MS培养基凝固效果和高温灭菌后pH值变化的研究

Studies on solidification of MS medium and its pH value changes after autoclaving

研究了培养基的pH值、琼脂浓度与MS培养基凝固的关系 ,以及不同成分对高温灭菌后MS培养基pH值的影响 .结果表明 ,调高培养基的pH值或增加琼脂浓度均可改善培养基的凝固效果 ;高温灭菌后 ,MS基本培养基的pH值由灭菌前的 5 .80下降为 5 .5 1 ,造成pH值下降的最主要原因是高温灭菌过程中EDTA铁盐与其它微量元素发生相互作用所致 ;同基本培养基相比 ,培养基中加入 3 0 .0g·L- 1 蔗糖、食用白糖、葡萄糖或果糖使高温灭菌后的培养基的pH值分别下降了 0 .0 6、0 .1 0、0 .2 8和 0 .98个单位 ,而添加 2 .0g·L- 1 水解酪蛋白、蛋白胨、酵母提取物或 1 .0～ 5 .0g·L- 1 活性炭则使高温灭菌后的培养基的pH值分别上升了 0 .2 3 ,0 .1 8,0 .3 9和 0 .1 9～ 0 .

Both the effects of pH values and agar concentrations on the solidification of MS medium and the effects of different components on the pH value of autoclaved MS medium were investigated. The results showed that increasing pH values or agar concentrations could improve the medium solidification, after autoclaving, the pH value of MS basal medium decreased from 5.80 to 5.51, and the interaction between ferrous-EDTA and other microelements during autoclaving was the critical reason causing this change; compared with the pH value of the basal medium, the addition of 30.0?gL-1 sucrose, edible sugar, glucose or fructose in medium caused the pH value of the autoclaved medium to drop by 0.06?0.1?0.28 and 0.98 unit, respectively; while the addition of 2.0?gL-1 casein hydrolysate, tryptone, yeast extract or 1.05.0?gL-1 active charcoal in medium increased the pH value of the autoclaved medium by 0.23,0.19,0.39 and 0.19 0.72,respectively.