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The present study aimed to evaluate the effects of water deficiency on the growth, and antioxidant metabolism of two sweetpotato cultivars [Ipomea batatas (L.) Lam. cvs. Canadense (CAN) and Arapey Uruguaia (URU)] during the initial tuberization stage. 20 and 100% soil field capacity water content was used to obtain drought-stressed and well-watered plants, respectively. Water deficiency decreased growth of both cultivars (as measured by their biomass and leaf area), but URU showed lower plant growth than CAN, indicating that URU has lower tolerance to drought. The leaves of drought-stressed plants of both cultivars showed increments in the concentration of carotenoids and anthocyanins, evidencing that these plant responses are common between both cultivars. However, only CAN exhibited an increased chlorophyll concentration in leaves of water-deficient plants when compared to the well-watered plants. While the concentration of phenolic compounds was decreased in URU grown in soil with water deficiency, it was maintained in CAN. Temporal evaluations of gas exchange-related variables showed that the low water supply to plants reduced photosynthesis, transpiration and stomatal conductance rates. We concluded that the short exposure to water deficiency reduces growth of sweetpotato plants, but the degree of drought-induced impacts depends on cultivar-specific protective responses that are mainly related with each genotype to maintain chlorophyll status and to modulate antioxidant compounds in their leaves.

Made available in DSpace on 2022-04-28T19:44:19Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-12-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) In the agricultural industry, advances in optical imaging technologies based on rapid and non-destructive approaches have contributed to increase food production for the growing population. The present study employed autofluorescence-spectral imaging and machine learning algorithms to develop distinct models for classification of soybean seeds differing in physiological quality after artificial aging. Autofluorescence signals from the 365/400 nm excitation-emission combination (that exhibited a perfect correlation with the total phenols in the embryo) were efficiently able to segregate treatments. Furthermore, it was also possible to demonstrate a strong correlation between autofluorescence-spectral data and several quality indicators, such as early germination and seed tolerance to stressful conditions. The machine learning models developed based on artificial neural network, support vector machine or linear discriminant analysis showed high performance (0.99 accuracy) for classifying seeds with different quality levels. Taken together, our study shows that the physiological potential of soybean seeds is reduced accompanied by changes in the concentration and, probably in the structure of autofluorescent compounds. In addition, altering the autofluorescent properties in seeds impact the photosynthesis apparatus in seedlings. From the practical point of view, autofluorescence-based imaging can be used to check modifications in the optical properties of soybean seed tissues and to consistently discriminate high-and low-vigor seeds. Center for Nuclear Energy in Agriculture (CENA) University of São Paulo (USP) Department of Crop Science College of Agriculture Luiz de Queiroz (ESALQ) University of São Paulo (USP) Department of Genetics College of Agriculture Luiz de Queiroz (ESALQ) University of São Paulo (USP) Department of Agronomy Federal University of Viçosa (UFV) Department of Biosystems Engineering School of Sciences and Engineering São Paulo State University (UNESP) Department of Biosystems Engineering School of Sciences and Engineering São Paulo State University (UNESP) FAPESP: 2017/15220-7

The Eucalyptus grandis L. plantations for industrial purposes (e.g., wood charcoal and pulp) are largely adopted worldwide, mainly in acidic and poorly fertile soils. The application of lime to soil is recommended for eucalyptus plantation, but lime reduces the availability of metallic micronutrients to plants. Therefore, the aim of this study was to investigate the performance of field-grown Eucalyptus grandis in Ferralsol amended with lime at different rates (0.0 and 1.6 and 3.7 Mg ha-1) and Cu plus Zn [0.0 and 0.0 kg ha-1 (-CuZn) and 0.5 and 1.5 kg ha-1 (+CuZn)]. The soil chemical attributes, shoot biomass, and nutrient accumulation were evaluated, while nutrient use efficiency, chlorophyll (Chl) and flavonoid (Flav) contents, and enzymatic antioxidant performance [superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), ascorbate peroxidase (APX), guaiacol peroxidase (GPOX), and glutathione peroxidase (GPX)] were assayed to assess the nutritional status of the plants. Despite the lime application rate increasing Ca and Mg soil availabilities, effective cation exchange capacity (eCEC), base saturation (BS), and pH values, the available Cu, Fe, and Zn concentrations decreased at 6 and 30 months after planting. Conversely, Mn soil availability increased with lime application rates. Liming augmented Cu-, Fe-, Mn-, and Zn-use efficiency, while +CuZn supply increased enzymatic antioxidant performance in 30-month-old plant. Overall, the combined application of lime and +CuZn enhanced shoot biomass relative to that of non-treated plants. However, there was no observed difference in shoot biomass in 30-month-old limed and non-limed eucalyptus trees that were supplied with +CuZn. This result can be partially explained by the improvement in soil chemical attributes, such as soil pH, eCEC, and BS. In conclusion, the use of integrative approaches and temporal evaluations provided new insights into wood yield, biochemical traits, antioxidant metabolism, and the nutritional status of field-grown eucalyptus under lime and +CuZn application rates.

