EMS Mutagenesis Creates Lilium Davidii Var. Unicolor Mutants

Lilium davidii var.unicolor is a diploid wild lily native to China.The flower is gorgeous,shade resistant and cold resistant,which is a good product for landscaping,but the flower is small and difficult to survive in the saline alkali land.In order to improve the salt tolerance,alkalinity and ornamental value of Lilium davidii var.unicolor,this experiment was the first time to use EMS as a mutagen to mutate the scale of Lilium davidii var.unicolor.The mutant was identified by ISSR molecular marker technology.The phenotype,cytology and histology of the mutant were observed,and the mutant with excellent shape was preliminarily selected,which laid a foundation for the innovation of Lilium davidii var.unicolor germplasm resources.The main results are as follows:1.Different concentrations of EMS(0,0.4%,0.6%,0.8%)and treatment time(2 h,3 h,4h)were used to mutate Lilium davidii var.unicolor scales.The results showed that when EMS concentration was 0-0.8%,the survival rate and differentiation rate of scales decreased with the extension of treatment time;when EMS concentration was 0.8%,the treatment time was 2 h,the survival rate of scales was 60% and the differentiation rate was 50%.300 scales of Lilium davidii var.unicolor were mutated by this combination,and 400 strains were obtained.2.Different concentrations of Na HCO3(0,40 mmol·L-1,50 mmol·L-1,60 mmol·L-1,70mmol·L-1,80 mmol·L-1)were added to MS medium,and the test tube plantlets of Lilium davidii var.unicolor were treated with stress for 30 days.The results showed that the survival rate and rooting rate of plants were negatively correlated with the concentration of Na HCO3.when the concentration of Na HCO3 was 70 mmol·L-1,the survival rate of plants was 11%,all the plants were dwarfed and did not take root,the concentration of Na HCO3 suitable for induction of salt alkali mutants was 0-12%,so 70 mmol·L-1 was determined Na HCO3 is the stress concentration.600 scales of Lilium davidii var.unicolor were mutated by EMS at half lethal dose,and then grew into small bulbs(23-25 mm in circumference)under salt and alkali stress.3.The ISSR-PCR system of Lilium davidii var.unicolor was optimized,and 11 ISSR primers suitable for Lilium davidii var.unicolor were selected from 20 primers.Nine mutants were identified in 400 EMS induced plants and 100 salt tolerant plants,of which three were salt tolerant,with mutation rates of 1.5% and 3%,respectively.The results of ISSR-PCR showed that there were 24,404 bands in 400 mutant plants,including 16 polymorphic bands,and 6,097 bands in 100 salt tolerant plants,including 5 polymorphic bands,both of which were increased and lost.4.The phenotype,cytology and histology of 9 mutants were observed.It was found that5 mutants had morphological variation,which were as follows: seed ball expanded,leaves widened,plants dwarfed,bulbs not tightly clasped,1 mutant had no morphological variation,and 3 salt tolerant mutants had more green leaves.The guard cells of two dwarfing mutants and three salt tolerant mutants were significantly reduced,while the stomata and guard cells of the other mutants were significantly increased;the arrangement of palisade tissue and sponge tissue in the leaves of the widened mutants was completely opposite to that of the control,while the change of palisade tissue and sponge tissue of the other mutants was less.The cells in the scales of the mutant were closely arranged,and the cells in the scales of dwarf mutant,the mutant with poor bulb cohesion and the three salt tolerant mutants were large and orderly arranged,while the other mutants had little change.