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IntroductionThe reduction of N supplied combined with the use of biostimulants can be an efficient strategy that allows sustainable agriculture to achieve better economic, nutritional and environmental goals without reducing production. Moreover, the industrial processing of celery generates large amounts of waste. Therefore the purpose of this study was improve crop management strategies to reduce nitrate pollution while turning crop waste into value-added products for others sectors.MethodsConsequently, in this work twelve treatments were examined: three N nitrogen content in the nutrient solution (100% control, 60%, and 30%) combined with the inoculation of the roots with Azotobacter salinestris, and foliar application selenium solution (8 μM, Na2SeO4). The celery parts from plants grown under limited N dose showed a higher antioxidant activity and TPC (total phenolic compounds) content.Results and discussionThe antioxidant activity increased 28% in leaves and 41% in by-products and TPC improved 27% in leaves and 191% in by-products respect to the control. Besides, a significant reduction of β-carotene content (56%, 11% and 43% in petioles, leaves and by-products respect to the control, respectively) was obtained in plants fed with restricted dose of N. The catalase activity was not affected by N dose. The inoculation of the plants with Azotobacter, together with a reduced N dose, achieved a greater accumulation of all the parameters studied. This accumulation was maximum when Se was applied to the leaves compared with the control and depending on the celery part: TPC (121-450%); antioxidant activity (60-68%), of catalase activity (59% - 158%), and of pigments content (50-90%). These findings can boost the valorization of celery by-products as excellent source of bioactive compounds.

There exist many research papers which pointed out the positive effects of using the mulching technique in stressful conditions, showing crop productivity and physicochemical quality improvement of the product. We hypothesized that a novel organic liquid mulching formulations (hydromulching) can be used in sustainable agricultural production under drought stress through both their direct influence on physicochemical and biological soil properties as well as by their effect on plant hormonal balance leading to the improvement of crop yield and quality. Artichoke plants were grown on bare soil (BS) or mulched with traditional polyethylene (PE) or with three different types of ecological hydromulching treatments obtained from recycled additives, namely: substrate used for mushroom cultivation (MS), rice hulls (RH) and wheat straw (WS); and were subjected to optimal (100% ETc) and reduced (70% ETc) irrigation regimes. Under water limitation, soil organic matter and carbon and mineral soil concentrations increased in the hydromulched soils (by 60% on average). Mulched treatments produced the highest crop yield (by 40% on average) attributed to increased artichoke head fresh weight, giving rise to the improvement of the important physical quality parameters in artichoke: color, firmness, and size. Furthermore, hydromulched treatments induced higher content of mineral nutrients in artichoke heads, while sugar concentrations were superior in non-mulched soil due to a major exposure to water stress. This may be related to the diminished carbohydrate metabolism activity under drought stress, including notable changes in the hormonal balance. The crosstalk of growth-promoting hormones (cytokinins) with the stress-related hormone factors (ethylene precursor 1-aminocyclopropane-1-carboxylic acid) has been shown to regulate adaptive responses such as sugar osmoregulation in artichoke heads under drought stress. Altogether, these results demonstrate that hydromulching is a sustainable alternative to plastic films to cope with drought stress by improving yield and physical quality characteristics of artichoke heads and maintaining their chemical and nutritional quality over bare soil.

Due to climate change and exacerbated population growth, the search for new sustainable strategies that allow for greater food productivity and that provide greater nutritional quality has become imperative. One strategy for addressing this problem is the combined use of fertilization with a reduced dose of nitrogen and biostimulants. Celery processing produces a large amount of waste with its concomitant pollution. Therefore, it is necessary to address the valorization of its byproducts. Our results revealed reductions in the biomass, Na, P, Mn, B, sugars, and proteins in the byproducts and increased lipid peroxidation, Fe (all celery parts), and K (byproducts) when the N supplied was reduced. Plants inoculated with Azotobacter salinestris obtained a greater biomass, a higher accumulation of K (byproducts), a build-up of sugars and proteins, reduced concentrations of P, Cu, Mn, B, Fe (petioles), and Zn (byproducts), and reduced lipid peroxidation. The application of Se at 8 μM reinforced the beneficial effect obtained after inoculation with Azotobacter salinestris. In accordance with our results, edible celery parts are recommended as an essential ingredient in the daily diet. Furthermore, the valorization of celery byproducts with health-promoting purposes should be considered.

