Sementes de forrageiras tropicais: produção, colheita e beneficiamento

TCC (graduação em Agronomia) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias, 200

GERMINAÇÃO DE SEMENTES DE ARATICUM: DOSES DE GA3 E PERÍODOS DE EMBEBIÇÃO

Sementes de Annona crassiflora apresentam dormência morofofisiológica, e estudos de mecanismos que permitam a sua germinação, garantirão a sobrevivência da espécie. Objetivou-se verificar ação do ácido giberélico (AG3) em distintos períodos de imersão na quebra de dormência das sementes. O experimento foi conduzido em delineamento inteiramente casualizado (DIC), com 630 sementes divididas em 7 tratamentos (escarificação mecânica + 1000 mg L-1 de AG3 nos tempos de 24, 48 e 72 horas; escarificação mecânica + 2000 mg L-1 + AG3 nos tempos 24, 48 e 72; e controle). O tratamento de escarificação mecânica + 2000 mg L-1 de AG3 por 72 horas aumentou a germinação das sementes em 10% quando comparado ao controle

Bioregulators on seed germination and seedling growth of sweet basil

Basil (Ocimum basilicum L.) plants have multiple uses, ranging from spice to cosmetic purpose, besides being a source of essential oil and aromatic. These plants were commonly propagated by seed, however, few agrotechnologies are used to enhance the seed germination and initial growth in this crop. For this reason, our research aimed to evaluate aspects of seed germination of Ocimum basilicum L. cv. Limoncino, subjected to different bioregulators applied via substrate imbibition. The experiment was carried out in completely randomized design, with four treatments, as follows: T1: control (distilled water), T2: T13 a solution of a product formulated based on indolbutyric acid + naphthalene acetic acid + gibberellic acid (0.2 mL L-1, Liko Química), T3: gibberellic acid (0.5 mM L-1, progibb-400®) and T4: brassinosteroids (0.1 mM L-1). We evaluated: germination rate, germination speed index (GSI), first count, root and shoot length and chlorophyll a, b, total and carotenoids. The bioregulators did not influence germination, first count, GSI and photosynthetic leaf pigment, but application of gibberellic acid and brassinosteroids improve the shoot and root length, respectively. The gibberellic acid and brassinosteroids are promising bioregulators for stimulating initial basil growth.Basil (Ocimum basilicum L.) plants have multiple uses, ranging from spice to cosmetic purpose, besides being a source of essential oil and aromatic. These plants were commonly propagated by seed, however, few agrotechnologies are used to enhance the seed germination and initial growth in this crop. For this reason, our research aimed to evaluate aspects of seed germination of Ocimum basilicum L. cv. Limoncino, subjected to different bioregulators applied via substrate imbibition. The experiment was carried out in completely randomized design, with four treatments, as follows: T1: control (distilled water), T2: T13 a solution of a product formulated based on indolbutyric acid + naphthalene acetic acid + gibberellic acid (0.2 mL L-1, Liko Química), T3: gibberellic acid (0.5 mM L-1, progibb-400®) and T4: brassinosteroids (0.1 mM L-1). We evaluated: germination rate, germination speed index (GSI), first count, root and shoot length and chlorophyll a, b, total and carotenoids. The bioregulators did not influence germination, first count, GSI and photosynthetic leaf pigment, but application of gibberellic acid and brassinosteroids improve the shoot and root length, respectively. The gibberellic acid and brassinosteroids are promising bioregulators for stimulating initial basil growth

