Effect of Some Rare Earth Elements on Dry Matter Partitioning, Nodule Formation and Chlorophyll Content in Arachis Hypogaea L. Plants (Report‪)‬

Introduction Rare earth elements (REEs) frequently occur together as rare earth minerals and have similarities in ionic radii and chemical activities (Henderson, 1984). Application of REEs in agriculture has been carried out intensively since 1972, aiming to increase crop yields (Brown et al., 1990; Xiong, 1995). Many research works have been done to show the beneficial effects of REEs on the synthesis of chlorophyll, seedling development (Chang, 1991; Wu et al., 1983) and stimulation of root and shoot growth in crops. Rare earth elements in plants induce metabolism and so they are used as fertilizer in agriculture. Metabolism of nutrients in plants increased by rare earth elements by the transfer of N from inorganic to organic form, which is beneficial for protein synthesis and regulation of nutrient balance (Yang and Zhang, 1986). Rare earth elements can enhance chlorophyll content and improve photosynthetic rate. Thus they can increase plant biomass. When an appropriate amount of rare earth elements was applied, the uptake of nutrients by plant and their transformation and utilization were promoted. Guo et al., (1988) Rare earth elements could enhance the plant's resistance against stress such as to cold, drought, acid rain and metal (Wen et al.,1992; Yan et al., 1999; Zhou et al., 1999). Rare earth element in plants enhances the rate of respiration rate and decrease loss of water. Spraying rare earth on pepper foliars improved the total chlorophyll content of chlorophyll a and chlorophyll b (He et al., 1998). Many studies suggest that REEs can stimulate plants to absorb, transfer and assimilate nutrients.