Oryzalin离体诱导小果型西瓜四倍体及倍性鉴定研究

以3个二倍体小果型西瓜优良自交系048、032、047-1为试验材料,研究培养方式、Oryzalin浓度、处理时间对离体诱导西瓜四倍体的诱变效果,并对变异植株进行形态学比较、气孔测定及染色体鉴定。研究结果表明,采用液体培养的四倍体诱导率比固体培养高。在含50 mg/L Oryzalin的液体培养基中振荡处理2 d,四倍体诱导率最高达33.3%。变异植株通过染色体计数法鉴定得出染色体数为44,确定为四倍体植株。再生植株表现为叶片肥厚,叶色深绿,茎节缩短,株型紧凑矮小,茎蔓挺直,叶形指数变小;叶片气孔密度明显减小,保卫细胞体积增大,叶绿体数目增多;花瓣颜色深黄,且增宽、增厚。此结果说明Oryzalin对不同基因型的四倍体诱变效果存在一定差异。

In Vitro Induction of Tetraploid Mini-watermelon using Oryzalin and Identification of the Ploidy

Three excellent inbred lines of diploid mini-watermelon(048,032 and 047-1) were used for experiment material.The mutagenic effect of in vitro tetraploid induction was studied by using herbicide oryzalin as mutagen in different treatment method,different concentrations and different treatment time.The results showed that the induction rate of tetraploid in vitro depended on treatment method,concentration of oryzalin and duration of treatment.At the same concentration of oryzalin,the induction rate of tetraploid using liquid culture was higher than that using solid culture.The highest induction rate of tetraploid(33.3%) was obtained from the explant cultured in the liquid medium supplemented with 50 mg/L oryzalin for 2d on a rotator.The chromosome number of root-tip cell of the variant plants was 44 by the chromosome analysis and so they were identified as tetraploid plants.The variant tetraploid plant was characterized with thick leaf,dark green leaf,compact plant type,short internode,erect stem,smaller leaf shape index.By observing from the microscope,it was found that the density of the stoma obviously decreased,the volume of the guard cells increased,chloroplast number increased.And the petals were deep yellow,broadened and thickened.There was difference of the mutagenic effect of oryzalin among various genotypes of materials.