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The use of high-quality Urochloa decumbens seeds is an essential factor for the establishment of pastures, and osmopriming under stress conditions may improve seed performance. This study was conducted at the Universidade Federal de Viçosa in a completely randomized design and aimed to evaluate the effects of osmopriming and its relationship with physical and physiological attributes of U. decumbens seeds subjected to water deficit. Seeds from ten lots were primed in H2O (0 MPa) and PEG (−0.8 MPa), KNO3 (0.2%), and SNP (0.10 mmol L−1) solutions for 24 hours. Unprimed seeds were used as control. The seeds were evaluated in two trials after osmopriming. Trial I consisted of the X-ray test to evaluate physical attributes and germination and vigor tests. In Trial II, the seeds were placed to germinate under favorable (0 MPa) and water deficit conditions (−0.2 MPa) to evaluate physiological attributes. In general, osmopriming of U. decumbens seeds assisted in increasing physical attributes such as area, gray scale, perimeter, and tissue density. Osmopriming does not contribute to the best physiological performance of U. decumbens seeds under ideal germination conditions (0 MPa). However, osmopriming with SNP (0.10 mmol L−1) and PEG (−0.8 MPa) for 24 hours contributes to the better physiological performance of seeds under water deficit.

Abstract: Seed treatments with chemical phytosanitary products can compromise mobilization of seed reserves for the seedlings under water deficit conditions. The aim of this study was to evaluate the physiological quality, the initial seedling development, and the mobilization of reserves in soybean seeds treated with phytosanitary products under water deficit. The trial was set up in a completely randomized design in a 4 × 4 factorial arrangement: chemical treatments (control, Thiamethoxam, Fludioxonil + Metalaxyl-M, and Fipronil + Pyraclostrobin + Tiophanate-methyl) × osmotic potentials (0, -0.1, -0.2, and -0.3 MPa). We analyzed the following variables: germination; hypocotyl length, root length, and total seedling length; seedling length vigor index; cotyledon dry matter weight; seedling dry matter yield; seed reserve reduction; relative dry matter yield; seed reserve reduction rate; and conversion efficiency of seed reserves into seedling dry matter. Seed quality and seedling development decline under water deficit conditions. The treatment with Fipronil + Pyraclostrobin + Thiophanate-methyl results in lower phytotoxicity. The estimated cotyledon dry matter (CDM) weight is an indicator of phytotoxicity and water deficit. Mobilization of reserves is compromised in seeds treated with insecticides, reducing the capacity of conversion of reserves into dry matter. There is an inversely proportional relationship between the reduction in conversion and the efficiency of conversion of reserves of treated soybean seeds under water deficit.

Abstract: The demand for techniques that make it possible to assess the physiological potential of seeds quickly and assertively make near-infrared spectroscopy (FT-NIR) and seedling analysis using ILASTIK software promising tools. The aim of this study was to evaluate the physiological potential of Urochloa decumbens seeds using near-infrared spectroscopy (FT-NIR) and ILASTIK software. Seeds from 10 lots of U. decumbens were classified according to their physiological potential (germination and vigor) and then FT-NIR spectra were obtained from individual seed samples, the original spectra being pre-processed with different dispersion correction methods used for the construction of a classification model through partial least squares discriminant analysis (PSL-DA). For the ILASTIK evaluation, the seedlings were photographed at 7 and 14 days of germination and the trained classifier was applied to the images, generating data on the numbers of strong seedlings, weak seedlings and non-germinated seeds. With data from the FT-NIR technique pre-processed by the 2nd derivative of Savitzky-Golay, it was possible to obtain a classification model with high efficiency to discriminate the classes regarding the physiological potential of the seeds. ILASTIK was efficient to classify seeds according to their physiological potential after only 7 days of germination. FT-NIR and ILASTIK analyses are non-destructive and fast alternatives, with great potential for quality control of U. decumbens seed lots.

