Hours Of Imbibition Research Articles

Relationship between seed coat colour and seed vigour in cowpea (Vigna unguiculata Walp (L.)

In the present study, the 25 genotypes were grouped into two seed color groups including pigmented (n = 19; black, brown, dark brown, grey, dark grey seed color) and unpigmented (n = 6; cream and white seed color) for studying the association of seed coat color with seed vigor. Despite high germination (>84%) of all genotypes in the laboratory, unpigmented genotypes recorded low (34-54%) field emergence than pigmented genotypes (52-78%). Rapid initial (30 min) rate of water uptake (-0.75**), water uptake at one hour of imbibition (-0.70**), low proportion of seed coat (0.67**), and greater electrical conductivity of seed leachate (-0.72**) was associated with low field emergence in unpigmented cowpea genotypes. No significant correlation or association was observed between field emergence and laboratory germination in the present investigation suggesting that laboratory germination can not be used for predicting field emergence in cowpea. Instead, the electrical conductivity of seed leachate could be used to predict the field emergence of cowpea.

Experimental study of water imbibition characteristics of the lacustrine shale in Sichuan Basin

Through the stimulation method of large-scale hydraulic fracturing, the spontaneous imbibition capacity of the water phase in the shale reservoir has great influence on the effect of stimulation. Generally, the lacustrine shale has the characteristics of high clay minerals content, strong expansibility, development of nanopores and micro-pores, and underdevelopment of fractures, which leads to the unclear behavior of spontaneous imbibition of aqueous phase. The lacustrine shale of Da'anzhai Member and marine shale of Longmaxi Formation in Sichuan Basin were selected to prepare both the shale matrix sample and fractured shale sample, and the spontaneous imbibition experiment of simulated formation water was carried out. By means of an XRD test, SEM observation, nuclear magnetic resonance test and linear expansion rate test, the mineral composition, the structure of pores and fractures, the capacity of hydration and expansion of both lacustrine and marine shale are compared and analyzed. The results show that the average spontaneous imbibition rate of lacustrine shale is 60.8% higher than that of marine shale within the initial 12 hours of imbibition. The lacustrine shale has faster imbibition rate than the marine shale in the initial stage of spontaneous imbibition. However, the lacustrine shale has underdeveloped pores and fractures, as well as poor connectivity of pores. Besides, the strong hydration and expansion of clay minerals can easily lead to dispersion and migration of clay minerals on the fracture surface, which will plug up the seepage channels, resulting in poor capacity of spontaneous imbibition. The spontaneous imbibition rate in the middle and late stage of Lacustrine shale is obviously lower than that of the marine shale. The overall spontaneous imbibition rate ability of the lacustrine shale is less than that of the marine shale. According to the characteristics of water imbibition of lacustrine shale, considering the dual effects of hydration expansion of clay minerals on the effective reconstructed volume, the microfractures can be initiated and extended by fully utilizing the hydration of shale. Acidification treatment, oxidation treatment or high temperature treatment can be used to expand pore space, enhance water phase imbibition capacity and improve multi-scale mass transfer capacity of the lacustrine shale.

Seed longevity studies in wild type, cultivated and inter-specific recombinant inbred lines (RILs) of soybean [Glycine max (L.) Merr.

Loss of seed viability is a serious hurdle in production and ambient seed storage of soybean. Understanding the factors affecting seed viability, and identification of soybean genotype(s) with higher viability is critical for higher soybean production. In this study, seeds of 125 soybean genotypes of three different species [Glycine tomentella Hayata, Glycine max subsp. soja (Siebold & Zucc.) H. Ohashi, and Glycine max(L.) Merr.] and 25 RILs (Glycine soja × Glycine max) were tested for germination immediately after harvest followed by 1, 2 and 3 years of ambient storage. Fresh seeds of all the genotypes recorded 78–99% germination with a mean of 94.02%. However, the mean value of per cent germination of all the genotypes after 1, 2 and 3 years of ambient storage decreased and found to stand at 79.51%, 52.24% and 29.18%, respectively. Among the genotypes tested, G. tomentella accession registered highest seed storability followed by G. soja, RILs and G. max. After 3 years of storage, 14 wild type genotypes and 3 RILs found to maintain > 70% germination and, were identified as ‘good storers’. Genetic divergence studies via k-mean clustering and principal component analysis grouped all genotypes in three clusters. Seed viability was significantly and negatively correlated with electrical conductivity. Good storers found to be having slow imbibition rate than poor storers in initial hours of imbibition. The good storing genotypes identified in this study will serve as an elite soybean genetic resource in developing the soybean cultivars with better seed longevity.

Etching of the seed cuticle by cold plasma shortens imbibitional leakage in Linum usitatissimum L.

