The Effects Of Colchicine Treament On The Mutagenesis Of Diploid Oats And The Characteristics Of Mutant Strains

Diploid oats have the advantages of strong adaptability,drought tolerance and cold resistance,but they also have disadvantages of lower plant height,weak stems,small seeds and less foliage.In this experiment,diploid oat Avena nudibreris and Zy003619(Avena hispanica L.)were treated with colchicines at different concentrations(0.05%,0.1%,0.15%,0.2%)and time duration(3 h,6 h,9 h,12 h,24 h,36 h,48 h);the changes of chromosome number and structural characteristics of the root tip cells of germchit were analyzed.The growth period,stem diameter,plant height,blade length and width,and chlorophyll content of tetraploid and and normal diploid were compared.The main results are as follows:(1)The effects of colchicine concentration,treating time and their interaction on the mutagenicity of diploid oats were significant(P < 0.05).The diameters of plumule and radical of mutant seedling obviously increased,but their length was shortened sharply.The variation rate of seedling increased with the colchicine concentration and the extension of treatment time.However,the survival rate of seedling decreased sharply,and the survival rate was zero after more than 24 hours treatment.(2)Colchicine treatment of diploid resulted in chromosome variation in root tip cells(2n=2x=14,2n=3x=21 and 2n=4x=28).The proportion of tetraploid was the highest(22.33%)under the treatment of 0.1% colchicine +12 h for Avena nudibrevis;and the highest value(23.00%)was observed under the treatment of 0.15%+9 h for Zy003619.(3)Colchicine treatment resulted in different variation degrees in chromosome structure of oats.The different ploidy chromosomes contains ‘m' and ‘sm' chromosomes,and the number of chromosomes with chromosome length and arm ratio greater than 2 was not different from that of the control group,and the karyotype was “2A” type.(4)Colchicine treatment had a significant effect on the growth period of the experimental materials.The growth period of the tetraploid was longer than that of diploid.The average growth period of variant of Avena nudibrevis was 126 days,25 days longer than that of control.The growth period of variant of Zy003619 was 109 days,11 days longer than that of control.(5)Compared with the diploid,the morphology of the tetraploid had the characteristics of dark green leaf,stout stems and large leaves.The stem diameter,plant height,leaf length and width,chlorophyll content were increased compared with the control.(6)Colchicine had a significant effect on the cytological characteristics such as stomatal guard cell size in the leaf epidermis.Compared with the control,the stomatal length of the variant of Avena nudibrevis increased by 29.36%,the stomatal width was increased by 97.30%,the length of guard cells increased by 38.24%,the width of guard cells increased by 40.54%,and the ratio of its length and width was 1.81.Compared with the control,the stomatal length of the variant of Zy003619 increased by 10.09%,the stomatal width increased by 68.57%,the length of guard cells in leaf epidermis increased by 15.95%,the width of guard cells in leaf epidermis increased by27.95%,the ratio of its length and width was 2.09.