Hello all;

I've been watching my reginae protocorms growing (very slowly) on Phytotech's M551 (Modified Malmgren). Just looked quickly at the consitituents of the media again and noticed, no sucrose was added. There's no other carbon source in this media is there? I plan to reflask all protocorms onto T839 since that's all I have available at present.

Can I just add grocery store sugar to the M551?

Lori

Hi Lori,

I'm sorry I don't know the answer but hopefully one of our Cyp experts would give you some pointers!

Hi, Lori,

Plain grocery store sucrose works fine with M551. You may also wish to use D-glucose, also called dextrose, which you can get from Phytotech next time you order. The Cyp's don't actually use fructose very well, so with sucrose you are getting only about half the carbon source that you would by adding 20 g/l of dextrose instead of sucrose. The T839 you have contains 20 g/l dextrose. I suspect that Phytotech doesnt add the sugar to M551 is because many people prefer to substitute dextrose for the sucrose.

Your protocorms will recover fine - just remember to add the russet potato - 1 cm cube per 25 ml of media - if you use T839.

Ron Burch

Hi, Lori,

Plain grocery store sucrose works fine with M551. You may also wish to use D-glucose, also called dextrose, which you can get from Phytotech next time you order. The Cyp's don't actually use fructose very well, so with sucrose you are getting only about half the carbon source that you would by adding 20 g/l of dextrose instead of sucrose. The T839 you have contains 20 g/l dextrose. I suspect that Phytotech doesnt add the sugar to M551 is because many people prefer to substitute dextrose for the sucrose.

Ron Burch

I'm a little confused here. Is not the pineapple powder included in Phytotechs M551 not a substitute for the sucrose?

I'm a little confused here. Is not the pineapple powder included in Phytotechs M551 not a substitute for the sucrose?


This stuff can be confusing! No, the pineapple powder supplies "hormones" of unidentified sorts but relatively little in the way of nutrition. A sugar source is needed, and at very high concentration. Usually either sucrose or glucose is used at about 20 grams per liter; I personally recommend glucose as it seems more usuable by the plants (at least the species I have dealt with).

Best,

Ron Burch