Effect Of Humic Acid On Root Elongation And Percent Seed Germination Of Wheat Seeds

An experiment was conducted to find out germination rate and radical elongation of wheat seeds primed with two sources of humic acid or water alone. There were 14 treatments including two sources of humic acid (HA1 and HA2) added with 0, 0.1, 0.2, 0.4, 0.8 and 1.6 g 100 mL-1 water in which wheat seeds were soaked for 18 h followed by drying to its original moisture level (about 14%) and incubation at 15oC for germination process in petridishes with wet blotting paper in place. The HA1 was extracted in the laboratory which had sulfuric acid and Na2SO4 deposition on its particles while HA2 was obtained from PCSIR laboratories, Karachi and had not such deposition on its crystal. The treatments also included dry seed germination for comparison of priming. The experiment was arranged in CR design with three replications where each treatment unit (petridishes) contained 15 wheat seeds. The data was recorded on daily basis for 168 h (7 d). The results showed that wheat seeds whether primed with water or either source of humic acid produced higher root elongation and percent seed germination as compared to dry seeds. The HA2 at all levels produced higher radical length than seed primed in HA1 solution or alone water indicating the beneficial effect on seed germination and rapid growth at early stage of the plant. The highest radical length of 2.5 cm was recorded at 168 h for 1.6% HA2. However, except of 24 h readings where HA1 at 0.2% resulted in larger radical length, all other concentrations of HA1 at all days showed inferior radical length than water alone which could be attributed to H2SO4 and Na2SO4 deposition on the particles of humic materials. It was concluded from the study that seed priming with humic acid could enhance plant growth and should be evaluated in the field, however, the HA1 which had acid deposition on the crystal should not be used for priming purposes.