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ABSTRACT The use of cold plasma is effective in overcoming seed dormancy. However, its effects, both in the long-term and during storage, is still not fully understood. The aim of this study, therefore, was to evaluate the immediate and post-storage effect of atmospheric plasma on the seeds of Pityrocarpa moniliformis in overcoming seed coat dormancy. The seeds were treated with plasma for 0, 1.0, 2.0, 3.0, 4.0 and 5.0 minutes. Following application, 50% of the seeds were stored for two years while the remainder were submitted to immediate analysis. The seeds were evaluated for germination and the germination speed index, in addition to seedling length and dry weight. The experimental design was completely randomised, and included regression analysis. The plasma treatment resulted in an increase in the germination rate and vigour of the seeds, both immediately after exposure and after two years of storage. In particular, the seeds treated for five minutes showed around 39% germination, which was outstanding compared to seeds from other exposure times. Plasma is effective in overcoming seed coat dormancy in seeds of P. moniliformis treated for five minutes and tested immediately. The effect of plasma on the seeds of P. moniliformis after storage was less for all the conditions under test.

ABSTRACT Exposing seeds to agents that elicit tolerance to abiotic stress, such as phytohormones and organic acids, during hydration and dehydration cycles can determine their response to later stimuli, e.g. exposure to salt stress. The aim of this study was to evaluate the action of priming cycles with different eliciting agents of salt stress tolerance on seeds of the cowpea varieties Sempre Verde and Pingo de Ouro. The seeds were subjected to the following treatments: 0.0 mM NaCl (control); 100 mM NaCl (salt stress); salt stress + three seed-priming cycles (PC) in water; salt stress + PC in gibberellic acid; salt stress + PC in hydrogen peroxide; salt stress + PC in salicylic acid; salt stress + PC in ascorbic acid. The following variables were analysed: germination, growth, dry weight, salt tolerance index, total soluble sugars, total free amino acids and proline. Salt stress (100 mM NaCl) reduced germination, length and biomass accumulation in the Sempre Verde and Pingo de Ouro varieties. These showed the best response to the priming cycles with gibberellic and salicylic acids, which promoted greater germination potential, length and biomass under a salt stress of 100 mM NaCl, affording greater tolerance via osmotic regulation, especially in the Sempre Verde variety.

RESUMO: O teste de tetrazólio avalia de forma rápida a viabilidade das sementes, cuja eficiência depende de ajustes metodológicos para cada espécie. Com isso, objetivou-se avaliar a viabilidade em sementes de Anadenanthera colubrina por meio desse teste. As sementes foram envelhecidas por 12 e 24 horas para obter diferenças na qualidade fisiológica. A qualidade inicial foi avaliada pelos testes de germinação; emergência; IVG e IVE; TMG e TME. Para o teste de tetrazólio utilizou-se o delineamento experimental inteiramente casualizado em esquema fatorial 3 x 9 e os tratamentos constaram: três condições de envelhecimento acelerado - EA (0, 12 e 24 h de EA) e nove combinações entre concentrações e tempo de imersão no sal de tetrazólio: 0,075%/4 h; 0,075%/6 h; 0,075%/8 h; 0,1%/4 h; 0,1%/6 h; 0,1%/8 h; 0,5%/4 h; 0,5%/6 h; 0,5%/8 h, com quatro repetições de 25 sementes, avaliados sob as temperaturas de 35 e 40 °C. As sementes foram classificadas em viáveis e vigorosas, viáveis e não vigorosas e inviáveis. O teste de tetrazólio foi eficiente para estimar a viabilidade de sementes de A. colubrina. Para isso, deve-se realizar o desponte na região oposta a micrópila, com pré-umedecimento em água por 10 h, seguido da remoção do tegumento e imersão na solução de tetrazólio a 0,1%, por 4 h, a 35 °C. Nessa condição, o teste de tetrazólio foi eficiente para identificar diferenças na qualidade fisiológica de sementes não envelhecidas e envelhecidas por 12 e 24 horas.

Phaseolus lunatus L. is a species of landrace bean widely cultivated in Northeast Brazil. The integration of new technologies in the agricultural sector has highlighted the significance of seed images analysis as a valuable asset in the characterization process. The objective was to assess the morphology of 18 P. lunatus varieties gathered from four states in the Brazilian Northeast. To achieve this, 100 seeds from each variety were utilized, and their images were acquired using a flatbed scanner with a digital resolution of 400 dpi. Subsequently, the images were processed using the ImageJ software package for analyzing seed size, shape and color characteristics. Statistical analyses were performed with SPSS software applying stepwise Linear Discriminant Analysis (LDA). The overall accuracy rate for correct identification was 80.5%. Among the varieties, the lowest classification percentage was attributed to the ‘Coquinho Vermelha’ variety (39%), while the highest rates were observed for ‘Fava Roxa’ and ‘Fava de Moita’ (98%). The morpho-colorimetric classification system successfully discriminated the varieties of P. lunatus produced in the northeastern region of Brazil, highlighting the -+*/high degree of diversity within them. In particular, seeds with uniform coloring or clearly defined secondary color patterns were easier to classify. The varieties showed low correlation, forming distinct groups based on background color, secondary color, or seed size.

ABSTRACT This study investigated the effectiveness of using the X-ray technique to assess the viability of papaya seeds. The X-ray images were performed in eight replicates of 25 seeds, placed on transparent acrylic plates on double-sided adhesive tape, previously identified, and then submitted to radiation in X-ray equipment "HP Faxitron". After exposure to X-ray radiation, the seeds were submitted to the germination test in rolls of germitest paper and kept in a germination chamber at 20-30 °C for 30 days. Seedlings were photographed and evaluated as normal seedlings, abnormal and non-germinated seeds. Afterward, the X-ray images and the seedlings from the same seeds were visually compared, and the X-ray images clearly showed seeds with and without internal filling. All abnormal seedlings were full seeds; therefore, X-ray images were not able to separate normal and abnormal. A 100% accuracy was verified by comparing the X-ray images and their respective seedlings, full seeds originated normal or abnormal seedlings, and empty seeds corresponded to non-germinated seeds. Therefore, using X-ray images is a promising technique to identify the viability of papaya seeds. The automated analysis of X-ray images is a simple, fast, and efficient technique to provide information on seed viability and generate parameters related to their germination capacity.

Abstract: Melon is one of the most consumed cucurbits and commercially significant cucurbits in the world. It is planted predominantly through seedlings, and seed quality is essential in this process. Among the rapid tests used in seed analysis, the pH testing of exudate has shown promise for several cultivated species. Thus, this study aimed to verify the viability of melon (Cucumis melo L.) seeds through the pH testing of exudate. For this, seeds of the hybrids Premier and Supreme (three lots each) were subjected to germination and vigor tests (first germination count, tetrazolium, accelerated aging, emergence speed index, and emergence). The pH testing of exudate was evaluated using phenolphthalein and sodium carbonate solutions. The results indicated the possibility of classifying the lots into three quality levels for both hybrids, similar to most tests used to assess initial quality. Therefore, the pH testing of exudate was effective in determining the viability of lots of melon seeds and can be conducted with a soaking period of 120 minutes at 25 or 30 °C.

