Search

Sesame is a plant with great economic and social potential, being used for various purposes such as the food, pharmaceutical, medicinal industries, and more recently, as a source of renewable energy for the production of biofuel. One of the factors that most limit the productivity of this crop is salt stress. Based on this, the present work aimed to evaluate the germination and vigor of hybrid and creoles sesame seeds subjected to saline stress. The experiment was carried out at the Phytotechnics Laboratory of the Engineering and Agricultural Sciences Campus/UFAL. Two sesame cultivars were studied, BRS Anahí and Creole from the state of Sergipe. The seeds were aseptically treated by immersion in 70% alcohol for 1 minute, followed by washing in running water before being subjected to the treatments. To simulate salt stress, sodium chloride (NaCl) was used as a solute at concentrations of 0.0 (control); -0.1; -0.2; -0.3; -0.4 and -0.5 MPa. The material was placed, Biochemical Oxygen Demand (B.O.D.) germination type chamber, regulated at an alternate temperature of 20-30 °C. The experimental design used was completely randomized, with four replications of 25 seeds per treatments in a 2 x 6 factorial scheme (sesame cultivars x saline concentrations). Data were submitted to analysis of variance and polynomial regression, and the analyzes were performed using the SISVAR 5.6 software. The parameters evaluated were: water content, germination, first germination count, germination speed index, seedling length and dry mass. The results for the germination of sesame seeds submitted to salt stress showed that as the salinity levels increased there was a reduction in the percentage of germination of the sesame seeds studied, but until the concentration of -0.4 MPa they are within the standards allowed for commercialization of that culture. In the first count of germination, the Creoles sesame seeds showed the highest values, demonstrating better germination performance compared to BRS Anahí. In the germination speed index, BRS Anahí outperformed Creoles in all salt concentrations, except for the control. For seedling length, it was found that at the lowest salt concentrations both sesame varieties obtained the highest averages, with a significant reduction in length at the highest concentration (-0.5). The dry mass of the seedlings decreased as the water salinity increased, being more evident after the -0.3 MPa NaCl solution, especially for BRS Anahí. Thus, it can be concluded that salinity affects the physiological potential of sesame seeds, being more evident when at salt concentrations from -0.3 MPa. Creoles sesame seeds are less sensitive to saline stress.

To evaluate the physiological potential of the seeds, the tetrazolium test would be an interesting alternative, as it is a quick test that provides a detailed analysis of viability and vigor. Therefore, it is necessary to define pre-conditioning conditions, such as temperature and duration of soaking, concentration of the tetrazolium solution, and method of exposing the seeds to staining. Moringa oleifera Lam., belonging to the family Moringaceae, is widely distributed in tropical countries and easily adapted to semi-arid conditions, possessing medicinal value, as forage, condiment, in the cosmetics industry, melliferous, fuel, and in water purification treatment through the coagulant solution made from seeds. Based on the above, the objectives of the present work were to establish the most appropriate procedure for conducting the tetrazolium test to evaluate the viability and vigor of M. oleifera seeds. Only the cotyledons containing the embryo were placed in 50 mL plastic cups and immersed in a solution of 2,3,5-triphenyl chloride tetrazolium salt at concentrations of 0.05; 0.075 and 0.1% for staining periods of 1, 2, and 3 hours in a Biochemical Oxygen Demand chamber at 30 ºC in the dark. The seeds were evaluated one by one for tissue condition (firm or flaccid) and seed color, and by the location and size of the lesions on the cotyledon and embryonic axis. For the standardization of the tetrazolium test, the Completely Randomized Design was used in a 3x3+1 factorial scheme (three concentrations of tetrazolium solution x three staining periods + control = germination test) with four repetitions of 25 seeds. M. oleifera seeds were found to have a high germination rate (100%), there was no significant difference between the control and the percentage of viable seeds (TZ) for the 2 and 3 hours staining periods, immersed in tetrazolium solution at concentrations of 0.075 (96%) and 0.05% (99%), respectively. The most appropriate procedure for conducting the tetrazolium test to assess the viability and vigor of M. oleifera seeds is to use a concentration of 0.05% for 3 hours of salt immersion

