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Pretreatment of seeds results in faster emergence of seedlings and uniform stand, especially under stress. Thus, the objective was to evaluate the action of plant regulators as stress attenuators during germination and initial development of pumpkin seedlings, cv. ‘Baiana Tropical’, irrigated with saline water. For this, a completely randomized design was established, in a 4 x 3 factorial scheme, with four replications. Treatments consisted of four types of water (W1 - 100% supply water; W2 - 100% fish farming effluent; W3 - 100% artesian well water; W4 - mixture of 50% fish farming effluent + 50% artesian well water) and three seed treatments (control, salicylic acid and gibberellic acid). The variables measured were germination, first germination count, shoot and root length, shoot and root dry mass, total soluble sugars, total amino acids and proline. The data were subjected to analysis of variance and Scott-Knott test. Pumpkin seedlings performed osmotic adjustment under saline conditions of W4 water. In addition, the treatment of pumpkin seeds with plant regulators (gibberellic and salicylic acids) favors the germination and initial development of seedlings under conditions of salt stress. RESUMO O pré-tratamento de sementes resulta em emergência de plântulas mais rápida e estande uniforme, principalmente, quando sob estresse. Sendo assim, objetivou-se avaliar a ação de reguladores vegetais como atenuantes de estresse durante a germinação e desenvolvimento inicial de plântulas de abóbora, cv. Baiana Tropical, irrigadas com água salina. Para isso, estabeleceu-se o delineamento inteiramente casualizado, em esquema fatorial 4 x 3, em quatro repetições. Os tratamentos foram constituídos de quatro tipos de água (A1 – 100% água de abastecimento; A2 – 100% efluente de piscicultura; A3 – 100% água de poço artesiano; A4 - mistura de 50% efluente de piscicultura + 50% água de poço artesiano) e três tratamentos de sementes (controle, ácidos salicílico e giberélico). As variáveis mensuradas foram germinação, primeira contagem de germinação, comprimento da parte aérea e raiz, massa seca da parte aérea e raiz, açúcares solúveis totais, aminoácidos totais e prolina. Os dados foram submetidos a análise de variância e teste de Scott-Knott. As plântulas de abóbora realizaram ajustamento osmótico em condições salinas da água A4. Além disso, o tratamento de sementes de abóbora com reguladores vegetais (ácidos giberélico e salicílico) beneficia a germinação e o desenvolvimento inicial de plântulas sob condições de estresse salino.

Combretum leprosum Mart., commonly known as ‘mofumbo’, is used for medicinal purposes, recovery of degraded areas and apiculture. The objective of this study was to evaluate the effect of water stress on the germination and vigor of C. leprosum seeds as function of different temperatures. To compose the treatments, the substrate used was paper roll moistened with polyethylene glycol solutions (PEG 6000), at the following levels of osmotic potential: 0.0; -0.1; -0.2; -0.2; -0.4; and -0.5 MPa, and placed in chamber at constant temperatures of 25, 30 and 35 and alternating temperature of 20-30 °C, forming a 6 x 4 factorial. The seeds were submitted to the following evaluations: germination percentage, germination speed index, root length, shoot length, root dry matter, shoot dry matter. There was a significant interaction for all variables, with a negative effect as the osmotic potentials decreased. Thus, C. leprosum showed high sensitivity to low osmotic potentials, showing a steeper decrease from the potential of -0.2 MPa for all evaluated temperatures. Initial germination and development of C. leprosum seedlings was negatively affected by low osmotic potentials, with a tolerance limit of -0.4 MPa. Temperatures of 25 and 35 °C accentuate the negative effect of the low osmotic potential of water on the germination and early development of C. leprosum seedlings. RESUMO Combretum leprosum Mart., conhecida popularmente como mofumbo, é utilizada para fins medicinais, melífera, forrageira e recuperação de áreas degradadas. Objetivou-se avaliar o efeito do estresse hídrico sobre a germinação e vigor de sementes de C. leprosum em diferentes temperaturas. Para isso, as sementes foram semeadas em substrato rolo de papel, umedecido com soluções de polietileno glicol (PEG 6000), nos potenciais osmóticos de 0,0; -0,1; -0,2; -0,3; -0,4; e -0,5 MPa; os testes de germinação foram conduzidos em germinadores sob as temperaturas de 25, 30, 35 e 20-30 °C, formando o fatorial 6 x 4. As avaliações foram as seguintes: germinação, índice de velocidade de germinação, comprimento da raiz, comprimento da parte aérea, massa seca da raiz e massa seca da parte aérea. Houve interação significativa para todas as variáveis, verificando-se efeito negativo com a diminuição dos potenciais osmóticos. A C. leprosum apresentou alta sensibilidade a baixos potenciais osmóticos, com decréscimo mais acentuado a partir do potencial de -0,2 MPa para todas as temperaturas avaliadas. A germinação e o desenvolvimento inicial de plântulas de C. leprosum foram afetados de forma negativa pelos baixos potenciais osmóticos, com limite de tolerância máximo partir de -0,4 MPa. As temperaturas de 25 e 35 °C acentuam o efeito negativo do baixo potencial osmótico da água sobre a germinação e o desenvolvimento inicial de plântulas de C. leprosum.

