Effects Of Aqueous Extract Of Safflower Prunuspersica On Seeds Germination And Seedling Growth Of Lolium Perenne Under Copper Stress

Allelopathy is a kind of plant chemical defense mechanism to enhance their survival competitiveness.To date,allelopathy has been widely used in community composition and landscape construction,however,there are few reports about the allelopathy of plants under pollution stress.Here,the effects of Safflower prunuspersica on seeds germination and seedling growth of Lolium perenne,Cu enrichment situation,and soil enzyme activity under copper stress were studied by adding aqueous extract of S.prunuspersica,to provide a reference for cultivation with a reasonable collocation between plants and building the phytoremediation experiment plot,which takes S.prunuspersica and ryegrass as the main plants in copper contaminated soil region.The main conclusions as following:1.The results of seed germination in L.perenne showed that: In the group of taking the aqueous extract of farmland soil as a base solution,different concentrations of the aqueous extract of S.prunuspersica made obviously inhibitory effects on the root length and germination rate of L.perenne,and the inhibition was more significant with the increase of aqueous extract concentration.In addition,the phenomenon of "low to promote,high to inhibit" was confirmed for the height of seedling.For the germination potential of L.perenne,all concentration levels of root aqueous extract had inhibitory effects,but different concentrations of leaf aqueous extract taken on the phenomenon of "low to promote,high to inhibit ".In the group of taking the aqueous extract of tailing soil as a base solution,different concentrations of aqueous extract made a similar allelopathy effect on the seedling height and root length of L.perenne.While the seed germination rate and germination vigor of L.perenne showed a trend of "low to promote,high to inhibit ".2.The results of physiological and ecological index showed that: In the control treatment of no copper solution,the low concentrations of aqueous extract of S.prunuspersica could promote the SOD activity in the seedlings of L.perenne,but whichwas inhibited under high concentration.Under the copper stress,the inhibition effects could be found only when the copper solution concentration is respectively 400,800mg·kg^-1,and with the increase of the concentration,the inhibition effect was more obvious.Dissimilar with the influence on SOD activity,POD activity showed the regularity of "low to promote,high to inhibit " under the 400 mg·kg^-1 copper concentration.All concentrations of aqueous extract in S.prunuspersica had significantly inhibitory effects on the CAT activity of L.perenne.However,the content of MDA,the product of membrane lipid peroxidation,was increased.Under the low concentrations of aqueous extract and copper solution,the chlorophyll content of L.perenne increased,besides of the group that the concentration of leaves aqueous extract and copper solution were 20 g·L-1and 400 mg·kg^-1 respectively,and with the increase of the concentration of aqueous extract,the chlorophyll content continue to decline.The relative conductivity of leaf of L.perenne had obviously rising trend,with the increasing of concentration of leaves aqueous extract and copper solution.The results about the Cu content in ryegrass showed that when the copper solution concentration was 400 mg·kg^-1,the Cu content in plant body was significantly lower than the group of 800 mg·kg^-1 copper solution,and the enrichment of L.perenne for copper could be promoted only in the group that the concentration of root aqueous extract and copper solution were 20 g·L-1 and 400 mg·kg^-1 respectively,yet the copper contents in the L.perenne were reduced in the other treatment group.3.The results of rhizosphere soil enzyme activities of L.perenne showed that: In the group of no copper solution,the aqueous extract of S.prunuspersica made a double effect of "low to promote,high to inhibit " on the soil catalase.Under the 400 mg·kg^-1 copper concentration,the root aqueous extract still presented this law,while the leaves aqueous extract showed continuous inhibition.At the copper concentration of 800 mg·kg^-1,both of them had inhibitory effect on catalase activity.The effects of the aqueous extract of S.prunuspersica on soil invertase activity were almost same with soil catalase.While the copper concentration were 400 mg·kg^-1and 800mg·kg^-1,the aqueous extract inhibited the soil invertase activity,and the higher the copper solution concentrations were,the stronger the inhibition was.With no copper solution adding,the aqueous extract of S.prunuspersica made a promoting effects on soil urease activity,however,it showed the opposite effects under copper stresss.The root aqueous extract of S.prunuspersica couldpromote the soil alkaline phosphatase activity,but the leaves aqueous extract showed the opposite effects,and with the increasing of copper solution concentration,the effects of promoting or inhibiting were more obvious.