ABSTRACT The tetrazolium test is a fast and effective method to determine seed viability. In this context, the objective was to adapt the methodology of the tetrazolium test, in relation to preconditioning, to determine the viability (Eugenia stipitata McVaugh ssp. sororia McVaugh) under different times of immersion in solution and seed size. The seeds of E. stipitata ssp. sororia need to go through preconditioning, fractionation being an indispensable technique to be performed before immersion of the seed in the tetrazolium solution, as it allows the contact of the salt with the tissue to be analyzed, which, when feasible, staining occurs (formation of the substance triphenyl-formazan). The immersion time of 26 hours in the tetrazolium solution (1% at 26 °C) is indicated for determining the viability of E. stipitata ssp. sororia seeds, regardless of the seed mass classes used.

Invasive species threaten crops and ecosystems worldwide. Therefore, we sought to understand the relationship between the geographic distribution of species populations and the characteristics of seeds using new techniques such as seed image analysis, multivariate analysis, and machine learning. This study aimed to characterize Leucaena leucocephala (Lam.) de Wit. seeds from spatially dispersed populations using digital images and analyzed their implications for genetic studies. Seed size and shape descriptors were obtained using image analysis of the five populations. Several analyses were performed including descriptive statistics, principal components, Euclidean distance, Mantel correlation test, and supervised machine learning. This image analysis technique proved to be efficient in detecting biometric differences in L. leucocephala seeds from spatially dispersed populations. This method revealed that spatially dispersed L. leucocephala populations had different biometric seed patterns that can be used in studies of population genetic divergence. We observed that it is possible to identify the origin of the seeds from the biometric characters with 80.4% accuracy (Kappa statistic 0.755) when we applied the decision tree algorithm. Digital imaging analysis associated with machine learning is promising for discriminating forest tree populations, supporting management activities, and studying population genetic divergence. This technique contributes to the understanding of genotype-environment interactions and consequently identifies the ability of an invasive species to spread in a new area, making it possible to track and monitor the flow of seeds between populations and other sites.

The scarcity of surface water has led to the use of underground sources as an alternative for crop irrigation by farmers in semi-arid regions. However, these water sources generally have high salinity, which prevents agricultural production. The objective of this study was to determine the effects of pre-germination treatments with plant growth regulators and bioactivators on melon seeds to attenuate salt stress caused by irrigation water during germination and seedling development. Two trials were carried out separately with the hybrids, Goldex and Grand Prix. The design was completely randomized in a 4 × 3 factorial scheme (four seed treatments and three dilutions of irrigation water). Seeds were treated with salicylic acid and gibberellic acid and the insecticide, thiamethoxam, in addition to the control. Local supply water, artesian well groundwater, and dilution of these waters at a 1:1 ratio were employed for irrigation. Fourteen days after sowing, morphological and physiological analyses were performed, and the material was collected for biochemical determination. The use of saline well water affected the initial development of melon seedlings of the Goldex and Grand Prix hybrids. Pre-germination treatment of Goldex hybrid seeds with gibberellic acid was inefficient at mitigating salt stress. However, the effects of irrigation water salinity on Grand Prix melon seeds pretreated with salicylic acid and thiamethoxam were attenuated.

ABSTRACT The objective was to verify if the primary root emission can be recommended as a vigor test for soybean seeds. For this, five lots of varieties ANTA 82, NA7337 and BRS1074IPRO were evaluated by first count, germination, emergence, emergence speed index and tetrazolium tests. In the root protrusion test at 20, 25 and 30 ºC, two evaluation criteria were adopted: primary root emission precocity index (PREPI) and percentage of seeds that emitted the primary root (PRE). The seeds counted were those with a primary root equal to or greater than 2 mm, every 12 h from the installation of the test until 120 h. The design was completely randomized and means were compared, within each evaluation time, using the Scott-Knott test at 5% probability. Pearson’s linear correlation was performed for PREPI and PRE with emergence. PREPI was not considered efficient. For the PRE, at 20 ºC, there was a correlation at 72 h, for the three varieties. At 25 ºC there was a correlation for a period of 36 h for ANTA 82 and NA7337 and 60 h for BRS1074IPRO. At 30 ºC there was a correlation in the time of 36 h for the three cultivars. Considering that speed in obtaining results is important in vigor tests, it is concluded that primary root emission for 36 h after installing the test at 30 ºC is recommended as a vigor test in the quality control of soybean seeds.

ABSTRACT Among the main problems that compromise the development of forest species are water and salt stresses, especially in the early stages of development, when seedlings are more sensitive. Thus, the objective of this study was to evaluate the morphophysiological and biochemical changes in Enterolobium contortisiliquum seedlings subjected to abiotic stresses. The experimental design was randomized complete blocks (RCB), composed of five treatments, with four replicates, and the experimental plot consisted of twenty plants. From the 31st day after sowing, when the seedlings reached approximately 15 cm in height, they began to receive the treatments, which consisted of different levels of electrical conductivity of irrigation water (0.3; 2; 4; 6; 8 dS m-1) for salt stress and periods of water restriction (0; 4; 8; 12 and 16 days without irrigation) for water stress. The traits evaluated were: plant height, root length, stem diameter, number of leaves, leaf area, total dry matter, Dickson quality index, height/shoot dry matter ratio, total soluble sugars, starch, total amino acids and proline. An increase in the electrical conductivity of irrigation water and days without irrigation compromised the development of E. contortisiliquum seedlings, which was intensified from 2 dS m-1 and four days without irrigation for salt and water stresses, respectively. The mechanism of survival of E. contortisiliquum to abiotic stresses involves reduction in the growth and quality of seedlings, with activation of biochemical defense mechanisms of the species.

A cenoura é uma hortaliça com papel socioeconômico importante, tanto pelo elevado emprego de mão-de-obra, quanto por sua alta comercialização. Para otimizar o estabelecimento dessa cultura em campo se torna imprescindível sementes com germinação rápida e uniforme. Por isso, tem-se utilizado o tratamento de sementes como técnica para viabilizar o desempenho germinativo e expressão de vigor. Desse modo, objetivou-se avaliar os efeitos do tiametoxam no desempenho fisiológico de sementes de cenoura durante a germinação e desenvolvimento inicial de plântulas. O delineamento experimental foi o inteiramente casualizado, em esquema fatorial 5 x 4, sendo cinco cultivares de cenoura e quatro dosagens de tiametoxam (0; 0,4; 0,8 e 1,2 mL). Avaliaram-se a germinação, primeira contagem de germinação, comprimento e massa seca de plântula, além de análises bioquímicas do conteúdo de açúcares totais, aminoácidos totais e prolina. Os dados coletados foram submetidos à análise de variância (p ≤ 0,05) seguido do teste de Tukey e análise de regressão. O tratamento de sementes de cenoura com tiametoxam, no geral, influenciou positivamente a germinação das sementes das cultivares estudadas. No entanto, as dosagens de 0,4 e 0,8 mL de tiametoxam para cultivar Tropical não houve influência positivamente o desenvolvimento de plântulas. A dose de 1,2 mL do bioativador, para a cultivar Alvorada, foi benéfico ao desenvolvimento de plântulas e acúmulo de metabólitos.

