Impact of mercuric chloride on the seedlings of Macrotyloma uniflorum growth profile

Abstract

Various toxic substances are regularly released into the environment as effluents. Among these, mercury is highly toxic. It affects the growth of plants, seed germination, etc. This study aims to understand the effects of mercury on seed germination and seedling growth of fifteen seeds of Macrotyloma uniflorum (Horse gram) at different concentrations. Mercuric chloride is used as the mercury source at concentrations of 0.2, 0.4, 0.6, 0.8, and 1.0 M and compared against a control. Horse gram seeds were soaked in a mercuric chloride solution in a petri dish at ambient temperature and germination and seedling growth were monitored after 10 days; the average was reported.  Concentrations of 0.2 M and 0.4 M didn’t exhibit any significant reduction, and concentrations of 0.6 M, 0.8 M, and 1.0 M had a remarkable reduction in the germination of horse gram seeds. Furthermore, 0.8 M and 1.0 M concentrations significantly affected root length. The 1.0 M concentration of mercury was found to be sufficient to cause significant reductions in seedling dry weight as compared to the control. High concentrations of Mercury decreased seed germination, shoot, and root length, and seedling dry weight. An increase in mercury concentration up to 1.0 M showed the highest percentage decrease in seed germination (52%), with no significant effect on shoot length and root length (2.4%) of horse gram relative to the control. Macrotyloma uniflorum was more sensitive to mercury in seedling growth and root elongation than in seed germination. Minimal use of mercury compounds in fungicides and nematicides is recommended. Special care should be taken to monitor toxic pollutants, as larger concentrations can produce harmful effects to crops and the ecosystem as well.