Influence of humic acid on germination, morphological characteristics and photosynthesis pigments of Trifolium alexandrium L. under salinity stress

The study was done to determine the effect of humic acid on germination, morphological properties, and photosynthesis pigments of Trifolium alexandrium L. under salt stress. Methods: This study was conducted in a as a completely randomized design was humic acid (0,0.009mg Li−1). The second factor was salt stress (0,0.75,1.5,3dSm−1). Seed germination, vigor index, allometric coefficient, radicle and pedicle length, totally dry and fresh weight, and photosynthetic contents were measured. Findings: The minimum and maximum germination rate (4.00 and 4.90seed/day) and vigor index (1.79 and 6.33) were related to 3dSm-1 and H+3dSm-1 treatments, respectively. The germination percentage did not show a significant difference (p<0.05). The radicle and pedicle lengths, allometric coefficient, germination rate, and vigor index in the zero treatment were more than the H treatment, but they decreased with increasing salinity. The minimum and maximum radicle (0.79 and 2.30cm), pedicle lengths (0.79 and 2.55cm) and dry weight (0.0014 and 0.0026g) were related to the 3dSm-1 and H+3dSm-1 treatments, respectively. The highest chlorophyll a (0.31 mg g-1 fresh weight), carotenoid (0.07 mg. g-1 fresh weight) and total chlorophyll (0.48mg. g-1 fresh weight) were related to H+1.5dS. m-1. The highest amount of chlorophyll b (0.34mg. g-1 fresh weight) was observed in H+3dS. m-1. Conclusion: Humic acid had different but positive effects on the plant’s quantitative properties and germination characteristics in salinity stress. The use of this fertilizer in salinity stress for salinity-sensitive plants can be helpful, but a more comprehensive survey in the field is recommended. Copyright© 2021, the Authors | Publishing Rights, ASPI. This open-access article is published under the terms of the Creative Commons Attribution- NonCommercial 4.0 International License which permits Share (copy and redistribute the material in any medium or format) and Adapt (remix, transform, and build upon the material) under the Attribution-NonCommercial terms.