The effects of methanol and ethanol foliar application under salinity stress on some physiological characteristics of Pelargonium graveolens L.

To study the effects of methanol and ethanol foliar application (0, 10 and 20 % v/v) and NaCl salinity stress (0, 75 and 150 mM) on yield and some physiological traits of geranium (Pelargonium graveolens L.), a factorial experiment was conducted based on completely randomized design with three replications. Salinity showed significant effect on all characteristics, except root dry weight, chlorophyll b and Fe content. Effect of foliar application of methanol and ethanol was significant on proline, protein, chlorophyll a, essential oil, Fe and K content, root dry weight and IC50. The results also revealed the significant interaction of salinity by foliar application of alcohol in relation to the chlorophyll a and protein content. The greatest protein and chlorophyll a contents were recorded by the NaCl0 + methanol20% treatment, which was significantly different from the corresponding control. Dry weight of aerial parts, K/Na ratio, essential oil, K, P, Fe and Zn contents were negatively affected by the salinity stress. With increasing salinity stress the amounts of malondialdehyde and H2O2 were elevated. Among alcohol treatments, methanol foliar application was more effective than ethanol. Methanol had better effect on IC50, root dry weight, Fe, K and essential oil content, while ethanol20% increased the proline content significantly as compared to the methanol and control treatments. Overall, the results indicated that foliar application of methanol ameliorated the negative effects of salinity in geranium, when averaged over the salinity levels under study.