EFFECTS OF DIFFERENT HUMIC ACID AND SALINITY LEVELS ON SOME TRAITS OF KHUZESTANI SAVORY (SATUREJA KHUZISTANICA JAMZAD)

In order to study the impact of humic acid on some morphological, physiological and biochemical traits of Khuzestani savory under salinity stress condition, the present study was conducted in the greenhouse of the agricultural faculty of Lorestan University as a factorial experiment (combination of humic acid and salinity) in the form of randomized complete blocks design (RCBD) in 2017. Factors of the experiment included salinity in five levels (0, 25, 50, 75 and 100 mM of NaCl) and humic acid also in five levels (0, 10, 20, 30 and 40 mg/Kg of soil), which were applied as a pot experiment. Results revealed that in terms of morphological traits including stem length, root length, leaf length, leaf width and leaf area, the highest salinity (S5) and "without humic acid" (H1) (S5H1) produced the lowest values; whereas "without salinity" (S1) and highest humic acid (H5) (S1H5) produced the highest values for these traits. Moreover, S1H5 treatment produced the highest photosynthesis and transpiration rates of 24.04 mu mol CO2 m(-2) s(-1) and 2.85 mmol H2O2 m(-2) s(-1), respectively; whereas, lowest values for the traits were produced in S5H1 treatment to be 5.67 mu mol CO2 m(-2) s(-1) and 0.65 mmol H2O2 m(-2) s(-1), respectively. Furthermore, S1H5 treatment produced the highest (0.280mol CO2 m(-2) S-1) stomatal conductance rate and lowest substomatal CO2 (85 ppm); whereas, S5H1 treatment produced the lowest (0.013 mol CO2 m(-2) s(-1)) stomatal conductance rate and highest (406 ppm) substomatal CO2. The highest organic matter content (89.69% on average) was found in S2H3 treatment, whereas it reached to its lowest value (69.46% overage) in S4H5 treatment. Moreover, S5H2 treatment produced the highest (24.37% on average) and S1H5 treatment the lowest (10.35% on average) ash percentage trait. As for relative water content (RWC) of leaf, the highest (93.01% on average) and lowest (70.94%) values were produced in S1H5 and S5H1 treatments, respectively. S5H1 had the highest (0.334 mg/g of fresh weight) proline content and S5H5 had the highest (2.098 mg/g of dry matter) soluble sugar content; whereas, the lowest proline content (0.155 mg/g of fresh weight) and soluble sugar content (0.808 mg/g of dry matter) were produced in S1H5 and S1H1 (control) treatments, respectively.