A large number of reviews have discussed many aspects of oxidative burst due to plant exposure to biotic and abiotic stresses, including the dual role of reactive oxygen species (ROS) as both signaling and toxic compounds, and the strategies developed by plants to cope with this oxidative imbalance. In this review, we have concentrated on fresh new information and other promising and emerging topics of oxidative stress and antioxidant mechanisms in plants, giving particular attention to genotoxicity, transgenerational alterations and quantitative trait loci (QTL) associated with enhancements in the plant tolerance to stresses. Furthermore, besides the discussion of the “classical” enzymatic and non-enzymatic components of plant defense, novel aspects about the components of the antioxidant machinery, which now includes sugars, annexins and dehydrins, are also presented, along with a final section on future directions in this field.

Genetic, biochemical and physiological parameters can be changed by applying seaweed extract-based products. However, there is scarce information about the influence of seaweed extract on yarrow performance (Achillea millefolium L.), which is widely used in the folk medicine. Therefore, this study aimed to evaluate the effects of Ascophyllum nodosum extract on plant development (leaf and root biomass, and leaf area), physiological indexes (leaf weight ratio, and root: leaf ratio), secondary metabolite (phenolic compounds) content and antioxidant activity of yarrow. The experiment was carried out in a completely randomized design with 4 treatments (seaweed extract concentrations 0, 3, 6 and 9 mL L-1) and 10 replications. The higher concentration of seaweed extract caused higher total dry weight of plants (from 17.8 to 19%), especially due to increases in the root biomass (up to 28.5%). Only plants that received the highest concentration of seaweed-based product presented increments in the number of leaves when compared to the control plants (18.3 %). Furthermore, the use of A. nodosum extract 9 mL L-1 provided increases in the antioxidant activity and content of phenolic compounds in leaves (up to 30.44%). In conclusion, application of A. nodosum is a potential tool strategy to improve the quality of raw material from yarrow plants, since it increased the phenolic compound content and antioxidant activity in leaves, which are the plant organs commonly used in folk medicine.

Heat stress can impact crop development and yield and amino acids play diverse essential roles in plants. This work aimed to study the long-term effects of foliar spray with L-arginine in antioxidant machinery, physiology, nutrition, productivity and fruit quality of tomato plants subjected to transient heat stresses. Six concentrations of L-arginine were sprayed on the plants: 0 (control), 0.10, 0.25, 0.50, 1.0 and 2.0 g·L–1. The content of hydrogen peroxide (H2O2), a reactive oxygen species, decreased concurrently to the increasing arginine concentration. The ascorbate peroxide (APX) activity had an inverse behavior to that observed for H2O2 content (r = –0.79), not only indicating that arginine is able to modulate APX, but also suggesting that this enzyme plays an important role on the mitigation of H2O2 generation under heat stress. Ascorbate peroxide and catalase (CAT) activities had a positive correlation (r = 0.82), showing that these enzymes may work in tandem. The influence of arginine on photosynthesis activity and gas exchange was generally weak and depended mainly on the plant developmental stage. Yield was increased by 19.8 and 23.1% in plants that received 1.0 and 0.5 g·L–1 of arginine, respectively, when compared to control plants. In conclusion, the use of exogenous L-arginine can protect tomato plants against oxidative imbalance under transient heat within protected environments.

Made available in DSpace on 2022-04-28T19:42:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Industrial revolution markedly increased the environmental contamination by different pollutants, which include the metal lead (Pb). The phytoremediation potential of native species from tropical regions is little known, especially for woody plants. The present study aimed to evaluate the performance of Lonchocarpus cultratus (Fabaceae), a tree species from the Brazilian savanna, grown in soil that was artificially contaminated with increasing Pb concentrations (control and 4 Pb treatments, 56, 120, 180, and 292 mg kg−1) for 6 months. The biomass of L. cultratus was not depressed by exposure to Pb, despite the high accumulation of this metal (up to 7421.23 μg plant−1), indicating a high plant tolerance to this trace metal. Lead was mainly accumulated in roots (from 67 to 99%), suggesting that the low root-to-shoot Pb translocation is a plant strategy to avoid Pb-induced damages in photosynthetic tissues. Accordingly, the content of chlorophylls a and b was maintained at similar levels between Pb-treated and control plants. Moreover, increments in leaf area were noticed in Pb-treated plants in comparison to the control plants (on average, 24.7%). In addition, root length was boosted in plants under Pb exposure (22.6–66.7%). In conclusion, L. cultratus is able to endure the exposure to high Pb concentrations in soil, being a potential plant species to be used for Pb phytostabilization in metal-contaminated soils in tropical regions. Instituto Federal Goiano Campus Rio Verde, Rio Verde Departamento de Genética Escola Superior de Agricultura “Luiz de Queiroz”/Universidade de São Paulo Departamento de Biologia e Zootecnia Universidade Estadual Paulista “Julio de Mesquita Filho” Departamento de Biologia e Zootecnia Universidade Estadual Paulista “Julio de Mesquita Filho”