This study aimed to evaluate the tolerance of C. leprosum seedlings to salt stress during the emergence and early seedling development. The experiment was carried out between the months of August and September, in a greenhouse, and the substrate used was the commercial coconut fiber wetted with aqueous solutions of sodium chloride (NaCl), calcium chloride (CaCl2) and potassium chloride (KCl) with the electrical conductivities of 0.0, 1.5, 2.5, 3.5, 4.5, 5.5 and 6.5 dS m-1. We used a completely randomized design in a 3 x 7 factorial scheme (three salts x seven levels of electrical conductivity). We evaluated seedling emergence, emergence speed index, root length, shoot length, dry matter of roots and shoots. The results indicated significant interaction between both factors analyzed. The emergence and initial growth of C. leprosum plants decrease gradually due to the increase of the electrical conductivity levels, with root length being less affected by waters salinized with CaCl and KCl. C. leprosum seedlings show sensitivity to the three types of salts and are highly sensitive to KCl and NaCl.

Seed companies increasingly need to obtain rapid and reliable results on seed quality. In this context, this study aimed at verifying the efficiency of CO2 measurement for classifying West Indian gherkin (Cucumis anguria L.) seed vigor, using three seed lots of cv. “Do Norte” and three of cv. “Nordestino”. In order to assess seed physiological quality, the following tests were performed: germination, seedling emergence, emergence speed index, shoot length, total dry matter, electrical conductivity and respiratory activity. The experimental design was completely randomized, with four replicates, and the means were compared by Tukey test at 5% probability level. Pearson’s simple correlation was performed between the traditional vigor tests and the respiratory activity. The results of the germination and vigor tests allowed the West Indian gherkin seed lots to be classified into different levels of physiological quality. CO2 measurement is a promising method to identify vigor differences among West Indian gherkin seed lots.

Maturation of seeds involves a systematic sequence of physical and physiological alterations observed from fecundation until they become independent of the mother plant. These alterations comprehend a set of steps which prepare them for a successful germination in the future, characterized by the synthesis and accumulation of reserves. Thus, the objective was to evaluate the development and physiological quality of seeds of L. cylindrica accessions during maturation. Fruits of L. cylindrica accessions were harvested from the 10th day after anthesis (DAA) until the 50th DAA, at 10-day intervals. In each harvest, fruit fresh weight was determined, and then the seeds were manually extracted and subjected to the following evaluations: 100-seed weight, seed water content, seed dry matter content, seedling emergence and emergence speed index. The experiment was carried out in a completely randomized design, with four replicates, in a 3 x 4 factorial scheme (three L. cylindrica accessions and four harvest periods). At 10 DAA, no seeds were formed in the fruits harvested from any the accessions. The best physiological performance of seeds of the L. cylindrica accessions, under the studied conditions, was found at 50 DAA.

The tetrazolium test is a quick and effective method for evaluating viability in seeds. The aim of this study was to determine a methodology for using the tetrazolium test, and its efficiency in verifying viability in seeds of the gherkin (Cucumis anguria L.). Consequently, five batches of gherkin seed were initially evaluated by the tests for germination, first count and speed of germination. The batches were then subjected to treatments in order to adjust the methodology for the tetrazolium test, evaluating three concentrations of tetrazolium solution (0.100, 0.075 and 0.050%), kept in the dark for two, four and six hours, under temperatures of 35 °C and 40 °C, with four replications of 25 seeds per treatment. At the end of the staining period, the seeds were washed in running water, split lengthways between the cotyledons, and classified as viable and non-viable. Evaluation of viability in seeds of the gherkin by tetrazolium test is efficient when carried out at a concentration of 0.050%, either for six hours at 35 °C or four hours at 40 °C. RESUMO O teste de tetrazólio é um método rápido e eficaz para avaliar a viabilidade das sementes. Este trabalho teve como objetivo determinar a metodologia de execução do teste de tetrazólio e a sua eficiência para verificar a viabilidade em sementes de maxixe (Cucumis anguria L.). Para isso, cinco lotes de sementes de maxixe foram inicialmente avaliados pelo teste de germinação, primeira contagem e velocidade de germinação. Posteriormente os lotes foram submetidos aos tratamentos para adequação da metodologia do teste de tetrazólio, sendo avaliadas três concentrações da solução de tetrazólio (0,100; 0,075 e 0,050%), mantidas no escuro, por duas, quatro e seis horas, sob temperaturas de 35 e 40 °C, com quatro repetições de 25 sementes para cada tratamento. Decorridos os períodos de coloração, as sementes foram lavadas em água corrente, seccionadas longitudinalmente entre os cotilédones e classificados em viáveis e não viáveis. A avaliação da viabilidade de sementes de maxixe pelo teste de tetrazólio é eficiente quando realizada sob concentração de 0,050% por seis horas a 35 °C ou quatro horas a 40 °C.

