表 1 

注：“ 母液倍数”为笔者建议 ，具体浓度应以具体用量为准。 

按照表 1的要求，每一个“分类别”为一瓶母液，按照相应的成分配制好后，4℃避光保存，用时按照母液倍数进行稀释即可。

母液分类的依据，是要避免MS培养基中某些成分发生沉淀反应。例如，如果将全部的大量元素混合在一起配制， 则KH₂PO₄和CaCl₂ 易产生Ca₃( PO₄)₂沉淀，而CaC1₂和 MgSO₄ 将生成CaSO₄ 沉淀。 

除上述成分外，还必须加上蔗糖、琼脂以及激素，才构成用于组织培养的MS培养基。 

2 激素的溶解方法

MS培养基中常用的激素，如2,4 - D、NAA、6-BA，也要配制成 10～20倍母液，这样便于称量(激素的用量极小，给称量造成不便)，且可以多次取用。激素的配制与一般的药品不同，需要助溶剂。

如要配制 10 mL的 1mg／mL 2，4- D母液，则应称取0.01g 2，4 - D固体，置于小烧杯中， 再以 1～3 mL的95％乙醇(或 0.1 mo l／L NaOH) 溶解，最后缓慢加入蒸馏水定容。即每加入1 mL蒸馏水，立即搅拌均匀，使白色沉淀消失。重复数次，直至定容 。

一般而言，生长素类物质2,4-D、 N AA) 要用95％乙醇(或0.1 mo l／L NaOH)助溶，而细胞分裂素类物质(如6-BA)要用0.1 mo l／L的HC1助溶。助溶剂的用量一定要小，不能因其溶解效果好而过量使用，否则将影响培养基的质量(改变培养基成分或 pH值) 。配制好的激素要常温避光保存，尽快使用(尽量不超过一个月)。将激素母液保存在 4 ℃冰箱中， 希望获得较长的保存时间。但事实上这种做法是不可取的，因为激素在低温环境中易析出沉淀，影响使用效果。                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    

3 危险药品的使用与保管

尽管组织培养技术已经相当成熟，也很普及，但该技术并不安全。除注意灭菌锅、超净台等大型仪器的使用安全外 ，最重要的当属危险药品的使用与保管。原则上，MS培养基中任何一种药品都有一定的危险性。现只把最突出、最需要预防的药品注释如下。

( 1 ) NH₄NO₃、 KNO₃ 

此两种药品为易爆品，取用时一定要轻拿轻放，保存在阴凉处。另外，目前NH4NO3，的购买受到一定的限制，也可以考虑使用其他培养基，如N₆或B₅培养基，无 NH₄ NO₃成分，亦为组织培养所常用。

(2) EDTA- Na₂ 、CoC1₂、 2，4-D 此三种药品为致癌物，配制时要带胶皮手套，或两层塑料手套。EDTA-Na为金属螯合剂，有一定的粘性；CoCl₂能够导致基因突变，遗传学实 验中也常用其作为致突变剂；2，4 - D是高效农药，对人的皮肤有伤害作用。

4 热水定容原则

在母液、激素、蔗糖、琼脂都加入后，很多人习惯用微波炉或电磁炉加热溶解培养基(特别是琼脂) 。培养基熔化后，由于水分的蒸发，会造成体积的减少，从而需要定容。这时一定要用热水( 60℃左右) 进行定容，切忌用冷水( 30℃以下)，否则培养基中局部的琼脂将凝 固，造成营养成分浓度不均。 

5 关于调节 p H

适合的p H保证了营养成分的正常发挥，也决定了培养基的硬度(偏酸则过软，偏碱则过硬，都不利于组织的生长) ，故要十分留意。对于MS 培养基而言，只要各个成分按照用量精确加入，并且在熔化培养基时加热时间适合( 平均100 mL培养基加热60～90s ， 保证完全熔化的同时，尽量限制加热时间) ，则培养基的pH自然地将处于最适范围内。调解 pH时最好用电子pH计，以保证精确度。pH试纸的误差较大，要小心调节。可以将pH调到比最适值小一些，因为培养基在灭菌后，p H将变大。