The present study aimed to investigate the Cd-induced transgenerational effects on plants. Grafted tomato plants, which exhibited the same cultivar as scion and distinct cultivars with contrasting Cd-tolerance as rootstocks, were grown in soil without and with artificial addition of Cd (less than 2.0, and 6.9 mg kg-1 of Cd, respectively) in a pot experiment carried out in a greenhouse. Their fruits were harvested to extract seeds (i.e., the progenies), which were sown over either Cd-free (control) or Cd-containing germitest paper (germination testing paper with 0 and 35 μM of CdCl2, respectively) and grown in a growth chamber. The immediate progeny of all grafting combinations from stressed plants presented an elevated germinability, despite high internal Cd concentration. When sown in Cd-containing germitest paper, the immediate progeny of plants grown in soil with no Cd addition was generally able to maintain or even increase the content of carotenoids and chlorophylls a and b (up to 93.3, 62.8 and 76.1%, respectively), indicating a Cd-induced hormetic effect on photosynthetic pigments. Two of the grafting combinations from stressed plants yielded seeds that generated seedlings with enhanced dry mass when they were sown in Cd-free media (~41%), suggesting a Cd-induced transgenerational enhancement of biomass production. Because only one tomato cultivar was used as scion, data indicated that type and degree of Cd-induced transgenerational effects depend strongly on signals generated and/or processed in roots of the parental plants. When sown in Cd-contaminated germitest paper, the immediate progeny of Cd-treated plants presented major reductions in the leaf area (35-69%) and content of photosynthetic pigments (57-93%) in comparison to the progeny from control plants. However, one of the grafting combinations exhibited satisfactory performance after "double" exposure to Cd, showing 91% of the biomass that was produced in the seedlings of control seeds from control plants. Further investigation indicated that adjustments in the chlorophyll fluorescence behavior might counterbalance losses in leaf pigments and area. Taken together, our data provide new insights on the origin, outcomes and mode of action of the Cd-induced transgenerational effects.

Light-based methods are being further developed to meet the growing demands for food in the agricultural industry. Optical imaging is a rapid, non-destructive, and accurate technology that can produce consistent measurements of product quality compared to conventional techniques. In this research, a novel approach for seed quality prediction is presented. In the proposed approach two advanced optical imaging techniques based on chlorophyll fluorescence and chemometric-based multispectral imaging were employed. The chemometrics encompassed principal component analysis (PCA) and quadratic discrimination analysis (QDA). Among plants that are relevant as both crops and scientific models, tomato, and carrot were selected for the experiment. We compared the optical imaging techniques to the traditional analytical methods used for quality characterization of commercial seedlots. Results showed that chlorophyll fluorescence-based technology is feasible to discriminate cultivars and to identify seedlots with lower physiological potential. The exploratory analysis of multispectral imaging data using a non-supervised approach (two-component PCA) allowed the characterization of differences between carrot cultivars, but not for tomato cultivars. A Random Forest (RF) classifier based on Gini importance was applied to multispectral data and it revealed the most meaningful bandwidths from 19 wavelengths for seed quality characterization. In order to validate the RF model, we selected the five most important wavelengths to be applied in a QDA-based model, and the model reached high accuracy to classify lots with high-and low-vigor seeds, with a correct classification from 86 to 95% in tomato and from 88 to 97% in carrot for validation set. Further analysis showed that low quality seeds resulted in seedlings with altered photosynthetic capacity and chlorophyll content. In conclusion, both chlorophyll fluorescence and chemometrics-based multispectral imaging can be applied as reliable proxies of the physiological potential in tomato and carrot seeds. From the practical point of view, such techniques/methodologies can be potentially used for screening low quality seeds in food and agricultural industries.

The objective of the present study was to assess the response of tomato cultivars with different fruit colors to exposure to increasing Cd levels in the substrate by measuring the impacts of Cd on the oxidative stress indicators and physicochemical features of fruits, as well as plant development and yield components. A completely randomized experiment in a 3 × 3 factorial design [tomato cultivar (which produces purple, red, or white fruits) vs Cd level in the substrate (0, 3.6, or 12 mg kg−1)] was performed. The cultivation of plants in substrate containing 3.6 mg kg−1 Cd did not affect yield, but fruits exhibited nonpermissive Cd concentrations in both peel and mesocarp across all cultivars. By contrast, yield was decreased in plants with red and white fruits after their cultivation in substrate containing 12 mg kg−1 Cd, while the productivity of plants with purple fruits was maintained under such conditions. The hydrogen peroxide content in the fruit mesocarp depended only on cultivar. However, an increased lipid peroxidation level was detected in the mesocarp of purple fruits at the highest Cd concentration. No parameters of fruit quality [i.e., diameter, length, °Brix, pH, titratable acidity, color (L*, a*, and b*), and concentrations of lycopene and β-carotene in mesocarp] were affected by long-term exposure to Cd at 12 mg kg−1. In conclusion, the results of this study suggested that the potential Cd side effects on diverse tomato quality features can be buffered at the fruit level because these features were maintained at the usual values despite high Cd concentrations in tomato peel and pulp. Moreover, these buffering mechanisms are independent of lycopene and β-carotene concentrations in fruit peel, since the three tomato cultivars that were evaluated in the present study (white fruits, possessing no or negligible concentrations of these carotenoids, and red and purple tomato, possessing high lycopene and β-carotene concentrations) were able to sustain several fruit quality parameters after long-term exposure to high Cd concentrations in the substrate.