Phenology works as an indicator of the response of plants to local climatic and edaphic conditions, enabling a better understanding of the dynamics of the species. The seasonal climate also influences the occurrence of periodic rhythms of growth and reproduction (phenophases). Moringa oleifera Lam., belong to the Moringaceae family, is widely distributed in tropical countries and easily adapts to semiarid conditions, having medicinal value as a forage, flavoring, in the cosmetics, honey, fuel and in the treatment of water purification through the coagulant solution made from the seeds. The objectives of the present work were to study the phenological behavior of M. oleifera and to relate the variations in phenophases with climatic factors, precipitation and temperature. For collection of phenological data, ten trees were selected, and the records were carried out between the first half of August 2020 and the first half of July 2021. The observations were carried out at fortnightly intervals, recording the presence and absence of the flowering and fruiting phenophases including flowering – period in which the tree is in full flowering; fructification – which starts from the moment that small fruits are visible after the fertilization of the flowers and ends with the dispersal of seeds. The Fournier intensity index was determined using a semiquantitative interval scale of five categories (0 to 4), with an interval of 25% between each category. The phenological data of intensity of each phenophase (flowering and fruiting) were related to precipitation and average temperature fortnightly using Spearman's correlation. The flowering and fruiting phenophases of M. oleifera intensified in August, September and December 2020, showing Fournier intensity peaks of 47.5 and 77.5, 72.5 and 92.5, and 35 and 55 %, respectively, and April and June 2021, in the monthly intervals of greater rainfall, with percentage rates of 82.5 and 95, 77.5 and 80%, respectively. In general, we found that M. oleifera produced seeds between the first half of August and the first half of September, and the second half of December 2020, and the second half of April and the first half of June 2021. Thus, it can be stated that the production of fruits by M. oleifera is interrupted in the months with less rainfall (October to November 2020, and January to February 2021). The intensity and duration of the flowering and fruiting phenophases in M. oleifera are synchronized with the temporal distribution of the precipitation pulses in that habitat

The objective of this work was to evaluate the effects of brassinosteroid on chlorophyll a fluorescence parameters, the SPAD index, and leaf succulence in young tomato (Lycopersicon esculentum) plants under salt stress. The experimental design was a randomized complete block, in a 5×2 factorial arrangement - five levels of water salinity (0.5, 1.5, 3.0, 4.5, and 6.0 dS m-1) × two rates of 24-epibrassinolide (0 and 10-6 mol L-1 EBL). At 23 days, the treatment without EBL showed that the increase of water salinity reduced the maximum, primary, and effective photochemical efficiency of PSII, as well as the electron transport rate, the SPAD index, leaf succulence, total dry mass, and the stress tolerance index, but increased initial fluorescence and relative excess energy in PSII. With the increase of water salinity, in the EBL treatments, there was an increase in the effective photochemical efficiency of PSII, the electron transport rate, the SPAD index, leaf succulence, total dry mass, and the stress tolerance index. EBL promotes beneficial effects on PSII integrity, the chlorophyll index, and leaf succulence in young tomato plants subjected to salinity levels of up to 6.0 dS m-1 . Resumo O objetivo deste trabalho foi avaliar os efeitos de brassinosteroide sobre os parâmetros de fluorescência da clorofila a, o índice SPAD e a suculência foliar em plantas jovens de tomate (Lycopersicon esculentum) sob estresse salino. O delineamento experimental utilizado foi o em blocos ao acaso, em arranjo fatorial 5×2 - cinco níveis de salinidade da água (0,5, 1,5, 3,0, 4,5 e 6,0 dS m-1) × duas doses de 24-epibrassinolídeo (0 e 10-6 mol L-1 de EBL). Aos 23 dias, o tratamento sem EBL mostrou que o aumento da salinidade da água reduziu a eficiência fotoquímica máxima, primária e efetiva do PSII, assim como a taxa de transporte de elétrons, o índice SPAD, a suculência foliar, a massa de matéria seca total e o índice de tolerância ao estresse, mas aumentou a fluorescência inicial e o excesso relativo de energia no PSII. Com o aumento da salinidade, nos tratamentos com EBL, houve aumento da eficiência efetiva do PSII, da taxa de transporte de elétrons, do índice SPAD, da suculência foliar, da matéria seca total e do índice de tolerância ao estresse. O epibrassinolídeo promove efeitos benéficos sobre a integridade do PSII, o índice de clorofila e a suculência foliar em plantas jovens de tomate submetidas a níveis de até salinidade 6,0 dS m-1.

