Growth, ionic homeostasis, and physiological responses of cotton under different salt and alkali stresses

This study investigated the effects of different salt-alkali stresses (NaCl, Na₂SO₄, and Na₂CO₃ + NaHCO₃) on cotton growth, ionome, and physiological responses. Salt-alkali stress significantly inhibited cotton growth, reducing root development and increasing relative electrical conductivity (REC) and malondialdehyde (MDA) content. However, antioxidant enzyme activities and proline content also increased. Principal component analysis revealed significant differences in ion composition under different stresses. NaCl stress inhibited Ca absorption and reduced P, Mg, and Cu transport, while Na₂SO₄ stress inhibited P and Ca absorption and reduced Mg, B, and Cu transport. Na₂CO₃ + NaHCO₃ stress inhibited P and S absorption and Mg and B transport. GhSOS1 and GhNHX1 gene expression increased under salt stress but decreased under alkali stress. These results suggest cotton adapts to salt-alkali stress through antioxidant systems, osmotic adjustments, and ionic equilibrium reconstruction. Neutral salt stress primarily disrupts ion balance, while alkali stress reduces Na regulation and mineral element absorption.

Huijuan Guo, Zhijie Huang, Meiqi Li, Zhenan Hou