Acclimation of photosynthesis to nitrogen deficiency in Phaseolus vulgaris

Abstract

Nitrogen deficiency diminishes consumption of photosynthates in anabolic metabolism. We studied adjustments of the photosynthetic machinery in nitrogen-deficient bean plants and found four phenomena. First, the number of chloroplasts per cell decreased. Chloroplasts of nitrogen starved leaves contained less pigments than those of control leaves, but the in vitro activities of light reactions did not change when measured on chlorophyll basis. Second, nitrogen deficiency induced cyclic electron transfer. The amounts of Rubisco and ferredoxin-NADP(+) reductase decreased in nitrogen starved plants. Low activities of these enzymes are expected to lead to increase in reduction of oxygen by photosystem I. However, diaminobenzidine staining did not reveal hydrogen peroxide production in nitrogen starved plants. Measurements of far-red-light-induced redox changes of the primary donor of photosystem I suggested that instead of producing oxygen radicals, nitrogen starved plants develop a high activity of cyclic electron transport that competes with oxygen for electrons. Nitrogen starvation led to decrease in photochemical quenching and increase in non-photochemical quenching, indicating that cyclic electron transport reduces the plastoquinone pool and acidifies the lumen. A third effect is redistribution of excitation energy between the photosystems in favor of photosystem I. Thus, thylakoids of nitrogen starved plants appeared to be locked in state 2, which further protects photosystem II by decreasing its absorption cross-section. As a fourth response, the proportion of non-Q(B)-reducing photosystem II reaction centers increased and the redox potential of the Q(B)/Q(B)(-) pair decreased by 25 mV in a fraction of photosystem II centers of nitrogen starved plants.

Application of chlorophyll fluorescence performance indices to assess the wheat photosynthetic functions influenced by nitrogen deficiency

“…In terms of the mechanism, the nitrogen deficiency was proven to increase the cyclic electron transport and there is less PS I available for accepting electrons from PS II (Antal et al 2010). Similar to our results, Nikiforou and Manetas (2011) attributed the positive correlation between leaf nitrogen content and PI tot values to decrease of PS I activity in linear electron transport caused by nitrogen deficiency.…”

Multiple regulatory mechanisms in the chloroplast of green algae: relation to hydrogen production

“…Normally several protective mechanisms limit the production of ROS and remove their excess, and therefore ROS do not accumulate during steady-state photosynthesis unless conditions turn unfavorable. The equilibrium between production and scavenging of ROS can be perturbed by a number of adverse abiotic factors, including nutrient deficiency (Apel and Hirt 2004;Antal et al 2010). One can conclude that S depletion causes imbalance between three energy-related processes in the algal cell: carbohydrate consumption, carbohydrate production in photosynthesis, and generation of NADPH in the light reactions (Fig.…”

“…Such stresses as nitrogen deficiency or cold acclimation, inducing inactivation of the Calvin-Benson cycle, have occasionally been shown to be accompanied by specific changes of the redox potentials of electron-accepting quinones in PSII of plants (Ivanov et al 2001;Sane et al 2003;Antal et al 2010). These modifications decrease the energy gap between Qa and Qb and increase it between Qa and Pheo, facilitating PSII closure and energy dissipation in the reaction centers due to modifications of electron transfer pathways in PSII.…”

“…CET is enhanced when FNR is inactive or carbon fixation runs slowly, for instance, in dark-adapted plants or algae, or under certain environmental stresses, such as draught, chilling, or nutrient deficiency (Golding and Johnson 2003;Breyton et al 2006;Antal et al 2010). In CET, electrons from Fd are donated to PQ by two principal routes: the first pathway involves the NADH dehydrogenase complex (NDH), catalyzing electron transfer from NAD(P)H to the PQ pool; and the second one, an antimycin A-sensitive route, is mediated by a putative ferredoxin-quinone-reductase (FQR) (Joet et al 2001;Shikanai 2007;Hertle et al 2013) (Fig.…”

Mathematical Modeling of Photosynthetic Electron Transport Chain Considering Spatial Heterogeneity of the Thylakoid Membrane

“…Проростки фасоли (Phaseolus vulgaris L. cv Saxa) выращивали методом гидропоники на жидкой среде [37] как описано в [38]. Для измерений использовали листья 7-дневных растений.…”