The present study was carried out with the objective of evaluating the ecological and applied aspects of temperature in the germination of Colubrina glandulosa (Rhamnaceae), Chloroleucon dumosum (Fabaceae), Enterolobium contortisiliquum (Fabaceae), Mimosa bimucronata (Fabaceae) and Sapindus saponaria (Sapindaceae). Then we assessed germination, average germination time, germination uniformity and germination activation energy as a function of temperatures. The experiment was conducted at the Plant Propagation Laboratory, on the Engineering and Agricultural Sciences Campus, at the Federal University of Alagoas, Rio Largo, AL, Brazil. The experimental design was completely randomized with four replications of 25 seeds per treatment. The data were subjected to analysis of variance and the means were compared using the Tukey test at 5% probability. The isothermal incubation was performed in Biochemical Oxigen Demand (B.O.D.) germination chamber, at constant temperatures of 5, 10, 15, 20, 25, 30, 35 and 40 ºC and alternating at 20-30 ºC. The seeds of C. glandulosa, C. dumosum, E. contortisiliquum and M. bimucronata germinated in the range of 10 ºC ≤ T ≤ 35 ºC, and S. saponaria germinated in the range of 20 ºC ≤ T ≤ 35 ºC. We found that seeds in the optimal temperature range has unimodal distribution of relative frequency, concentrating germination in the shortest time. The activation energy was positive in the range of 10 ºC ≤ T ≤ 30 ºC, with an inversion of the signal at a temperature of 35 ºC. The studied species had a wide range of temperature tolerance and the speed was curvilinearly dependent on them. The germination process is predominantly endergonic

For most forest species the irregularity of fruiting, low seed production and spatial distribution of trees, make it impossible to supply seeds to meet seedling production programs. On the other hand, to prevent subsequent years of low production and maintain seed viability, it is necessary to adopt adequate storage procedures. Therefore, the objectives of the study were to evaluate the influence of water content and storage conditions on the physiological potential of seeds of Colubrina glandulosa Perkins (Rhamnaceae), Chloroleucon dumosum (Benth.) G.P. Lewis (Fabaceae), Enterolobium contortisiliquum (Vell.) Morong (Fabaceae), Mimosa bimucronata (DC.) O. Kuntze (Fabaceae) and Sapindus saponaria L. (Sapindaceae), which are native tree species in tropical forests in South America. The seeds were placed in paper packaging and glass packaging and stored in a laboratory environment (uncontrolled), during storage periods of zero (recently harvested), three, six, nine, 12 and 15 months. For each storage period, the water content and physiological potential of the seeds were evaluated. The design was entirely randomized with four repetitions of 25 seeds. The germination (G) and germination uniformity (U) data were subjected to analysis of variance in a 2 x 6 factorial arrangement (two types of packaging x six storage periods), and application of polynomial regression. Seeds of Colubrina glandulosa, Chloroleucon dumosum, Enterolobium contortisiliquum, Mimosa bimucronata and Sapindus saponaria, packed in paper packaging or glass packaging, and stored under uncontrolled conditions of natural environment, presented higher G and U, in the storage period of 15 months. The physiological potential of the seeds can be maintained for a long time, as long as they are packed in a glass container with an adequate initial water content. With a water content of 8.2, 8.1, 7.9, 8.4% and 12.1%, the seeds of Colubrina glandulosa, Chloroleucon dumosum, Enterolobium contortisiliquum, Mimosa bimucronata and Sapindus saponaria, respectively, maintain the viability during storage. Therefore, the solution to store these seeds would be to rigorously dry them, and then use waterproof packaging. It is recommended that for the storage of seeds of these tree species, they are previously packaged in glass containers