Made available in DSpace on 2022-04-28T19:10:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-01-01 Abiotic stresses negatively affect crop development and yield. However, the use of seaweed extracts can alleviate production losses through improvement of the antioxidant system and synthesis of compatible osmolytes. The aim of this study was to assess the effects of Ascophyllum nodosum extract on antioxidant response and yield of common bean plants (Phaseolus vulgaris) under drought stress. Therefore, two methods of application (foliar spray and soil irrigation) and two doses (5 and 10 mL L-1) were tested, whereas untreated plants were used as control. There were no significant differences in malondialdehyde and hydrogen peroxide contents among treatments, indicating that application of seaweed extract did not change the oxidative status in treated plants when compared to the control ones. On the other hand, the use of seaweed extract increased proline content even prior to drought stress (46.3 to 145.4% when compared to the control), and this increment remained until the 10th day of stress (from 60.1 to 201.7% over the reference plants), supporting early evidences that A. nodosum extract is a plant elicitor. The yield parameters were not affected by the extract, probably due to the severe drought stress which plants were submitted. The results suggest that A. nodosum extract affects proline metabolism in Phaseolus vulgaris plants, making the synthesis of this osmolyte more responsive to drought stress because seaweed-treated plants presented a higher proline content than the control ones during the exposure to water deficit. São Paulo State University São Paulo State University

This work aimed to develop a reliable and fast approach to estimate the plant tolerance degree to heavy metal (HM) phytotoxicity. Two independent experiments were carried out using tomato accessions, with contrasting morphological features, that were grown in a hydroponic solution containing different CdCl2 concentrations for 7 days. Plant dry weight and chlorophyll content (SPAD units) were evaluated, and tolerance degree to Cd toxicity was estimated according to the tolerance index (TI), which is a new mathematical formula based on plant biomass proposed in this study. Although with different magnitudes, tomato exhibited reductions in their dry weight concurrently with the increasing CdCl2 concentration. By contrast, chlorophyll content presented no standard response, decreasing and even increasing according to CdCl2 concentrations, indicating that only under certain conditions (particularly, at CdCl2 50 μM), this parameter can be used to estimate plant tolerance to Cd toxicity. TI was efficiently able to segregate tomato cultivars with similar performance (based on the total dry weight of plants), and such segregation was optimized when the hydroponic solution contained from 25 to 50 μM CdCl2. Within this range, data pointed at 35 μM CdCl2 as the best concentration to be employed in studies related to the tomato tolerance/sensitivity to Cd toxicity. In conclusion, TI proved to be a reliable estimator of tolerance degree to Cd exposure in genetically distinct tomato accessions. Moreover, TI can be used for this same purpose in plants under other HM-induced stresses.

In general, the effects of Cadmium (Cd) on crop quality are evaluated solely by Cd accumulation in the edible plant parts; thus, the potential effects on several nutritional features are not often taken into account. This study evaluated Cd effects on the enzymatic activities of lysine (Lys) metabolism, storage protein and amino acid profile in maize. Stress parameters were also assessed. In vegetative organs, Cd was accumulated in the following decreasing order: roots > stems > leaves. Cadmium accumulation in grains decreased at grain maturity (from 0.25 to 0.07 µg g−1 DW). In leaves, neither hydrogen peroxide content nor superoxide dismutase, catalase, ascorbate peroxide and guaiacol peroxidase activities did not change in Cd-treated plants compared to control plants. Lipid peroxidation was not detected in immature grains and leaves of plants under Cd exposure, indicating that Cd accumulation mainly in the roots is a mechanism to avoid oxidative stress in aboveground parts of the plant. However, Lys metabolism in immature grains was modified, showing increases in the specific activities of aspartate kinase (AK) and dihydrodipicolinate synthase (DHDPS) after Cd exposure. AK sensitivity to Lys feedback inhibition increased, but decreased in DHDPS in Cd-treated plants, suggesting differential regulation for these enzymes. In mature grains, the Lys content did not change, while the proline content increased by 54 % in Cd-treated plants. This is the first report on Cd effects on amino acid profile, storage protein contents and enzymes from Lys metabolism in grains of a cereal plant species.

This work aimed to quantify the concentration of soluble amino acids, nitrogen (N) and Cd in the developing seeds of maize plants that were grown in Cd-contaminated soil from seed sowing to the reproductive stages. The specific activities and feedback inhibition properties of lysine (Lys) metabolic enzymes were also determined in developing seeds. The potential maize yield was depressed by Cd exposure. Cadmium concentration in plant organs followed the decreasing order: roots > stems = leaves > developing seeds (37.04, 1.95, 1.46 and 0.22 mg kg−1 Cd, respectively). The relatively low Cd concentration in the remained developing seeds was a result from root- and ear-mediated reductions of the Cd translocation in plants. Plants under Cd exposure presented developing seeds with an increased N concentration (up to 7%) when compared to control plants. Furthermore, the level of soluble amino acids (particularly histidine, glycine, tyrosine, methionine, isoleucine and valine) was increased in the developing seeds of Cd-treated plants. In addition, changes in the feedback properties of dihydrodipicolinate synthase (DHDPS), an enzyme from lysine metabolism, were observed in developing seeds. In conclusion, the current study showed that maternal plant exposure to Cd can alter the concentration of soluble amino acids and the behavior of Lys metabolic enzymes in developing seeds. This study provided not only new information about the influence of the long-term Cd exposure on plants, but also data about protective plant strategies against Cd toxicity.

Tolerance level to cadmium (Cd) toxicity is generally associated with reductions of the internal Cd accumulation in living organisms. In plants, Cd exposure frequently triggers negative effects on their growth and productivity. However, an increased number of studies has reported the improved performance of some plant species (or their accessions/genotypes/varieties/cultivars/clones) to Cd exposure, despite Cd accumulation in their roots and shoots. These results indicate that plants have developed protective strategies to neutralize the side-effects from Cd toxicity or, more controversially, mechanisms that employ Cd as beneficial element. Here, we gathered information about Cd-induced hormetic effects on plants, and explored the potential mechanisms that allow them to have a better performance under Cd exposure. The promotion of plant development depends on both direct and indirect Cd-induced alterations in the metabolism of plants and their surround environment. In addition, the mechanisms behind the positive Cd-induced transgenerational effects were also discussed in the present paper.