O pereiro-vermelho e uma especie florestal pertencente a familia Rubiaceae, considerada endemica do bioma Caatinga. O presente trabalho teve como objetivo definir o tipo de substrato e a temperatura mais adequados para a germinacao de sementes de pereiro-vermelho (Simira gardneriana M.R. Barbosa & Peixoto). Dessa forma, realizou-se experimento em delineamento inteiramente ao acaso e arranjo fatorial 5 x 4, constituidos pelas combinacoes de cinco substratos (entre areia, sobre areia, rolo de papel, sobre papel e sobre vermiculita) e quatro temperaturas (constantes de 25; 30; 35 °C e alternada de 20-30 °C), com quatro repeticoes de 25 sementes cada. Foram analisadas as seguintes variaveis: porcentagem de germinacao, porcentagem de plântulas anormais, indice de velocidade de germinacao, comprimento e massa seca das plântulas. As temperaturas de 25 e 30 °C e os substratos rolo de papel ou areia sao condicoes ideias para a germinacao das sementes de pereiro-vermelho.

Control of the vegetable leafminer is essential in areas of melon production in the states of Rio Grande do Norte and Ceara, Brazil. The aim of this study therefore, was to evaluate the effect of different concentrations of aqueous neem seed extract (Azadirachta indica) on the leafminer (Liriomyza sativae). The experiment was carried out in a completely randomised design, comprising seven treatments: control (distilled water), positive control (Vertimec® 1.8 EC insecticide - Abamectin), and five concentrations of aqueous neem seed extract (1, 5, 10, 15 and 20 g 100 mL-1 distilled water), with 10 replications (melon plants). The treatments were applied by spraying with a hand sprayer. Evaluation was divided into two stages for each treatment, larval mortality being recorded in the first and pupal mortality in the second. Increased larval and pupal mortality inL. sativae was found with increasing concentrations of the aqueous neem seed extract. Concentrations of 15 and 20 g 100 mL-1 of the extract caused 91 and 91.8% larval mortality with 89.7 and 90.6% control efficiency respectively. All the concentrations tested caused significant pupal mortality in the surviving larvae, especially the concentrations of 5, 10, 15 and 20 g 100 mL-1, with 99.4, 100, 100 and 100% mortality respectively.

Os testes de germinacao e de vigor sao componentes essenciais do processo de controle de qualidade das empresas produtoras de sementes. Diante disso, nesta pesquisa o objetivo foi estudar a metodologia do teste de condutividade eletrica, verificando sua eficiencia na identificacao de diferentes niveis de vigor de lotes de sementes de coentro. Para tanto, utilizaram-se quatro cultivares (Portugues, Super Verdao, Tabocas e Verdao), cada uma representada por quatro lotes de sementes, que inicialmente foram submetidas as avaliacoes do grau de umidade, germinacao, primeira contagem de germinacao e emergencia de plântulas. O teste de condutividade eletrica foi realizado com 25 e 50 sementes embebidas em 50 e 75 mL de agua destilada, a 25 oC, por 2, 8 e 24 horas. O teste de condutividade eletrica e eficiente para a avaliacao do potencial fisiologico de sementes de coentro quando conduzido com 50 sementes imersas em 50 mL de agua destilada, a 25 oC, apos duas horas de embebicao.

RESUMO - O objetivo do trabalho foi desenvolver procedimentos apropriados para a conducao do teste de tetrazolio com o intuito de verificar a viabilidade de sementes de feijao-caupi. Foram avaliadas duas temperaturas, 35 e 40 °C; tres concentracoes de tetrazolio, 0,05; 0,075 e 0,1%; por tres tempos, 90; 150 e 210 minutos. Paralelamente, foram conduzidos testes de germinacao e emergencia de plântulas, condutividade eletrica e envelhecimento acelerado, estabelecendo-se criterios para avaliacao da viabilidade e vigor. As sementes foram tipificadas em dois grupos, viaveis e inviaveis, as quais apresentaram adequada relacao com a emergencia. A avaliacao da viabilidade e vigor das sementes de feijao-caupi, por meio do teste de tetrazolio, e eficiente com o emprego do pre-condicionamento de imersao direta em agua por 16 horas, a 25 °C, e utilizacao da solucao de tetrazolio na concentracao de 0,05%, por 210 minutos, na temperatura de 40 °C. Palavras-chave: Feijao-caupi. Germinacao. Vigor.