Aluminum Tolerance in Sunflower Plants Is Associated with Phosphorus Content in the Roots

Sunflower is considered one of the most promising crops for agro-industry development. This plant is adaptable to different soil and climate conditions but is very sensitive to aluminum (Al). Considering that the different plant species have developed different mechanisms to cope with Al, this work evaluated the effect of Al stress on plant growth and nitrogen (N), phosphorus (P), and potassium (K) contents in 25 sunflower genotypes. The results showed that Catissol, EXP 11-26, HLA 860 HO, and H 358 were the most Al-tolerant and IAC-Uruguai, AG 960, EXP 44-49, IAC-Iarama, BRS G27, EXP 887, and H 251 were the most Al-sensitive. We also observed that maintenance of P content in roots of stressed plants seems to play an important role in Al-stressed sunflower plants, suggesting that it could be used as a physiological marker during the screening for Al tolerance in this species.