Total Amino Nitrogen Contents Research Articles

Irrigation with industrial wastewater activates antioxidant system and osmoprotectant accumulation in lettuce, turnip and tomato plants

We focused on the impact of industrial wastes on the water quality of the El-Amia drain in Egypt and the effect of irrigation with industrial wastewater on the growth, cell membranes, photosynthetic pigment content, the antioxidant system and selected osmoprotectants (proline, total amino nitrogen and soluble sugars) in three crop plants: turnip, tomato and lettuce. Furthermore, the present work focused on the analysis of the heavy metal content and its accumulation in the studied plants. For this purpose, water samples were collected 1, 10 and 19km from the beginning of the drain and used for irrigation, with fresh water as a control. We found that industrial wastewater contained significant amounts of heavy metals (Cd, Ni and Co) warranted a pollution problem as their amounts exceed the maximum recommended concentrations according to FAO guidelines for trace metals in irrigation water. The three crop plants accumulate significant amounts of heavy metals in their shoots and roots and showed a significant decrease in leaf area, fresh weight and dry weight of shoots and roots, accompanied by a marked reduction in photosynthetic pigment content and damage to cell membranes, as indicated by increased electrolyte leakage and a lower membrane stability index. Significant increases in the activities of antioxidant enzymes and in the glutathione, proline, soluble sugar and total amino nitrogen content in response to irrigation with wastewater may be defense mechanisms induced in response to heavy metal stress.

White Particulate Formation as a Result of Enzymatic Proteolysis of Protein Substrates in Brine-fermented Foods

Rice koji and rice-soy koji (1:1, w/w) were used as enzyme sources in combination with parahydroxyl benzoate (paraben), sulfanilamide, tetracycline, chloramphenicol or glacial acetic acid as antimicrobial agents for sufu fermentation. After 1 year of fermentation, no formation of white particulate was observed in rice koji products and in the rice-soy koji products with 10 mL/L of glacial acetic acid in the brines. Compositional analyses revealed that pH, tyrosine content and total amino nitrogen content of rice koji brines were lower than those of rice-soy koji brines. In a model system, a series of test tubes containing NaCl solution (150 g/L) and autoclaved soy koji or soybean used as protein substrates with supplements of various enzyme sources were fermented for 3 months at 35 °C. When an indigenous strain of Zygosaccharomyces rouxiiisolated from a fermented sufu brine or the sufu brine in which white particulates were present was respectively introduced into the systems using autoclaved soy koji as substrate, no white particulate was observed. However, white particulates were observed in the systems supplemented with soy koji extract, trypsin or pancreatin. When autoclaved soybean was used as the protein substrate, a white particulate was observed only in the system containing soy koji extract. Amino acid analysis of the particulates showed tyrosine to be the major component and independent of protease origin and presence of microorganisms.

Effect of Drought Conditions at Boiling Stage on Some Chemical Constituents of Cotton Plant

AbstractThe investigation was carried out to study the effect of drought conditions at boiling stage on chloroplast pigments and anthocyanin, in leaves, carbohydrate, phenols and total amino nitrogen content in leaves and roots, oil and protein contents in bolls of different ages. Seeds of cv. Giza 75 cotton were sown during 1987 and 1988 seasons in pots of 30 cm in diameter containing 11 kg of soil; after complete germination, thinning was carried out leaving one plant per pot. Plants were subjected to water stress conditions at boiling stage till the sign of wilting, while the control plants were irrigated regularly at this stage without allowing the plants to reach wilting stage and kept in turgid state. The results obtained can be summarized as follows:1. Drought conditions decreased reducing sugar, nonreducing sugar, total soluble sugar and total amino nitrogen in leaves, while the reverse was true in roots.2. Drought conditions reduced total and polyphenols content in leaves while it had no effect on phenols compounds in roots.3. Drought conditions had no significant effect on pigments except total carotenoid in 1987 season.4. Oil content in seeds of different boll ages decreased as a result of drought in both seasons.5. In general drought condition increased protein content in 1987 season while the reverse was true in 1988 season.6. Leaves and roots of wilted plants had more inhibitors as compared to turgid plants.

