辣椒矮秆突变体的表型及其对外源激素的响应

于EMS诱变辣椒自交系6421种子所构建的突变体库获得1份矮秆突变体(命名为E29),观察E29的表型和细胞学特征,研究E29突变性状的遗传规律和赤霉素(GA3)、24-表油菜素内酯(24-e BR)及生长素(IAA)对E29种子萌发和幼苗生长的影响。结果表明:与自交系6421相比,E29表现出植株矮化,叶片变大、变厚,叶色变深等特征;显微观察结果显示,E29变矮是由于其茎秆伸长区细胞长度缩短,叶片变大、变厚是由于其叶肉细胞变大及细胞数增加;遗传分析结果表明,突变性状由单隐性基因控制;外施不同质量浓度的激素,发现4.0 mg/L GA3处理显著促进E29的根与下胚轴伸长,1.0~4.0 mg/L的IAA处理显著抑制E29的根与下胚轴伸长,0.5~2.0 mg/L的24-e BR处理对E29的根和下胚轴伸长影响不明显,各激素处理均不能使之恢复至野生型6421的根与下胚轴长度,表明E29为BR不敏感型突变体,其突变性状与GA3、IAA调控无关。

Phenotypic characteristic of a dwarf mutant in pepper and its response to exogenous hormones

We have identified a dwarf mutant line, E29, through a screen from inbred line 6421 of ethyl methanesulfonate (EMS) mutagenized population in the pepper. In this paper, E29 was studied from its phenotypes, stem and leaf morphology by means of light microscope, genetic characteristics, and also including its physiological responses to GA3, 24-eBR and IAA. The results showed that E29 and 6421 had similar phenotypes, which showed severe dwarf accompanied with wide, thick leaf blades and dark green leaves. The mutation phenotype was controlled by a single recessive gene. It was proved from the longitudinal sections of the stems that the length of mutant cell reduced, which resulted in the short stature. Transverse sections of leaf blades also revealed that mesophyll mutant cells became larger and the number of mesophyll mutant cell was more than their wild counterparts, which explained its wide and thick leaves. It was further showed that GA3 (1.0 mg/L) promoted root and hypocotyl elongation of E29, while IAA (1.0 - 4.0 mg/L) gave rise to the opposite effects, and 24-eBR(0.5-2.0 mg/L) had no effects on inhibiting or promoting root and hypocotyl elongation. Exogenous GA3, IAA or 24-eBR was failed to recover the mutant of E29 to its wild phenotype, which indicated that the dwarf phenotype was not sensitive to BR.