Influência do manitol e NaCl na germinação de sementes de duas espécies de leguminosas com importância no semi-árido baiano

The present work studied the germinative response of seeds of Cenostigma gardnerianum Tul. and Anadenanthera colubrina (Vell.) Brenan, of the Family Fabaceae, under conditions of water and saline stress that are often present in the semi-arid region of Northeastern Brazil. The water stress obtained with manitol solution and the saline stress obtained with NaCl solution were tested by means of different osmotic potentials. The experiment was conducted in a box lined with paper filter and 50 seeds for each potential of each treatment. Material was kept in a germinating chamber at 25°C, in 10h of light alternating with 14h of darkness. Percent germination and average rate of germination were measured daily, beginning after ten days. The germination of the seeds diminished as the osmotic potential of the solutions of the two types of stresses diminished. The species demonstrated an acclimation to the drought conditions, because the decreases in osmotic potential typically had been limited between -0.2 to the -0.8 MPa.Foi objetivo do presente trabalho estudar a resposta germinativa de sementes de Cenostigma gardnerianum Tul. e Anadenanthera colubrina (Vell.) Brenan, pertencentes à família Fabaceae, a condições de estresse hídrico e salino que estão freqüentemente presentes na região semi-árida do nordeste brasileiro. O estresse hídrico obtido com solução de manitol e salino com solução de NaCl foram testados por meio de diferentes potenciais osmóticos (0,0 a -1,4 MPa). O experimento foi conduzido em caixa tipo gerbox forradas com papel filtro e com um lote de 50 sementes para cada potencial de cada tratamento. Este material foi mantido em um germinador sob temperatura de 25°C, com 10h de luz e 14h de escuro. As avaliações foram feitas diariamente durante dez dias e posteriormente foram calculadas as porcentagens de germinação, velocidade média de germinação, tempo médio de germinação e velocidade de germinação. A germinação das sementes foi diminuída à medida que o potencial osmótico das soluções dos dois tipos de estresses era menor. As espécies demonstraram uma adaptação às condições de seca, já que os decréscimos em potencial osmótico foram tipicamente limitados entre –0,2 a –0,8 MPa

Produção biossalina de mudas de espécies florestais nativas da Caatinga

The Caatinga dry forest species are well adapted and resilient to the climatic conditions of the Brazilian semiarid region. However, this is one of the more vulnerable ecosystems to climate change, due to increasing deforestation and drought in the last years.Water shortage in this region has prompted studies into the possibility of safe brackish water use/reuse for forage and forest seedling production. We tested, in this study, alternative sources to potable water to irrigate forest seedlings in nurseries, which have high water expenditure. The trail was performed in a completely randomized design with three irrigation water sources and four replications with five seedlings. Biosaline fish cropping water; brackish groundwater and tap water were used for irrigation of seedlings of Anadenanthera colubrina, Erythrina velutina and Aspidosperma pyrifolium, grown in a screened nursery greenhouse in polyethylene bags filled with sand and soil (1:1 v/v). Seed germination and seedlings growth were evaluated for up to 80 days. Results showed that irrigation with biosaline fish farming waste water with electrical conductivity values > 6 dS.m-1 did not compromise the seed germination nor the seedlings growth in nursery. Brackish ground water, however, slowed the development of seedlings. Faced with the possibility of water shortages due to climate change, the use of non-potable sources of water, can therefore, be an alternative and low input technique for the production of seedlings of native species from Caatinga.As espécies florestais da Caatinga estão adaptadas e são resilientes às condições climáticas da região semiárida brasileira. No entanto, este é um dos ecossistemas mais vulneráveis às mudanças climáticas, devido ao aumento do desmatamento e à seca dos últimos anos. A escassez de água nessa região induziu estudos sobre a possibilidade de utilização/reutilização segura da água salobra para a produção de forragem e de mudas florestais. Testaram-se, nesse estudo, fontes alternativas à água potável para irrigação de mudas florestais em viveiros, que apresentam elevado gasto de água. O ensaio foi realizado em delineamento inteiramente casualizado com três fontes de água para irrigação e quatro repetições de cinco plântulas. Água biossalina, provinda de cultivo de peixe; água subterrânea salobra e água de abastecimento foram utilizadas para irrigar mudas de Anadenanthera colubrina, Erythrina velutina e Aspidosperma pyrifolium, cultivadas em viveiro telado em embalagens de polietileno preenchidas com areia e solo (1:1, v/v). A porcentagem de germinação das sementes e o crescimento das mudas foram avaliados até 80 dias. Os resultados mostraram que a irrigação com água biossalina residual de piscicultura, com valores de condutividade elétrica < 6 dS.m-1 não comprometeu a germinação das sementes, nem o crescimento de mudas em viveiro. A água salobra subterrânea reduziu a velocidade de desenvolvimento das mudas. Diante a possibilidade de escassez de água devido às mudanças do clima, o uso de fontes não potáveis de água pode, portanto, ser uma técnica alternativa de baixo custo, para a produção de mudas de espécies da Caatinga