Cratylia argentea is a shrub legume native to tropical regions of South America where it is used for animal feed and green manure. In the absence of germination guidelines, the key aim of this study was to define the most suitable temperature for conducting germination and accelerated aging tests. The biochemical attributes of seeds were also assessed. Seeds with 10% moisture from 4 different seed lots were germinated using the between paper method in a germinator at temperatures of 20, 25, 30 and 35 °C and alternating temperatures of 20/30 °C (16 h:8 h), with daily counting until germination was stable (seven days without germination). For the accelerated aging test, two temperatures (41 and 45 °C) and six aging periods (0, 24, 48, 72, 96 and 120 h) for seeds with between 10–40 % moisture content were used. Carbohydrates (%), ethereal extract (%), crude protein (%) and macro and micronutrient contents of the seeds were measured. Results showed that C. argentea seeds consist predominantly of starch (22.67 %) and protein (26.45 %) reserves with a low percentage of lipids. For the germination test, the temperature of 30 °C is recommended, allowing greater percentage and speed of germination, with seedling evaluation at 10 and 20 days. For the accelerated aging test, aging for 48 h at 41 °C is recommended to discriminate C. argentea seed lots in terms of quality.

Abstract: Tomato is a crop sensitive to water deficit and the responses of seeds to germination under these conditions involve biochemical, physiological, and molecular processes. The aim of this study was to evaluate the physical, physiological, and biochemical changes in tomato seeds osmoprimed with selenium (Se) and subjected to water deficit during germination. Tomato seeds of the LA 4050 and LA 3475 accessions were osmoprimed with PEG 6000 solution (-1.0 MPa) plus Na2SeO4 (12.5 μM) or only with PEG 6000 solution for 24 h or unprimed. The seeds from the different treatments were subjected to water deficit (-0.3 MPa) or to control (0 MPa). Image analyses were performed (X-ray), physiological variables were obtained by the germination test and activities of SOD, CAT and POX enzymes were determined. Osmopriming, especially with PEG, provided the seeds of both accessions with higher densities and gray mean when compared to unprimed ones. Seeds under water deficit showed lower physiological performance and lower enzymatic activity. Se did not induce seed resistance to water deficit. Osmopriming with PEG 6000 at -1.0 MPa is an efficient technique for improving the physiological quality of seeds of tomato accessions susceptible and tolerant to water deficit. Moreover, the antioxidant enzyme CAT proved to be an indicator of oxidative stress tolerance in tomato seedlings under water deficit.

The use of multispectral images has great potential to assess seed quality and represents a significant technological advance in the search for fast and non-destructive analysis techniques. However, the devices currently available are expensive. Thus, this study aimed to propose a low-cost method for acquisition and processing of multispectral images of soybean seeds and to evaluate their potential for rapid determination of seed physiological potential. The study was conducted in three steps: implementation of the multispectral image acquisition system, development of an algorithm for automatic image processing, and evaluation of the relationship between the data obtained through image analysis and the results of standard tests used to evaluate seed physiological potential. A total of 43 variables were assessed, eight related to seed physiological potential (germination and vigor) and 35 obtained from the analysis of the multispectral images. Of the variables obtained from multispectral images, 21 were related to pixel values in the images in the different bands evaluated (green, red, and infrared) and 14 associated with seed morphometric characteristics. The proposed system is efficient in obtaining multispectral images and the algorithm developed was efficient to extract morphometric characteristics and pixel information from the images. The parameters obtained from the NIR spectrum region showed a good relationship with the physiological potential of soybean seeds.

Weathering deterioration affects seed quality, especially in areas with excessive rainfall. This study aimed to evaluate the oxidative stress, physiological quality, and protein metabolism of seeds of different soybean cultivars under weathering deterioration at the pre-harvest phase. Six soybean cultivars (BMX Apolo, DM 6563, NS 5959, NA 5909, BMX Potência, and TMG 1175) were subjected to simulated rainfall at the R8 stage. Each level was divided into two applications at 72-h intervals: 60 mm (30 + 30), 120 mm (60 + 60), and 180 mm (90 + 90). Then, the seeds were harvested and evaluated for physiological potential, antioxidative enzymes, hydrogen peroxide, malondialdehyde, proteins, and protease activity. The simulated rainfall allowed the variation in seed moisture, promoting a significant reduction in germination and seed vigor, especially at 120 and 180 mm levels. There were also reductions in antioxidative enzyme activity with weathering deterioration (mainly for catalase, ascorbate peroxidase, and peroxidase), accumulation of hydrogen peroxide and malondialdehyde, and reductions in protein content and protease activity. The proposed rainfall system is efficient in inducing weathering deterioration during the pre-harvest phase and its deleterious effects. Weathering deterioration in soybean seeds in the pre-harvest stage is directly influenced by genotype.

