Exogenously applied nitrate improves the photosynthetic performance and nitrogen metabolism in tomato (Solanum lycopersicum L. cv Pusa Rohini) under arsenic (V) toxicity

Abstract

Tomato (Solanum lycopersicum L.) being a widespread and most commonly consumed vegetable all over the world has an important economic value for its producers and related food industries. It is a serious matter of concern as its production is affected by arsenic present in soil. So, the present study, investigated the toxicity of As(V) on photosynthetic performance along with nitrogen metabolism and its alleviation by exogenous application of nitrate. Plants were grown under natural conditions using soil spiked with 25 mg and 20 mM, As(V) and nitrate, respectively. Our results revealed that plant growth indices, photosynthetic pigments, and other major photosynthetic parameters like net photosynthetic rate and maximum quantum efficiency (F v /F m ) of photosystem II (PSII) were significantly (P B 0.05) reduced under As(V) stress. However, nitrate application significantly (P B 0.05) alleviated As(V) toxicity by improving the aforesaid plant responses and also restored the abnormal shape of guard cells. Nitrogen metabolism was assessed by studying the key nitrogen-metabolic enzymes. Exogenous nitrate revamped nitrogen metabolism through a major impact on activities of NR, NiR, GS and GOGAT enzymes and also enhanced the total nitrogen and NO content while malondialdehyde content, and membrane electrolytic leakage were remarkably reduced. Our study suggested that exogenous nitrate application could be considered as a cost effective approach in ameliorating As(V) toxicity.

Response of cytokinins and nitrogen metabolism in the fronds of Pteris sp. under arsenic stress

“…In our experiment, frond biomass declined with increasing As supply in the soil and increasing As content in plants (Figs 1 and 2). Growth reduction is the most common symptom of As stress in plants [51,52] and represents the result of an activation of plant defense mechanisms and the regulation of stress metabolism.…”

Effect of arsenic stress on 5-methylcytosine, photosynthetic parameters and nutrient content in arsenic hyperaccumulator Pteris cretica (L.) var. Albo-lineata

“…As is widely reported to inhibit the rate of photosynthesis in plants and to reduce chlorophyll concentration [7]. Agnihotri and Seth [8] showed a decline in photosynthetic pigments and gaseous exchange parameters in plants exposed to As, indicating the onset of senescence. Foyer and Noctor [9] also confirmed that oxidative stress activates senescence associated with the degradation of photosynthetic pigments and remobilises the basic nutrients C, N, P, and S. Modified stress metabolism due to extended reversible senescence releases nutrients from catabolic processes and transports them from old leaves into young leaves more efficiently.…”

Interactive effect of potassium and spermidine protects growth, photosynthesis and chlorophyll biosynthesis in Vigna angularis from salinity induced damage by up-regulating the tolerance mechanisms

“…Increased nitrogen metabolism contributes to maintenance of sufficient N within cells. Greater nitrate reductase activity has significant contribution to nitric oxide production which can assist in integrating the signalling and response mechanisms under stressful condition (Agnihotri and Seth, 2016;Berger et al, 2020). Earlier, Khan et al (2014) have reported significant decline in NR activity under salinity stress resulting in reduced photosynthesis probably restricting the allocation of N for Rubisco synthesis.…”