ABSTRACT Cowpea suffers significant production losses when subjected to salt stress, but the response varies among genotypes. The objective of this study was to evaluate the phenology and production of traditional cowpea seeds under saline water irrigation. The experiment was conducted in two stages, the first one in a greenhouse to evaluate the phenology and production of cowpea genotypes and the second one in the laboratory to assess the viability and vigor of the seeds produced in the first stage. The treatments resulted from the combination of two salinity levels of the irrigation water (0.5 and 4.5 dS m-1) and 14 traditional cowpea varieties (Boquinha, Ceará, Costela-de-vaca, Lisão, Canário, Pingo-de-ouro, Roxão, Branco, Canapum-branco, Canapum-miúdo, Baêta, Coruja, Paulistinha, and Sempre-verde) acquired from traditional farmers in the western region of Rio Grande do Norte, Brazil. Canário, Baêta, and Coruja varieties have a higher number of flowers per plant and earlier flowering. Salinity reduced the number of flowers per plant, increased abortion in all traditional varieties and reduced production in the early varieties Branco, Canapum-miúdo, Baêta, and Coruja. Cultivation under saline water irrigation did not affect the viability of the seeds from the second generation of cowpea, but reduced the vigor of the seeds of the varieties Lisão, Pingo-de-ouro, Roxão, Branco, Canapum-branco, Canapum-miúdo, Baêta and Coruja. The traditional varieties Boquinha, Ceará, Costela-de-vaca, Canário, Paulistinha and Sempre-verde are indicated for the production of cowpea seeds under irrigation with saline water.

The adoption of technologies that allow the mitigation of environmental stresses, such as the use of regulators in seed treatment, is an alternative for crops in high temperatures regions. This study aimed to assess the heat stress mitigation on the germination and initial development of carrot seedlings using plant growth regulators. The study was divided into three experiments performed at the temperatures of 25, 30 and 35 ºC. A 5 × 3 factorial arrangement was used, with five carrot cultivars (Alvorada, Brasília, BRS Esplanada, Tellus and Tropical) and two products (Stimulate® and thiamethoxam), in addition to the control (untreated seeds). The following variables were evaluated: germination, first germination count, seedling length and dry mass. When the cultivars had their seeds treated with the plant growth regulators at 25 ºC, the germination for the Tellus cultivar was 28 % higher than for the control, while, at 30 ºC, the seed germination for BRS Esplanada and Tellus was twice as high as for the control, and showed a higher vigor than that of Alvorada, Brasília and Tropical. Overall, the thiamethoxam promoted increments at the initial development of carrot seedlings at 25 and 30 ºC. However, the germination of the carrot cultivars was disrupted at 35 ºC.

ABSTRACT Pitaya (Hylocereus undatus and H. costaricensis) is found in the group of exotic fruits and its cultivation in Brazil is expanding, especially in the semi-arid region of the Northeast. In this region, the problems of water quantity and quality usually cause environmental stresses which limit the survival of plants, especially during germination and seedling establishment. Thus, the objective was to evaluate the mitigating action of pre-germination treatments in pitaya seeds under salt stress. The experiment was conducted in a completely randomized design, in a 2 × 6 factorial scheme, corresponding to two species of pitaya (H. undatus and H. costaricensis) and six pre-germination treatments (T1 = 0.0 MPa (control); T2 = salt stress (-0.4 MPa); T3 = hydropriming + salt stress; T4 = gibberellic acid + salt stress; T5 = salicylic acid + salt stress; T6 = thiamethoxam + salt stress). After 20 days of sowing, germination, germination speed index, shoot length, primary root length, total dry mass, total soluble sugars and total free amino acids were analyzed. H. costaricensis was more tolerant to salinity than H. undatus. Salicylic acid stimulated the germination and growth of H. undatus, besides increasing the soluble sugar content in H. costaricensis. Seed hydropriming attenuated salt stress during germination of H. undatus and favored dry mass gain. Gibberellic acid stimulated the germination of H. undatus and the growth of H. undatus and H. costaricensis seedlings, in addition to increasing the levels of soluble sugars in H. undatus.

The aim of this work was to identify efficient vigor tests for differentiating the seed lots, forecasting seedling emergence in the field and assessing the physiological quality of Panicum maximum seeds. 12 seed lots from the cultivar Tanzania and 11 seed lots from the cultivar Massai were evaluated for water content, germination, first count and germination speed index, emergence and first emergence count of seedlings in sand, root length and shoot length, analysis of SVIS® images (seedling length, vigor and uniformity index) and seedling emergence in the field. The work was conducted in a completely randomized design for tests performed in the laboratory and in randomized blocks for tests in the field. The data were subjected to analysis of variance and the means compared by Scott Knott's test at 5% probability and statistical multivariate clustering analysis and principal components analysis. The shoot and root length tests are efficient for the evaluation of the physiological potential of P. maximum cv. Massai, while the seedling length, vigor index and growth uniformity index tests using image analysis, seedling emergence in sand and first seedling emergence count in sand are efficient in assessing the physiological potential of seeds of P. maximum cv. Tanzania, and providing information similar to that of seedling emergence in the field.

Saline stress impairs germination and initial plant growth. However, discontinuous hydration cycles induce osmotic tolerance in seeds and can improve the response of maize seeds to saline stress. The objective of this study was to evaluate the action of discontinuous hydration cycles with different salt stress tolerance elicitors on germination, growth, and osmotic adjustment of maize cultivars. Maize seeds of BR 206 and BRS 5037 Cruzeta cultivars were subjected to the following treatments: 0.0 mmol of NaCl (control), 250 mmol of NaCl (salt stress), salt stress + three discontinuous hydration cycles (DHCs) of seeds in water, salt stress + DHCs with gibberellic acid, salt stress + DHCs with hydrogen peroxide, salt stress + DHCs with salicylic acid, and salt stress + DHCs with ascorbic acid. Salt stress reduced the germination, growth, and biomass accumulation in maize seedlings—the BR 206 cultivar outperformed BRS 5037 Cruzeta. Discontinuous hydration cycles with water failed to improve the salt stress tolerance of maize seeds. However, discontinuous hydration cycles with gibberellic acid, hydrogen peroxide, and salicylic acid promoted salt stress tolerance in maize due to increased synthesis of osmoprotectants. Our results revealed salicylic acid is appropriate for discontinuous hydration cycles in maize seeds.

