Effect of salicylic acid foliar application on flowering and growth characteristics of lantana (Lantana camara Linn.) under salinity stress

Lantana camara Linn. is a flowering ornamental plant belonging to family Verbenaceae. The aim of the present study was to investigate the effect of salicylic acid foliar application on flowering improvement and growth characteristics of lantana under salinity stress. In a factorial experiment and completely randomized design (CRD), three levels of SA (0, 0.5 and 1mM) and five levels of salinity (0.5, 3, 5, 7 and 9 dS.m-1) were applied. The results indicated that increasing salinity levels from 0.5 to 9 dS.m-1 significantly reduced all studied growth parameters levels, chlorophyll contents and potassium uptake. While Na+uptake, Na+/K+ and ion leakage were increased relative to control. Also, the results indicated that the salicylic acid significantly increased plant growth and physiological traits. Application of salicylic acid (0.5 mM) improved vegetative, flowering growth and nutrient uptake under salt stress. At salinity level of 9 dS m-1, application of 1mM salicylic acid increased the height of the main branch and the number of flowers by3.22 and 2.14 times, respectively, compared to the control and decreased the sodium uptake by 2.46 times. At the same level of salinity, treatment of plants by 0.5mM salicylic acid increased plant height, stem diameter, increased diameter of main branch, number of flowers and fresh weight of flowers by 70.64%, 2.15, 2.14 and 5.8 times respectively, in compare to the control. Considering that the plants maintained their vegetative growth and flowering well up to salinity level of 7dS.m-1, it seems that the lantana is able to tolerate salinity. In general, It seems that under high salinity levels, salicylic acid (0.5 mM) was the most effective treatment for mitigating the deleterious effect of salt stress in lantana plants.