Effects of heavy metal stress on seedling growth and antioxidant system in sorghum (Sorghum bicolor (L.) Moench)

Plants take the substances they need to complete their physiological period from the soil through their roots. Plants encounter environmental negativities while taking plant nutrients. These negativities cause limitations in the growth and development of plants. The interaction of the environment or any organism with the plant can cause the activation of several pathways in the plant cell. These activated pathways are biological processes that cause the plant to react to stress. The factors that prevent the normal growth and development of plants are defined as "stress" and cause yield loss in the plant. Stress factors can be divided into two groups as biotic and abiotic stress factors. Viruses, insects, fungi, weeds, nematodes and parasites are biotic stress factors that cause plant damage. Stress factors caused by environmental changes and caused by non-living factors are called abiotic stress. They can be included in the group of high salinity, temperature, drought, heavy metal, changes in photoperiod, light intensity and quality, nutrient abundance and starvation, air and soil pollution, abiotic stress factors. Heavy metals and their toxic levels can affect physiological and biochemical processes by causing the emergence of ROS species. For this purpose, the effects of heavy metals on some physiological and biochemical properties of Sorghum were investigated by applying HgCl2 and CdN2O6 heavy metal doses (3, 6, 9, 12 and 15 ppm) to Sorghum (Sorghum bicolor (L.) Moench). The effects of enzyme activity (SOD, POX), chlorophyll content, wet weight, dry weight and proline content of sorghum plant were investigated. For this purpose, Öğretmenoğlu 77 variety was used. After the seeds sown in the pots were grown for 33 days, heavy metal solution was applied at two-day intervals. At the end of the growing period, analyzes were made with the samples taken from the leaves. According to the results of the research, mercury and cadmium applications caused first increase and then decrease in POX and SOD enzyme activities. As a result of heavy metal application, chlorophyll content first increased and then decreased. As a result of the study, decreases were observed in fresh and dry weights.