SEED GERMINATION AND EARLY SEEDLING GROWTH OF SAFFLOWER AS AFFECTED BY HEAVY METAL MIXTURE

摘要

The study was conducted to evaluate the effect of mixed cadmium, copper, nickel and zinc on seed germination and early seedling growth of safflower (Carthamus tinctorius L.) under controlled light and temperature conditions. Treatments included 0 (control), 60, 120, and 180 mg kg~(-1) which made by equal amount of cadmium (1/4), copper (1/4), nickel (1/4), and zinc (1/4). The heavy metal mixture treatment showed toxic effects on seed germination and early seedling growth of safflower plant. Increasing the concentration of heavy metal mixture to 180 mg kg~(-1) showed a significant decrease in seed germination as compared to control treatment (P<0.01). The heavy metal mixture concentration of 60 mg kg~(-1) reduced shoot fresh and dry weight (P<0.01). Although shoot fresh and dry weight was diversely affected by the heavy metal treatment, the heavy metal mixture concentration of 180 mg kg~(-1) produced lowest amount of both root fresh and dry weight. Furthermore, a negative response of root and shoot length of safflower to heavy metal mixture application relative to control treatment was observed at 120 mg kg~(-1) (P<0.01). The study suggests that cultivation of safflower in metal polluted soils should be avoided or appropriate control measures be adopted to maintain the heavy metal content of the soil below the damage threshold level.