Rice (Oryza sativa L.) has the ability to uptake and accumulate cadmium (Cd) in different amounts within the plant parts. A pot experiment was conducted to investigate the variations of plant growth and levels of accumulation of Cd among eight rice genotypes (new improved varieties-NIVs and traditional varieties- TVs) grown under different soil Cd levels. Two soil Cd concentrations (50 and 100 mg/kg) were provided in the form of cadmium chloride and the effect of Cd on rice plant growth was measured with respect to the plant height, number of tillers, flag leaf chlorophyll content, leaf area of the flag leaf, and root dry weight. The soil without added Cd was considered as the control. The initial Cd concentration in the soil used was 1.958 mg/kg. The total amount of Cd in unpolished rice grains, shoots and roots were analyzed with Graphite Furnace Atomic Absorption Spectrophotometer and Flame Atomic Absorption Spectrophotometer. The results revealed that the rice variety, soil Cd level and interactions between rice variety and Cd level significantly affected (p<0.05) the plant height, flag leaf area, root dry weight and Cd accumulation. The variety Suwandel could not withstand soil Cd levels at 50 mg/kg and 100 mg/kg. Increasing soil Cd level reduced the plant height and root dry weight except in At 307. The variety Bg 300 was the lowest grain Cd accumulator without Cd chloride addition. Grain Cd accumulation in TV was high at 0 mg/kg level whereas NIV showed the highest accumulation at 50 and 100 mg/kg Cd levels. The shoot Cd level was increased with increasing soil Cd level. The Cd distribution within the rice plant is grains< shoots< roots.
Tropical Agricultural Research Vol. 25 (4): 532 – 542 (2014)