Abstract: Thousand-seed weight (TSW) is used to calculate the sowing density, number of seeds present in a sample, and predict seed size. Our aim was to establish an alternative methodology for thousand-seed weight determination in forest species using image analysis techniques. The traditional methodology was compared with the alternative one, testing them on seeds from 16 forest species. The traditional method was performed by manually counting eight repetitions of 100 seeds, weighing of samples, and computation of thousand-seed weight. The alternative methodology was performed by counting seed samples captured by images and processing in ImageJ® software, followed by weighing a single sample, and computation. All steps were timed, and each methodology was repeated ten times per species. The TSW obtained by the alternative methodology was similar to that obtained by the traditional one, and the average execution time of the activities was reduced by 62%. The proposed thousand-seed weight determination by image analysis is an efficient and optimized alternative to the traditional method. Thousand-seed weight determination from image analysis reduces execution time for the seed analyst and forest seedling producer.

Abstract: “Mofumbo” (Combretum leprosum Mart. (Combretaceae) is a neotropical species of wood, pharmacological, beekeeping and environmental importance. Thus, the objective was to evaluate the biochemical and physiological responses in C. leprosum seeds under different storage environments. The experiment was carried out in a factorial (2 x 7), with two storage conditions (natural and climate-controlled environments) and seven storage periods (0; 60; 120; 180; 240; 300 and 360 days), in four replications per treatment. At the beginning of storage and at 60-day intervals, the seeds were analyzed for water content, physiological potential (germination, germination speed index, root and shoot lengths and seedling dry mass) and biochemical (neutral lipids, lipid peroxidation, total and reducing sugars, total free amino acids, and starch). The results indicated that storing “mofumbo” seeds for 360 days reduced viability, being more pronounced after 180 days, regardless of the storage environment. “Mofumbo” seeds were stored in a natural environment for 180 days, resulting in less lipid degradation. After this period, the reduction was associated with the attack of reducing sugars on amino acids. Thus, it is concluded that “mofumbo” seeds must be stored in a natural environment for up to 180 days.

ABSTRACT 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.

Abstract: Simira gardneriana (Rubiaceae) is a newly discovered tree species endemic to the Caatinga. For this reason, studies aimed at propagation, seed and seedlings analysis are essential for morphology, identification, classification, and conservation. Our objective was to characterize the seeds, the morpho-physiology of germination and seedling establishment of S. gardneriana. Therefore, we performed physical, biometric, biochemical, and morphological characterization of the seeds, as well as an evaluation of the germination process and seedling establishment. Hydration of seeds was carried out by three methods (immersion in water, on a wire mesh, and between paper rolls) and at two temperatures (25 and 30 °C). Morphological characterization of the seedlings was performed on paper substrate at 30 °C for 28 days. Seeds of S. gardneriana are orthodox, amylo-lipid, have an endosperm and do not exhibit physical dormancy. Hydration and germination of the seeds can be achieved in a paper roll at 30 °C with root protrusion on the sixth day, and complete seedling formation on the 28th day after sowing. Seedlings of S. gardneriana are phanero-epigeal cotyledonous with photosynthetic cotyledons and have ability to regrow the root system. Characterization of S. gardneriana seeds, germination and seedlings contributes to its propagation and may help in subsequent taxonomic and phylogenetic studies in Rubiaceae.

Cucumis melo is one of the most appreciated and consumed vegetables in the world, however, producing areas have been suffering from increased salinity in irrigation water. Therefore, accesses of melon, from the germplasm bank of the Federal Rural Semi-Arid University (UFERSA), were tested for salinity and the physiological responses of the seedlings were evaluated. For the 24 accesses of C. melo, salinity of 0.06 and 3.45 dS m^-1 was applied. For this, four subsamples of 25 seeds per access were used, which were seeded in polystyrene trays having as a substrate washed and sterilized sand, initially moistened at 50% field capacity. The design was completely randomized in a factorial scheme (two salinity levels and 24 accesses). Salinity affected the physiological quality (germination and mean germination time) of melon seeds, germinating on average 62%, with an average germination time of 4 days, mean height of 10.5 cm and reduction of dry matter accumulation. The saline treatment increased the electrical conductivity (EC) of the soil saturation extract, indicating the presence of stress. The accesses that presented intolerance to salinity were: A35, A24, A41, A31, A09, A28 and A43. The moderately tolerant accesses were: A16, A19, A15, A17, A34, A25, A27, A18, A42. The salinity tolerant accesses were: A45, A08, A37, A50, A14, A36, A07, A39 which may serve as a basis for genetic improvement.

Abstract: The purpose of this research was to verify the efficiency of physical and biochemical indices in determining the physiological maturity of Tabebuia aurea seeds, as well as to evaluate the post-harvest storage of fruits with different maturation stages on germination and vigor. For this, 200 fruits were classified as dark green (stage I), light green (stage II), and light brown (stage III) epicarp. Freshly harvested fruits were evaluated for length, width, and weight and their seeds for length, width, thickness, thousand-seed weight, water content, electrical conductivity, and chemical composition. Subsequently, a factorial consisting of three maturation stages and four storage periods of fruits (0, 5, 10 and 15 days) were used, and water content, germination, germination speed index, root length, shoot length, and seedling dry matter were evaluated. Physical and biochemical indices can be used as maturation indicators in T. aurea seeds, except fruit length, seed thickness, electrical conductivity, and protein content. The maximum germination and vigor of T. aurea seeds were obtained in fruits at stages I (dark green) or II (light green) associated with post-harvest storage of fifteen days.

ABSTRACT The objective was to evaluate the physical characteristics and physiological behavior of A. oleracea seeds during imbibition and germination, under different temperatures and photoperiods, as well as to determine the duration of the germination test. For this, biometric parameters (length, width and thickness) were measured in 100 seeds and thousand-seed weight was determined. In addition, the external structures of seeds and seedlings were described and the imbibition curve was monitored. Subsequently, the germination test was conducted at temperatures of 20, 25, 30, 35, 20-30 and 25-35 ºC, under constant and alternating light and dark photoperiods (12 h), arranged in 6 x 3 factorial scheme, with four replicates of 50 seeds. Seeds were sown in transparent plastic boxes with blotting paper as substrate, germinated in Biochemical Oxygen Demand (B.O.D) incubator, and evaluated for six days. The following variables were analyzed: germination, germination speed index, seedling length and seedling dry mass. The imbibition pattern test was conducted at 25 ºC with 4 replicates of 100 seeds, evaluated until 50% root protrusion occurred. A. oleracea seeds exhibit uniform physical characteristics and the three-phase model as a water absorption pattern. Constant temperatures of 25 and 30 °C and alternating temperatures of 20-30 °C, regardless of the photoperiod, led to higher germination values. For A. oleracea, the germination test evaluations can be performed on the fourth and sixth day after sowing, as first and last counts, respectively.