Made available in DSpace on 2022-04-28T19:52:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-05-01 Due to the expansion of planted forests, Eucalyptus may end up being planted in saline soil areas. The aim of this study was to assess ion accumulation, antioxidant activity and the growth and tolerance indices of Eucalyptus clones as indicators of salt tolerance. This study used a randomized block design in a 3 × 4 factorial scheme consisting of three Eucalyptus clones (VC865, I224 and I144) and four concentrations of NaCl (0, 1, 2 and 3 g of NaCl kg−1 of soil) with five repetitions. The Eucalyptus clones responded differently to soil salinity: I144 showed lower declines in Ψw, K+ concentrations, leaf dry weight and stem dry weight. In addition, a lower Ψs was associated with an increase in Na+ and proline and a low Na+/K+ ratio, indicating greater osmotic adjustment. This clone, considered the most tolerant to soil salinity, also exhibited greater superoxide dismutase, ascorbate peroxidase and catalase antioxidant enzymes activity, higher relative increment and tolerance indices and lower hydrogen peroxide and lipid peroxidation content. However, the clones VC865 and I224 are moderately tolerant and sensitive, respectively. Based on the soil salinity variables, Eucalyptus clones were classified in the following order of tolerance: I144 > VC865 > I224. Laboratório de Fisiologia Vegetal Centro de Engenharias E Ciências Agrárias Universidade Federal de Alagoas, BR 104 Norte, km 85, Alagoas Laboratório de Ecofisiologia Aplicada à Agricultura Faculdade de Ciências Agronômicas Universidade Estadual Paulista Júlio de Mesquita Filho, Avenida Universitária, 3780, 18610-034, Altos do Paraíso, SP Laboratório de Ecofisiologia Aplicada à Agricultura Faculdade de Ciências Agronômicas Universidade Estadual Paulista Júlio de Mesquita Filho, Avenida Universitária, 3780, 18610-034, Altos do Paraíso, SP

Sugarcane is one of the most important crops in the world, but subject to yield losses caused by sporadic droughts during the growing season. To mitigate the effects of drought stress, different strategies have already been used, including the foliar application of glycine betaine (GB). Thus, the present study aimed to evaluate the effect of GB spraying via leaf on gas exchange, chlorophyll fluorescence and on the sugarcane water status subjected to drought stress and rewatering. The experiment was carried out in a greenhouse, using the RB92579 sugarcane variety. A randomized block design was used, in a 3 × 2 factorial scheme, composed of three GB applications (G0—without GB, G1—one application and G2—two applications) and two water treatments: irrigated (Control) and non-irrigated (Drought Stress), with subsequent rewatering. The foliar application of GB minimized the impact of drought stress on gas exchange, on the photochemical efficiency of photosystem II (PSII) and leaf tissue water status in stressed plants. In addition, it favored the energy use in the PSII and reduced photoinhibition, a fact not observed in the G0 stressed plants. Thus, it can be inferred that the GB foliar application mitigates the negative effects of drought stress on gas exchange and photochemical apparatus of PSII in young sugarcane plants.

O presente trabalho teve como objetivo avaliar o efeito de diferentes concentracoes salinas na agua de irrigacao sobre a emergencia e o crescimento inicial de mudas de Libidibia ferrea, considerada de grande importância na recuperacao de areas degradadas em regioes do Nordeste brasileiro, onde e intensamente explorada por possuir cerne duro, acarretando uma madeira de elevada densidade. Os experimentos foram conduzidos no laboratorio de propagacao de plantas pertencente ao Centro de Engenharias e Ciencias Agrarias, da Universidade Federal de Alagoas, sendo conduzidos sob delineamento em blocos casualizados, com cinco blocos e cinco repeticoes, totalizando 25 parcelas experimentais. Os regimes de teor de salinidade na agua para irrigacao adotados foram: controle, semi-moderado, moderado, semi-severo e severo (0, 1, 2, 3 e 4 g de NaCl/L, respectivamente). Foram avaliados, percentagem de emergencia e indice de velocidade de emergencia, bem como o numero de folhas, altura da planta, diâmetro do caule e indice SPAD. Ao final do experimento, as mudas foram seccionadas em folha, caule e raiz, para se determinar a massa secada raiz, parte aerea e total. O incremento da salinidade afetou negativamente todas as variaveis estudadas, indicando que as mudas de pau-ferro foram sensiveis a salinidade.