O presente estudo tem como objetivo comparar a rentabilidade da produção de cana-de-açúcar através dos sistemas de arrendamento e fornecimento próprio, visando auxiliar na tomada de decisão do proprietário da terra quanto a alternativa mais viável diante da atual situação de mercado. O sistema de fornecimento foi divido em duas modalidades: "cana spot" e "cana esteira". Para a análise financeira, foram utilizados dados da safra de 2014/2015 de fornecedores filiados à uma associação, localizada em Chavantes, região centro-oeste de São Paulo. Em seguida foram projetados fluxos de caixa para cada sistema de produção; calculados o valor presente líquido (VPL), a taxa interna de retorno (TIR), o payback simples e realizada a análise de sensibilidade. Os cálculos indicaram a inviabilidade da produção de cana-de-açúcar em todos os casos, pois apresentaram VPL negativo e TIR inferior à taxa mínima de atratividade (TMA). No entanto, após a análise de sensibilidade com valores de remuneração mais altos ao produtor, as opções de fornecimento de "cana spot" e arrendamento exibiram resultados otimistas. Deste modo, conclui-se que a produção de cana-de-açúcar é uma atividade inviável para proprietários de terra com pequenas área em Chavantes/SP. Porém, considerando a análise de sensibilidade, a modalidade de fornecimento próprio de cana "spot" é a alternativa mais atrativa economicamente, pois o VPL e TIR apresentaram valores mais elevados do que aqueles encontrados no arrendamento. No entanto, aquela opção possui elevado risco para o produtor, que fica condicionado à demanda de mercado.

O presente estudo tem como objetivo comparar a rentabilidade da produção de cana-de-açúcar através dos sistemas de arrendamento e fornecimento próprio, visando auxiliar o proprietário da terra na tomada de decisão quanto a alternativa mais viável diante da atual situação de mercado. O sistema de fornecimento foi divido em duas modalidades: "cana spot" e "cana esteira". Para a análise financeira, foram utilizados dados da safra de 2014/2015 de fornecedores filiados à uma associação, localizada em Chavantes, região centro-oeste de São Paulo. Projetou-se fluxos de caixa para cada sistema de produção, calculou-se o valor presente líquido [VPL], a taxa interna de retorno [TIR], o payback simples e realizou-se a análise de sensibilidade. Os cálculos indicaram a inviabilidade da produção de cana-de-açúcar em todos os casos, pois apresentaram VPL negativo e TIR inferior à taxa mínima de atratividade [TMA]. No entanto, após a análise de sensibilidade com valores de remuneração mais altos ao produtor, as opções de fornecimento de "cana spot" e arrendamento exibiram resultados otimistas. Deste modo, conclui-se que a produção de cana-de-açúcar é uma atividade inviável para proprietários de terra com pequenas áreas (100 ha, em média) em Chavantes/SP. Porém, considerando a análise de sensibilidade, a modalidade de fornecimento próprio de cana "spot" é a alternativa mais atrativa economicamente, pois o VPL e TIR apresentaram valores mais elevados do que aqueles encontrados no arrendamento. No entanto, a opção de cana "spot" possui elevado risco para o produtor, que fica condicionado à demanda de mercado. = The objective of this study was to compare the sugarcane production profitability by land leasing and by own supply systems, aiming to help landowners choosing the most viable alternative in current market situation. The supply system was divided into two categories: "cana spot” (sugarcane sold during the year crop without a contract) and “cana esteira” (sugarcane sold with a previous contract). For analysis, we used data from sugarcane suppliers (2014/2015 year crop) affiliated to an association located in Chavantes, in the midwest region of São Paulo state. Calculating the cash flows for each production system, the net present value [NPV], internal rate of return [IRR], simple payback and a sensitivity analysis were obtained. The results indicated infeasibility of sugarcane production in all cases, since NPV was negative and IRR value was lower than the minimum rate of attractiveness [MRA]. However, sensitivity analysis simulating higher compensation values to producers revealed that supply of "cana spot" and lease system showed optimistic results. Therefore, it can be concluded that sugarcane production is not a feasible activity for landowners with small areas (100 ha, approximately) in Chavantes/SP. Considering sensibility analysis, the supply system of “cana spot" is the most economically attractive alternative, because NPV and IRR presented values higher than those of lease system. However, the option of “cana spot" is risky for the producer for being conditioned by market demand.

Cadmium (Cd) is an environmental pollutant that limits crop production. Among the deleterious effects by metal induced stress on plant development, cell leakage and nutrient losses have been observed, whereas root morphology is severely affected. However, the mechanisms by which genotypes contrasting in tolerance level to heavy metal excess maintain root cells integrity and nutrient absorption are still unclear. In this work, tomato (Solanum lycopersicum) genotypes with contrasting tolerance to Cd toxicity, Calabash Rouge (sensitive) and Pusa Ruby (tolerant), were used to shed some light on possible tolerance mechanisms against Cd toxicity. For this purpose, plants were grown in hydroponics containing 0 or 35 μM CdCl2 for 7 days. Temporal variations (on the 1st, 4th and 7th days of Cd exposure) in nutrient management (absorption and use efficiency), relative plant growth, biomass partitioning, root morphology and Cd accumulation were evaluated in control and Cd-treated plants. Furthermore, multivariate analyses, in which information about the antioxidant machinery was also included, were performed in order to identify the set of parameters related to plant tolerance. The results showed that Pusa Ruby was able to improve biomass allocation to roots, further increasing their capacity to accumulate this metal. The tolerant genotype was also more capable to modulate nutrient uptake by roots under Cd excess. In conclusion, the current study revealed that Pusa Ruby is more tolerant to Cd exposure than Calabash Rouge due to its ability in reducing Cd-induced damages on root morphology and on nutrient absorption and use efficiency.