The use of nitrogen as a fertilizer can be highly risky when used excessively, and it is therefore necessary to find novel techniques to reduce its use. Aquaponics reduces the use of synthetic fertilizers and water, and the leaching of nitrate into the environment. One way to avoid problems due to a reduction in nitrogen availability could be the use of plant growth promoting rhizobacteria (PGPR). This study examines the effect of PGPR on kohlrabi plants grown with a traditional nutrient solution (100S), in combination with “fish water” (50F/50D), or with a supplement of synthetic fertilizers (50F/50D + S). Two formulations were used: T1 (Azospirillum brasilense and Pantoea dispersa) and T2 (Azotobacter salinestris). Irrigation with 50F/50D caused a reduction in several of the measured parameters. The combined application of 50F/50D with T1 attenuated the negative effects. T2 did not present significant effects on the parameters measured. The results obtained with 50F/50D + S hardly showed differences with the 100S. Thus, by irrigating with 50F/50D + S, we were able to maintain the yields while reducing fertilizer use and water. The combined use of T1 and 50F/50D was also positive; however, it would be necessary to continue adjusting the amount of nitrate supplied to maintain production.

Consumers are becoming increasingly concerned about eating healthy, and the products they consume are produced in an environmentally friendly way. Therefore, in this work, production techniques such as aquaculture and the use of plant growth-promoting bacteria in kohlrabi cultivation (Brassica oleracea L.) were studied. To this end, we applied three types of irrigation treatments (control, mixed water (50% fish effluent/50% drainage water) (mixed water), and mixed water enriched with synthetic fertilizers (mixed water + S)) combined with two formulations of plant growth-promoting bacteria (B1 and B2) in kohlrabi plants. Our data showed that the B1 inoculum combined with control irrigation caused both the increase in dry matter and the diameter of the bulb (17.8% and 8.9%, respectively); moreover, this inoculum increased the concentration of Ca when applied with mixed irrigation solution (water + S), and Zn for the B2 inoculum. The nitrogen utilization efficiency (NUtE) was augmented by the mixed irrigation treatment, with the lowest concentration of nitrates observed in the bulbs. Both inocula increased the total phenolic compounds in the control irrigation, whilst an increase in fructose and sucrose concentrations was only observed with B2.

Abstract In the last years, the atmospheric CO2 concentration has increased significantly, and this increase can cause changes in various physiological and biochemical processes of plants. However, the response of plants to elevated CO2 concentration (e[CO2]) will be different depending on the nitrogen form available and the plant species. Therefore, hydroponic trials on cucumber plants, with two CO2 concentrations (400 and 1000 ppm) and two nitrogen sources (NO3 −/NH4 +; 100/0 and 90/10), were conducted. Physiological parameters—such as gas exchange, GS, GOGAT and GDH activities, cation composition, soluble sugar and starch content- were measured. The results showed that when plants were grown with NH4 + and e[CO2], parameters such as photosynthesis rate (ACO2), instantaneous water use efficiency (WUEi), the content of NH4 +, Ca2+ and Mg2+, and the concentration of starch, were higher than in control plants (irrigated with nitrate as sole nitrogen source and ambient CO2 concentration (a[CO2])). Furthermore, an improvement in N assimilation was observed when the GS/GOGAT pathway was enhanced under these conditions (NH4 + and e[CO2]). Thus, our results contribute to the reduction of the negative environmental impacts of the use of nitrogen fertilizers on this crop, both by reducing nitrogen leakage (eutrophication) and greenhouse gas emissions.

Frequency, intensity and duration heat-related events have profound implications for future food supply through effects on plant growth and development. This concern needs effective and urgent mitigation tools. However, the effectiveness of potential solutions may decrease according to the specific cultivar response rather consider at specie level. The metyl-jasmonates are essential cellular regulators which are involved in pivotal plant development processes and related to confer protection to heat shock. Thus, our aim was to study the response of three pepper cultivars, Agio (Hungarian type), Basque (Chilli type), and Loreto (Lamuyo type), subjected to heat shock (40°C/72 h) and foliarly-sprayed with methyl-jasmonate (MeJA; 100 µmol), and the effects on several physiological traits. Our results show that despite the important differential impact of heat shock caused on each cultivar, MeJA application did not affect gas exchange, chlorophyll A concentration or efficiency of the photosystem in these cultivars. However, P concentration was reduced when MeJA was applied to Basque chilli, and a significant effect on leaf carbohydrates concentration was observed for Agio and Loreto. Moreover, Agio was the only cultivar in which the amino-acid profile was affected by MeJA under heat shock. Under that condition, putrescine increased for all cultivars, whist the effect of MeJA was only observed for spermine and histamine for Agio and Loreto. Thus, the results indicated that the ameliorative impact of MeJA on this stressor was clearly influenced by cultivar, revealing specific traits. Thus, these results could be used as valuable tools for the characterization of this intraspecific tolerance to heat shock during the vegetative growth stage of pepper.