Made available in DSpace on 2022-04-28T19:51:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-01-01 Fundação de Amparo à Pesquisa do Estado de Alagoas This study aimed to adapt the methodology of the electrical conductivity test to detect differences in vigor between seeds of Libidibia ferrea of different masses. The seeds were classified according to their individual mass: small seeds ≤ 0.14 g, medium seeds 0.15 ≤ x ≤ 0.19, large seeds ≥ 0.20 g. Subsequently, seed morphology (length, width, thickness, water content, and weight of 1000 seeds), and the initial physiological potential of the seeds (germination, first count, average time, average speed, germination rate coefficient, germination and emergence rate index, emergence percentage, seedling length, and dry mass) were determined. The electrical conductivity was conducted in a 3 × 12 factorial scheme with three seed masses and 12 immersion periods (2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, and 24 h), in volumes of 50 and 75 mL of water, with 25 and 50 seeds, respectively. The physical and physiological variables of the seeds were highly correlated with the electrical conductivity test. The seed mass of L. ferrea has a direct relationship with its physiological potential, with the seeds of mass ≥ 0.20 g classified with high vigor; the seeds of mass 0.15 ≤ x ≤ 0.19 with intermediate vigor; and the seeds of mass ≤ 0.14 g with low vigor. The electrical conductivity test is efficient in the evaluation of the physiological potential of L. ferrea seeds of different masses when conducted with 25 seeds soaked in 50 mL of distilled water for 4 h. Federal University of Alagoas - Engineering and Agrarian Science Campus, AL, BR-104,Km 85,s/n,Mata do Rolo Federal University of Agreste of Pernambuco, PE, Avenue Bom Pastor,s/n,Garanhuns Departament of Production and Plant Breeding - São Paulo State University “Júlio de Mesquita Filho”, SP, Avenue Universitária,3780,Altos do Paraíso Departament of Production and Plant Breeding - São Paulo State University “Júlio de Mesquita Filho”, SP, Avenue Universitária,3780,Altos do Paraíso

Sugarcane cultivar RB0442 has a high yield, late maturation and good drought tolerance. It is recommended for planting in restrictive environments, mainly with water-deficient soils, and is resistant to the major sugarcane diseases of the Northeastern region of Brazil.

The objective of the present study was to evaluate the effects of the application of treated sewage sludge on the initial development of soybean plants (Glycine max L.). Seven treatments were used: (T1) only the soil (absolute control); (T2) soil + residue at the dose of 5.0 g/dm3; (T3) soil + residue at a dose of 10.0 g/dm3; (T4) soil + residue at the dose of 15.0 g/dm3; (T5) soil + residue at the dose of 20.0 g/dm3; (T6) soil + residue at the dose of 25.0 g/dm3; and (T7) culture with PK. The variables of emergence, first count and emergence speed of seedlings, green mass, shoot length, root length, dry shoot mass and dry root mass of the plants were analyzed. The experimental design was in randomized blocks, with four replicates of 25 plants for each treatment. The use of the organic residue positively influenced the characteristics observed in relation to the control and the PK, and in the appropriate dose, it can be recommended as an input and soil conditioner. Sewage sludge presents high potential as a fertilizer for soybean cultivation.

This study aimed to characterize the maturation stages of the papaya fruits and to evaluate the physiological quality of papaya seeds produced in an agroforestry system as a function of postharvest maturation. Papaya fruits were used (Carica papaya L.) from two groups, Formosa Tainung 1 and Solo Sunrise Solo, harvested at maturation stage I (up to 15% of the yellow bark). The seeds were obtained, without sarcotesta: soon after harvest (T1); 14 days after standing at room temperature (T2); and 14 days after standing at 10 °C (T3). The variables analyzed included: germination, first count, speed, and mean germination time and length of seedlings. The experimental design was completely randomized, in a 2 × 3 factorial scheme (2 groups and 3 rest periods), with 4 replicates of 50 seeds for each treatment. The papaya fruits produced maximum germinating seed in a less average time at room temperature and maturation stage V and the final stage (76%–100% of the yellow bark), allowing maximum number of seedlings with greater vigor. Fruits in stage I impaired the physiological quality of the seeds. The agroecological production presented a systemic approach in the management of papaya.

Maricá (Mimosa bimucronata (D.C.) O. Kuntze.) is a species that presents great importance in reforestation programs, in the recovery of permanent preservation areas, landscaping projects and is considered soil improver, being recommended for erosion and for planting on flooded land. The objective of the present study was to evaluate the viability of the seeds of M. bimucronata by the tetrazolium test and to determine the crude oil content and the percentage composition of fatty acids. The experiments were conducted at the Plant Propagation Laboratory of the Agricultural Sciences Center (CECA) of the Federal University of Alagoas (UFAL), located in the municipality of Rio Largo, Alagoas, Brazil. The obtained data submitted to the analysis of variance and the comparison between the means of viable seeds for each of the combinations in the tetrazolium test were performed by the Dunnett test at 5%. The concentration of 0.075% tetrazolium salt for two hours at 35 °C is an efficient combination for evaluating the viability of M. bimucronata seeds. The oil content was 2.75%, with unsaturated fatty acids prevailing (63.8%).

