千日红无菌苗生长及试管开花诱导

Growth and in vitro flowering of Gomphrena globosa

为进一步探究千日红(Gomphrena globosa)无菌苗生长和试管开花诱导机制,在组培条件下,以带顶芽的千日红茎段为对象,研究培养基中蔗糖含量、外源激素种类(细胞分裂素BA和生长素NAA)及浓度、生长素运输抑制剂(TIBA和NPA)对氮诱导的千日红生长和试管开花的影响。结果表明,蔗糖是千日红无菌苗生长和开花诱导最关键的因素,在不含蔗糖的培养基中,开花率为0且生根较少;随蔗糖含量的增加开花率逐渐提高,并在80g·L^(-1)时达最大(80.72%);而根系长度和数量及植株长势在蔗糖含量为20~40g·L^(-1)时较好。BA对无菌苗生长和开花的诱导效应大于NAA,当BA浓度为1.0mg·L^(-1)时,开花率达最大值60.14%,此时无菌苗长势也较好;而NAA对各指标均无显著性影响。TIBA明显降低了千日红试管开花率并且显著抑制根系的生长,而且在同等条件下对开花率和各生长指标的抑制效应大于NPA。综上所述,氮诱导千日红离体开花和正常生长过程中蔗糖是不可缺少的,并且受外源细胞分裂素的影响和体内激素的调控。

To clarify the mechanism of growth and in vitro flowering induction of Gomphrena globosa, the shoots with apical bud were used as explants on modified Murashige and Skoog （MS） medium to explore the effects of different concentrations （0, 20, 40, 60, or 80 g·L-1） of sucrose, and different combinations of cytokinins [N6 benzyladenine （BA） and α naphthaleneacetic acid （NAA）] and auxin polar transport inhibitors TIBA and NPA on nitrogen regulated growth and flowering in vitro. The results indicated that sucrose was the key factor in floral morphogenesis and growth, and that treatments without sucrose （modified MS supplied with 6.5 g·L-1 agar） produced no flowers and few roots. An increasing concentration of sucrose could promote flowering, and the highest percentage of flowering （80.72%） was obtained on medium containing 80 g·L-1 sucrose. The height, leaf number, and particularly the root volume of G. globosa were all higher in treatments with 20~40 g·L-1 sucrose. L9（34） orthogonal experiment results showed that BA was more effective than NAA in promoting growth and flowering induction, with the highest percentage of flowering （60.14%） and growth being obtained on media containing 1.0 mg·L-1 BA. Auxin polar transport inhibitors prevented flowering and rooting of G. globosa, with the inhibition effects of TIBA being stronger than those of NPA at the same concentrations, although auxin itself did not induce flowering. Therefore, sucrose is indispensable for the growth and in vitro flowering of G. globose. BA also plays an important role, and the effect was also regulated by endogenous hormones.