Differential Nitrogen Nutrition Modifies Polyamines and the Amino-Acid Profile of Sweet Pepper Under Salinity Stress

Abstract

The horticultural industry demands high-quality resources to achieve excellence in yield and optimal revenues. Nitrogen is a pivotal nutrient to accomplish these goals for plant growth and product quality. However, competition for water in semi-arid regions can force the use of brackish waters, which can impair N uptake. The lower N uptake can be due to several reasons, such as an antagonism between ions, an absence of ATP, and/or alteration of N metabolism. The effect of supplying N as alone or in combination with , coupled with low or high salinity (8 or 20 mM NaCl), has been studied in sweet pepper fruits ( Capsicum annuum L. cv. Melchor). The application of at high salinity affected chromatic parameters (a ∗ , b ∗ , and C ∗ ), while chlorophyll a and b levels declined and β-carotene increased. The concentrations of P, K, Ca, Mg, and Cu were reduced in the fruits of plants irrigated with . The concentration of Na was only reduced when was supplied. Likewise, the concentration of total phenolics was also reduced at high salinity. However, total protein was unaffected. The amino acid profile was altered by the supply of , which reduced the concentrations of histidine and phenylalanine. Moreover, the concentrations of putrescine and cadaverine were increased by at high salinity, whereas that of cadaverine was reduced by at low salinity. The observed changes in fruit quality triggered by salinity, under the conditions of this study, should be borne in mind for this crop with regard to the envisaged palliative effect of the supply of N- .

Transcriptome Analysis of Acid-Responsive Genes and Pathways Involved in Polyamine Regulation in Iron Walnut

“…Two nearly identical large sub-clusters and a small sub-cluster in cluster X all contained sequences related to photosynthesis and chlorophyll, indicating that differences in nucleotide sequences occurred within the high-expression genes in cluster X, although these nucleotide sequences have similar biological functions. A similar phenomenon was also found in Arabidopsis thaliana [42], Capsicum annuum [43], Lactobacillus kefiranofaciens [44], Rana arvalis [45], and Zea mays [46].…”

“…The hypothetical roles of polyamines include antioxidant responses, programmed cell death, acting as a compatible solute in higher plants, acting as a signaling molecule during stress responses, regulating ion channels and Ca 2+ homeostasis, and other unknown pathways. Previous works [4,9,11,15,16,17,18,20,43,46,52,53,62] have indicated that accumulated polyamines may play vital roles in counteracting stress (1) as antioxidants, free radical scavengers, and membrane stabilizers that can interact freely with DNA/RNA/proteins/membrane lipids to prevent the membrane system from denaturing under acid stress conditions; (2) through the cationic nature of spermine +4 > spermidine +3 > putrescine +2 at physiological pH and/or improvement of the K + /Ca 2+ ion balance; (3) as cellular signals in intrinsic cross-talk with abscisic acid (ABA), hydrogen peroxide, and nitrous oxide during acid stress responses by a complex network; and (4) by increasing cell proliferation, decreasing apoptosis and increasing the expression of genes associated with tumor invasion and metastasis, thus making their metabolism a target for cancer treatment and prevention.…”

Hydroponic horticulture using residual waters fromOreochromis niloticusaquaculture with biofloc technology in photoautotrophic conditions withChlorellamicroalgae

“…In the case of photoautotrophic treatments, the relations were similar to Copper 1 and 2 hydroponic solutions (Figure 6b Figure 6b). González, Rodríguez, Sánchez, and Gaytán (2009) indicated that the optimal combination of NO 3 with NH 4 produced higher growth in certain plants and could also reduce the effect of salt stress (Piñero et al, 2019). The presence of NH 4 + in the nutrient solution stimulates the uptake of NO 3 -.…”

Effects of Different Nitrogen Forms and Exogenous Application of Putrescine on Heat Stress of Cauliflower: Photosynthetic Gas Exchange, Mineral Concentration and Lipid Peroxidation

“…However, the problem that arises now is that the lack of nutrients could lead to less healthy crops with a lower yield [ 21 ]. It has been observed that nitrogen fertilization that provides ammonium (NH 4 + ), aside from promoting plant growth, can also reduce the negative effects of heat stress [ 22 , 23 ]. However, the most appropriate NO 3 − /NH 4 + ratio depends on the species.…”