- Sun Aug 13, 2023 5:31 pm
Many plants do well in vitro at a pH different than that at which they grow in the wild. Plus, the pH normally drops after autoclaving, and it normally drops even lower as it ages- so starting a bit high isn't a problem.
Mainly the reason we worry about pH in tissue culture is because of nutrient availability; if you use chelated iron, most of that problem goes away- and virtually every medium uses iron chelate (FeEDTA), so it's not a concern. The other metals that get wonky with pH (mainly zinc and manganese) are less of a concern, and- frankly- unless the iron is "annealed" with the chelate BEFORE it's added (hint: it's usually not), the EDTA will pick up some of the other metals as well.