In vitro development of sugarcane seedlings using ethephon or gibberellin

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.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

Mitigation of glyphosate side effects on non-target plants: use of different agrochemicals as protectants in common bean plants Mitigação dos efeitos colaterais do glifosato em plantas não alvo: uso de diferentes agroquímicos como protetores

Objetivou-se avaliar o efeito de diferentes agroquímicos na reversão da fitotoxidez do glyphosate (Roundup WG 0,06 kg ha-1) em feijoeiro (Phaseolus vulgaris cv. Carioca), a aplicação do herbicida foi realizada em todas as plantas exceto na testemunha absoluta, aos 31 dias após o plantio (DAP), no estádio de 3° trifólio. Aos 36 DAP, as plantas foram tratadas com: ácido fúlvico 25% (1000 ml ha-1 e 2000 ml ha-1), aminoácido (500 ml ha-1 e 1000 ml ha-1), fosfito (2000 ml ha-1 e 4000 ml ha-1), além de bioestimulante (250 ml ha-1 e 500 ml ha-1). Aos 36, 40, 46 e 54 DAP foram conferidas notas às plantas e aos 54 DAP as plantas foram coletadas e determinou-se a área foliar e a massa seca de três plantas. Pelas notas conferidas verificou-se que somente a testemunha absoluta e o aminoácido 500 ml ha-1 apresentaram menores danos do que o tratamento com glyphosate. A área foliar somente mostrou-se maior na testemunha absoluta, sendo que a massa seca revelou-se superior na testemunha absoluta e nos tratamentos com aminoácido 500 e 1000 ml ha-1.AbstractGlyphosate 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 (Nutex0-30-20®, 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 andstems, 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  Codamin BR 500 mL ha-1) reduces, even partially, glyphosate phytotoxicity in ‘Carioca’ common bean plants

Are plant growth retardants a strategy to decrease lodging and increase yield of sunflower?

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.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

Growth retardants in dry bean plants: impacts on the architecture, photoassimilate partition, and their consequences on the yield

The objective of this study was to evaluate the effects of three growth retardants on the development and yield of dry bean plants. The treatments were control (water), maleic hydrazide (0.09 g a.i. L-1), ethyl-trinexapac (0.5 g a.i. L-1) and propiconazole (0.125 g a.i. L-1). Maleic hydrazide decreased the plant growth rate, resulting in the height reduction (46%). It also inhibited the twining shoot development, thus controlling the vigor excess of this genotype which has indeterminate growth. On the other hand, plants which were treated with ethyl-trinexapac and propiconazole showed the higher heights (from 25 to 52%, respectively), indicating that both compounds provide the plant growth. These compounds also increased the number of pods (48 to 52%) and grains (47 to 102%), when compared to the control. However, ethyltrinexapac and maleic hydrazide decreased 50-grain dry mass (41 to 52%), indicating changes in the photoassimilate partition among plant structures. This change was evidenced by the correlation coefficient of the biomass allocated between the shoots and grains, which was inversely proportional (r=-60.57) and highly significant (p=0.0002). It is concluded that maleic hydrazide is an efficient growth inhibitor of dry bean plants. Propiconazole and ethyl-trinexapac provide the plant growth, and also improve the main yield components. However, ethyl-trinexapac and maleic hydrazide decrease grain biomass

