蓖麻DNA的提取及SRAP反应体系的建立

为建立蓖麻快速有效的DNA提取方法和SRAP标记的技术体系，本研究采用SDS法和CTAB法对蓖麻不同叶片（新鲜嫩叶、老叶和陈旧的嫩叶、老叶）的基因组DNA进行提取，并以DNA模板用量、Mg^2＋浓度、引物浓度和Taq酶用量4个因素的不同水平配制了10个反应体系对蓖麻SRAP反应体系进行优化。结果表明，SDS法和CTAB法均可获得较高质量的DNA，多数样品的A260／A280值介于1．7～1．9之间，但以CTAB法更为省工省时，不同叶片DNA的提取效果，以嫩叶效果最佳；设计的10个反应体系中，以反应体系A（总体积为15μL，40ng DNA模板，1．5mmol／L Mg^2＋浓度，0．2mmoL／L dNTPs，0．3μmol／L引物浓度和1Unit Taq酶）最为经济适用，将该体系用于蓖麻的SRAP扩增能获得稳定、清晰的多态性条带。本实验为蓖麻的遗传多样性研究及目标性状的分析定位提供了技术支撑。

DNA extraction and establishment of SRAP reaction system in castor

In order to find an effective and quick method of DNA isolation and construct an optimal reaction system of SRAP marker for castor, different leaves such as fresh young leaves, fresh old leaves, reserved young and old leaves were used to extract DNA by SDS method and CTAB method respectively, and ten reaction systems for castor SRAP amplification were designed with different concentration levels of DNA template, magnesium ion,primers and Taq polymerase. The results showed that the DNA isolated with SDS method and CTAB method had good quality, the A260/A280 values of most samples were between 1.7 - 1.9. However, CTAB method was more convenient and time efficient than SDS method, and the fresh young leaves were optimal to isolate castor genomie DNA. Among the ten screened reaction systems, the system consisted of 15μL total volume including 40ng DNA,1.5mmol/ L Mg^2＋ ,0.2mmol/L dNTPs,0.3μmol/L primers and 1 Unit Taq polymerase was the most economical and practical, the stable and legible polymorphic bands were recorded when amplified with this system. This research provided technical support for analysing genetic diversity and locating the genes of objective characteristics in castor.