Response of Vigna radiata L. (Mung Bean) to Ozone Phytotoxicity Using Ethylenediurea and Magnesium Nitrate.

The response of Vigna radiata L. (mung bean) to tropospheric ozone (O₃) phytotoxicity using Ethylenediurea (EDU) and magnesium nitrate (Mg(NO₃)₂, 20 mg/L and 50 mg/L) was assessed through field experiment in Peshawar, Pakistan. For this purpose, semi-urban area was selected and the concentration of tropospheric ozone was monitored. The mean monthly ozone ranged between 36.5 and 51.0 ppb for the three months experimental period. Accumulated Ozone exposure over a Threshold of 40 ppb (AOT40) was substantially high i.e. 6.9 ppm h for three-month growing period. The results showed that the tallest plant was measured in the group treated with Mg(NO₃)₂ 50 mg/L (18%), followed by EDU (10.8%) and Mg(NO₃)₂ 20 mg/L (2.9%) than the control plants. Similarly, Mg(NO₃)₂ 50 mg/L was more effective in producing longer and more number of pods/plants followed by EDU and Mg(NO₃)₂ 20 mg/L. The chlorophyll contents showed better results in Mg(NO₃) 50 mg/L than the other groups. Similarly, against the control group, increased biomass (73%) was observed in Mg(NO₃)₂50 mg/L, followed by EDU (58%) and Mg(NO₃)₂ 20 mg/L (42%). Elemental contents (Mg, Ca and Na) in seeds were observed in the sequence of Mg(NO₃)₂ 50 mg/L > Mg(NO₃)₂ 20 mg/L > EDU > control. Average crude protein was in the sequence of Mg(NO₃)₂ 50 mg/L (127%) > Mg(NO₃)₂ 20 mg/L (114%) > EDU (102%) than the control group. Moreover, protein fragmentation obtained through Gel electrophoresis image showed that 25 kDa band was visible in the treated plants and absent in the control group. Only leaves of the control group showed moderate foliar injury. The results of the current study showed that Mg(NO₃)₂ 50 mg/L was more effective followed by EDU in reducing the phytotoxic effects of O₃. [ABSTRACT FROM AUTHOR]