Kinetin ameliorates cadmium induced toxicity on growth, pigments and photosynthesis by regulating antioxidant potential in tomato seedlings

The effect of cadmium (Cd) on growth, photosynthesis, biochemical attributes and antioxidant enzymes activities in tomato (Solanum lycopersicum L.) seedlings was studied and the role of kinetin (KN) to ameliorate Cd toxicity was examined. Tomato seedlings were subjected to two doses of Cd viz. 3 and 9 mg Cd kgP P sand. Cadmium at both the doses significantly declined the growth and photosynthesis, total chlorophyll, protein and carbohydrate contents in its concentration dependent manner. The oxidative stress markers such as superoxide radical (SOR), hydrogen peroxide (HR2ROR2R), malondialdehyde (MDA) equivalents and electrolyte leakage were enhanced by both the doses of Cd. Test metal at both the doses reduced the contents of leaf protein, total carbohydrate and total chlorophyll and also reduced the rate of net photosynthesis while enhanced the level of respiration, PAL activity, total phenolics, DPPH radical scavenging activity and the activities of enzymatic antioxidants: SOD, CAT, GST and contents of non-protein thiols and proline. Exogenous KN in Cd stressed seedlings improved growth performance as well as photosynthesis by regulating antioxidant potential of test seedlings and this effect was more pronounce in CdR1R treated seedlings. Major improvement in radical scavenging potential as attested by the improved antioxidant activity as well as contents suggests the vital role of foliar application of KN in reducing Cd toxicity in tomato seedlings resulting improved growth performance as well as quality in the terms of antioxidants of seedlings which could be grown even in metal contaminated sites.