Study Of Rare Earth Effect On Protein, Amino Acid And Potential Effector In Crops

In the past 30 years, most studies concentrated on investigate the effect of REE content and the effect of REE on plant physiology, a little involved the effect of REE on plant mechanism. Although some researchers have been contributed themselves to study REE influence on plant mechanism, the investigations are not systematized and not widely recognized by academe.Soluble protein and free Amino acid are the physiological activities, and often used as parameters to determining the change of plant physiology, which under external enviroment stimulation. Investigate the Rare Earth Effector in crops, which is one of our research directions for many years, is a very difficult work but we gain some precious experiences and data, these will definitely contribute great to the further study. In this study, the effect of rare earth elements (La and Nd) on soluble protein, free amino acid and potential effector were investigated by using wheat and rape seedlings as samples and applying relatively analytical instruments.The concentration of lanthanum(La) and neodymium(Nd) were 0 mg/L,5 mg/L,10 mg/L,25 mg/L,50 mg/L respectively. Coomassie brilliant blue G-250 was used to testing the soluble protein content, and precolumn derivatization with ophthaldialdehyde(OPA) and fluorenylmethyl chloroformate(FMOC chloride) of RP-HPLC was used to determining free amino acid in samples. A confirmatory method based on high-performance liquid chromatography tanderm mass spectrometery(HPLC-MS) was uesd to analyze the"potential effector".The result showed that the concentration of La and Nd in the range of 0-50 mg/L has effect on the metabolic activity of soluble protein and free amino acid, that made them change greatly in plant tissue.From the view of soluble protein content change, the change tredency in the root was different from that in the aerial for both seedlings. La and Nd in different concentrations could improve the soluble protein contents to aerial part of seedlings both for wheat and rape, however inhibit those to the root one, and inhibition intensity increases with the increasing of concentration of each element. This is probably because enrichment degree of rare earth in both parts was different from each other, resulting to a higher concent of rare earth elements in the root while to a lower one in the aerial, and eventually to stimulation of synthesis to soluble proteins in the later while to inhibition of those in the former. From the view of amino acid, there was no change in the number of amino acid types of rape seeding, which stimulated by La and Nd in drfferent concentrations, this is very different form the wheat seeding. Threonine and Serine were determined from the aerial part of wheat, this is probably because REE has influence on amino acid biosynthesis. Form the view of free amino acid content change, La and Nd in different concentrations could improve the free amino acid contents of crop seedings, this is probably due to REE accelerate the synthesis of glutamate.From the view of differert type of rare earth elements, the stimulated effect(stimulation and inhibition) of La on the content of soluble protein and free amino acid was greater than Nd in rape, but this effect was not found in wheat. This indicated that the REE effect on plant physiological active substances has some differences due to the REE property of physical and chemical(such as ion radius, electric charge et.al), and plant species are different.From the view of different species of crop, the change tredency of soluble protein and free amino acid content, and the proper concentration, which maximized the content, in the rape seeding were quite different from in the wheat seeding. This suggested that different species of crop has different utilize threshold in REE.The tredency of U1, U2, MY2, MG, UG, which were REE potential effectors, response to La, Nd stimulation was changed regularly. By analyzing the chromatograms, the molecular weight of U1, U2, MY2 could determine as 117.087, 245.243, 564.154, and the chemical formula could speculate as C₅H₁₁NO₂, C₁₄H₃₁NO₂, C₂₂H₂₄N₆O₁₂ respectively. Combining Plant Physiology, we could conclude that these effectors may be alkaloids or alkaloid-related substances, and these substances could be identified accurately after applying infrared spectroscopy, nuclera magnetic resonance and other instruments in analysis their chemical structures.