Crescimento radicular em sementes de trigo e arroz tratadas com Bioativador

This research aimed to evaluate the initial root growth of wheat and rice subjected to increasing doses of thiamethoxam, the doses were 0; 8.75; 17.5; 35 e 70 g a.i. per 100 kg of seeds for wheat and 0; 17.5; 35; 70 e 105 g a.i. per 100 kg of seeds for rice, applied in seeds and to growing in mini-rhizotrons placed at greenhouse. Daily evaluations began after the emergence of the root, for ten days. The bio-activator showed great variability in the response of daily root growth, when the effect was significant the increasing doses led to length reductions.Esse trabalho objetivou avaliar o crescimento inicial das raízes de trigo e arroz, submetidas a doses crescentes do tiametoxam. As doses do bioativador foram 0; 8,75; 17,5; 35 e 70 g i.a. por 100 kg de sementes para trigo e 0; 17,5; 35; 70 e 105 g i.a. por 100 kg de sementes para arroz, aplicadas via tratamento de sementes, com cultivo em mini-rizotrons alocados em casa-de-vegetação. Avaliações diárias iniciaram-se após a emergência da raiz, por um período de dez dias. O bioativador apresentou grande variabilidade na resposta do crescimento radicular diário, quando seu efeito foi significativo as doses crescentes levaram a reduções no comprimento. Root growth in wheat and rice seeds treated with bio-activatorThis research aimed to evaluate the initial root growth of wheat and rice subjected to increasingdoses of thiamethoxam, the doses were 0; 8.75; 17.5; 35 e 70 g a.i. per 100 kg of seeds for wheatand 0; 17.5; 35; 70 e 105 g a.i. per 100 kg of seeds for rice, applied in seeds and to growing in minirhizotronsplaced at greenhouse. Daily evaluations began after the emergence of the root, for tendays. The bio-activator showed great variability in the response of daily root growth, when the effectwas significant the increasing doses led to length reductions

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

Biorreguladores em feijoeiro cultivado sob dois regimes hídricos

Restrictions on water available lead to possible damages in the bean crop, and the use of bioregulators can improve the plant signal and boost tolerance against drought stress. This study aimed to characterize physiological, biochemical, and biometric alterations in bean plants subjected to foliar application of bioregulators under different soil water levels. The following treatments were applied: control (water) and three bioregulators (5 μM of abscisic acid - ABA, 50 μM of methyl jasmonate – MeJA, and 5 μM of ABA + 50 μM of MeJA). Also, the plants were subjected to two soil water levels (60 and 80% of field capacity), in a 4 x 2 factorial scheme. The variables studied were: content of photosynthetic pigments, leaf gas exchange, and biometric indexes in the common bean plants. Our results showed that the ABA + MeJA treatment increased the concentration of chlorophyll b, ascorbate peroxidase (APX), and catalase (CAT) activities. At the same time, the photosynthetic rate was stimulated by the mixture of bioregulators on 36 days of planting (DAP). ABA and MeJA, applied isolated, caused a higher photosynthetic rate in the bean in the 34 DAP, whereas for the biometric variables, they were only influenced by the soil water levels. Regarding the biochemical mechanisms, it was verified that the ABA + MeJA treatment increased the activity of antioxidant enzymes and improved gas exchange responses in a condition of lower water availability. The bioregulators assessed in this research are beneficial in the modulation of plant physiology in plants under drought stress. However, the adequate water supply represents a better development of the plants.Restrições na disponibilidade hídrica favorecem eventuais danos à cultura do feijoeiro, e o uso de biorreguladores aprimora a sinalização vegetal e potencializa a indução de tolerância ao déficit hídrico. Este estudo objetivou caracterizar alterações fisiológicas, bioquímicas e biométricas em plantas de feijão submetidas à aplicação foliar de biorreguladores sob diferentes regimes hídricos. O ensaio consistiu na aplicação de um controle (água) e três biorreguladores (5 µM de ácido abscísico - ABA; 50 µM de metil jasmonato - MeJA e 5 µM de ABA + 50 µM de MeJA), além de apresentar dois regimes hídricos (60 e 80% da capacidade de campo), num esquema fatorial 4 x 2. Foram analisados: conteúdo de pigmentos fotossintetizantes, trocas gasosas foliares e índices biométricos das plantas de feijoeiro. Com resultado observou-se que o tratamento ABA+MeJA incrementou a concentração de clorofila b, atividades de ascorbato peroxidase (APX) e catalase (CAT), enquanto a taxa fotossintética foi estimulada pela mistura de biorreguladores aos 36 dias após o plantio (DAP), ABA e MeJA, isolados, propiciaram maior taxa fotossintética no feijoeiro aos 34 DAP, enquanto para as variáveis biométricas somente foram influenciadas pelos regimes hídricos, com relação aos mecanismos bioquímicos, constatou-se que o tratamento ABA+MeJA incrementou a atividade das enzimas antioxidantes e melhorou as respostas de trocas gasosas em condição de menor disponibilidade hídrica. Os biorreguladores avaliados nesta pesquisa são benéficos na modulação da fisiologia vegetal em plantas sob estresse hídrico, entretanto o suprimento de água adequado retrata um melhor desenvolvimento das plantas

Desempenho fisiológico e composição química de sementes de soja cultivadas em distintos arranjos espaciais