Abstract: Nitric oxide (NO) has been standing out as a seed germination process stimulator, mainly under stress conditions. This work aimed to evaluate the physiological and biochemical effects of NO on germination and vigor of pea seeds submitted to water deficit. Seeds of cv. Itapuã 600 were sown in moistened substrate with water (control), PEG 6000 solution (-0.15 MPa) and PEG 6000 solution with sodium nitroprusside (SNP) (-0.15 MPa + 50 μM), an NO donor. The germination, vigor (germination speed and seedling development), activity of antioxidant enzymes, reactive oxygen species, lipid peroxidation, and amylase activity were evaluated. Germination and vigor of pea seeds were reduced under water deficit, but the application of SNP was able to improve the physiological and biochemical performance of the seeds under this condition. Water deficit promotes an increase in oxidative stress, but the application of NO promotes greater activity of antioxidative apparatus enzymes and amylases, softening the damage caused by water deficit during seed germination and growth of pea seedlings.

Sementes de soja são suscetíveis à deterioração em campo após atingirem a maturidade fisiológica, que em geral, ocorre no estádio R7 sendo a colheita realizada em R8. Objetivou-se com esse trabalho avaliar as alterações bioquímicas e fisiológicas em sementes de diferentes cultivares de soja submetidas ao atraso de colheita no campo. Sementes das cultivares NS 5959, BMX Potência e TMG 1175 foram colhidas em quatro épocas (0, 10, 20 e 30 dias após atingirem R8). Em cada período de colheita, foram realizados os testes de umidade, germinação, primeira contagem, envelhecimento acelerado, emergência e tetrazólio. Também foram avaliadas as atividades das enzimas antioxidantes catalase (CAT), peroxidase (POX) e ascorbato peroxidase (APX). O experimento foi conduzido em DIC, em esquema fatorial 3 x 4 (três cultivares e quatro épocas de colheita). Em R8 + 20 e R8 + 30 dias, foi encontrada redução na germinação e vigor das sementes das diferentes cultivares de soja devido à deterioração em campo pelo atraso de colheita. Sob atraso de colheita, as sementes das cultivares não diferiram quanto à viabilidade, mas diferiram quanto às respostas antioxidantes e fisiológicas. No estádio R8 e em R8 + 10 dias foi possível observar melhor desempenho das sementes da cv. ‘BMX Potência’ e pior para a cv. ‘TMG 1175’.

Abstract: The tetrazolium test has been recommended for evaluating the viability of seeds with slow and ununiform germination, especially agroforestry species. The aim of this study was to propose a methodology to evaluate the viability of J. curcas L. seeds using the tetrazolium test and to generate visual aids to support the interpretation of the test. In the first trial, methods of seed preparation and staining were evaluated. The most promising methodologies were used to conduct the second test, which consisted of the evaluation of different concentrations (0.10 and 0.25%) and times (2 and 3 h) of immersion of the seeds in the tetrazolium solution, using five lots. The seeds were analyzed individually and classified as viable or non-viable. At the same time, germination, first count, emergence and seedling emergence speed index tests were conducted. The tetrazolium test is efficient for evaluating the viability of seeds of J. curcas L. providing results correlated with germination and seedling emergence. Pre-soaked seeds should have their integument removed and then sectioned longitudinally and medially lengthwise for immersion in 0.10% solution of 2,3,5-triphenyl chloride tetrazolium for three hours at 35 °C.

