Cobalt reduces nitrate inhibition of nodulation in mungbean (Vigna radiata)

A cobalt-mediated decrease in ethylene production reduced the inhibition of nodulation by nitrate in Vigna radiata (mungbean). Nitrate increased the e thylene production in 5-day-old seedlings, while it caused a reduction in t he nodulation status (nodule number and nodule weight) and nodule efficienc y (acetylene reduction activity) in mungbean plants. The application of cob alt chloride inhibited nitrate-affected ethylene production and also decrea sed the inhibitory effect of nitrate on nodulation. The effect of cobalt wa s most marked on nodule number.