, through physiological and biochemical identification.(1) In the arid environment, the water content of leaves of declined with the drought stress.the plants of were restrained under drought stress.they were wilting lightly and the leaves got curled,there were more thichomes on the surface layer of the leaves in the7th day without watering.the membrane permeability of the mesophyll, the soluble sugar content of increased severely when the plants were under drought stress.but when watered normally,the plants returned to fresh. The result of water content of P. capitatum leaves showed that:0.2%> CK>0.4%>0.6%>0.8%, while the water content showed that:52.3%,47.8%,43.8%,43.0%and42.1%, no significant difference were observed between EMS and contrast Polygonum capitatum.Based on the above stated physiological indicators, drought resistant mutants might exist in the0.4%EMS.