Abstract: Nitric oxide (NO) can act in biochemical pathways of the germination process; however, there is little information about how it acts on the performance of pea seeds. The aim of this study was to evaluate the physiological and biochemical effects of NO on pea seed germination and vigor. Pea seeds cv. Itapuã 600 obtained from three seed lots with different levels of physiological quality were sown in a substrate moistened with water (control) or sodium nitroprusside (SNP) solution, a NO donor (50 μM), to assess germination, vigor, activity of antioxidant enzymes, reactive oxygen species, lipid peroxidation, and amylase activity. NO application does not alter pea seed germination, but it increases vigor. It is more effective in seeds with lower physiological potential. In addition, NO leads to reduction in oxidative stress, favors the translocation of reserves to the embryo, and has potential for use in the treatment of pea seeds to increase seed vigor.

disponibilidade de água é um dos principais fatores responsáveis pela produtividade do trigo, bem como da qualidade das sementes produzidas. O silício (Si) possui importante papel na atenuação dos efeitos de diversos estresses bióticos e abióticos. Desta forma, a aplicação de Si pode ser uma ferramenta para mitigar os efeitos de diferentes lâminas de irrigação na produção e qualidade de sementes de trigo. O objetivo do trabalho foi avaliar a produtividade e a qualidade fisiológica de sementes de trigo produzidas a partir de plantas fertilizadas com Si foliar e cultivadas sob diferentes lâminas de irrigação. O delineamento experimental foi blocos casualizados, em esquema de parcelas subdividas, com quatro repetições. As parcelas foram constituídas por três lâminas de irrigação (0, 50 e 100% da irrigação total necessária [ITN]). Nas subparcelas foram alocados os tratamentos de silício (sem aplicação [0 mM] e 5 mM de SiO2, aplicado na fase de perfilhamento). Foram avaliados: balanço hídrico do sistema; umidade do solo; produtividade; massa de mil sementes; germinação; condutividade elétrica; envelhecimento acelerado; comprimento e emergência de plântulas. O balanço hídrico do sistema foi negativo para a lâmina de 0% da ITN após a antese e houve menor umidade do solo nesta lâmina. Não houve efeito das lâminas de irrigação e da aplicação de Si na produtividade das plantas. As menores lâminas de irrigação impostas reduziram a massa de mil sementes e aumentaram a condutividade elétrica das sementes produzidas. Sementes produzidas em plantas fertilizadas com Si não diferiram quanto a germinação, porém originam plântulas mais vigorosas com maior crescimento e uniformidade.

A técnica de condicionamento osmótico reduz o período entre a semeadura e a emergência de mudas no campo, além de favorecer o desempenho das sementes em condições de estresse. O objetivo do estudo foi avaliar o efeito do condicionamento osmótico no desempenho fisiológico e na atividade enzimática antioxidativa de sementes de girassol com diferentes níveis de vigor e expostas ao estresse térmico. Foram utilizados três lotes de sementes de girassol, cultivar Hélio 250. Inicialmente, as sementes foram avaliadas pelos testes de germinação e vigor para caracterizar os lotes. Em seguida, foram condicionadas em solução de polietilenoglicol 6000 a -2,0 MPa, a 15 °C por 8 h. Posteriormente, as sementes condicionadas e não condicionadas foram testadas quanto à qualidade fisiológica (germinação, contagem de primeira germinação, porcentagem e índice de velocidade de emergência das plântulas e matéria seca das plântulas) e determinação da atividade das enzimas superóxido dismutase (SOD), catalase (CAT ), ascorbato peroxidase (APX) e peroxidase (POX) sob três temperaturas: 15 °C (sub ótima), 25 °C (ótima) e 35 °C (supra ótima). Através de testes fisiológicos, os lotes 1, 2 e 3 foram classificados em três níveis diferentes de vigor, sendo alto, médio e baixo, respectivamente. O condicionamento osmótico favoreceu o desempenho das sementes de girassol na germinação e vigor em todas as temperaturas analisadas. Este efeito foi mais pronunciado em lotes de qualidade fisiológica mais baixa em temperaturas sub ótima e supra ótima. As temperaturas sub e supra ótimas causaram uma redução no desempenho fisiológico das sementes, principalmente nos lotes menos vigorosos. Em geral, o condicionamento osmótico favoreceu um aumento na atividade das enzimas SOD, CAT, POX e APX, principalmente em sementes de baixo vigor expostas às temperaturas sub e supra ótimas. O condicionamento osmótico de sementes de girassol no PEG 6000 a -2,0 MPa, por 8 horas, é eficiente para melhorar o desempenho dos lotes com menos vigor sob estresse devido às temperaturas sub e supra ótimas, favorecendo o aumento da atividade das enzimas do sistema antioxidativo.