Distinct tomato genotypes possess different tolerance degree to cadmium (Cd), but the mechanisms behind this phenomenon are scarcely understood. To this end, the physiological, biochemical, anatomical, nutritional and molecular mechanisms associated to the plant tolerance against Cd toxicity were investigated in five tomato accessions with contrasting sensitivity to Cd exposure. Firstly, the data revealed that larger biomass loss was not always coupled to higher Cd concentration, indicating that other events, in addition to the internal Cd accumulation, impact tomato performance at early stages of Cd exposure. Secondly, the results indicated that the fine regulation of nutrient status, particularly magnesium (Mg), boron (B) and manganese (Mn), is associated to the mitigation of Cd toxicity. Magnesium status was coupled to the modulation of root development, resulting in changes in root hair formation and biomass allocation. Boron accumulation in leaves was linked to Cd toxicity, suggesting that tolerance mechanisms involved strategies to decrease or even avoid B excess in photosynthetic tissues. Disturbances in Mn status, i.e. Mn excess in leaves and Mn deficiency in roots, were also related to tomato sensitivity to Cd exposure. Thirdly, plant capacity to maintain leaf blade expansion is a relevant strategy for a better tomato development after short-term Cd exposure. Fourthly, tomato tolerance to Cd-induced stress does not depend on CAT activity enhancements in such conditions. In conclusion, tomato ability to quickly manage its nutritional status is necessary for alleviation of the Cd effects at early stages of exposure to this metal. The better understanding about tolerance mechanisms and mode of action of Cd toxicity in plants can help in the establishment of strategies to mitigate its impacts on crops.

Cadmium (Cd) is a heavy metal highly toxic to plants and human and animal health. The increased concentration of this metal in the environment in recent decades is the result of anthropogenic activities that include the production of mineral fertilizers, pesticides, intense mining, waste disposal, and foundries. Cd accumulation is known to induce oxidative stress in plant cells due to overproduction of reactive oxygen species, which may result in severe damage at the cellular level, ultimately impairing plant growth and productivity. In response to such stress, different molecules having enzymatic or nonenzymatic actions contribute to mitigate plant cellular damage and balance redox homeostasis in plant cells. This chapter aims to summarize current knowledge about the prospecting of important components of the molecular mechanisms associated with antioxidant machinery in plant response and tolerance to Cd toxicity. Insights into antioxidant response regulation, which includes hormones, signaling molecules, transcription factors, and microRNAs, are also presented.

This study aimed to investigate the mode of action of cadmium (Cd) toxicity at cell level, especially at early stages of plant exposure. Tomato seedlings were cultivated in growth media containing from 0.1 to 70 µM CdCl2 for 24 h. Mitotic index, chromosome abnormality, DNA integrity and organization of tubulin-based structures were assessed in root cells. As higher the Cd concentration in the growth media, higher was the DNA damage intensity and the occurrence of chromosomal abnormalities that included chromosome lost, bridges, stickiness, C-metaphase and polyploidy. The profile of chromosomal aberrations also varied with elevated Cd concentration, being observed increases in the frequency of chromosome stickiness. The mitotic index was reduced at the lowest Cd concentration, but such reduction was statistically similar to that detected at the highest concentration, suggesting that mitotic depression is a rapid outcome and, at same time, a Cd-induced effect that is limited at the first 24 h of direct root exposure to this metal. Under exposure to 20 µM CdCl2, heterogenous distribution of the spindle fibers, formation of two spindle complexes in both of the cell poles, absence of centrosome center, polarization of the spindle fibers during cell division, and non-uniform tubulin deposition in microtubule and phragmoplast were noticed. The results indicate that the tubulin-dependent components of cytoskeleton are Cd targets, and the sensitivity of tubulin-based structures to Cd exposure depends on cell cycle phase. Moreover, DNA damage intensity and chromosomal abnormality profile can be employed as markers of Cd toxicity level.

Cadmium (Cd) toxicity is frequently coupled to its accumulation in plants, but not always the highest Cd concentration triggers the worst damages, indicating that additional events influence the magnitude of Cd side-effects. We investigated the early mechanisms behind the differential Cd-induced impacts on plant development of four tomato accessions with contrasting tolerance to Cd toxicity. At organ level, the highest Cd concentration was not associated with the largest biomass losses. In leaves, changes in superoxide dismutase and catalase activities were not related to differences in Cd concentration, which was unable to provoke H2O2 overproduction on the sixth day of plant exposure to this metal. Further investigation in the mineral profile revealed that magnitude of Cd toxicity depends probably on synergic effects from increased B status, in addition to the own Cd accumulation. Furthermore, disbalances in Mn status (i.e., excess in leaves and deficiency in roots) may enhance Cd toxicity degree. According to data, however, the low magnesium (Mg) status can be linked to tomato tolerance against Cd toxicity. In conclusion, the tomato tolerance degree under short-Cd exposure depends on actively, finely regulation of mineral homeostasis that results in different development of plant organs. The better understanding on the mode of action of Cd toxicity in plants can help in the establishment of strategies to mitigate its impacts on crop yield.

