In order to explore the role of salicylic acid (SA) in alleviating lead (Pb) toxicity on wheat ( Triticum aestivum L.), wheat seedlings exposed to 50 mg·L ^-1 Pb as Pb(NO 3 ) 2 were treated with 80 mg·L ^-1 SA. The physiological and biochemical indexes of wheat seedlings were measured by solution culture method. The results showed that Pb exposure depressed plant growth. However, after root-applying SA, the plant height, root length, fresh and dry weights of plant and root were increased by 17.67%, 24.85%, 23.46%,18.69%,18.95%, and 25.41%, respectively. In addition, SOD, POD, CAT, and APX increased by 215.73%, 98.92%, 137.45%, and 111.47%, respectively. The contents of O2 ^-· and H 2 O 2 in the roots decreased by 23.82% and 28.99%, respectively. Whereas the contents of soluble sugar increased by 13.59% while the content of proline decreased by 40.11%. The content of MDA in the roots decreased by 16.78% and root activity increased by 694.52% after root-application of SA under Pb stress. Therefore, root-applying SA significantly improved the antioxidation capability of wheat roots, which could, in turn, enhance the resistance of wheat roots to Pb stress and alleviate Pb toxic effects.
Agricultural Research in the Arid Areas
wheat root system
root-applying salicylic acid