O objetivo deste trabalho foi caracterizar a morfometria de sementes, padronizar o teste de germinação e identificar a condição ideal de armazenamento das sementes de Triplaris brasiliana Cham., uma espécie pioneira, com grande potencial para recuperação de áreas degradadas, de preservação permanente, áreas de mata ciliar e terra firme. Para a caracterização morfométrica, determinou-se o comprimento e espessura, massa de 1000 sementes, coloração, formato e localização do hilo e da micrópila, tipo de embrião, sua localização e tipo de germinação. O teste de germinação foi avaliado a partir das sementes com e sem escarificação em diferentes temperaturas. O armazenamento foi testado em embalagens de vidro e papel e em condições de geladeira, câmara seca e ambiente. O embrião é axial, sendo o eixo embrionário localizado na parte central da metade inferior da semente, a germinação é do tipo epígea e as plântulas são fanerocotiledonares. A semeadura das sementes escarificadas sobre papel submetida à temperatura de 30°C foi favorável para germinação e desenvolvimento das plântulas de Triplaris brasiliana, sendo as sementes sensíveis à desidratação (intermediária), preservando sua qualidade fisiológica por mais tempo, quando armazenadas em geladeira e câmara seca, nas embalagens utilizadas.

The sugar-energy sector is highlighted in Brazilian agribusiness; however, poor water distribution and soil acidity have limited the yield and quality of cane fields. Gypsum improves the physical and chemical properties of the soil, attenuating the effects of water shortage and acidity in the edaphic environment. The aim of this study was to determine the effect of gypsum doses on the nutritional status, photochemical efficiency and technological quality of sugarcane. The experiment was conducted under field conditions using a randomized block design in a 3 x 5 factorial scheme with four replications. The treatments consisted of the combination of three sugarcane varieties (RB011941, RB92579, and RB991536) with five doses of gypsum (0 Mg ha-1; 2.5 Mg ha-1; 5.0 Mg ha-1; 10 Mg ha-1; and 20.0 Mg ha-1). The results showed that gypsum did not influence the evaluated variables. A varietal effect for leaf contents of P, K, Mg and S was observed. The RB92579 presented the highest levels of P (1.65 g kg-1) and K (14.55 g kg-1), while RB011941 showed the highest concentrations of Mg and S, 1.25 and 1.05 g kg-1, respectively. The mean values of the macronutrients presented the following concentration order: N > K > Ca > Mg > P > S. Genotypes were similar in terms of photochemical efficiency, which in turn, was not influenced by gypsum application. The best technological quality was verified in RB92579, which showed the highest Brix percentage (22.35%), Pol (19.75%), and the highest levels of TRS (151.3 kg t-1) of sugarcane.

The marica ('Mimosa bimucronata' (DC) O. Kuntze) is a forest species, belonging to the family Fabaceae, considered endemic to the Atlantic Forest biome. The present work aimed to study the germinative behavior of 'M. bimucronata' seeds under different temperatures and light qualities, as well as to evaluate the effect of the amount of water (humidity) in the substrate and the osmoconditioning during germination. Thus, the experiment was performed using a completely randomized design. The treatments were distributed in a 4 x 4 factorial scheme (temperatures and light qualities), with 4 replicates of 25 seeds each. The means were compared by Tukey's test at 5% probability. The volume of water and osmoconditioning of substrate was evaluated and data were subjected to regression analysis. The following variables were analyzed: first count of germinated seeds, germination, germination speed index, and electrical conductivity. The results revealed that seeds are neutral photoblasts, needing a constant temperature of 30 degreesC along with a white light for appropriate germination and vigor. Seeding on two sheets of paper towel moistened with water volume (mL) from 2.62 to 2.70 times was more suitable for conducting the germination test. The osmotic conditioning was inefficient in maintaining germination of these seeds.

