Cadmium Uptake, Accumulation and Tolerance in Hydroponic Brassica chinensis (Pak Choi).

Cadmium (Cd) is a very poisonous and non-essential heavy metal which is easily absorbed by plants. The metal makes living organisms susceptible to its acute and chronic toxicity through plant food. Similarly, Cd hinders the growth of plants by causing the loss of chlorophyll, which in turn negatively impacts the activities of photosynthesis. Therefore, this current study aims to evaluate the effects of Cd on the germination behaviour, morphology, growth and development of Pak Choi plants. The sterilized Pak Choi seeds were germinated on a soaked filter paper of a petri dish. The petri dish included seven different treatments of Cd chloride with concentrations of 0, 0.01, 0.05, 0.1, 0.2, 0.3, and 0.4 mM. Each treatment was replicated five times. The germination and growth of the seeds were observed for 15 days. Pak Choi seedlings were also planted under hydroponic conditions to investigate their morphological characteristics, growth and development. After two weeks of growth, the application of CdCl2 was made with four treatments consisting of nutrient solution without CdCl2 (control) and 0.1, 0.5 and 1.0 mM CdCl2 -nutrient solution. Two weeks of plant growth were allowed before the experiment was terminated. At the end of the experiment, the chlorophyll content (SPAD), root and shoot length (cm), and fresh and dry weight (g) of plants were quantified accordingly. The increase in CdCl2 concentration led to a significant decrease in the length of root and shoot of germinated seedlings significantly. The seedling's growth of Pak Choi was inhibited three days after germination, and the seedling's height (root and shoot) in higher concentrations of CdCl2 was lower than lower doses of Cd. Chlorosis symptoms in the leaf were visible in hydroponic Pak Choi containing Cd. The growth of Cd-treated hydroponic Pak Choi was adversely affected by Cd treatment. The Cd treatment also reduced SPAD, biomass content (fresh and dry), and length of root and leaves number significantly. It can be concluded that exogenous Cd inhibits the Pak Choi germination and growth under hydroponic conditions. [ABSTRACT FROM AUTHOR]