【文章內(nèi)容簡介】 by the high cationexchange capacity of cell walls, unless the metal ion is transported as a noncationic metal chelate. The strong affinity for these cations to form plexes with sulphur interferes with normal enzymatic functions within humans. Numerous enzymes which function as metabolic regulators contain sulphur within ‘sulfhydryl’ groups, and it is these groups which attract, or are attracted to, the metal cations. This consequently alters the capacity of the enzyme to function properly and thus causes often lethal sideeffects. Whilst toxicity may differ according to the metal species, the most potent forms are those which can be absorbed into the tissues of organisms often causing serious inhibitive effects on the nervous system, physical damage or even death, Heavy metals are known to be toxic metal that can cause severe damage to plants and animals. Heavy metalsinduced oxidative stress involves induction of lipid peroxidation in plants that causes severe damage to cell membranes. Oxidative stress induced by heavy metals initiates the degradation of photosynthetic pigments causing decline in seed germination and seedling growth. High heavy metals concentration can disturb the chloroplast ultrastructure thereby disturbing the photosynthetic process. Heavy metals can affect antioxidant metabolism in plants the test, we concluded that the study isn’t very well designed too。 still there exist many problems to be improved, for example: the concentration should be changed a little for some species of this test。 before the study, some necessary knowledge must be understand well, some other test should be done to make the test much more perfect.The development of chemical industry and the three waste of industry given of seriously polluted the soil, air and water, which the plant lived on. The planted under polluted environment, content heavy metal and other pollutants, these affected people health and lives. Metallic contaminants may enter soil from farm manures, sewage sludge, municipal solid wastes, and pesticides. Metallic contaminants in feedstock are not lessened quantitatively during metals are difficult to be deposed under natural environment, however, the bioavailability of metallic contaminants may be lessened by posting. Those heavy metals must take some negative effect to environment and ecosystem, a lot of domestic and international scholars have made a large number of experiment research about the influence of heavy metals to seed germination. Consequently, the study of heavy metal pollution on plants and the seed is urgently results suggested that when at low density some heavy metals may be accelerate seed germination, but when exceeding certain density range nearly all heavy metals inhibit seed germination. This study investigated the possible involvement of Seed germination, seedling growth, photosynthetic pigment production and metal accumulation response to heavy metal stress. Radish (Raphanus Sativus) is a popular vegetable in China. This vegetable has a large number of varieties and can be cultured throughout the year depending on the varieties. In recent years a relatively large area of farmland has been contaminated by heavy metals because of industrialization and urbanization in China. This vegetable often is grown on farmland near highways, in mining areas where soils are usually contaminated by heavy metals. This suggests that the plant can tolerate some extent of heavy metal contamination and that as a food supply it could create a health risk to consumers. With the developing of the economy and urbanization, polluted material including heavy metals entered the environment more and more seriously, an increased frequency in the number of outbreaks of illness associated with the consumption of fresh fruits and vegetables .For the test, seeds of Radish (Raphanus Sativus) were offered by Gansu Academy of Agricultural metals are the main environmental factor accountable for decreasing crop productivity in many geographic areas. Despite the enormous studies that have investigated the effects of heavy metals on plants, only few have embraced the reality of multiple, interacting environmental factors. In order to offer the basis for relevant research, a summary has been done about heavy metals such as Hg、Pb、Cd、Co and Cr influence seed germination, drawing the conclusion that heavy metals inhibit the sprouting of most tested studied the effects of several doses of CdCl2 (, , , , mg/l), K2Cr2O7 (, , , , mg/l), CoCl26H2O (2, 4, 8, 16, 32 mg/l), PbCl2 (, , , , mg/l), HgCl2 (, , , , mg/l) and ZnCl2 (, , , , mg/l) on different seeds’ germination, seedling growth, chlorophyll and the carotenoid content and the heavy metals content.This study investigated the possible involvement of Seed germination, seedling growth, photosynthetic pigment production and metal accumulation response to heavy metal stress. Firstly filter the seeds, choose those satiation and slick seeds for the after using, wash the test Petri with tap water for three times, then wash another time with distilled water, and then put the Petri under sunlight until dry。 Seeds were surface sterilized in % sodium hypochlorite solution for1020 min and washed thoroughly with distilled water. The seeds were germinated in Petri dishes with double layer of filter paper soaked in distilled water (control) and different heavy metal seeds were put in each Petri. The seeds were set under a photoperiod of 12h, and 2530177。1/2025177。1℃ day/night temperature. The germination rate was recorded at different time, after germination, the root and shoot length were measured the sprout up to half of the seed length was regarded as germinated, according to the different seed and different heavy metals, the note time of different test were different too, at the end of the test, the root and shoot length of every seed were measured using Digital Caliper. All the data of the thesis were means of six replicated.