Asparagine Biosynthesis in Alfalfa (Medicago sativa L.) Root Nodules

Rapid direct conversion of exogenously supplied [(14)C]aspartate to [(14)C] asparagine and to tricarboxylic cycle acids was observed in alfalfa (Medicago sativa L.) nodules. Aspartate aminotransferase activity readily converted carbon from exogenously applied [(14)C]aspartate into the tricarboxylic acid cycle with subsequent conversion to the organic acids malate, succinate, and fumarate. Aminooxyacetate, an inhibitor of aminotransferase activity, reduced the flow of carbon from [(14)C]aspartate into tricarboxylic cycle acids and decreased (14)CO(2) evolution by 99%. Concurrently, maximum conversion of aspartate to asparagine was observed in aminooxyacetate treated nodules (30 nanomoles asparagine per gram fresh weight per hour. Metabolism of [(14)C]aspartate and distribution of nodulefixed (14)CO(2) suggest that two pools of aspartate occur in alfalfa nodules: (a) one involved in asparagine biosynthesis, and (b) another supplying a malate/aspartate shuttle. Conversion of [(14)C]aspartate to [(14)C]asparagine was not inhibited by methionine sulfoximine, a glutamine synthetase inhibitor, or azaserine, a glutmate synthetase, inhibitor. The data did not indicate that asparagine biosynthesis in alfalfa nodules has an absolute requirement for glutamine. Radioactivity in the xylem sap, derived from nodule (14)CO(2) fixation, was markedly decreased by treating nodulated roots with aminooxyacetate, methionine sulfoximine, and azaserine. Inhibitors decreased the [(14)C]aspartate and [(14)]asparagine content of xylem sap by greater than 80% and reduced the total amino nitrogen content of xylem sap (including nonradiolabeled amino acids) by 50 to 80%. Asparagine biosynthesis in alfalfa nodules and transport in xylem sap are dependent upon continued aminotransferase activity and an uninterrupted assimilation of ammonia via the glutamine synthetase/glutamate synthase pathway. Continued assimilation of ammonia apparently appears crucial to continued root nodule CO(2) fixation in alfalfa.

Comparative Investigation of the Action of Several Chlorosis-inducing Herbicides on the Biogenesis of Chloroplasts and Leaf Microbodies

Seedlings of Triticum aestivum L. and Secale cereale L. were grown in the presence of six different (five having different chemical structures) chlorosis-inducing herbicides: aminotriazole and its derivative SDR 5175, haloxidine, Sandoz 6706, fluometuron, and EMD-IT 5914. Concentrations were applied which allowed the leaves to grow normally and to reach normal total amino nitrogen contents but evoked a complete chlorosis (less than 6% chlorophyll). The effects of the herbicides on the accumulation of several chloroplast constituents and on peroxisomal and mitochondrial marker enzyme activities were compared. Wheat and rye, in general, gave very similar results, wheat being more sensitive to unspecific inhibitory effects.In dark-grown plants, the herbicides had no or only minor effects on the rRNA pattern and on enzyme activities of the leaves. In the light, all herbicides applied prevented the accumulation of carotenoids and of chloroplastic rRNA. Consequently, ribulose-1,5-bisphosphate carboxylase activity was virtually absent. After all herbicide treatments in light, the leaves contained only rather low catalase activity. In the presence of aminotriazole and haloxidine, the chloroplast-specific NADP-glyceraldehyde-3-phosphate dehydrogenase and the peroxisomal enzymes glycolate oxidase and hydroxypyruvate reductase had high or even normal activities, as in untreated leaves. In leaves treated with Sandoz 6706, fluometuron, or EMDIT 5914, the activities of the latter three enzymes were, in parallel, only very low. Some herbicides interfered with enzyme activities in vitro, particularly with those of catalase and of glycolate oxidase. Among mitochondrial enzymes, cytochrome c oxidase activity was either unaffected or lower, while fumarase had considerably higher activities in the herbicide-treated, as compared to untreated leaves. The specific effects on peroxisomal enzymes cannot be explained by the hypothesis of herbicide-induced photodestructions in carotene-deficient plastids. Alternative explanations for the genesis of the chlorosis are discussed.