ABSTRACT Determination of seed physiological maturity allows predicting the most appropriate time for harvest, aiming to obtain seeds with high physiological potential. Physalis angulata (Solanaceae) has pharmacological and agro-industrial potential, but there is little information on its reproductive phenology. Thus, this study aimed to evaluate the physiological maturity of P. angulata seeds according to fruit age. Fruits were harvested at 7, 14, 21, 28 and 35 days after anthesis (DAA) and the following evaluations were conducted: fruit weight and diameter, seed moisture content, 100-seed dry weight, 1000-seed weight, electrical conductivity, germination, germination first count, emergence, and seedling dry weight and length. The experimental design was completely randomized. Fruit weight and diameter increased until 35 DAA and seed dry weight increased until 21 DAA. Highest seed physiological potential occurred at 35 DAA, with highest germination percentage (97%). The results allow concluding that P. angulata seeds become physiologically viable from 21 DAA, with highest physiological potential at 35 DAA. However, harvest should be carried out around 28 DAA, before fruits fall.

ABSTRACT Information on the effects of climate conditions on the survival of species grown in semi-arid regions is essential and at the same time scarce, especially regarding rustic species such as West Indian gherkin (Cucumis anguria L.). Thus, this study aimed to evaluate germination, growth and biochemical alterations in C. anguria seeds under water stress and different temperature regimes. The experimental design was completely randomized, in 5 x 5 factorial scheme, composed of five osmotic potentials (0.0; -0.1; -0.2; -0.3 and -0.4 MPa) and four temperatures (20; 25; 30 °C and alternating temperatures of 20-30 ºC), with each treatment composed of four replicates of 50 seeds. The seeds were sown on paper towel (Germitest®) and germinated in Biochemical Oxygen Demand (B.O.D.) germinators, under 8-h photoperiod. Germination percentage, germination speed index, mean time of germination, seedling length and contents of chlorophylls, carotenoids, proline, free amino acids and free sugars were determined along the experiment. Decrease in osmotic potential reduced germination, growth and contents of chloroplast pigments of C. anguria seedlings, but was more drastic at levels lower than -0.2 MPa. Low temperatures intensify the effects of water stress on the germination of C. anguria seeds. The synthesis of protecting osmolytes increased in C. anguria seedlings but these components did not promote efficient osmotic adjustment in their initial development stage.

Simira gardneriana M.R. Barbosa & Peixoto (Rubiaceae), é uma espécie exclusiva do bioma Caatinga, utilizada como forrageira, e a madeira usada para lenha e estacas na construção de cercas. Espécies desse bioma são submetidas, constantemente, a estresses abióticos, entre eles o salino e o térmico. Dessa forma, objetivou-se avaliar o efeito da salinidade da água de irrigação na germinação e no desenvolvimento inicial de plântulas de S. gardneriana em diferentes temperaturas. Nesse estudo foram utilizadas sementes com teor de água inicial em torno de 12,32% às quais foram arranjadas em esquema fatorial com oito níveis de salinidades, obtidos a partir da adição de cloreto de sódio (NaCl) e diluídos em água destilada nas concentrações de 0,0 (testemunha); 1,5; 2,5; 3,5; 4,5; 5,5; 6,5 e 7,5 dS m-1 e quatro temperaturas de 25, 30, 35 e 20-30 °C, em quatro repetições de 25 sementes cada. Os efeitos da salinidade e da temperatura foram avaliados por meio da germinação, índice de velocidade de germinação, comprimento da parte aérea e da raiz, massa seca da parte aérea e da raiz e total de plântulas. O aumento dos níveis de salinidade da água interfere em todas as variáveis analisadas na germinação de sementes de S. gardneriana, principalmente sob a temperatura de 35 °C. Nas temperaturas de 25 e 30 °C a germinação e o desenvolvimento inicial das sementes são menos afetados pela salinidade. As sementes de S. gardneriana são sensíveis à salinidade causada pelo aumento do NaCl a partir de 1,5 dS m-1, o que indica baixa tolerância desta espécie em ambientes salinos. Os resultados obtidos neste trabalho mostram que o efeito negativo na germinação e desenvolvimento inicial de plântulas de S. gardneriana pode ser explicado pelo aumento dos níveis salinos e temperatura, reduzindo o poder da planta em absorver água e nutrientes, o que indica respostas de sensibilidade dessa espécie a salinidade e ao estresse térmico.

The economically profitable production of crops is related, among other factors, to seed quality, the production system, and the water used in irrigation or preparation of nutrient solutions. Therefore, the objective was to evaluate the phenology, production, and vigor of seeds of mini watermelons grown in saline nutrient solution and different substrates. In the fruit and seed production phase, the experiment occurred in a greenhouse with five electrical conductivities of water for nutrient solution preparation, ECw (0.5, 2.4, 4.0, 5.5, and 6.9 dS m−1), and two growing substrates (coconut fiber and sand). We evaluated the physiological quality of seeds previously produced under the five electrical conductivities of water and two substrates. High salinities for the hydroponic cultivation of the mini watermelon cultivar ‘Sugar Baby’ accelerated fruit maturation and crop cycle, decreasing fruit size. However, in both substrates, the seed production of mini watermelons, seed viability, and seed vigor occurred adequately with a reject brine of 6.9 dS m−1 in the hydroponic nutrient solution. The seed production of ‘Sugar Baby’ mini watermelons using reject brine in a hydroponic system with coconut fiber and sand substrates is viable in regions with water limitations.

Salvia hispanica L. is an alternative crop cultivated by farmers who want to diversify their production. However, this species is sensitive to salinity, which affects its germination negatively. Seed priming with different attenuators is a technique with potential to mitigate the effects of salt stress. Thus, the objective of this study was to evaluate the effect of seed priming with the use of different attenuators on the germination, growth, and organic solute accumulation of S. hispanica seedlings under salt stress. The experimental design was completely randomized, with treatments distributed in a 4 × 5 factorial scheme, corresponding to four seed priming treatments and five osmotic potentials, with four replicates of 50 seeds in each treatment. The seed treatments consisted of presoaking seeds for 4h in salicylic acid, gibberellic acid, and distilled water and the control treatment, which did not involve soaking. These seeds were germinated at osmotic potentials of 0.0, -0.1, -0.2, -0.3, and -0.4 MPa, using NaCl as an osmotic agent to simulate the different salinity levels. Among all the treatments implemented, S. hispanica seed priming with salicylic acid was the most efficient in mitigating the salt stress effects.

