Effects of Manganese Deficiency and Added Cerium on Nitrogen Metabolism of Maize

Abstract

Manganese is one of the essential microelements for plant growth, and cerium is a beneficial element for plant growth. However, whether manganese deficiency affects nitrogen metabolism of plants and cerium improves the nitrogen metabolism of plants by exposure to manganese-deficient media are still unclear. The main aim of the study was to determine the effects of manganese deficiency in nitrogen metabolism and the roles of cerium in the improvement of manganese-deficient effects in maize seedlings. Maize seedlings were cultivated in manganese present Meider's nutrient solution. They were subjected to manganese deficiency and to cerium chloride administered in the manganese-present and manganese-deficient media. Maize seedlings grown in the various media were measured for key enzyme activities involved in nitrogen metabolism, such as nitrate reductase, glutamate dehydrogenase, glutamine synthetase, and glutamic-oxaloace transaminase. We found that manganese deficiency restricted uptake and transport of NO(3)(-), inhibited activities of nitrogen-metabolism-related enzymes, such as nitrate reductase, glutamine synthetase, and glutamic-oxaloace transaminase, thus decreasing the synthesis of chlorophyll and soluble protein, and inhibited the growth of maize seedlings. Manganese deficiency promoted the activity of glutamate dehydrogenase and reduced the toxicity of excess ammonia to the plant, while added cerium relieved the damage to nitrogen metabolism caused by manganese deficiency in maize seedlings. However, cerium addition exerted positively to relieve the damage of nitrogen metabolism process in maize seedlings caused by exposure to manganese-deficient media.

Comparative Proteomics Analysis of the Seedling Root Response of Drought-sensitive and Drought-tolerant Maize Varieties to Drought Stress

“…Additionally, it was found that glutamate synthase (tr|A0A1D6NFL0|A0A1D6NFL0_MAIZE, tr|A0A1D6G281|A0A1D6G281_MAIZE) was also up-regulated in two varieties. Ammonia produced by reduction of NO 3 − or NO 2 − is toxic if it is accumulated in plant cells [37], and the up-regulation of glutamate synthase leads to an increase in the abundance of glutamate, which can be used for maize growth [38], and for eliminating ammonia produced under adverse conditions [39,40].…”

Overexpression of a High-Affinity Nitrate Transporter OsNRT2.1 Increases Yield and Manganese Accumulation in Rice Under Alternating Wet and Dry Condition

“…Nitrate and Mn are essential nutrients in plants, and it has been reported that Mn deficiency decreases N uptake and metabolism ( Gong et al, 2011 ). Excessive NO 3 - was shown to enhance Cd uptake in Thlaspi caerulescens ( Xie et al, 2009 ) and wheat ( Li et al, 2011 ).…”

“…Simultaneously, Mn can influence NO 3 - reductase activity and is associated with photosynthesis in plants ( Botrill et al, 1970 ; Gong et al, 2011 ). Mn also influences N metabolism and regulates protein synthesis ( Jiang, 2006 ).…”

Comparative Proteomics of Contrasting Maize Genotypes Provides Insights into Salt-Stress Tolerance Mechanisms

“…These two enzymes are involved in glutamate synthesis, which is critical for decreasing ammonia levels. 25,26 Meanwhile, hydroxymethyltransferase, dihydrolipoyl dehydrogenase, and NAD-dependent malic enzyme were significantly up-regulated to synthesize serine, aspartate, and alanine, which also help to decrease ammonia levels (Figure 6C).…”