Ethylene and ethane production in response to salinity stress

Ethylene and ethane production in mung bean hypocotyl sections were evaluated as possible indicators of stress due to contact with four salts that are common in natural sites. Ethylene production decreased with increasing concentrations of applied NaCl and KCl. When CaCl2 was applied, the ethylene evolution was greater. However, when MgCl2 was applied, ethylene evolution remained high then decreased and at higher salt concentrations again showed an increase. NaCl (up to 0.1 kmol m−1) and KCl (up to 0.5 kmol m−3) caused a concentration‐dependent increase in ethane production. The ethane production with CaCl2 was the lowest among the salts tested and only a minute increase was noticed with the increase of concentration from 0.01 to 1 kmol m−3. Ethane production showed a distinct maximum at 0.2 kmol m−3 MgCl2. The introduction of 0.01 kmol m−3 CaCl2, as well as anaerobic conditions obtained by purging vials with N2, eliminated that high ethane production. Respiratory activity of the mung bean hypocotyl sections in MgCl2 concentrations from 0 to 0.5 kmol m−3 was correlated with ethane but not with ethylene production. The ethane/ethylene ratio showed three patterns for the four salts tested.