Effects of Ascophyllum nodosum extract on the crop development and yield

Com o objetivo de melhorar o desempenho de culturas agrícolas, a utilização de extratos de algas tem aumentado, principalmente por ser uma alternativa ao uso de fertilizantes e por ser ecologicamente correta. A alga marinha Ascophyllum nodosum destaca-se dentre as espécies comumente empregadas para esta finalidade, e tem sido muito estudada por suas propriedades que incluem desde a promoção de crescimento vegetal ao uso na alimentação humana e animal. Numerosos estudos têm revelado vários efeitos benéficos da aplicação de extratos de algas em plantas, tais como a precocidade germinativa de sementes e de seu estabelecimento, melhoria do desempenho e da produtividade vegetal e elevada resistência a estresses bióticos e abióticos. Múltiplos processos fisiológicos, bioquímicos e genéticos estão envolvidos nas respostas dos vegetais e os efeitos observados a partir das aplicações podem ser diretos ou indiretos. Entretanto, os mecanismos de ação do extrato de A. nodosum ainda são pouco conhecidos e a sua elucidação é importante para a elaboração de estratégias que favoreçam o aumento da produtividade vegetal. Deste modo, torna-se relevante o estudo dos efeitos do extrato de alga sobre a fisiologia do crescimento, desenvolvimento e produtividade de espécies utilizadas em grandes culturas. O milho, a soja, o trigo e o feijão figuram entre as 10 culturas com maiores áreas de cultivo e volumes de produção no Brasil. Todas possuem múltiplas utilidades, alcançando relevância econômica e social não somente para este país, como também para o mundo, e por isso foram escolhidas para este estudo.Aiming to improve the crop performance, the use of seaweed extracts has increased mainly because it is an alternative to the use of fertilizers and for being environmentally friendly. The seaweed Ascophyllum nodosum stands out among the species commonly employed for this purpose, and has been widely studied for its properties, which provide the plant growth as well as food for human and animals. Many studies have shown several beneficial effects of seaweed extracts in plants, such as the early germination of seeds and their establishment, improving the crop performance and productivity and a high resistance to biotic and abiotic stresses. Multiple physiological processes, biochemical and genetic factors are involved in the plant responses and the effects observed from applications can be direct or indirect. However, the action mechanisms of the A. nodosum extract are still poorly understood and their elucidation is important to develop strategies that provide higher plant productivity. Thus, it is important to study the seaweed extract effects on the physiology of the growth, development and yield of species used in crops. Corn, soybean, wheat and bean were chosen for this study due to their multiple uses and for being among the 10 crops that have the largest areas of cultivation and production volume in Brazil; achieving social and economic relevance not only for this country but also for the world

Abordagem integrada de parâmetros anatômicos, fisiológicos e bioquímicos para o estudo de mecanismos de tolerância ao cádmio em acessos de tomateiro