Comparative analysis of the action of cytokinin and light on the growth of rye leaves

In etiolated rye seedlings (Secale cereale L.) the cytokinin supply controls leaf growth. Dry weight and total amino-nitrogen, protein, total nucleic acid, DNA, and rRNA levels were similarly lowered in leaves depleted of their endogenous cytokinin supply by early excision of the seedling roots and increased by 70-100% after the addition of kinetin. The proportion of cytoplasmic ribosomes bound as polyribosomes was only slightly increased from 40% in cytokinin-deficient to 50% in kinetin-treated darkgrown leaves. White light increased the polyribosome proportion to 61%. In cytokinin-supplied leaves uptake and accumulation of L-[(3)H]leucine were greater than in cytokinin-deficient leaves. Under all conditions of cytokinin supply the same proportion of the total amino nitrogen content (80%) was present as protein nitrogen and virtually, the same percentage (60%) of the total uptake of L-[(3)H]leucine was incorporated into protein in dark-grown leaves. In light, significantly higher proportions of the amino nitrogen content and of the L-[(3)H]leucine uptake were incorporated into protein. The results suggest that the accumulation of substrate is a main cytokinin-controlled step determining the growth of the leaves.

Occurrence of a High Temperature Sensitivity of Chloroplast Ribosome Formation in Several Higher Plants

A specific high temperature-induced deficiency of chloroplast ribosome formation, as indicated by the absence of chloroplast rRNA, has been observed in the leaves of light- or dark-grown seedlings of Avena sativa L., Hordeum vulgare L., and Triticum aestivum L. at certain temperatures between 28 and 34 C. While the growth of the leaves (size, morphology, total amino nitrogen content) was little affected by the elevated temperature, chlorophyll accumulation was strongly inhibited, amounting to only 2 to 20% of its content in 22 C-grown leaves which were used as a reference for normal development. The carotenoid contents were also lower but still reached at least 15 to 20% of the corresponding measurements at 22 C. Ribulose-1,5-bisphosphate carboxylase was absent at the higher temperature while NADP-glyceralde-hydephosphate dehydrogenase reached high activities. For the peroxisomal marker enzyme hydroxypyruvate reductase, 30 to 70% of the activity present in 22 C-grown leaves was found in extracts from high temperature-grown leaves. Fumarase reached 1.5- to 4-fold higher activities at the elevated growth temperature than at 22 C. Leaves of Pisum sativum L. were completely chlorotic and deficient of 70S ribosomes at 33 C but simultaneously suffered from a severe general inhibition of their growth. In Zea mays L., a formation of chlorotic leaves was not observed at elevated temperatures.

The effect of soil moisture and nitrogen on yield and quality of the Russet Burbank potato

A study was conducted to obtain more information on the effects of soil moisture and nitrogen on yield and quality of the Russet Burbank potato. Total yield of tubers increased with nitrogen rates as a result of more tubers per plant and larger tubers but the percent of malformed tubers also increased. Increased nitrogen rates decreased of dry matter of tubers and increased the total amino-nitrogen content of the tubers. Placing all of the nitrogen in bands on each side of the row produced more tubers having growth cracks, culls and reduced yield of No. 1’s when compared with broadcasting. Applying a moisture stress to potato plants during the early tuber set period increased the percentage of malformed tubers having pointed stem ends, bottlenecks and dumbbell shapes; although total yield and grade of tubers were not significantly affected. Irrigating when available soil moisture was 75 or 85 percent instead of 65 percent during the growing season did not affect total yield, grade or tuber quality at the five percent probability level.