In recent years, the interest on baby-leaf lettuce has grown steadily, because it is richer in bioactive compounds than other traditional vegetables. However, the quality of lettuce is being increasingly affected by climate change. It is very rare for a climatic effect to occur in isolation. Even then, a large body of work has only focused on the effect of isolated heat stress, fertilization, and elevated CO2, on morphological, physiological and biochemical parameters. Thus, very few works have focused on how the combination of several of these factors can affect these parameters. For first time, the present work studied the combined effect derived from the application of two different levels of CO2 (400 and 1000 ppm of CO2), four different NO3-/ NH4+ ratios (100/0 (T-I), 100/0 before the short-term heat stress and finally without NO3- (T-II), 80/20 (T-III) and 50/50 (T-IV)), and a short-term heat stress (25 and 43°C), on some physiological and quality parameters (dry biomass, photosynthetic parameters, pigments content, lipid peroxidation and total soluble proteins content) of baby-leaf lettuce cv Derbi. Additionally, a comparison of that combined effect of all these parameters between inner and outer leaves was also performed. The results obtained indicated that the interaction between the nutrient solution containing a 50/50 NO3-/ NH4+ ratio and a high concentration of CO2 (1000 ppm) improved the biomass, photosynthesis, intercellular/external CO2 concentration ratio (ci/ca), stomatal conductance (gs), evapotranspiration (E) and lipid peroxidation, and protein content in this baby-leaf lettuce. The results obtained in this work lead us to conclude that this existing interaction between the NO3-/ NH4+ ratio and the elevated CO2 concentration may be considered as a new strategy for making baby-leaf lettuce more resistant to heat stress, in other words, stronger against the ever more frequent heat waves.

To improve water and nutrient use efficiencies some strategies have been proposed, such as the use of mulching techniques or arbuscular mycorrhizal fungi (AMF) inoculation. To gain insights into the interaction between the use of hydromulch and AMF inoculation on plant growth and productivity, escarole plants (Cichorium endivia, L.) were inoculated with the AMF Rhizophagus irregularis and grown with non-inoculated plants under different soil cover treatments: ecological hydromulching based on the substrate of mushroom cultivation (MS), low-density black polyethylene (PE), and non-covered soil (BS). AMF inoculation or the use of mulching alone, but especially their interaction, increased the plant growth. The growth improvement observed in AMF-inoculated escarole plants grown under hydromulching conditions was mainly associated with the upgrading of nitrogen and phosphorous use efficiency through the regulation of the hormonal balance. Both hydromulching and AMF inoculation were found to increase the active gibberellins (GAs) and cytokinins (CKs), resulting in a positive correlation between these hormones and the growth-related parameters. In contrast, the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) and abscisic acid (ABA) decreased in AMF-inoculated plants and especially in those grown with the MS treatment. This study demonstrates that there exists a positive interaction between AMF and hydromulching which enhances the growth of escarole plants by improving nutrient use efficiency and hormonal balance.

Mulching the soil with organic-based formulations (hydromulching) is a sustainable alternative to plastic mulching that is here hypothesized to maintain crop production under drought stress by hormonal and metabolic regulation of source–sink relationships. To test this hypothesis, artichoke plants were grown on non-mulched soil and on soil mulched with polyethylene and three different organic mixtures, and subjected to optimal and reduced irrigation regimes. Under drought stress, the growth parameters were higher in plants grown with the different mulching treatments compared to non-mulched plants, which was related to a higher photosynthetic rate and water-use efficiency. Importantly, mulching-associated growth improvement under stress was explained by higher sucrolytic activity in the leaves that was accompanied by a decline in the active cytokinins. Besides this, salicylic acid decreased in the leaves, and abscisic acid and the ethylene precursor 1-aminocyclopropane-1-carboxylic acid were impaired in the artichoke heads, which is associated with better regulation of photoassimilate partitioning. Taken together, these results help to explain the hydromulching-associated growth improvement of artichokes under water stress through the hormonal regulation of sucrose metabolism, which could be very useful in future breeding programs for drought tolerance.

