T-2 toxin decreases logarithmic growth rates of tobacco callus tissues.

T-2 toxin, a mycotoxin produced by Fusarium tricinctum, decreases logarithmic growth rates of tobacco (Nicotiana tabacum L.) pith callus tissues. Toxin concentrations as low as 0.003 mum will decrease growth rates; a concentration of 0.081 mum will halt growth completely. Additional exogenous cytokinin will reduce the inhibition by toxin only when the initial cytokinin and toxin concentrations are quite low (about 0.01 mum). When inhibited tissues are transferred to media lacking toxin, they assume the faster, control rates almost immediately. Maximal yields of tissue (yields at the point at which no sugar was detected in the medium) are not affected by toxin concentrations of 0.01 to 0.036 mum.