Germinative metabolism of Caatinga forest species in biosaline agriculture

The production of seeds and seedlings by these species is of utmost importance to prevent a loss of biodiversity of the Caatinga, a unique and exclusively Brazilian biome. Biosaline agriculture is conducted over a range of salinity levels in groundwater and/or in soils. The current study evaluated the application of biosaline agriculture to Anadenanthera macrocarpa, Myracrodruon urundeuva, Aspidosperma pyrifolium and Erythrina velutina by examining the germinative metabolism of seeds subjected to different electrical conductivities (ECs) of NaCl solutions and biosaline water. The seeds were germinated in biosaline water (4.94 dS.m-1) and in NaCl solutions with ECs of 0, 2, 4, 6, 8, 10, 12, 14, 16 and 18 dS.m-1 at 25 ºC, 12-h photoperiod. The kinetic variables of germination were assessed, and the seeds and seedlings were assayed for reserve biomolecules, proline content and antioxidant enzyme activity. The seeds were highly tolerant to salinity, with germination-limiting ECs above 12 dS.m-1. Although high EC promoted alterations in seed metabolism that enabled salinity tolerance, seedling production was indicated with ECs no higher than 6 dS.m-1. These results demonstrated that Caatinga seedling production is viable through biosaline agriculture beucause the groundwater salinity of this region is within the tolerance levels of the seeds

Activity of antioxidant enzymes and proline accumulation in Erythrina velutina Willd. seeds subjected to abiotic stresses during germination

The aim of this study was to evaluate the effect of different abiotic stresses on the activity of antioxidant enzymes and on accumulation of proline in Erythrina velutina Willd. seeds during germination. Mulungu seeds were scarified and placed to germinate at constant temperatures of 15, 25, and 35 ºC, moistened with distilled water, and exposed to 12 h of light. Other seeds were exposed to solutions of NaCl (EC of 0, 4, and 8 dS.m-1) and polyethylene glycol (osmotic potentials of 0.0, -0.2, and - 0.6 MPa) and maintained in a germination chamber set at 25 ºC and 12 h photoperiod for seven days. At the end of each period of imbibition, the embryonic axis and cotyledons of the seedlings were collected separately and used to quantify proline content and the activity of antioxidant enzymes. These were detected in both the cotyledons and embryonic axis of the mulungu seeds. Antioxidant activity varied depending upon the type and degree of stress applied. It was concluded that under the aspect of the detoxification process, the mechanism found in mulungu seeds is more efficient when subjected to different temperatures followed by salt stress and water stress

Germinative metabolism of Caatinga forest species in biosaline agriculture

The production of seeds and seedlings by these species is of utmost importance to prevent a loss of biodiversity of the Caatinga, a unique and exclusively Brazilian biome. Biosaline agriculture is conducted over a range of salinity levels in groundwater and/or in soils. The current study evaluated the application of biosaline agriculture to Anadenanthera macrocarpa, Myracrodruon urundeuva, Aspidosperma pyrifolium and Erythrina velutina by examining the germinative metabolism of seeds subjected to different electrical conductivities (ECs) of NaCl solutions and biosaline water. The seeds were germinated in biosaline water (4.94 dS.m-1) and in NaCl solutions with ECs of 0, 2, 4, 6, 8, 10, 12, 14, 16 and 18 dS.m-1 at 25 ºC, 12-h photoperiod. The kinetic variables of germination were assessed, and the seeds and seedlings were assayed for reserve biomolecules, proline content and antioxidant enzyme activity. The seeds were highly tolerant to salinity, with germination-limiting ECs above 12 dS.m-1. Although high EC promoted alterations in seed metabolism that enabled salinity tolerance, seedling production was indicated with ECs no higher than 6 dS.m-1. These results demonstrated that Caatinga seedling production is viable through biosaline agriculture beucause the groundwater salinity of this region is within the tolerance levels of the seeds

