Characteristics Of Resistance To Cadmium And Cadmium Uptake And Subcellular Distribution Of Ryegrass (Lolium Perenne L) Seedling

Effects of different cadmium (Cd) concentrations (0,10,20,60,100 mg?kg-1) of the Ryegrass (Dong Mu70) seed germination was studied in this experiment. The effect of different Cd concentrations and treatment time (30,50,70d) on some physiological characteristics (chlorophyll content, root activity, soluble protein, proline content, superoxide anion levels ,MDA content, membrane permeability, superoxide dismutase and peroxidase) and morphological indicators of the Ryegrass seedlings were studied with pot experiments.The absorption,accumulation and subcellular distribution of Cd in Ryegrass were researched by using atomic absorption spectrophotometry and differential centrifugation. The major results are as follows:1 Under the stress of low Cd concentration (10,20 mg?L-1), The seed germination characteristics such as ,seed germination percentage, germination energy, vigor index are not significant different compared with control (P> 0.05); when the Cd concentration increased to 60,100 mg?L-1 , the Ryegrass seed germination percentage, germination, vigor index, and root tolerance index were significantly lower compared with control (P <0.05). The result Showed that Ryegrass seed can resistant of Cd to some extent.2 With the increase of Cd concentration, Ryegrass biomass, chlorophyll content, root activity, soluble protein content showed a downward trend; O2.- levels, MDA content, membrane permeability increased gradually; SOD, POD activity was increased at first, then decreased. Under stress of Cd, Ryegrass roots were injuried more severe than leaves.3 Pot experiments showed that with the increase of Cd concentration and stress of Cd prolonged ,the accumulation of Cd in vivo Ryegrass were significantly increased (P <0.05). Cd content of various organs of Ryegrass were in the older: root> stem> leaf, and the underground part of the Cd content is much larger than above ground. The enrichment factor of Ryegrass is more than 1 at the Cd concentration of 10,20 mg?kg-1, with strong ability to accumulate,but at the Cd concentration of 60,100 mg?kg-1, the enrichment factor was less than 1, may be the capacity of accumulation Cd of Ryegrass were limited at high concentrations of Cd .4 With the increase of Cd concentration ,the content of Cd in cell of Ryegrass increased and the content of Cd are higher in root cells compared with in shoot cells. Cd mainly distributed in the F1 (cell wall), the F3 (cell soluble fraction) followed, the content of Cd in F2 (organelles) is lowest.