Abstract: Melon is a vegetable crop of food and nutritional importance whose cultivation is growing worldwide. In this sense, investments in technologies are necessary, especially regarding the quality of seeds used in the establishment of new areas. This study aimed to verify the effectiveness of the Automated Seed Vigor Analysis System (Vigor-S) in the evaluation of the physiological potential of melon seeds. Eight seed lots (four lots of the hybrid Supreme and four of the hybrid Premier) were used. The physiological potential of the seeds was evaluated through tests indicated for analyzing the quality of melon seeds associated with the image analysis by using the software Vigor-S, which included the analysis of seedlings from the germination test and accelerated aging in saturated NaCl solution. The experiment was conducted in a completely randomized design, with five replications. The results indicated the effectiveness of Vigor-S, especially when it was used associated with the accelerated aging test in saturated NaCl solution, with results similar to those obtained in traditional vigor tests. Thus, the Automated Seed Vigor Analysis System (Vigor-S) was effective in evaluating the physiological potential of melon seeds.

ABSTRACT: Erythrina velutina Willd. (Fabaceae) is a tree species that bears social, ecological, and economic importance for northeastern Brazil, a region with frequent temperature variations. The objective of this work was to evaluate the mobilization of reserves during seed germination and seedling establishment of E. velutina at different temperatures, and how these mechanisms are affected in a thermal-stress situation. The seeds germinated at 5, 15, 25, 35, and 45 °C, and the physiological and biochemical aspects of reserve mobilization (starch, lipids, and total proteins) were assessed during seedling establishment. Germination, vigor, and the mobilization of reserves from the cotyledons to the embryonic axis are affected according to the incubation temperature. The temperature of 25 °C favors the mobilization of reserves during seed germination and seedling establishment in E. velutina. In a situation of thermal stress, high temperatures affect the establishment of the seedlings, whereas low temperatures compromise the mobilization of reserves.

ABSTRACT: Erythrina velutina Willd. (Fabaceae) is a Brazilian native tree with economic, ecological and social potential. The aim of this study was to evaluate isoenzyme activity and changes in DNA integrity during germination of E. velutina at different temperatures. The seeds were placed to germinate at 5, 15, 25, 35 and 45 °C, evaluating isoenzyme activity and degradation of the DNA during germination. Isoenzyme expression occurs differently for seed germination under different temperatures, with varied expression between seedlings and cotyledons. The esterase enzyme was more sensitive to express the response of the E. velutina germination seeds at different temperatures. DNA repair is more efficient during the germination of E. velutina seeds when submitted to a temperature of up to 25 °C, with damage to the genetic apparatus with an increase higher than this temperature.

ABSTRACT The physiological potential of seeds is one of the main factors that should be considered at the planting of a crop. This study aimed to evaluate the exogenous application of biostimulant in zucchini, cv. Caserta Italiana, under salt stress conditions. For this, the experiment was divided into two parts. The first one was carried out in the laboratory, using a completely randomized experimental design, in a 5 x 3 factorial scheme (biostimulant doses and seed soaking times), with four replicates of 25 seeds. The second one was carried out in a greenhouse, in a completely randomized experimental design, in a 2 x 6 factorial scheme with four replicates, corresponding to two levels of irrigation water salinity (0.5 and 5.0 dS m-1) and six forms of biostimulant application in seeds and leaves. Treatment of zucchini seeds, cv. Caserta Italiana, with biostimulant (Stimulate®) at the dose of 10 mL L-1, for 8 hours, proved to be viable and resulted in vigorous seedlings when irrigated with 5.0 dS m-1 saline water.

Abstract Catingueira (Poincianella pyramidalis Tul. L. P. Queiroz) is an endemic species of the Caatinga, with great economic potential. Research on the development of this species under conditions of water restriction, common in the Northeastern semi-arid region, is still scarce. This study evaluated the effects of water restriction on the morphological and biochemical characteristics of catingueira seedlings subjected to water restriction. The experimental design was a randomized complete block design, with five treatments and four replicates. The treatments consisted of periods of water restriction (0, 6, 12, 18 and 24 days without irrigation). The characters evaluated were shoot height, leaf diameter, number of leaves, leaf area, total dry mass, ratio between shoot height and dry mass, Dickson quality index, chlorophylls a and b content, total soluble sugars and free proline. Periods of water restriction longer than six days caused damage to the seedlings development, with reduced growth and quality.

Water availability and substrate type are essential factors in seed germination tests, influencing imbibition and seedling development. The objective of this study was to evaluate the influence of two substrates and different water volumes on the germination and vigor of chia seeds. The experimental design was completely randomized in a 2 x 6 factorial scheme, which consisted of two substrates, paper towel (Germitest®) and blotting paper, soaked with six water volumes equivalent to 1.5, 2.0, 2.5, 3.0, 3.5, and 4.0 times their dry weight, in four replicates of 50 seeds each. Germination percentage, mean time of germination, shoot length, radicle length, shoot dry matter, radicle dry matter, total dry matter (seedling), and root/shoot ratio were evaluated. Based on our results, germination tests for seeds of chia should be conducted using blotting paper (on paper) as substrate, with a water volume of 2.5 to 4.0 times its dry weight. Chia seedlings grown on blotting paper showed greater growth and dry matter accumulation compared to those grown on paper towel.

This study evaluated the physical and physiological attributes of saved cowpea seeds (Vigna unguiculata L. Walp.) used in the Brazilian semi-arid area and compared them with certified seed varieties. The study tested 37 saved seed samples from the state of Rio Grande do Norte and two varieties of certified seeds (“BRS Guariba” and “BRS Pujante”) from the production field of Embrapa Products and Market, Petrolina, PE, Brazil. The seeds were tested for moisture, hectoliter weight, weight of 1,000 seeds, and physical purity to evaluate the physical quality. Germination, first germination count, field emergence, emergence rate index, shoot dry mass, and accelerated aging were tested for physiological quality. The saved cowpea seeds showed great differences, suggesting the influence of genetic variability and different growing environments. The use of saved cowpea seeds by small farmers in the semi-arid areas of Northeastern Brazil is impractical, because these seeds have inferior physical and physiological qualities compared to certified cowpea seeds.

Abstract: The aim of this study was to adapt the vigor test methodology of (strong) normal intact seedlings of Amburana cearensis and evaluate efficiency in physiological classification of seed lots. The study was conducted in two stages: morphological characterization of seedlings and physiological analysis of seed lots. To do so, the following tests were carried out: (strong) normal seedlings, germination, emergence, first count, germination speed index, tetrazolium, length of strong normal seedlings, length and dry mass of seedlings. The experimental design was completely randomized. The Tukey and Kruskal-Wallis tests were used to compare the results, and the correlation between the variables was analyzed by Spearman and Pearson coefficients. The seedlings of A. cearensis are semi-hypogeal phanerocotylar, with development of normal seedlings on the ninth day after sowing. The vigor test of strong normal seedlings, length of strong normal seedlings, dry matter, and tetrazolium led to physiological classification into different vigor levels. The vigor test of (strong) normal seedlings, the length of strong normal seedlings, and tetrazolium (vigor) were effective for vigor classification of A. cearensis seeds.