The objectives of the present study were to morphologically characterize the seeds, study post-seminal development, and report the best treatment to overcoming dormancy of colubrina (Colubrina glandulosa Perkins). Eight replicates of 100 seeds were weighed and the length, width, and thickness of each seed were measured for the physical characterization. External and internal aspects were considered for the morphological description of the seeds. Seven pre-germination treatments were used to overcoming dormancy: (T1) intact seeds; immersion in sulfuric acid for 60 (T2) and 90 min (T3); (T4) manual scarification in the region opposite the hilum; (T5) immersion in water at 80 degreesC, followed by standing in the same water outside the heat for 24 hours at room temperature; and immersion in distilled water for 24 (T6) and 48 hours (T7). The germinative process was recorded for 19 days in the post-seminal study. The variables analyzed were germination, first count, speed, average germination time, germination uncertainty and synchrony, seedling length, and dry mass. This was a completely randomized designed study, with four replicates of 25 seeds in each treatment. The seeds were morphologically highly variable. The testal and the embryo were the invaginated type. Germination was epigeal and the phanerocotyledonal type. Manual scarification induced maximum germinability in the mean time, resulting in a unimodal distribution of the relative frequency and high synchronization of germination, which allowed for the maximum number of highly vigorous seedlings. These results indicate a treatment for overcoming dormancy in C. glandulosa.

This study aimed to characterize the biometric characteristics of Mimosa bimucronata (DC.) O. Kuntze seeds and to elucidate their physiological characteristics with respect to the effect of treatme...

Sugarcane (Saccharum spp) is an expanding culture for the production of bioethanol around the world which requires certain practices to improve its productive performance at the different ecosystems. This work's aim is to evaluate the initial Sugarcane growth and drought tolerance through the application of biostimulants. For this purpose an experiment was conducted in a greenhouse using completely randomized design. Prior to planting, the cuttings were treated with: T1 - Water; T2 - Indolebutyric Acid (IBA); T3 - Boron + Zinc; T4 - Tryptophan; T5 - Kymon Plus® + Potamol®; and T6 - Stimulate®. Morphological analysis was performed at 40 and 124 days after planting (DAP) to assess the plant initial growth. The biostimulants effect on drought stress mitigation was evaluated at 120 DAP, after 3 days of suppression irrigation. The IBA and Stimulate® application delivered higher growth rates and biomass accumulation. When compared to Control treatment, the application of Ubyfol® and Stimulate® provided higher photosynthesis in the absence of drought stress and had higher PSII effective quantum yield even when plants were under drought stress. The application of Stimulate® enabled plants to maintain higher photosynthetic, transpiration and stomatal conductance rates under moderate drought stress. Key words: Drought stress, photosynthesis, Saccharum spp, transpiration

A major challenge in sugarcane breeding program is the obtaining of enough number of seeds (caryopses) for the development of new improved cultivars. Genotypes differ in their function as pollen recipient and pollen donor, which also affect the seed performance. Thus, the aim of this study was to verify the production and performance of sugarcane seeds from different hybridizations involving RB92579 as pollen recipient and pollen donor. Twelve bi-parental crossings were carried out involving RB92579 and other different genotypes randomly chosen. Seed production potential was evaluated by percentage of fertile spikelets and caryopsis fresh weight. The seed physiological potential was determined by evaluating germination and vigor (index of germination rate, number of normal seedlings per gram of fuzz, and seedling dry weight). The results showed better performance for RB92579 as pollen donor for all characteristics studied. Therefore, RB92579 sugarcane cultivar should be used as pollen donor during hybridizations, condition that permits a greater production and physiological performance of seeds for the sugarcane breeding programs.

Nos canaviais, espécies do gênero Euphorbia são relatadas como plantas daninhas capazes de reduzir a produtividade em até 85%. Para traçar estratégias corretas de controle dessas plantas é necessário o conhecimento tanto da sua biologia quanto do seu crescimento. Assim, objetivou-se com este trabalho avaliar o crescimento de três espécies daninhas do gênero Euphorbia ocorrentes nos canaviais. O estudo foi realizado em casa de vegetação, utilizando delineamento experimental inteiramente casualizado, em esquema de parcela subdividida, com cinco repetições. Os fatores foram três espécies de Euphorbia (E. heterophylla, E. hyssopifolia e E. hirta) e 13 períodos de avaliação: 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, 84, 91 e 98 dias após a semeadura (DAS). Em cada avaliação foram mensuradas a altura da planta (AP), a área foliar (AF), o número de folhas (NF) e a matéria seca total (MST). Com valores médios de matéria seca da parte aérea (MSPA), MST e AF foram calculadas as taxas de crescimento absoluto (TCA) e relativo (TCR), a razão de área foliar (RAF) e a razão massa foliar (RMF). Os dados foram submetidos à análise de variância e à regressão não-linear. E. heterophylla foi maior em AP até os 63 DAS, a partir desse ponto, E. hyssopifolia ultrapassou obtendo maior altura dentre as espécies estudadas. E. heterophylla destacou-se por ter maior acúmulo de AF, MST e TCA dentre as espécies estudadas, seguida da E. hyssopifolia e E. hirta. O ponto máximo de crescimento das espécies avaliadas ocorreu aos 77 DAS. Dentre as espécies estudadas, E. heterophylla apresenta maior crescimento e desenvolvimento.

