西瓜短侧枝突变体下胚轴形态特征

Morphological characteristics of hypocotyl of watermelon short lateral branch mutant

西瓜属于合轴分枝,现有品种均为长侧枝.在田间发现一份西瓜短侧枝自然突变体材料s1b1.迄今,尚未见此类西瓜短侧枝突变体报道,研究其形成机理对西瓜轻简化、机械化栽培具有重要意义.将短侧枝突变体s1b1与长侧枝品系GWAS-38进行下胚轴长度及其显微结构比较.结果表明,短侧枝突变体s1b1的下胚轴长度显著大于GWAS-38.横切显微结果表明,s1b1下胚轴横切髓部所占比例较大,髓的外部有一圈小的细胞相连接,把髓的部分包裹在里面,而GWAS-38髓的外部没有这层细胞;s1b1细胞比GWAS-38的细胞更大.纵切显微结果表明,s1b1细胞明显伸长,且排列疏松、有序,GWAS-38的细胞排列紧密,形状大小不一致.研究结果为此西瓜珍贵突变体形成机理研究提供了一定的细胞学依据.

Watermelon belongs to syncytial branch,and the existing varieties are long lateral branches.A natural mutant s1b1 with short lateral branches of watermelon was found in the field.So far,no such watermelon short lateral branch mutant has been reported.Studying its formation mechanism is great significance for light,simplified and mechanized cultivation of watermelon.The hypocotyl length and microstructure of short lateral branch mutant s1b1 were compared with long lateral branch strain gwas-38.The results showed that the hypocotyl length of short lateral branch mutant s1b1 was significantly longer than that of GWAS-38.The results of cross cutting microscopy showed that the cross cutting medulla of s1b1 hypocotyl accounted for a large proportion.There was a circle of small cells connected outside the medulla and wrapped the part of the medulla,while there were no such cells outside the GWAS-38 medulla;s1b1 cells were larger than GWAS-38.The results of longitudinal section microscopy showed that s1b1 cells were significantly elongated,loosely arranged and orderly,and GWAS-38 cells were closely arranged with inconsistent shape and size.The results provide a cytological basis for the study of the formation mechanism of watermelon precious mutants.