ABSTRACT: Successive cycles of water absorption and loss favor weathering deterioration, one of the main factors that affect the quality of soybean seeds. This study evaluated the physiological, physical, and morpho-anatomical changes in soybean seeds under weathering deterioration at the pre-harvest phase. Six soybean cultivars (BMX Apolo, DM 6563, NS 5959, NA 5909, BMX Potência, and TMG 1175) were produced in a greenhouse and underwent weathering deterioration through a rainfall simulation system, applying 0, 60, 120, and 180 mm of precipitation at pre-harvest phase. Each rainfall level was divided into two applications at an interval of 72 h: 60 mm (30 + 30), 120 mm (60 + 60), and 180 mm (90 + 90). After harvest, the seeds were evaluated for germination, vigor, physical and morpho-anatomical properties. Weathering deterioration induced by simulated rainfall at the pre-harvest phase contributes to the reduction in soybean seed germination and vigor and is conditioned by the soybean genotype. The increase in intensity of simulated rainfall led to a more significant weathering damage in seeds, as evidenced by the X-ray and tetrazolium test. Cultivars DM 6563 and BMX Potência were more susceptible, while NA 5909 was less susceptible to weathering deterioration (especially at the highest level; 120 mm and 180 mm). Anatomical changes caused by weathering deterioration lead to cell compaction and rupture, mainly in the cell layers of the hourglass and parenchyma, forming intracellular spaces. The presence of weathering damage caused a reduction in physiological soybean seed quality.

Rapid emergence and uniform seedling growth are essential attributes in the production of vegetables such as carrots, whose sowing is direct in the field. The experiment was conducted to evaluate the effect of carrot seed vigor on seedling emergence, plant development, and yield. Four seed lots of carrot, cv. Brasília were characterized for their physiological potential by germination and vigor tests. A field experiment was conducted, where the seeds of each lot were sown in in the field to evaluate seedling emergence at 10 and 14 days, the length of the shoot and root at 30, 45 and 60 days after sowing, the crop growth rate, commercial, non-commercial and commercial total roots yield. Seed vigor significantly affected the seedling emergence and development of carrot plants in the field. The less vigorous lot showed lower final emergence than the most vigorous lots and these negative vigor effects extended to the most advanced stages of plant development. Carrot seed vigor affects seedling emergence and plant growth in the field. Vigorous seeds causes greater emergence, plant height and plant dry matter during the vegetative phase. The use of less vigorous seeds causes yield losses of up to 27%.

ABSTRACT The assessment of the quality of native forest species seeds is extremely important and, in this sense, it is necessary to integrate new technologies that can complement the quality analysis traditionally used. This study aimed to evaluate the physical and physiological quality of Piptadenia gonoacantha seeds using image analysis techniques and to relate aspects of tissue integrity with physiological attributes. Seeds from 10 lots were collected and submitted to automatic and visual analyses of radiographic images, with the determination of parameters related to tissue density and seed filling. After the X-ray test, the seeds were subjected to physiological analyses of germination and vigor. It was observed that the lots that presented higher values of tissue density, filling, and solidity, presented higher germination and vigor. It was also evident that the damage present in the seeds was causally related their physiological condition. Therefore, the results showed that the use of the X-ray technique in seeds combined with the automated analysis of the radiographs is efficient in the evaluation of the internal morphology of P. gonoacantha seeds. The physical integrity of the seed tissues is directly related to the physiological quality and allows the classification of different lots as to vigor. Visual analysis of digital radiographs is adequate to identify malformation in P. gonoacantha seeds.