Sweet pepper is susceptible to changes in temperature conditions, especially above 30 °C. In this research study, two cultivars, Melchor and Tamarín, were subjected to three different temperatures. For this, the experiment was run at three specific temperatures (24 °C, 28 °C, and 32 °C), keeping the rest of the parameters the same in all experiments. In fully mature fruits, parameters such as weight, color, TSS, total phenols, mineral content, and amino acid content were analyzed. Our results showed that high temperatures reduced fruit weight and increased color parameters, mainly in Melchor. In addition, a temperature of 28 °C advanced the maturation of the Tamarín fruits by 14 days with respect to 24 °C. At a nutritional level, high temperatures caused a reduction in TSS, total phenols, and cations, and on the contrary, increased the content of anions. In the case of amino acids, a temperature increase to 28 °C caused a general increase in the amino acids measured, except for proline, which was reduced. Thus, the data from this study support the need to study new strategies in crop management to reduce the negative effects that the unstoppable rise in temperatures due to climate change will produce.

In order to mitigate the detrimental impact that climate change is having on plants, the study of new practices that allow for the reduction of such effects has become imperative. In addition, the revaluation of the promotion of healthy plant by-products has also markedly increased in importance in recent years. In this work, the modifications in biomass and some antioxidant compounds of cauliflower by-products treated with putrescine under extreme temperatures in two different CO2 scenarios (the control (400 ppm) and a high concentration of CO2 (1000 ppm)) were studied. Additionally, the compositions of inner and outer leaves were also compared. According to results found in this work, cauliflower grown under elevated CO2 and treated with putrescine (2.5 mM) prior to heat stress showed the highest biomass accumulation (20%) compared to the control. Moreover, in the outer leaves from cauliflower grown under elevated CO2 and treated with putrescine prior to high temperature exposure, the highest biosynthesis of sugars (20%) was recorded. Although cauliflower by-products turned out to be rich in polyamines (208.6 nmoles g−1 fresh weight (FW) and 124.3 nmoles g−1 FW for outer and inner leaves, respectively) and phenolic compounds (1070.2 mg gallic acid equivalents ( (GAE) 100 g−1 FW in outer leaves and 772.0 mg GAE 100 g−1 FW in inner leaves), it was the outer leaves that after applying the new strategy showed the greatest increase in polyamines (68%) and phenolic compounds (39%), obtaining here the highest increase in antioxidant activity (3%). Thus, they should no longer be regarded as mere by-products and should be used for pharmaceutical or nutraceutical purposes. The novel strategy presented in this work may allow us to take advantage of both the continued increase in CO2 and heat waves that are becoming more frequent.

Drought is considered as one of the major limiting factors to plant growth and productivity. Drought stress reduces stomatal conductance, affecting water relations and decreasing CO2 assimilation rate and photosynthesis. Several strategies have been developed to alleviate the negative effects of drought in the agricultural industry. One of these strategies is the use of the mulching technology, which retains water in the soil surface. Knowing that hormones play a key role in plant growth and drought stress responses, we hypothesized that the use of a new ecological mulching technology called hydromulching would improve growth over bare soil under drought stress through changes in the hormonal balance. To test this hypothesis, escarole plants (Cichorium endivia L.) were grown in pots filled with coco fiber, non-covered (bare soil) or covered with polyethylene film (PE) and three types of hydromulches made up with recycled additives: wheat straw (WS), rice hulls (RH), and substrate used for mushroom cultivation (MS). Half of the plants were subjected to drought by reducing the volume of irrigation water to 70% of crop evapotranspiration. Despite drought stress impaired escarole growth-related parameters in all treatments, plants mulched with MS maintained significantly superior growth, due to improved plant water relations and photosynthetic function. This can be explained by an efficient interaction hydromulch/soil/plant in regulating the hormonal balance under water depletion. Indeed, the concentrations of the active cytokinins (CKs), trans-zeatin and isopentenyladenine, were higher in plants grown with MS treatment, associated with shoot growth-enhancing and photosynthetic rate maintenance under stress conditions. The concentrations of the stress-related hormone, abscisic acid (ABA), varied antagonistically to those of the active CKs. In this regard, ABA increased with drought but to a lower extent in MS plants thus regulating stomata opening, which, in crosstalk with the ethylene precursor 1-aminocyclopropane-1-carboxylic acid and salicylic acid, improved plant water relations. The results obtained demonstrate that hydromulching is an efficient and sustainable management strategy to ameliorate the drought effects on escarole plants through fine regulation of the CKs/ABA balance, which will be of utmost interest and applicability in the actual climate change scenario.