The use of plant growth regulators is directly related to the success of in vitro propagation, which is an advantageous alternative to obtain seedlings on a commercial scale. This study aimed to evaluate the in vitro development of ‘IAC 95-5000’ sugarcane seedlings after the addition of different doses of ethephon (0, 25, 50, 100 and 200 mg L-1) or gibberellic acid (0, 2.5, 5.0, 7.5 and 10.0 mg L-1) to the culture medium. Ethephon increased the number of tillers (up to 231.70%), reduced height of the main tiller (44.66 to 60.47%), and did not affect the shoot´s fresh and dry mass. On the other hand, gibberellin decreased the number of tillers and negatively changed biomass partitioning. It is concluded that the use of ethephon is a potential strategy to enhance in vitro production of ‘IAC 95-5000’ sugarcane seedlings, since it increased the number of usable shoots in subsequent subcultures, and its effects on height reduction can be reversible. However, the use of the tested doses of gibberellic acid is not recommended, because it impaired seedling development of this sugarcane variety.

Although negative effects on the offspring fitness can be triggered by the mother-plant exposure to environmental stresses, some plants are able to “remember” past incidents and enhance the progeny tolerance. Here, the mineral profile, cytogenetic modifications, and physiological potential of seeds from two tomato cultivars, with contrasting tolerance degrees to cadmium (Cd) toxicity, were evaluated after plant exposure to this metal. Both cultivars exhibited high Cd translocation to the seeds; however, the tolerant tomato accumulated more Cd than did the sensitive one. As a consequence of the Cd accumulation, reductions in the Mn concentration in Cd-challenged plants were detected. Surprisingly, seed germination and vigor were increased in the tolerant tomato cultivar after Cd exposure, despite increases in the chromosomal abnormalities. By contrast, seeds from the sensitive cultivar exhibited no changes in their physiological potential after Cd exposure, despite Cd-induced reductions in the mitotic index. Moreover, bunch position exerted effects on the vigor and type of chromosomal abnormality. The results show that maternal plant exposure to Cd can affect tomato offspring by changing the seed physiological potential, and such effect can be partially explained by alterations in the seed-derived elements (essential and non-essential) and genotype-dependent tolerance mechanisms.

The production of medicinal plants as raw material for industry must associate quality with biomass formation and, with this purpose, the application of plant growth regulators has been studied in these crops. The objective of this study was to evaluate the effect of a biostimulant on growth, inflorescence production and flavonoid content in marigold. The experiment was conducted in a greenhouse and the treatments consisted of increasing doses of the biostimulant (0, 3, 6, 9, 12 and 15 mL L-1) applied by foliar spraying in ten consecutive applications. The experiment was arranged in a completely randomized design, with six treatments and ten repetitions. The number of leaves and flowerheads and dry matter of roots increased linearly with increasing doses of the growth promoter, with 20%, 36.97% and 97.28% increases, respectively, compared with the control. The total dry mass and shoot dry mass showed maximum values at the highest dose tested of 15 mL L-1 (with increases of 40.09% and 46.30%, respectively). Plant height and flavonoid content reached the highest values at a dose of 6 mL L-1. The biostimulant promoted the development of marigold and positively influenced the synthesis of the secondary compound of medicinal interest. Among the tested doses, the application of rates between 6 and 9 mL L-1 of the biostimulant is recommended for more efficient large-scale production of marigold. A produção de plantas medicinais como matéria-prima para a indústria deve associar aqualidade à formação de massa e, para tanto, o emprego de reguladores vegetais tem sido estudado nestas culturas. O objetivo deste trabalho foi avaliar o efeito de bioestimulante no crescimento, produção de inflorescências e teor de flavonoides em calêndula. O experimento foi conduzido em casa-de-vegetação e os tratamentos consistiram em doses crescentes do bioestimulante (0, 3, 6, 9, 12 e 15 mL L-1), aplicadas por pulverização foliar, com dez aplicações consecutivas do produto. O delineamento experimental foi o inteiramente casualizado, com seis tratamentos e dez repetições. O número de folhas e de capítulos florais e a massa da matéria seca de raízes aumentaram, linearmente, em função do acréscimo da dose do bioestimulante, apresentando incrementos de 20%; 36,97% e 97,28% respectivamente, em relação aos do controle. As massas da matéria seca da parte aérea e total apresentaram valores máximos na maior dose testada de 15 mL L-1 (com acréscimos de 40,09 e 46,30%, respectivamente). Por outro lado, a altura de plantas e o teor de flavonoides alcançaram os maiores valores na dose de 6 mL L-1. A aplicação de bioestimulante promove o desenvolvimento da calêndula, influenciando positivamente também a síntese do composto secundário de interesse medicinal. Dentre as doses testadas, a aplicação de concentrações entre 6 e 9 mL L-1 do bioestimulante é indicada para tornar mais eficiente o sistema de produção vegetal da calêndula para a utilização em larga escala.