ABSTRACT There is little information regarding the germination pattern, seed characterization, and seedling development of Melaleuca alternifolia. This study aimed to determine the ideal temperature for the germination of M. alternifolia seeds, as well as to characterize the seeds and the post-seminal development of the species. Three lots of M. alternifolia seeds were placed to germinate at 20, 25, 20-30, 20-35, 30, and 35 °C, with daily evaluations to determine germination rate, germination speed index (GSI), speed of germination (SG), and mean time for germination of 50% (t50) and 100% (t100) of seeds. The inner morphology of the seeds was evaluated through X-ray images and seedling morphology by photographs. Alternating temperatures (20-30 and 20-35 °C) led to germination rates higher than the other temperatures. The GSI had the lowest values at the constant temperature of 20 °C and the highest values at the constant 30 °C for all the lots. The SG was lowest at a temperature of 20 °C and the highest at the temperature of 35 °C. At alternating temperatures (20-30 and 20-35 °C), t50 was around 5 days and t100 reached 16 days. In conclusion, the alternating temperatures of 20-30 °C and 20-35 °C are recommended for germination of M. alternifolia, and final evaluation can be performed at 16 days after sowing. The inner structures of seeds could be visualized by X-ray analysis, and full seeds could be distinguished from empty seeds and impurities. Seeds exhibit epigeal germination and seedling development is stabilized after 30 days.

Abstract: Post-harvest storage of fleshy fruit is a strategy used for improving seed quality. The aim of this study was to evaluate post-harvest storage of the fruit of C. baccatum var. baccatum (cumari pepper) and relate it to antioxidant enzyme activity and seed physiological potential. Red-colored fruit (65 days after anthesis) was gathered and stored at 20 °C for 0, 5, 10, 15, and 20 days. The seeds were removed and evaluated for moisture content, physiological quality, antioxidant enzyme activity, and protein content. The means were fitted to regression equations and then passed through multivariate analysis (PCA). Seed moisture and 100-seed weight decreased through post-harvest storage. The 5- and 10-days storage periods led to an increase in the germination. Electrical conductivity was greater for the 0- and 20-day storage periods. Dry matter and protein increased in the 5- and 10-days. Enzymes exhibited reductions of activity comparing 0 and 20 days. The post-harvest storage of C. baccatum fruit for 5 and 10 days improves seed physiological potential and is related to physiological maturity. The incomplete maturation of cumari seeds obtained from unstored fruit (0 days) is related to greater enzyme activity, greater oxidative stress, and low germination and vigor. The lack of post-harvest storage of fruit and storage of fruit for longer than 10 days contributes to a lower physiological potential of cumari pepper seeds.

Abstract: Seed vigor may be determinant for field performance, especially under water restriction conditions. Sunflower is a crop subject to these conditions in the field and, therefore, the aim of this study was to evaluate the physiological and antioxidant changes in sunflower seeds under water restriction. Two lots of sunflower seeds (cv. Hélio 253) with different vigor levels were used. After initial characterization, seeds were placed to germinate under water potentials of 0.0, -0.2, -0.4, -0.6 and -0.8 MPa and evaluated by tests of germination, first germination count, shoot length and primary root length. The activities of the antioxidant enzymes SOD, CAT, POX and APX were also evaluated at 0, 2, 4 and 6 days after sowing. Water restriction led to a decrease in germination and slower seedling growth, regardless of seed vigor level. SOD activity was similar in the two lots, with reduction in activity four days after sowing. CAT activity was affected differently during germination in the two lots, and it was generally higher in the most vigorous lot. In higher vigor seeds, there was lower POX activity in water restriction treatments compared to the control. In general, seeds of lower vigor have lower capacity for activation of antioxidant enzymes, especially peroxidases.

Global demand for pulses such as the mung bean has grown in the last years. For successful production of these crops it is necessary to use high quality seeds. Methodologies based on X-ray image analysis have been used as a complementary tool to evaluate the physical quality of seeds due to their speed and potential for automation. The aim of this study was to evaluate the efficiency of X-ray analysis for non-destructive evaluation of the physical quality of Vigna radiata seeds and to relate the variables obtained with their physiological potential. For this, seeds from eight lots were X-rayed and subsequently subject to germination test. In total, 18 physical and physiological parameters were determined. The X-ray image analysis was efficient for evaluating the internal morphology of Vigna radiata seeds and allowed the identification of various damage types. However, it was not possible to relate the physical variables to the seed quality as the lots presented similar germination percentage. Physical variables such as solidity and circularity are related to percentage of root protrusion and length of seedling hypocotyl. Low relative densities indicate deteriorated tissues, related to severe morphological damage and non-viable seeds.

