Effects of Pb2+stress on seed germination & seedling growth of Rabdosia rubescens

The seeds of Rabdosia rubescens were as the materials to research the impacts of different lead (Pb2+) concentrations(0, 135, 270, 540, 1 080 mg x L(-1)) on seed germination and seedling growth. The results show that: Low concentration of lead had no obvious effect on early germination of the seed, the germination vigor and germination speed were lightly higher but not significantly differed at the level of Pb concentration 135 mg x L(-1) with control group; Mid-high concentration of Pb solution (270-1 080 mg x L(-1)) significantly inhibited the seed germination and seedling growth, which reduced the seed germination rate, germination vigor, germination index, embryo root length and shoot length, growth index with increasing of Pb concentrations. There was a inhibitory effect on embryo shoot length and root length at mid-high lead concentrations stress, and stronger inhibitory effect on root , which was more sensitive than shoot to Pb stress(P < 0.05). Pb bioaccumulation coefficient (BC) was 0.76-2.59, increased with concentration of Pb; Pb enrichment in seedling mainly caused the growth inhibition. The fitting model predictive analyses show, the critical concentration of Pb, which causes the germination rate and biomass fresh weight reducing 10%, is 195.18, 101.65 mg x L(-1).