Poucos estudos apresentam interações entre a fisiologia das plantas e sua posterior composição química, quando cultivadas em diferentes arranjos. Esta pesquisa buscou compreender a relação entre o espaço de cultivo da soja e sua influência sobre a qualidade da semente. Foram estudadas duas cultivares de soja (Tec 7849 Ipro e Monsoy 6972 Ipro) em quatro arranjos espaciais distintos (50,0 x 7,1; 40,0 x 8,9; 30,0 x 11,9 e 18,9 x 18,9 ou 16,2 x 16,2 cm, respectivamente). Durante os estádios fenológicos V4 e R2, foram analisadas trocas gasosas e na colheita, foram constituídos 2 grupos, um de sementes frescas e outro de sementes envelhecidas, para ambos os grupos se analisaram: teste de germinação, vigor, índice de velocidade de germinação, massa fresca das plantas, além de determinar os constituintes químicos das sementes. Para o ensaio conduzido nas análises fisiológicas das plantas, adotou-se o esquema fatorial 2x2x4 (dois períodos de avaliação x duas cultivares x quatro arranjos espaciais), e para o ensaio de qualidade das sementes e composição química, adotou-se o esquema fatorial 2x4 (duas cultivares x quatro arranjos espaciais). O estágio vegetativo foi crucial para a melhor eficiência de trocas gasosas, e o arranjo espacial influenciou positivamente a qualidade química e fisiologia das sementes colhidas, onde, o arranjo espacial com melhor ajuste foi 40,0 x 8,9cm, para Tec 7849 Ipro, e 50,0 x 5,3 cm para Monsoy 6972 Ipro. Ajustes nos arranjos espaciais podem representa respostas benéficas na produção de sementes de melhor qualidade.Few studies present interactions among plant physiological and seed chemical composition of soybean cultivates under different arrangements. Therefore, this study seeks to understand this relationship between space occupation and product quality. We grew two soybean cultivars (Tec 7849 Ipro and Monsoy 6972 Ipro) in four different spatial arrangements (50.0 x 7.1; 40.0 x 8.9; 30.0 x 11.9 and 18.9 x 18.9 or 16.2 x 16.2 cm, respectively). During V4 and R2 phenological stages, we analyzed the gas exchange, and at the harvest were composed two different lots: freshly harvested seeds and the seeds subjected to accelerated aging; in both lots, we evaluated germination test, vigor, germination speed index, seedling fresh mass, and the determination of the chemical composition of the seeds. For experiment conducted to analyze physiological parameters we adopted the factorial scheme 2x2x4 (two evaluation periods x two soybean cultivars x four spatial arrangements), and for seed quality and chemical composition, we adopted the factorial scheme 2x4 (two soybean cultivars x four spatial crop arrangements). The vegetative stage was crucial for better gas exchange efficiency, and the spatial arrangements positively influenced the physiological and chemical quality of the seeds for soybean crop, where the fitted arrangement was observed in 40.0 cm between rows and 8.9 cm between plants for the cultivar Tec 7849 Ipro and 50.0 cm between rows and 5.3 cm between plants, for Monsoy 6972 Ipro. Adjusts in spatial arrangements can promote beneficial responses in seed quality

Physiological analysis and nutritional quality of maize: a comparative study between hybrid and landraces varieties

Maize (Zea mays L.) is important for animal production systems, and the use of unimproved maize varieties has increasinglybecome a viable option for small farmers. This study aimed to characterize and evaluate the physiologicaland feed potential of maize populations, as a raw material for silage production, in the mesoregion of the AltoParanaiba, Minas Gerais (MG). We used nine varieties of unimproved maize from the Germplasm Bank at EmbrapaMaize & Sorghum - BAGMilho (Sete Lagoas, MG), as follows: (milho stands for maize; crioulo, for landrace) MG110 – Milho Amarelão, MS 043 – Crioulo, MG 083 – Milho Branco, RN 013 – Milho Metro, MG 073 – Milho Vermelhinho,MS 016 – Palha Roxa 90, MG 079 – Milho Cunha, RR 040 – Crioulo de Roraima, AC 015 – Milho Bolivianoand a commercial hybrid variety of Pioneer, P4285. The hybrid maize Pioneer P4285 showed better physiologicaland nutritional performance. Among the accessions of the Germplasm Bank, the MG 110 – Milho Amarelão andMG 015 – Milho Boliviano were distinguished by their physiological adaptation to the Cerrado of Minas Gerais,and for showing characteristics suitable for use in the silage process for animal feed