Boron (B) retranslocation may confer greater tolerance to B deficiency or toxicity, resulting in plants and fruits with better nutritional quality. Most plants do not demonstrate phloem mobility for B; however, some plants have natural mobility and others express it under stress conditions, such as nutritional stress. Therefore, we investigated the phloem mobility of B in cherry tomato plants with different nutritional status. The plants were cultivated in nutrient solution with adequate and insufficient doses of Potassium (K) and B. Furthermore, the plants received foliar fertilization with B in a mature leaf (F) in a localized form. The B content and amount in leaves near F were compared with leaves of the same age and position on control plants. The experiment was carried out in a protected environment and conducted in a randomized complete block design in a subdivided plot scheme with four replicates. Re-translocation of B between neighboring leaves was observed when the plant was without K deficiency and with B deficiency. In this nutritional status, leaves next to fertilized leaf with B (F) showed higher B amount when compared to leaves of the same position of control plants. Evidence suggests that retranslocation of B over relatively short distances (between leaves) can be influenced by the nutritional status the cherry tomato plants.

Boron (B) retranslocation may confer greater tolerance to B deficiency or toxicity, resulting in plants and fruits with better nutritional quality. Most plants do not demonstrate phloem mobility for B; however, some plants have natural mobility and others express it under stress conditions, such as nutritional stress. Therefore, we investigated the phloem mobility of B in cherry tomato plants with different nutritional status. The plants were cultivated in nutrient solution with adequate and insufficient doses of Potassium (K) and B. Furthermore, the plants received foliar fertilization with B in a mature leaf (F) in a localized form. The B content and amount in leaves near F were compared with leaves of the same age and position on control plants. The experiment was carried out in a protected environment and conducted in a randomized complete block design in a subdivided plot scheme with four replicates. Re-translocation of B between neighboring leaves was observed when the plant was without K deficiency and with B deficiency. In this nutritional status, leaves next to fertilized leaf with B (F) showed higher B amount when compared to leaves of the same position of control plants. Evidence suggests that retranslocation of B over relatively short distances (between leaves) can be influenced by the nutritional status the cherry tomato plants.

Global demand for pulses such as the mung bean has grown in the last years. For successful production of these crops it is necessary to use high quality seeds. Methodologies based on X-ray image analysis have been used as a complementary tool to evaluate the physical quality of seeds due to their speed and potential for automation. The aim of this study was to evaluate the efficiency of X-ray analysis for non-destructive evaluation of the physical quality of Vigna radiata seeds and to relate the variables obtained with their physiological potential. For this, seeds from eight lots were X-rayed and subsequently subject to germination test. In total, 18 physical and physiological parameters were determined. The X-ray image analysis was efficient for evaluating the internal morphology of Vigna radiata seeds and allowed the identification of various damage types. However, it was not possible to relate the physical variables to the seed quality as the lots presented similar germination percentage. Physical variables such as solidity and circularity are related to percentage of root protrusion and length of seedling hypocotyl. Low relative densities indicate deteriorated tissues, related to severe morphological damage and non-viable seeds.

O cultivo de grão-de-bico (Cicer arietinum L.) tem sido dificultado devido às interferências das plantas daninhas. Objetivou-se verificar o efeito da interferência de seis diferentes espécies invasoras (Bidens pilosa, Commelina benghalensis, Eleusine indica, Ipomoea grandifolia, Uruchloa brizantha e Uruchloa ruziziensis) na qualidade e produtividade de dois cultivares de grão-de-bico (BRS Aleppo e FLIP 86-77c). A interferência das plantas daninhas reduziu o período vegetativo de ambos os cultivares. A espécie Uruchloa ruziziensis influenciou negativamente o número de vagens do cultivar BRS Aleppo sugerindo ser prejudicial ao cultivo. Além disso, os resultados indicaram que há relação entre o período de convivência e o nível de infestação no número de grãos por vagem e peso de cem grãos. Contudo, apesar de todas as espécies daninhas terem afetado a produtividade dos cultivares, tal efeito foi mais sobressalente no cultivar FLIP 86-77c, sobretudo na presença de C. benghalensis, U. brizantha e U. ruzizinsis. O teor de nutrientes no grão variou de acordo com a espécie daninha analisada. C. benghalensis, E. indica, U. brizantha e U. ruziziensis apresentam maior potencial de competição, sendo responsáveis pelos maiores danos na produtividade e nas características qualitativas dos grãos.

