光照和植物生长物质对宁夏枸杞正常根和发状根离体生长的影响

Effects of light and plant growth regulators on growth of normal and hairy root of Lycium barbarum in vitro

目的:探索光照和植物生长物质对宁夏枸杞无菌苗正常根和发状根离体生长的影响,建立离体根的最佳培养体系。方法:以宁夏枸杞无菌苗正常根和发根农杆菌A4诱导叶外植体再生的发状根为材料,观察根切段在光照、植物生长物质种类和含量等不同的培养条件下的生长(长长、侧根形成)情况。结果与结论:MS培养基中添加植物生长物质(IAA,IBA,NAA)能够诱导宁夏枸杞正常根切段的生长和分枝形成,而1 mg.L-1IBA的存在最适合于正常根的长期离体培养。在无激素培养基上,光照能促进Ⅱ型发状根的长度增长和分枝侧根,却不利于Ⅰ型发状根的生长。在添加的3种外源植物生长物质(IAA,IBA,NAA)中,低含量的IAA更适合于Ⅰ型发状根的增长培养;而在促进Ⅱ型发状根的增长和侧根形成方面,1 mg.L-1IBA的作用最强。随着植物生长物质添加含量的增加,Ⅱ型发状根的愈伤组织化程度也加大,同时也抑制了从发状根或其形成的愈伤组织上形成新的分枝侧根。

Objective： To study effects of the cycle of light and exogenous plant growth regulators on growth of normal root and hairy root of Lycium barbarum and establish a long-term system of in vitro culture of L. barbarum roots. Method： Using normal roots from aseptic seedlings and hairy trots originated from Agrobacterium rhizogenes A4-mediated genetic transformation of L. barbarum, the growth of root segments was examined after 20 days of culture under different culture conditions. Result and Conclusion： When cultured on the MS medium with different plant growth regulators （IAA, IBA, NAA）, normal root segments of L. barbarum could elongate and branch, and the addition of 1 mg·L^-1BA into the medium was the most suitable for long-term in vitro culture of L. barbarum root. When cultured on MS medium without hormone, light promoted the elongation and lateral root formation of type Ⅱ hairy root, but not of type Ⅰ hairy root. Among three tested hormones, IAA at low concentration was the best for growth of type Ⅰ hairy root, while 1 mg·L^-1 IBA was the most suitable for growth of type Ⅱ hairy root. With the increase of hormone level added into MS medium, callusing frequencies of type Ⅰ , Ⅱ hairy roots were increased, at the same time, the formation of lateral root from hairy root or callus was inhibited.