Study on physiological and morphological traits of purple shamrock (Oxalis triangularis A. St.-Hil. ) as affected by humic acid under salinity stress

Abstract

Salinity is one of the main environmental factors that limit plant growth and productivity. Humic acid (HA) can directly have positive effects on plant growth, and absorption of nitrogen, potassium, calcium, magnesium, and phosphorus by plants. This study aimed to concentrate on the impact of HA under salinity stress on Oxalis triangularis to use it as an ornamental plant in green spaces and landscaping. Treatments included three salinity stress levels (0, 40 and 80 mM NaCl) and four concentrations of HA (0, 200, 400, and 600 mg l-1) on O. triangularis with four replicates. Applying HA under salinity stress at 40 and 80 mM increased stem length compared to the control, but this increase was lower at medium and high salinity levels. HA at 400 mg l-1 had the best effect on rhizome length under salinity stress at 40 and 80 mM. The reduced trend on proline content in HA at 0, 200, 400, and 600 mg l-1 under salinity stress at 40 mM was 19.65, 18.45, 16.92, and 13.57 %, respectively. By increasing the concentrations of HA, anthocyanin content was raised when compared to the control. Leaf sodium and potassium decreased by applying HA with or without salinity stress.

Keywords

• anthocyanin
• leaf
• proline
• rhizome