Study On The Mechanism Of Calcium,Iron And Zinc Nutrition Formation In Alfalfa

Alfalfa?Medicago sativa L.?is the leguminous forage with the largest planting area and high application value in the world.It has high yield and rich protein and is known as the“king of forage”.Currently,there are few reports on the effects of different mineral elements in the environment on the growth of alfalfa,in this study,Aohan alfalfa?Medicago sativa L.CV.Aohan?distributed in ChiFeng region of Inner Mongolia was used as the material to investigate the effects of different concentrations of Ca²⁺,Fe²⁺and Zn²⁺on alfalfa under different pH conditions and the effects of Ca²⁺deficiency treatment on the lipid content of alfalfa.The main results of the experiment are as follows:?1?Under the conditions of pH=5.7,6.2,7.0 and 7.5,the treatments with Ca²⁺concentration of 0 mM and 60 mM all had significant inhibitory effects on the main root length,the number and length of root hairs and the fresh weight of the samples;The condition of high pH will enhance the inhibitory effect of Ca²⁺deletion?0 mM?and high concentration of Ca²⁺?60 mM?on the growth of alfalfa;In the experiment that explored the alfalfa's absorption and accumulation of Ca²⁺in the environment,it was found that with the increase of the concentration of Ca²⁺in the environment,the content of calcium in the alfalfa plant also showed an increasing trend,which was the same conclusion in the Ba²⁺absorption experiment and when the pH is 7.5,the plant's absorption and storage capacity of Ba²⁺significantly decreases when the pH is 5.7.?2?Under the condition of pH=5.7,6.2,7.0,7.5,high concentration of Fe²⁺?1 mM?significantly inhibited the main root length,the number and length of root hairs,and the fresh weight of the sample,low Fe²⁺concentration?0.5?M?has no significant effect on plant growth,while high concentration of Zn²⁺?0.3 mM?and low concentration of Zn²⁺?0.15?M?have no significant inhibitory effect on the length,fresh weight and root hair growth of alfalfa;In the alfalfa Fe²⁺and Zn²⁺hydroponic phenotype experiments,it was found that the low concentration of Fe²⁺?0.5?M?and the high concentration of Zn²⁺?0.15 mM?will cause the leaves and leaf buds on the top of the alfalfa plants to appear yellow and lighten;The conditions of high concentration of Fe²⁺?0.5 mM?and low concentration of Zn²⁺?0.15?M?had no significant effect on the growth of alfalfa.It shows that the alfalfa needs to supplement Fe nutrition at the seedling stage.?3?In the experiment exploring the effect of Ca²⁺deletion?0 mM? treatment on the lipid composition of alfalfa,it was found that the content of Free Fatty Acids?FFA?,Phosphatidyl Choline?PC?,Phosphatidyl Ethanolamine?PE?,Phosphatidyl Inositol?PI?,and Digalactosyl Diglyceride?DGDG?in the root tissue of alfalfa increased significantly,while the content of Phosphatidic Acid glycerol?PA?decreased significantly.It shows that when alfalfa is treated with Ca²⁺deficiency,the decrease of PA content affects the integrity and stability of the membrane,and resists adversity pressure through the increase of FFA,PC,PE,PI and DGDG content.The purpose of this paper is to investigate the effects of mineral nutrients calcium,iron,and zinc on the growth of alfalfa and calcium on lipid composition,so as to lay a theoretical foundation for the molecular mechanism of subsequent alfalfa's response to mineral elements,and also provides basic reference data for alfalfa's mineral nutrition fertilization.