Tomato (Solanum lycopersicum L.) consumption has increased every year due to the fruit attractiveness, several utilizations, and beneficial effects for human health. However, tomato fruits can accumulate a Cd concentration that exceeds the safety threshold for human consumption of vegetables, even when plants are grown in soil with acceptable Cd level. Cd is a non-essential, hazardous element to biological systems, triggering several diseases in humans. In plants, Cd disturbs the antioxidant machinery, changes the nutritional status, and impairs the photoassimilate production and/or partitioning, hence reducing fruit yield and quality. However, distinct tomato accessions can present contrasting tolerance degree to Cd toxicity, as detected by our group in previous studies. The use of these accessions is a powerful approach to identify strategies employed by plants to cope with Cdinduced challenges, and the acknowledgement of such strategies can be potentially used in breeding and biotechnological programs to improve fruit yield and quality in crops that were cultivated in contaminated fields. The set of studies that compose the present thesis aimed (i) to identify the main mechanisms for the contrasting tolerance degree to Cd-induced toxicity in tomato accessions after short and long-term Cd exposure; (ii) to evaluate the relationship among tolerance degree and fruits attributes in plants that were grown in Cd-containing soil, and (iii) to determine the transgenerational effects of Cd-induced stress. In the first experiment, nine tomato accessions with a varied tolerance degree, which was based on biomass accumulation, to Cd exposure were grown in hydroponic solution containing CdCl2 35 μM for 6 days. Avoidance of high Mg concentration in roots was identified as a plant strategy to mitigate Cd toxicity by preventing formation of root hairs. Regarding the mode of action of Cd toxicity, Mn excess in leaves, in addition to the high Cd concentration per se, seems to be coupled to leaf damages that are enhanced by the increased Zn and B concentrations in the photosynthetic tissues. In the second experiment, tolerant (Yoshimatsu) and sensitive (Tropic Two Orders) genotypes were grown in Cd-containing soil, in order to evaluated production parameters. After plant exposure to Cd, the tolerant genotype presented an increased fruit diameter, height and weight, when compared to the control plants. In both cultivars, Cd concentration varied according to the following descending order: roots = leaf blade > (floral receptacle, peduncle and sepals) > stem = fruit peel = fruit pulp. Moreover, data suggested that floral receptacle and its related-structures acted as a barrier to the Cd transportation to the fruits, but it was not enough to avoid Cd reaching the fruits. Furthermore, Cd exposure provoked remarkable reductions in the Mg concentration in roots of sensitive and tolerant genotypes, revealing that both tomato cultivars are able to employ this mechanism for plant acclimation to long-term Cd exposure. Considering such information, it is possible that, under the short-term Cd exposure, tolerant accessions activate this mechanism either early or faster than sensitive genotypes. In addition, positive transgenerational effects on seed germination and vigor of the tolerant genotype were triggered by the plant-mother cultivation in Cd-containing media, despite of the increased chromosomal abnormality. This work reported new insights about the effects of Cd exposure on tomato development, tolerance mechanisms, fruit quality and yield of tomato, as well as Cd distribution in the plants.O consumo de tomate (Solanum lycopersicum L.) tem aumentado a cada ano devido a atratividade dos frutos, suas diversas utilizações e efeitos benéficos para a saúde humana. No entanto, os frutos de tomate podem acumular uma concentração de cádmio (Cd) que excede o limiar de segurança para o consumo humano, mesmo quando as plantas são cultivadas em solo com níveis aceitáveis de Cd. Cádmio e um elemento não-essencial, extremamente perigoso para os sistemas biológicos, desencadeando varias doenças em seres humanos. Nas plantas, o Cd perturba a maquinaria antioxidante, altera o estado nutricional e prejudica a produção e /ou o particionamento de fotoassimilados, frequentemente reduzindo a produtividade e qualidade de frutos. No entanto, diferentes acessos de tomateiros podem apresentar contrastantes graus de tolerância a toxicidade gerada pela exposição ao Cd, como detectado em estudos anteriores de nosso grupo. O uso desses acessos e uma abordagem poderosa para identificar as estratégias empregadas pelas plantas para lidar com os desafios induzidos pelo Cd; e o conhecimento de tais estratégias pode ser potencialmente utilizado em programas biotecnológicos e de melhoramento genético. Deste modo, o conjunto de estudos que compõem a presente tese objetivou (i) identificar os principais mecanismos que suportam o grau de tolerância contrastante a toxicidade induzida por Cd em acessos de tomate após exposição a curto e longo prazos a este metal pesado; (ii) avaliar a relação entre o grau de tolerância e os atributos físico-químico de frutos oriundos de tomateiros cultivados em solo contendo Cd, e (iii) determinar os efeitos transgeracionais do estresse induzido por Cd. No primeiro experimento, nove acessos de tomateiro com graus variados de tolerância a exposição ao Cd, baseado na acumulação de biomassa, foram cultivados em solução hidropônica contendo 35 μM de CdCl2 durante 6 dias. O impedimento de elevada concentração de magnésio (Mg) em raízes foi identificado como possível estratégia da planta para mitigar a toxicidade de Cd, por meio da evitação da formação de pelos radiculares. Em relação ao modo de ação da toxicidade induzida por Cd, o excesso de Mn, em adição a elevada concentração de Cd, parece estar acoplado aos danos foliares que são acentuados ainda mais pelas altas concentrações de zinco (Zn) e boro (B) nos tecidos fotossintéticos de plantas sob exposição ao Cd. No segundo experimento, os genótipos tolerantes (Yoshimatsu) e sensíveis (Tropic Two Orders) foram cultivados em solo contendo Cd, a fim de avaliar os parâmetros de produção. O genótipo tolerante apresentou frutos com maior diâmetro, altura e peso após o cultivo em solo contendo Cd, quando comparado as plantas controle. Em ambas as cultivares, a concentração de Cd variou de acordo com a seguinte ordem descendente: raízes = folíolos> (receptáculo floral, pedúnculo e sépalas) > caule = casca de fruta = polpa de fruta. Alem disso, dados sugerem que o receptáculo floral e suas estruturas atuaram como uma barreira ao transporte de Cd para os frutos, entretanto, ela não foi suficiente para evitar que o Cd atingisse os frutos. Em adição, a exposição ao Cd provocou notáveis reduções na concentração de Mg nas raízes de genótipos sensíveis e tolerantes, revelando que a aclimatação das plantas depende do baixo status de Mg em tecidos radiculares. Desde que ambas as cultivares são capazes de empregar este mecanismo, os dados sugerem que, durante a exposição a curto prazo ao Cd, acessos tolerantes são capazes de ativa-lo ou mais cedo ou mais rápido do que acessos sensíveis. Ademais, efeitos transgeracionais positivos na germinação e vigor das sementes do genótipo tolerante foram desencadeados pelo cultivo planta-mãe em solo com Cd, apesar do aumento de anormalidades cromossômicas. Este trabalho reportou novos conhecimentos sobre os efeitos da exposição ao Cd sobre o desenvolvimento do tomateiro, mecanismos de tolerância, qualidade e rendimento de frutos, bem como a distribuição de Cd dentro da planta

Rentabilidade da produção da cana-de-açúcar em sistema de arrendamento e fornecimento em Chavantes/SP = Profitability of sugarcane production in the lease and supply systems in Chavantes/SP

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

Effect of biostimulant application on production and flavonoid content of marigold (Calendula officinalis L.)

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

Lysine metabolism and amino acid profile in maize grains from plants subjected to cadmium exposure

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

In vitro development of sugarcane seedlings using ethephon or gibberellin

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