The use of plastics in agriculture has increased food production and reduced irrigation, pesticides, and pests. However, according to the Food and Agriculture Organization of the United Nations (FAO), “disastrous” use has occurred, as agricultural soils are being contaminated and have begun to threaten food security, peoples’ health, and the environment. One of the most challenging plastic wastes that must be removed from plants, and instead recycled, is the raffia used to tutor crops. This work studied the economic risk of introducing raffia made from a biodegradable polymer in greenhouse pepper and tomato crops. An expert survey was carried out to analyze the evolution of breaks throughout the season of four biodegradable raffias: cellulose, cellulose + kraft paper, compostable biopolymer, and jute-rayon, comparing them with a polypropylene control for two years (2019–2020) in pepper and tomato crops. Fuzzy logic-ordered weighted averages (OWA) were used to treat and aggregate this information. Income, costs, and the risk of biodegradable raffia breakage were studied. The results show that the material that performed the best was the biopolymer in the two crops studied, as it presented a much lower risk of breakage. The breaks in tomatoes were higher than those produced in pepper for each material. For the biopolymer, the internal rates of return (3.49% in tomatoes and 8.14% in peppers) and the recovery period (18.50 and 13.45 years for tomato and pepper crops, respectively) were very similar to those of polypropylene.

Aquaponics is a sustainable technique that is respectful to the environment, as it reuses products and minimizes the consumption of new materials. The combination of this technique with the foliar application of selenium (as Na2SeO4) could lead to healthier and more sustainable products, which are increasingly requested by consumers. Lettuce (Lactuca sativa L.) plants were grown in an aquaponics system (fish water) as compared with a control (conventional soilless fertigation), and sprayed with different concentrations of selenium (0, 4, 8, and 16 µmol L−1). The results showed a reduction in the dry weight and N content of lettuce plants irrigated with the fish water mixture treatment. However, the application of Se relieved this stress, increasing the photosynthetic rate and ABTS, and reducing the content of chlorophylls, β-carotene, and several of the measured amino acids. The best results were observed with the highest concentration of Se (16 µmol L−1), as an increase in nitrogen content was observed, as shown by a greater weight of the plant. Furthermore, this treatment produced the greatest increase in ABTS and the least reduction in amino acid content. This novel study highlights the possibility of improving the efficiency of N utilization in lettuce by applying foliar selenium in combination with an aquaponics system.

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 NO3− alone or in combination with NH4+, 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 NH4+ 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 NH4+. The concentration of Na was only reduced when NH4+ 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 NH4+, which reduced the concentrations of histidine and phenylalanine. Moreover, the concentrations of putrescine and cadaverine were increased by NH4+ at high salinity, whereas that of cadaverine was reduced by NH4+ 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-NH4+.

This work has been focused on the study of how we can affect the short heat stress on the bioactive compounds content. Some recent investigations have observed that management of nitrogen fertilization can alleviate short-term heat effects on plants. Additionally, the short-term heat stress can be also ameliorated by using putrescine, a polyamine, due to its crucial role in the adaptation of plants to heat stress Therefore, different NO3−/NH4+ ratios and a foliar putrescine treatment have been used in order to increase tolerance to thermal stress in order to take advantage of the more frequent and intense heat waves and make this crop more sustainable. So, other objective of this work is to make the cauliflower waste more attractive for nutraceutical and pharmaceutical preparations. Thus, the effect of a thermal stress combined with a 50:50 NO3−/NH4+ ratio in the nutrient solution, and the foliar application of 2.5 mM putrescine increased in the content of various sugars (inositol, glucose, and fructose), total phenolic compounds and polyamines, as well as in the antioxidant activity. The greatest accumulation of these compounds was observed in young leaves. Our results show from a physiological and agronomic point of view, that the foliar application of putrescine and the 50:50 NO3−/NH4+ treatment managed to alleviate the negative effects of the abiotic stress suffered at high temperature, yielding plants with higher antioxidant compounds content.