Tomato is an important crop worldwide. Cadmium (Cd) concentrations in fruits depend on tomato genotype. This work aimed to study the relation among Cd accumulation, tolerance mechanisms, and fruit features in two tomato cultivars with contrasting tolerance to Cd stress. Tolerant (Yoshimatsu) and sensitive (Tropic Two Orders) plants were grown in control and contaminated soils (0.04 and 3.77mg/kg Cd, respectively) from the seedling stage to fruit production. Both cultivars were able to acclimatize to Cd exposure, probably through mechanisms associated with reductions in the magnesium status. Cadmium concentrations varied according to the following descending order: roots=leaf blades > (peduncle+sepals) > stem=fruits. However, the tolerant cultivar accumulated more Cd than did the sensitive one. Although Cd reached the fruits from the first to the fourth bunches, peduncle and sepals may act as a barrier to Cd entrance in tomato pulp and peel. The Cd-induced changes in the fruit mineral profile varied according to plant cultivar, organ, tomato tissue, and bunch position. Moreover, plant yield was not affected by the Cd stress, which was able to improve fruit size and weight in the tolerant cultivar. In conclusion, new insights about the Cd-induced effects on tomato development and fruit attributes were provided by growing plants in soil, which is the media generally used to cultivate this crop, rather than hydroponics. It was shown that tomato cultivars with contrasting tolerance to Cd toxicity can reach sexual maturity and produce fruits with no yield losses, despite impacts on development from long-term Cd exposure. This study also revealed the role of floral receptacle and its related structures in limiting, even partially, Cd translocation to the fruits. Furthermore, Yoshimatsu's capacity to produce bigger and heavier fruits, in plants under Cd exposure, may probably be associated with enhanced Cd accumulation. Fundacao de Amparo a Pesquisa do Estado de Sao Paulo [2009/54676-0, 2013/15217-5]; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico [303749/2016-4, 476096/2013-8]

Glyphosate is an herbicide widely used in agriculture. However, it may causes phytotoxic effects on non-target plants (crops), generating productivity losses. Currently there are evidences about agrochemicals as potential mitigators of glyphosate side effects. Therefore, the objective of this study was to evaluate the effects of distinct doses of fulvic acid 25% (k-tionic® 1000 and 2000 mL ha-1), amino acids (Codamin BR® 500 and 1000 mL ha-1), phosphite (Nutex 0-3020®, 2000 and 4000 mL ha-1) and biostimulant (Byozime TF® 250 and 500 mL ha-1) in reversion of fitotoxicity caused by glyphosate on ‘Carioca’ common bean plants. For comparison, plants treated only with glyphosate, and untreated plants (control) were also evaluated. Glyphosate spray (Roundup WG 0.06 kg ha-1) was performed at 31 days after planting (DAP), and agrochemicals were applied at 36 DAP. Phytotoxicity symptoms, as well as leaf area, dry mass of leaves and stems, and physiological indexes were evaluated at 54 DAP. Application of amino acid-based product (500 mL ha-1) significantly reduced (29.90%) phytotoxicity symptoms. Both doses of amino acid-based product increased dry mass of leaves; therefore, they were able to maintain the leaf weight ratio similar to the control plants. However, there was a decrease in leaf area, which was not reverted by any of the agrochemicals. It is concluded that application of amino acid-based product 1 Dra.; Engenheira Agronoma; Funcionaria da Isagro Brasil Comercio de Produtos Agroquimicos Ltda; Endereco: Rua Joaquim Floriano, 466 / Cj 1205, Itaim Bibi, CEP: 04534-002, Sao Paulo, Sao Paulo, Brasil; E-mail: chryz.serciloto@fmc.com 2 MSc.; Biologa; Doutoranda em Genetica e Melhoramento de Plantas na Escola Superior de Agricultura “Luiz de Queiroz” ESALQ/USP; Endereco: Avenida Padua Dias, 11, Sao Judas, CEP: 13418-900, Piracicaba, Sao Paulo, Brasil; E-mail: marcia198811@usp.br 3 Dr.; Engenheiro Agronomo; Professor Titular da Universidade de Sao Paulo, USP; Endereco: Avenida Padua Dias, 11, Agronomia, Caixa Postal: 09, CEP: 13418-900, Piracicaba, Sao Paulo, Brasil; E-mail: prcastro@usp.br (*) Autor para correspondencia.

One of the major disadvantages of sunflower cultivation is the increased plant height, making it prone to the lodging. The use of plant growth retardants can be an alternative strategy to reduce plant height; however, these compounds may affect productivity. The aim of this study was to evaluate the effects of plant growth retardants on sunflower development and yield. Four treatments were studied: 1- control; 2- gibberellic acid (GA) 10 mg L−1; 3- trinexapac-ethyl (TE) 5 mL L−1, and 4- maleic hidrazide (MH) 8 mL L−1. TE and MH decreased plant height (16.9 and 35.9%, respectively); however, only TE positively influenced capitulim diameter and dry mass (46.7 and 311%, when compared to control) at 60 days after planting (DAP). At 81 DAP, dry mass of capitulum did not differ among control and TE-treated plants. On the other hand, MH impaired diameter and dry mass of capitulum (92.9 and 74.7%, respectively). It can be concluded that the application of TE is a potential strategy to decrease lodging probability without affecting sunflower yield. Furthermore, although MH negatively affected sunflower development, its use on the crop cannot be excluded since other doses, frequencies and moment of application can be studied.