Salinity influences all germination stages and may adversely affect the seedlings establishment in the field. This study aimed at assessing the effects of salt stress on the physiological potential of melon (Cucumis melo L.) seeds. Germination and activity of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POX) enzymes were assessed at the osmotic potentials of 0.0 MPa, -0.1 MPa, -0.2 MPa, -0.3 MPa, -0.4 MPa and -0.5 MPa. The enzymatic activity was assessed after 24 h, 48 h and 72 h of imbibition. Seed germination was zero at -0.5 MPa and 91 % and 85 % at -0.1 MPa and -0.2 MPa, respectively. In general, the activity of SOD, CAT and POX enzymes increased with the salt-induced stress, in the different times of imbibition, and these increases were more evident at -0.4 MPa and -0.5 MPa. The salt stress induced by NaCl diminishes the germination rate of melon seeds, particularly from the osmotic potential of -0.2 MPa. There is a significant increase in the activity of SOD, CAT and POX enzymes, mainly after 48 h of exposure.

Abstract: Seeds vigor can influence seed performance under stress conditions. The objectives of this study were to evaluate the effect of water and thermal stress on germination and performance of melon seedlings, and to verify if germination under stress conditions is an efficient parameter to evaluate the vigor of these seeds. Four lots of ‘Golden Mine’ melon had their initial quality characterized by germination, first count, accelerated aging and seedling emergence tests. Germination under water stress was performed on a paper moistened with PEG 6000 solution at 0.06, -0.3, -0.6 and -0.9 MPa. The percentage and speed of germination, length and dry mass of the seedlings were evaluated. For the thermal stress experiment, cold test and germination at sub- (15 ºC) and supra-optimal (35 ºC) temperatures were performed, as well as at the ideal temperature (25 ºC). The germination of melon seeds under water stress induced by PEG 6000 at -0.3 and -0.6 MPa is an efficient method to detect differences in the physiological potential of lots of melon seeds, but these differences disappear under severe water stress (-0.9 MPa). Germination under sub-optimal temperatures also allows to identify differences in seeds performance and to classify them according to the vigor level.

Abstract: Studies show the positive effect of the nitric oxide donor in the seed germination process. However, there are no precise reports about which compound present in sodium nitroprusside would cause these effects in seeds under salt stress. The aim of this study was to evaluate the effects of SNP on germination of Senna macranthera seeds under salt stress. The osmotic potentials of -0.3, -0.4, and -0.5 MPa of NaCl were used, as well as the concentration of 100 μM of sodium nitroprusside, inactive sodium nitroprusside, and ferrocyanide. The sodium nitroprusside in germination was applied before, during, and after salt stress. Germination rate, germination speed index, percentage of normal seedlings, and seedling development components were evaluated. The treatments that proved to be more promising in recovery of germination under salt stress are -0.4 MPa together with SNP; -0.4 MPa together with inactive SNP; -0.5 MPa together with SNP and -0.5 MPa together with inactive SNP. Effects similar to those brought about by the sodium nitroprusside treatment were also observed in the treatments with inactive sodium nitroprusside and ferrocyanide, indicating that the effects observed were related to release of the cyanide present in the sodium nitroprusside.

Abstract: The effects of NO donors on germination under saline stress have been much investigated for many species, however, there are reports that the effect caused by donors are effects of cyanide present. The aim of this study was to evaluate the effects of sodium nitroprusside (SNP) on germination, antioxidative system and lipid peroxidation of Senna macranthera seeds under saline stress. The osmotic potentials of -0.4 and -0.5 MPa of NaCl were used, as well as the concentration of 100 μM of sodium nitroprusside, inactive sodium nitroprusside. Germination rate, imbibition curves, antioxidant enzyme activity, lipid peroxidation, and protein content were evaluated. Similar effects were observed for sodium nitroprusside and inactive sodium nitroprusside, indicating that these effects were related to the release of the cyanide present in sodium nitroprusside. The sodium nitroprusside (SNP) improves the germination of Senna macranthera seeds under salt stress conditions, through release of cyanide. The cyanide favored germination, reducing lipid peroxidation and increasing the activity of the antioxidant enzymes.