固定流沙先锋树种沙生柽柳无性繁殖生根机理研究

Tamarix.taklamakanensis M.T.Liu is, an endemic to China, a pioneer species found in the moving sand dunes in the desert of China, with the strong resistance to drought and hight temperature, and only distributed in Taklimakan and Kumutage Desert. Due to the ordeal ecological conditions, the species is in imminent danger. So it is very important scientific significance for understanding the characteristics of flora in central Asia and Tamarix phylogeny to carry out the introduction and propagation. The purpose of the research is to explore the optimum condition of rooting by cuttage tender stem and improving survival rate of cuttage by selecting scion, combination with all kinds of hormones and requirements of cuttage to rooting, to obtain tissue culture technology by choosing the explant and culture condition and to confirm the rooting types in botany by anantomical structure analysis of rooting course, to obtanin the rooting mechanism of vegetation propagation by exogenous horone induction and analyze the response of vegetation progation rooting to endogenesis horome and finally obtained the rooting mechanism of cuttings and provided with some theorietical basis Tamarix.taklamakanensis M.T.Liu of vegetation propagation.

沙生柽柳（Tamarix.taklamakanensis M.T.Liu）是我国荒漠地区流动沙丘上最抗旱耐热的固定流沙先锋树种，为我国荒漠区特有物种，仅分布于我国新疆塔里木盆地塔克拉玛干沙漠及盆地东部的库姆塔格沙漠，分布区生境严酷，面临着濒危威胁。因此，实施沙生柽柳引种繁育对研究亚洲中部荒漠植物区系特点和本属的系统发育有重要的科学意义。项目以沙生柽柳无性繁育入手，对沙生柽柳插穗优选、激素及浓度组合及扦插条件控制，探索沙生柽柳插穗生根条件，提高扦插成活率，同时开展沙生柽柳外植体培养及培养条件优化，寻求组培快繁技术途径；通过对沙生柽柳无性繁殖生根过程解剖结构分析，判定其生根类型，探讨外源激素诱导沙生柽柳无性繁殖生根机制，分析内源物质变化对沙生柽柳无性繁殖生根的响应，揭示沙生柽柳扦插繁殖生根机理，为沙生柽柳无性繁殖提供论理论支撑；开展沙生柽柳扦插育苗试验，凝练沙生柽柳扦插繁殖技术规程指导育苗生产。

沙生柽柳作为我国荒漠区特有物种，天然分布范围小，分布生境严酷，面临着濒危，已被列为国家珍惜濒危植物名录，其生态地位及生态意义的重大。项目围绕沙生柽柳无性繁育生根技术难点，开展扦插和组培繁育试验，优化无性繁殖生根条件，进行沙生柽柳无性繁殖生根过程解剖结构观察及其内源物质动态变化分析，探讨沙生柽柳无性繁殖生根机理。结果表明：（1）沙生柽柳选用15cm 的1年生硬枝插穗进行扦插，扦插基质以壤土为宜，扦插平均成活率17.04%。插穗扦插以200mg/l的IBA浸泡20min激素诱导萌芽生长效果较好，以150mg/l的ABT或GGR浸泡120min生根粉诱导生根生长效果明显。（2）沙生柽柳催根培育以12～15天为宜，催根插穗成活率50%以上。催根以高浓度短时间或低浓度长时间浸泡的生根粉预处理诱导较好，催根插穗成活率75%以上。催根后扦插生长效果以催根培育9～12天的硬枝插穗较好，扦插生根率74.3%。（3）沙生柽柳愈伤组织培养选用当年生嫩叶为外殖体，适宜培养基为MS+0.5mg/L2,4-D。丛生芽培养及生根培养选用当年生嫩枝为外殖体，最佳丛生芽培养基为MS+1.5mg/L 6-BA，生根培养基为MS+0.8mg/L IBA或1/2MS+0.4mg/L IBA。（4）沙生柽柳插穗皮孔处可萌芽或生根，而切口处未形成愈伤组织，其插穗生根类型为皮部生根型。插穗生根过程中中柱鞘薄壁细胞恢复分裂，其根的发生源于中柱鞘薄壁细胞，生根方式为内起源。（5）沙生柽柳插穗不定根形成期插穗激素水平低，不定根形成前IAA保持较高水平，对诱导插穗根原基形成起到关键作用，ABA、ZR激素水平相对较低，有利于插穗愈伤组织和根原基的形成。 PPO、POD、SOD活性在生根初期迅速升高，并随着不定根的发育有不同程度的下降，而IAAO活性则通过不断调节插穗内源IAA水平，促使插穗根原基生长。