Abstract: In order to understand the regulative effect of salicylic acid (SA) on the salt tolerance physiology of Helianthus tuberosus under NaCl stress, this paper studied the effects of 100 μmol·L^-1 salicylic acid (SA) on the photosynthesis and ion absorption of H. tuberosus seedlings under the stress of different concentration NaCl. Applying SA not only effectively alleviated the NaCl stress on the inhibition of H. tuberosus photosynthesis, increased the pigments content, photosynthetic and transpiration rates, stomatal conductance, and water use efficiency, decreased the intercellular CO₂ concentration significantly, but also decreased the Na⁺ accumulation, and promoted the uptake and upward transport of K⁺ and Ca²⁺. For example, compared with no SA application under 100 mmol·L^-1 NaCl stress, applying 100 μmol·L^-1 of SA decreased the Na⁺ accumulation by 30.6%, and increased the uptake of K⁺ and Ca²⁺ by 12.9% and 14.7%, respectively, suggesting that applying definite concentration SA could help to improve the photosynthesis of H. tuberosus seedlings under NaCl stress, maintain the balance of mineral nutrients, and enhance the salt resistance and production of H. tuberosus under NaCl stress.

Key words: Rare earths, Nitrogen, Phosphorus, Soil-plant system, Interaction, Safety assessment