Study On Seedling Growth Of Corn And Canola Light Rare Earths And Heavy Rare Earths Lanthanum, Yttrium

In China,the rare earth have a wide application in agriculture. At present the research of rare earth biological in agriculture and application of farmland mainly use the light rare earth lanthanum and cerium. It researches the effect of plant germination the growth of the plant, the element content in plant and physiological index of plant, etc. The research for the effect on soil and plant by adding rare earth mainly adopt root device and morphology of root domain. The adding of rare earth by the effect of the soil cannot fully reflect the effect of rare earth to plant. Therefore using nutrient solution culture can fully reflect the physiological effects of rare earth elements on plants.The background of research subject is nutrient solution to the laboratory of plant growth. It researches the effect of the bioavailability of light rare earth lanthanum and heavy rare earth yttrium on the growth of corn and rape. Results and conclusion:The lanthanum and yttrium of suitable concentration(0-0.40mmol/L) have the promoting effect of germination rate germination potential and germination index on corn and rape. When the concentration of rare earth lanthanum and yttrium is0.40mmol/L germination rate、germination potential and germination index reach the peak. It is the best suitable concentration. In0.20mmol/L germination index also maintain high level. The effect of germination rate and germination potential on corn and rape by adding light rare earth lanthanum is better than heavy rare earth yttrium treatment. Then germination index is contrast. But when the concentration of rare earth lanthanum and yttrium(0.60-0.80mmol/L) is overtop it is inhibited germination of corn and rape. It reduces the germination rate germination potential and germination index of corn and rape. It has toxic effect on corn and rape. In0.60mmol/L the toxicity of yttrium to seeds is higher than the toxicity of lanthanum.The research results about effect of biomass and chlorophyll content on rare earth lanthanum and yttrium to corn and rape show that:The lanthanum and yttrium of suitable concentration(0-0.40mmol/L) have the promoting effect of biomass and chlorophyll content on corn and rape. Biomass reaches the peak at the concentration of0.40mmol/L. Then it can also have the high level in0.20mmol/L. The concentration of the maximum increase to chlorophyll content by lanthanum to corn and rape is0.40mmol/L. Then the peak of chlorophyll b concentration by yttrium on corn is at0.20mmol/L.And the peak of chlorophyll concentration by yttrium om rape at0.20mmol/L. At the appropriate concentration the effect of biomass enhancement by lanthanum on corn and rape is higher than the effect of yttrium. When the concentration of rare earth lanthanum and yttrium is0.60-0.80mmol/L it is the inhibitory effect of biomass and chlorophyll content to corn and rape. The inhibitory effect of high concentration yttrium is higher than the inhibitory effect of high concentration lanthanum.The research results about effect of the total nitrogen and total phosphorus on rare earth lanthanum and yttrium to corn and rape show that:With the increase of rare earth concentration the total nitrogen of corn and rape on the aboveground part and underground part reaches peak in0.20mmol/L. Only the total nitrogen of corn on the aboveground part reaches peak in0.10mmol/L. It is close the enhance effect of total nitrogen in underground part and aboveground part. The concentration of aboveground part total phosphorus in corn and rape reaches the peak in0.20mmol/L. The concentration of underground part total phosphorus reaches the peak in0.40mmol/L. The enhance effect of underground part total phosphorus is higher than the enhance effect of aboveground part total phosphorus. When the concentration reaches0.80mmol/L it has inhibitory effect. But the total nitrogen and total phosphorus have little difference to control.The research results about effect of the rare earth enrichment on rare earth lanthanum and yttrium to corn and rape show that:The rare earth elements in low concentration can promote the absorbed and using of rare earth by plants. When the concentration reaches0.10mmol/L the absorption reaches peak. When the concentration reaches0.60mmol/L the absorption of lanthanum and yttrium to plant reaches peak. It has remained a high level in0.80mmol/L.The mechanism of rare earth effect on plant may be:Rare earth elements added in the nutrient solution is absorbed by plant roots. Then rare earth concentrated in the leaves through transport into the ground. In the leaves into the cells rare earth affect the synthesis of chlorophyll in leaves. Then in the root and aboveground part rare earth elements effect the physiological changes of various plant. And through the effect on cell membrane permeability and cell division rare earth effects the absorption and utilization of nitrogen and phosphorus and the changes of plant biomass total nitrogen and total phosphorus chlorophyll content. In the case of low concentration, rare earth elements in plant participate in the normal metabolism of cells. It may increase the enzyme activity to promote plant growth and development. When the concentration is too high rare earth damage electronic balance of inside and outside in the cell membrane to inhibit the growth and development of plant.