Tabebuia aurea (Benth. & Hook. f. ex S. Moore) (Bignoniaceae) is a boreal species common in Brazil. It is used for ornamental parks and along sidewalks. Its timber is also used for furniture. The objective of this study was to evaluate the effect of nursery shading on the growth and photosynthesis of T. aurea and their photosynthetic adaptation after being transferred to direct sunlight. The T. aurea seedlings were grown under 0, 50, 70 or 95% shade. The photosynthetic active radiation and leaf gas exchange were measured over two distinct periods: 51 (young seedlings) and 70 days after having been sown under each shade treatment. Immediately after the measurements were taken, the seedlings were transferred into full sunlight and the measurements were repeated two times after 15 min and 3 days under ambient sunlight. T. aurea seedlings showed satisfactory growth up to 50% shade in the nursery, which could be verified both by growth measurement and by total biomass accumulation. Shading greater than 70% reduced the number of leaves, the leaf area and the stem diameter in relation to plants exposed to full sunlight. The results suggest that T. aurea seedlings should be grown under full sunlight or under shading up to 50% to maximize their growth in the nursery and to minimize stress when transferring the seedlings to their final planting sites.

This study aimed to compare the physiological adaptations of Jatropha curcas in two regions with different climates, the Agreste (a semi-arid tropical climate) and the Florest zone (a semi-humid tropical climate) subject to water stress. Measurements of gas exchange and photochemical and biochemical efficiency were performed in two seasons, the dry season (September to February) and the rainy season (April and August), between 2006 and 2007. During the dry season in the Florest zone, the J. curcas plants presented better photosynthetic performance, with smaller decreases in the rates of photosynthesis, stomatal conductance and transpiration because the conditions of water availability in the soil were slightly higher than in the semi-arid region. A greater vapor pressure deficit was observed during the dry season of the semi-arid region, showing a negative correlation with the stomatal opening of the leaves, which contributed to a reduction in the values of the net photosynthetic rate. During the dry season in the semi-arid region, dynamic photoinhibition occurred in the leaves of J. curcas around mid-day, with a rapid recovery during the afternoon. However, chronic photoinhibition may have occurred in some plants with a severe water deficit. A reduction in the effective quantum efficiency was also observed during the driest months. The increase of catalase activity and the accumulation of proline, total soluble sugars and amino acids during periods of low water availability in the soil suggest that J. curcas presents an efficient protection mechanism that allows the plant to survive under drought conditions.

Castor bean is one of the crops with potential to provide raw material for production of oils for biodiesel. This species possess adaptive mechanisms for maintaining the water status when subjected to drought stress. A better understanding these mechanisms under field conditions can unravel the survival strategies used by this species. This study aimed to compare the physiological adaptations of Ricinus communis (L.) in two regions with different climates, the semi-arid and semi-humid subject to water stress. The plants showed greater vapor pressure deficit during the driest hours of the day, which contributed to higher values of the leaf temperature and leaf transpiration, however, the VPD(leaf-air) had the greatest effect on plants in the semi-arid region. In both regions, between 12:00 p.m. and 2:00 p.m., the plants presented reduction in the rates of photosynthesis and intracellular CO2 concentration in response to stomatal closure. During the dry season in the semi-arid region, photoinhibition occurred in the leaves of castor bean between 12:00 p.m. and 2:00 p.m. These results suggest that castor bean plants possess compensatory mechanisms for drought tolerance, such as: higher stomatal control and maintenance of photosynthetic capacity, allowing the plant to survive well in soil with low water availability.