Effect of humic and salcylic acids on growth and physiological status of salt stressed apple seedlings (Malus domestica L.)‎

Abstract EN

A pot experiment was conducted to determine the effect of exogenous humic acid(HA) and salicylic acid (SA) application on growth rate, leaf and root Na, Cl contents, proline, electrolyte leakage, total chlorophyll content, leaf catalase(CAT) and peroxidase(POX) activities of apple seedlings grown under salt stress and greenhouse conditions.

Apple seedlings were treated with HA at(0, 1000, 2000 ppm as a soil application), or with SA at(0, 0.5, 1 mM as a soil application).

Salinity treatments were established by irrigating seedlings twice a week with saline solution contained 0, 25, 50 mM NaCl.

Salt stress negatively affected plant growth rate, chlorophyll content and catalase activity of apple seedlings.

However, seedlings treated with each of HA and SA had greater growth rate, chlorophyll content and catalase activity under salt stress.

Leaf peroxidase activity(POX), electrolyte leakage and leaf and root proline contents were increased in response to salt stress.

HA and SA treatments induced increases in POX activity and proline content while electrolyte leakage decreased under salinity level.

With respect to the nutrient content, Na and Cl contents increased under salinity level while HA and SA treatments decreased leaf and root Na and Cl contents compared with control.

The greatest values for most measurements were often obtained by the 2000 ppm HA and 1 mM SA treatments.

These findings suggest that the HA, SA treatments can ameliorate the negative effect of salinity on the growth of apple seedlings.