This study examines the effect of the exogenous application of polyamine putrescine together with the application of different ratios of nitrate/ammonium (NO3−/NH4+), on the physiology of cauliflower subjected to heat stress. The 50:50 NO3−/NH4+ ratio was the best ratio against heat stress. As a result of the joint application of these compounds, a higher photosynthetic rate, a higher accumulation of both photosynthesis-related compounds and pigments, total proteins, and a change in the status of nutrients were obtained. Particularly, the decrease in content of calcium, chloride and sulphate in plants under heat stress is ameliorated by the ammonium effect. Additionally, it is important to highlight that cauliflower waste contains a higher content of mineral nutrients than floret cauliflower. These effects were more marked in young leaves. Furthermore, a synergistic effect for coping with heat stress between the polyamine and the nutritional treatment was observed. For this, both the application of putrescine and the feeding of plants with a 50:50 NO3−/NH4+ ratio before heat stress is proposed for the first time as an agricultural practice for increasing the thermotolerance of cauliflower cv Moonshine. On the other hand, due to the lower lipid peroxidation rate obtained in cauliflower leaves, these plants could be used for health purposes as ointments or other nutraceutical products, making the cultivation of this kind of cruciferous more sustainable.

Growers in the cultivated areas where the climate change threatens the agricultural productivity and livelihoods are aware that the current constraints for good quality water are being worsened by heatwaves. We studied the combination of salinity (60 mM NaCl) and heat shock stress (43 °C) in pepper plants (Capsicum annuum L. var. Tamarin) since this can affect physiological and biochemical processes distinctly when compared to separate effects. Moreover, the exogenous application of 0.5 mM salicylic acid (SA) was studied to determine its impacts and the SA-mediated processes that confer tolerance of the combined or stand-alone stresses. Plant growth, leaf Cl− and NO3− concentrations, carbohydrates, and polyamines were analyzed. Our results show that both salinity stress (SS) and heat stress (HS) reduced plant fresh weight, and SA only increased it for HS, with no effect for the combined stress (CS). While SA increased the concentration of Cl− for SS or CS, it had no effect on NO3−. The carbohydrates concentrations were, in general, increased by HS, and were decreased by CS, and for glucose and fructose, by SA. Additionally, when CS was imposed, SA significantly increased the spermine and spermidine concentrations. Thus, SA did not always alleviate the CS and the plant response to CS cannot be directly attributed to the full or partial sum of the individual responses to each stress.

Greenhouse peppers are one of the most important crops globally. However, as in any production activity, especially agricultural, they are subject to important risk factors such as price fluctuations, pests, or the use of bad quality water. This article aims to evaluate the viability of these types of crops by using discounted cash flows. Risk evaluation has been carried out through the analysis of pepper plantations for 2016 and 2017. The traditional application of this tool has significant limitations, such as the discount rate to be used or the estimation of future cash flows. However, by using discount functions that decrease over time in combination with decoupled net present value, these limitations are expected to improve. The use of decoupled net present value has permitted an increase in the accuracy and quantification of risks, isolating the main risks such as price drops (EUR 3720 ha−1 year−1) and structural risks (EUR 1622 € ha−1 year−1). The use of decreasing discount functions has permitted a more realistic investment estimation. Finally, the sensitivity analysis shows that decoupled net present value (DNPV) is little affected by changes in interest rates in contrast to traditional net present value (NPV).

In the last decades, cauliflower consumption has increased due to its observed beneficial effects on human health, especially on chronic diseases. Furthermore, the use of arginine has been shown to improve the heat stress tolerance of plants by increasing the polyamine content. Thus, we aimed to investigate the effects of the exogenous application of arginine on the physical and chemical quality parameters of cauliflower florets under heat stress. For this, we applied two concentrations of arginine (1 and 4 mM) to the leaves of cauliflower (Brassica oleracea var. botrytis L.) plants grown in three different temperatures (ambient, elevated, and extreme). Our data show that potassium and phosphate, as well as iron were the most abundant macro- and micronutrients, respectively. The combination of high temperature and exogenous application of arginine increased the antioxidant activity, total content of phenolic compounds, polyamines, and proteins. The data presented herein indicate that the combination of an adequate heat stress and the appropriate foliar arginine treatment may be a useful strategy that could be used to increase the number of valuable plant compounds in our diet.