ABSTRACT The tetrazolium test is one of the promising alternatives to determine the viability of dormant, recalcitrant and slow-germinating seeds. The objective of this study was to adapt the tetrazolium test methodology to estimate the viability and vigor of Piptadenia stipulacea (Benth.) Ducke seeds. For this, a sample of seeds was classified into three sublots using round sieves, corresponding to six, five and four millimeters in diameter, respectively. Moisture content, imbibition curve, germination, emergence, germination and emergence speed indices, mean germination time and seedling emergence were initially evaluated. The second stage was conducted using a completely randomized experimental design, in 3 x 9 factorial scheme, corresponding to three sublots and nine combinations between concentrations and time of immersion in tetrazolium salt (0.05%/2 h; 0.05%/4 h; 0.05%/6 h; 0.075%/2 h; 0.075%/4 h; 0.075%/6 h; 0.1%/2 h; 0.1%/4 h; 0.1%/6 h), totaling twenty-seven treatments with four replicates of 25 seeds, evaluated separately at 35 and 40 °C. For each treatment, the seeds were divided into four classes: viable and vigorous seeds (class I), viable and non-vigorous (class II), unviable (class III) and dead (class IV). The period of 8 h of pre-imbibition and 4 h of staining in tetrazolium solution at 0.075%, under 35 or 40 °C, is adequate to estimate the viability and vigor of P. stipulacea seeds.

ABSTRACT 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.

ABSTRACT Identifying fast and efficient tests to evaluate the vigor of forage grass seed lots is desirable in the quality control programs of the companies in this sector. Thus, the objective was to evaluate the efficiency of vigor tests on the physiological quality of seeds of Panicum maximum, cv. Mombasa, for the differentiation of lots and prediction of seedling emergence in the field. Nineteen seed lots were subjected to evaluations of moisture content, germination, first count, germination speed index, seedling emergence in sand, first count of seedling emergence in sand, seedling root and shoot lengths, seedling emergence in the field and computerized analysis of seedling images obtained through SVIS® software. The experimental design was completely randomized for the tests performed in the laboratory and randomized blocks for the emergence test in the field. The data were subjected to analysis of variance and the means were compared by Scott-Knott test at 5% probability level. Cluster analysis of seed lots and principal component analysis were performed. The uniformity index, evaluated by image analysis and by the root length test, is efficient in evaluating the physiological potential of seeds of Panicum maximum, cv. Mombasa, providing information similar to those obtained with the test of seedling emergence in the field.

The discovery of several waterlogged plant remains in a Middle Ages context (1330–1360 AD) in Sassari (NS, Sardinia, Italy) enabled the characterisation of archaeological plum fruit stones and watermelon and grape seeds through computer image analysis. Digital seed/endocarp images were acquired by a flatbed scanner and processed and analysed by applying computerised image analysis techniques. The morphometric data were statistically elaborated using stepwise linear discriminant analysis (LDA), allowing comparisons among archaeological remains, wild populations and autochthonous cultivars. Archaeological samples of plum were compared with 21 autochthonous cultivars of Prunus domestica from Sardinia, while archaeological watermelon seeds were compared with 36 seed lots of Citrullus from Europe, Africa and Asia. Moreover, archaeological grape seeds were compared with 51 autochthonous traditional cultivars of Vitis vinifera subsp. vinifera from Sardinia, 16 cultivars from Tuscany, six cultivars from Liguria, and eight cultivars from Catalonia (Spain). Archaeological plum remains showed morphological affinity with five cultivars of Sardinia. Seed features of the archaeological watermelon remains demonstrated affiliation with a proper sweet dessert watermelon, Citrullus lanatus, and similarity with some Sardinian cultivars. Regarding the archaeological remains of grape, morphometric comparisons showed a high similarity with autochthonous cultivars from Catalonia and Liguria. This study provides new information about ancient fruit cultivated and consumed during the Middle Ages in Sardinia.

This study aimed to establish an adequate tetrazolium test procedure to estimate okra seed viability. Initially, seeds from four okra lots were immersed in alcohol (98%) for 60 minutes, followed by an 18-h soak in distilled water at 25 °C. Then, the seeds were longitudinally sectioned, immersed in 0.025, 0.050 and 0.075% tetrazolium solutions for 60, 90 and 120 minutes and maintained in an oven at 35 and 40 °C. Subsequently, the seeds were evaluated for viability, based on tissue color (bright red, pink or dark Carmine red). Simultaneously, a germination test was conducted, and its results were used as a reference for the tetrazolium test. The experiment was carried out in a completely randomized design, in a 3 x 3 + 1 factorial scheme (three concentrations of tetrazolium salt x three immersion periods, plus the control) in four replicates of 50 seeds for each treatment. The tetrazolium test to estimate okra seed viability should be conducted in 0.075% tetrazolium solution, for 90 minutes, at 35 °C.

Plasma technology is a fast, cost-effective, and pollution-free method that can be used in place of conventional methods to overcome seed dormancy. The goal of the present study was to determine the effect of different application times of atmospheric plasma on soaking and germination of Hybanthus calceolaria seeds in order to accelerate these processes. Helium plasma jet produced by dielectric barrier discharge was used to treat H. calceolaria seeds with applications of 1, 5, and 10 minutes. The treated seeds were characterized considering their weight variation during soaking, changes in electrical conductivity, and pH. It was found that germination depended on the plasma application time. The treatment of H. calceolaria seeds with atmospheric plasma for 1 minute provided 3.5 times greater germination in comparison to untreated seeds. Atmospheric plasma technology obtained by dielectric barrier discharge had potential of being used as a germination accelerant in H. calceolaria seeds. The treatment of H. calceolaria seeds using atmospheric plasma for 1 minute favored germination.

Mimosa tenuiflora Willd., popularly known as jurema-preta, is an arboreal species of great importance for the brazilian Northeast due to its uses as a medicinal plant and in the restoration of degraded soils. No information is available in the Rules for Seed Analysis and the Instructions for Seed Analysis of Forest Species regarding ideal conditions for of this species. Thus, this study aimed at evaluating the influence of pre-germination treatments, in addition to verifying the germination performance at different temperatures and in different substrates. In both experiments, four replicates of 25 seeds were used for each treatment. In experiment I, seeds were submitted to the following methods for overcoming dormancy: witness - Intact seeds (T1) immersion in water at 100 °C for 1 (T2), 2 (T3), 3 (T4), 4 (T5), 5 (T6) and 6 min (T7), immersion in concentrated sulfuric acid for 1 (T8), 4 (T9), 7 (T10), 10 (T11) and 13 min (T12), scarification on sandpaper n° 80 (T13) and lopping in the region opposite the micropyle (T14). In experiment II, seed germination was evaluated in four types of substrates: between sand, paper on, paper roll and between vermiculite and at six different temperatures: 20, 25, 30, 35, 40 °C and alternating between 20 and 30 °C. Immersion in hot water for 1, 2, 3, 4, 5 and 6 min, sulfuric acid treatment for 10 and 13 min, sand paper and lopping were the most appropriate treatments to overcome seed dormancy. The seed germination of M. Tenuiflora should be carried out at 25 °C on paper roll substrate.

