Impact of Exogenous Application of Salicylic Acid and Hydrogen Peroxide on Essential Nutrients and Silymarin in Silybum Marianum (L.) Gaertn Grown at Two Different Altitudes of Balochistan Under Cadmium Stress

Abstract

Cadmium (Cd+2) is a potentially toxic element that inhibits growth and development of several species of plants along with Silybum marianum (L.) Gaertn which is an essential medicinal plant belonging to family Asteraceae. The exogenous application with 0.25µM Salicylic acid (SA) and 10µM hydrogen peroxide (H2O2) to ameliorate harmful effects of cadmium (500 µM) on milk thistle were studied that were grown at two different ecological zones of Balochistan province of Pakistan i.e. Quetta (Qta) and Turbat (Tbt). The design of experiment was Randomized Complete Block Design (RCBD) with three replicates. Application of SA and H2O2, priming (P), Foliar spray (FS) and combinational treatments (P+FS) were highly helpful in alleviating the negative role of cadmium toxicity. The essential nutrients i.e. nitrate (NO3-), calcium (Ca2+) and potassium (K) were affected by Cd+2 induced toxicity however, the substantial role of SA and H2O2 widely helped to reduce the cadmium stress and boosted up the plant nutrients content. In a nutshell, exogenous treatments of SA and H2O2 enhanced the yield potential along with highest silymarin contents in milk thistle seeds which is of prime significance for its medicinal importance in treatment of liver diseases. The data obtained in this study highly recommend the priming and foliar spray of SA and H2O2 on milk thistle plants, as the best solution to alleviative the cadmium toxicity which will ultimately leads to better growth and yield of the plants.