关键词: 矮牵牛, 秋水仙素, 多倍体诱导, 种子；表型

Abstract: In order to obtain and identify Petunia axillaris polyploid in a short time，this study used 5% NaClO to sterilize the seeds of P.axillaris and treated them with different concentrations of colchicine，and then transferred them to MS medium for germination.Ploidy identification was performed by flow cytome ter.The optimal induction program was determined by comparing the effects of different colchicine con centrations on the induction rate.According to the difference analysis of initial phenotype，stomata and chlorophyll，the difference of morphological indexes in P.axillaris ploidy was counted.The results showed that P.axillaris tetraploid and octoploid with higher homozygous rate were obtained.While ensuring the survival rate of the mutant plants，the highest proportions of 4x(47.37%) and 8x(21.05%) were ob tained after treatment with 0.10% colchicine for 24 hours.Prolonging treatment time(36 h) could in crease the proportion of induced material with 8x ploidy( 33.33%) .The morphology，stomata and guard cells of different P.axillaris ploidy had the following rules: 4x was more rounded than 2x mutant plants in the first to second true leaves，and the morphology was similar after the third true leaves; The morphology of 8x P.axillaris was significantly different，which was characterized by short internodes，short petiole， thick and hairy leaves，dark green leaves and slow growth; The stomata and guard cell lengths of different P.axillaris ploidy nearly multiplied with the increase of ploidy，2x and 4x stomatal tissues were nearly round，but 8x stomata and guard cells did not increase by fold in the width and became elliptical．

Key words:  Petunia, Colchicine, Polyploid induction, Seed, Phenotype