Physiological changes in osmo and hydroprimed cucumber seeds germinated in biosaline water

Biosaline agriculture has been a viable alternative for agricultural production in regions with lack of good quality water. To enable the cultivation of vegetables in high electrical conductivities, seed priming has been used to increase tolerance to stress caused by use of brackish water. We aimed to evaluate the efficiency of osmo and hydropriming in cucumber seeds cv. Caipira germinated biosaline in water, regarding germination and biochemical changes during the germinative process. The experimental design was totally randomized, with four replications of 50 seeds or 10 seedlings, in a factorial scheme 6x3; with six priming conditions (control, osmopriming during 24 and 48 hours, hydropriming with 1, 2 and 3 cycles of hydration-dehydration) and three biosaline water (fish farming biosaline wastewater) concentrations in distilled water (0, 50 e 100%). We evaluated the kinetics and percentage of germination; germinative metabolism and activity of antioxidant enzymes. According to the results, one hydropriming cycle is faster and more efficient to improve the performance of cucumber seedling in biosaline water and this can be used in substrate for germinating seeds of cucumber cv. Caipira

Physiological quality of Gliricidia sepium (Jacq.) Steud. (Leguminosae - Papilionoideae) seeds subjected to different storage conditions

Studies of seed physiological processes represent the starting point for the sustainable utilization of native or cultivated plant species from the caatinga biome for which germination studies are still scarce. In order to determine adequate methods for the conservation of Gliricidia sepium seeds, the physiological quality of propagules exposed to different conditions and times of storage were examined. Recently collected seeds of G. sepium were analyzed immediately, while the other sample was stored for three, six, nine, or twelve months in plastic or paper bags under refrigeration or at room temperature for further analysis. The germination rates of seeds from each storage regime were determined and these rates compared to their water content. It was observed that germination capacity was directly related to changes in seed humidity. Storing seeds in plastic bags yielded the best conservation, mainly when they were stored at low temperatures. However, even at temperatures near 25°C it was possible to prolong seed viability when their water content was controlled through the use of impermeable packing

Influência do armazenamento na qualidade fisiológica de sementes de Caesalpinia pyramidalis Tul.

Objetivou-se com este trabalho apontar as melhores condições de armazenamento das sementes de C. pyramidalis (catingueira), visando ao estabelecimento de protocolos que possam servir de base para outras espécies do semiárido nordestino brasileiro. Sementes de catingueira foram armazenadas por 0, 3, 6 e 9 meses em ambiente de laboratório e em geladeira, nas embalagens saco de papel Kraft e saco de polietileno. A cada período de armazenamento, as sementes foram avaliadas quanto ao percentual de germinação (G%), ao tempo médio de germinação (Tm), à velocidade média de germinação (Vm), ao índice de velocidade de germinação (IVG) e ao conteúdo de água (Ca). Observou-se elevada taxa de germinação das sementes nos diferentes tratamentos propostos aos três (89,25%), seis (88,5%) e nove (91%) meses de armazenamento, sendo tais índices, inclusive, muito próximos ou ligeiramente superiores à taxa de germinação inicial (90%). O armazenamento favoreceu significativamente a elevação das taxas de IVG das sementes para índices superiores àquele verificado nas sementes recém-coletadas (11,24 aos 3 meses; 9,79 aos 6 meses; 10,29 aos 9 meses e 7,70 no mês zero). Os resultados indicaram que as sementes de catingueira possuem comportamento ortodoxo quanto à tolerância à secagem e ao armazenamento e que a possibilidade de manutenção de sementes viáveis em diferentes ambientes a um baixo custo pode ser uma boa estratégia para fornecimento de sementes em qualquer época do ano

Size and vigor of Anadenanthera colubrina (Vell.) Brenan seeds harvested in Caatinga areas

Abstract: Angico is a species found in several environments in Brazil, with several applications. It is used in the timber industry and mainly in folk medicine. In order to verify a variation in the biometric characteristics and the quality of seeds from different mother-plants in different harvesting years, the following variables were studied: moisture content, diameter, density, electrical conductivity, fresh and dry matter of seedlings, germination percentage and kinetics, in a completely randomized design with a 2x3 factorial arrangement (lots x size). The obtained results showed that angico seeds from different lots showed different physiological quality, possibly due to the climate variations to which mother-plants were submitted in the different years. Seed size directly interferes with seedling growth under both controlled and greenhouse conditions, and it can be used as a vigor indicator for angico seeds