Bidens subalternans DC. is a weed found in several tropical countries such as Brazil. Large number of produced seeds and easy dispersion favor the colonization of agricultural fields by this species. To know the factors that affect the germination of B. subalternans can help to understand its ecology, permitting to develop control strategies. Laboratory experiments were carried out to evaluate how the temperature, photoperiod, burial depth, water deficit, and salt stress affect the seed germination of B. subalternans. The means of the treatments of each experiment were shown in scatter plots with the bars indicating the least significant difference (LSD, p≤0.05). The results showed a germination percentage above 77% for a wide alternating temperature (15/20 C to 30/35 C night/day). The highest germination and uniformity occurred at 25/30°C night/day. Only 11% of the seeds germinated at a temperature of 35/40°C night/day. The deeper burial of seeds reduced their germination. Only 17% of the seeds germinated in darkness conditions. However, in constant light and 12 hours of light/dark conditions the germination percentage was over 96%, confirming the light dependence of the B. subalternans during germination. In constant light and 12 hours of light/dark, the germination was over 96%. B. subalternans seeds showed sensitivity to water and salt stress, and their germination was inhibited under a water potential of -0.4 MPa and 100.09 mM, respectively. The sensitivity of B. subalternans seeds to high temperatures, water stress, and salt stress explains the high frequency of this weed in south-central Brazil. The light and sowing depth showed that burial of seeds by mechanical control is a strategy to reduce the high infestation of B. subalternans.

Salvia hispanica seedlings have stood out for their potentialities in nutrients for agri-food industries. Nevertheless, studies related to this species are still scarce, especially with respect to agronomic factors that enable its propagation and development. Hence, this study aimed to evaluate germination, vigor and osmotic adjustment of S. hispanica seeds and seedlings subjected to water and thermal stress. The experimental design was completely randomized, with treatments arranged in factorial scheme, corresponding to five levels of polyethylene glycol (PEG 6000) (0.0; -0.1; -0.2; -0.3 and -0.4 MPa) and five temperatures (20, 25, 30 and 20-30 °C), with four replicates of 50 seeds in each treatment. Germination test was set on blotter paper, moistened with PEG 6000 solutions at the previously mentioned potentials, under 8-h photoperiod. The following variables were analyzed: germination, germination speed index, seedling shoot length, seedling root length, seedling dry matter and contents of chlorophyll, carotenoids, amino acids, proline and sugars. Polyethylene glycol levels of -0.4 MPa at all temperatures and -0.3 MPa at 30 °C and 20-30 °C enable germination and vigor of S. hispanica seedlings. S. hispanica seedlings are able to perform osmotic adjustment under water stress conditions up to the level of -0.3 MPa, when grown from seeds germinated at temperatures of up to 25 ºC.

Water availability influences plant metabolism during the various stages of development, especially in the period between germination and seedling emergence. The aim of this study was to evaluate the effect of water deficit during the germination process on seeds of A. oleracea. The experiment was carried out in a completely randomised design, with four replications of 50 seeds. The treatments were arranged in a 5 x 2 factorial scheme, with the first factor consisting of the osmotic potentials (-0.2, -0.4, -0.6, -0.8 and distilled water for the potential 0.0 MPa) and the second factor consisting of two lots of seed. The germination test was carried out on substrates moistened with solutions of mannitol and polyethylene glycol (PEG 6000) at the various potentials, in a Biochemical Oxygen Demand (BOD) germinator at a temperature of 30°C and under constant light. The test was evaluated daily for 14 days, considering the seeds that had a root length equal to or greater than two millimetres as having germinated. The variables under analysis were germination, germination speed index, seedling length and seedling dry weight. The germination process of A. oleracea is compromised at water potentials of -0.2 MPa and -0.4 MPa when submitted to PEG and mannitol respectively. Seeds from Lot 1 were more tolerant to the water deficit than were those from Lot 2.

Pithecellobium dulce destaca-se por apresentar potencial madeireiro e forrageiro, além de diminuir o risco de erosão do solo, aumentar a fixação de nitrogênio e possuir propriedades medicinais. A profundidade e a posição de semeadura são fatores importantes dentro do processo de germinação por garantir um desenvolvimento rápido e uniforme das plântulas. O objetivo deste estudo foi avaliar a influência da posição e da profundidade de semeadura na emergência e no desenvolvimento inicial de plântulas de P. dulce. Utilizou-se o delineamento inteiramente ao acaso, com quatro repetições de 25 sementes, dispostos em esquema fatorial 3 × 4 (posições e profundidades de semeadura). As posições de semeadura consistiram em: hilo voltado para cima (HC), hilo de lado (HL) formando um ângulo de 90º em relação ao eixo imaginário com o substrato e hilo voltado para baixo (HB). As profundidades de semeadura foram de 1,0, 2,0, 3,0 e 4,0 cm. Após 30 dias da semeadura, avaliaram-se a percentagem de emergência de plântulas, o índice de velocidade de emergência, o comprimento da parte aérea, o comprimento da raiz, o número de folhas e a massa da matéria seca total. A semeadura de sementes de P. dulce deve ser realizada na profundidade de até 3,0 cm com o HL.

Forage turnip (Raphanus sativus L. var. oleiferus Metzg.) progeny with seeds of higher physiological quality are of importance for farmers and seed producing companies. The objective of this work was to identify tests to be used in laboratories for the selection of turnip progeny having seeds of higher germination, vigor, seedling emergence in the field, and storage potential. Seeds of 100 turnip progeny of paternal half-sibs were evaluated as to water content, 1,000-seed mass, first count of the standard germination test, accelerated aging, and seedling emergence in the field. The seeds were subjected to storage for 12 months in unifoliate paper bags kept under room conditions and then evaluated by means of the standard germination test, first count of the standard germination test, and water content. The data were examined as to variance and genetic and phenotypic correlations, heritability, coefficients of genetic variation, and selection gain. The standard germination test, first count of germination, and the accelerated aging test can be used to select forage turnip progeny for seed physiological quality and storage potential. None of the tests used were efficient at selecting progeny with high field emergence.

RESUMO O pereiro-vermelho é uma espécie florestal pertencente à família Rubiaceae, considerada endêmica do bioma Caatinga. O presente trabalho teve como objetivo definir o tipo de substrato e a temperatura mais adequados para a germinação 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, constituídos pelas combinações 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 repetições de 25 sementes cada. Foram analisadas as seguintes variáveis: porcentagem de germinação, porcentagem de plântulas anormais, índice de velocidade de germinação, comprimento e massa seca das plântulas. As temperaturas de 25 e 30 °C e os substratos rolo de papel ou areia são condições ideias para a germinação das sementes de pereiro-vermelho.