Pre-sowing treatment of seeds with cold plasma, a reactive mixture of charged particles, is an emerging, environmentally friendly method, shown to improve water absorption, germination and seedling growth in many crop species. We studied how plasma affects different structural layers in flax seed coats, and focused on the effects on some of the earliest germination events, directly related to imbibition: solute leakage and mucilage extrusion. We characterized the ultrastructure of flax seed coats using scanning electron microscopy (SEM) and observed mucilage extrusion in situ, using environmental SEM. Time-courses of water uptake and solute leakage during germination were recorded, respectively, by weighing the seeds and semi-quantitative metabolite profiling of the exudates using GC–MS, LC–MS and LC–UV. Plasma treatment perforated the cuticle of flax seeds but did not visibly etch the underlying mucilage secretory cell (MSC) walls. Plasma treated seeds took up more water than untreated seeds during imbibition. Mucilage expansion of untreated seeds detached the distal MSC walls from the radial walls and extrusion occurred, relatively slowly, via sparse cracks in the distal cell wall layer. In plasma treated seeds, mucilage extrusion occurred fast, via rupture of distal cell walls of almost every single MSC, and the junctions between distal and radial MSC walls remained intact. Initially, imbibitional solute leakage was higher in plasma treated seeds but the leakage had quasi stopped after one hour of imbibition. In untreated seeds, the leakage continued amply more than two hours after the start of imbibition. Fragments of the lignan macromolecule, stored in parenchymatous cells under the MCS, were released more abundantly in the spermosphere of plasma treated than untreated flax seeds. It is concluded that plasma treatment etches the cuticle of flax seeds and weakens the underlying MSC cell walls, and that such treatment leads to significantly faster recovery of membranes during imbibition, reducing leakage time in germinating seeds.

ELETRICAL CONDUCTIVITY TEST TO EVALUATE THE PHYSIOLOGICAL QUALITY OF TOBACCO SEEDS / TESTE DE CONDUTIVIDADE ELETRICA PARA AVALIAÇÃO DA QUALIDADE FISIOLÓGICA DE SEMENTES DE TABACO

The electrical conductivity test has been used to evaluate the physiological potential of seeds for being a fast, reliable and of easy execution test, to complement informations provided by the germination test. It is necessary the adequacy of this test for each specie in particular. To investigate the possibility of use of the electrical conductivity test to evaluate the physiological quality of tobacco seeds, were used four lots form cultivar CSC 231 and four lots from cultivar CSC 444, which were analyzed separately. Seeds were submitted to periods of (0.5; 1; 2; 4; 6; 8 and 10 hours) of imbibition at 25°C in recipients containing 6 mL of water with 100 and 200 seeds. The conductivity in mass of seeds was determined using the equipment condutivimeter Digimed CD-21, used in the evaluation of conductivity in mass and by the automatic analyzer of seeds SAD 9000-S for the evaluation of the individual conductivity. For tobaco seeds, after six hours of imbibition occurs the stability of leaching curve. The genotype and the initial quality of seeds lots influene on the electrical conductive test for both methods. The use of electrical conductivity test in mass is promissing to be used for tobacco seeds.

In vivo and in vitro Activity of 1-aminocyclopropane-1-carboxylic Acid Oxidase in Germinating Seeds of China Aster (Callistephus chinensis Nees)

Abstract The activity of 1-aminocyclopropane-1-carboxylic acid oxidase (ACO; EC 1.4.3.3) in germinating seeds of Callistephus chinensis was studied. For maximum recovery of ACO activity in vitro, the presence of 10% (w/v) insoluble polyvinylpolypyrrolidone (PVPP) and 30% of glycerol in the extraction medium was necessary. The optimum pH for this activity was 7.0. Ethylene production by whole achenes or enzymatic extract increased due to increasing 1-aminocyclopropane-1-carboxylic acid (ACC) concentrations. Saturation level of ACC for in vivo ACO activity was 10−1 M and Vmax was 10.89 nL C2H4·mg protein−1·h−1. For in vitro ACO activity, the saturation level of ACC was 10−3 M and Vmax was 2.299 nL C2H4·mg protein−1·h−1. Both, in vivo and in vitro ACO activities did not follow Michaelis-Menten kinetics. The Hill coefficients (h) were estimated on the basis of non-linear estimation. Their values were 0.63 for in vivo ACO activity and 1.73 for in vitro ACO activity. The experimental data show that ACO from C. chinensis seeds is an oligomeric enzyme with at least two active sites. During seed germination, in vitro ACO activity was detectable after 12 hours of imbibition, while in vivo ACC conversion to ethylene was observed after 24 h, i.e. – after radicle protrusion. The activity of ACO in C. chinensis seeds is associated with germination sensu stricto, and might be a good marker of this process.

Effects of Salt Stimulation on Lunasin Accumulation and Activity during Soybean Germination.

Lunasin, a bioactive peptide, was originally found in soybeans, and it has exhibited multiple biological functions. On the basis of previous studies, salt stress was found able to induce changes in many polypeptides and translatable mRNA levels in plants. Salt stress was applied to soybean germination, with water treatment as a control group, to evaluate the effects of salt stimulation on lunasin accumulation and activity during soybean germination. Lunasin content gradually increased in the control group during germination, reached the highest level after six hours of imbibition, and then slowly decreased. Under salt exposure, lunasin content showed a similar trend to that of the control group. The lunasin content in salt-treated soybean was significantly higher than that in the control group. Lunasin peptide was purified from soybean after six hours of imbibition and it was then used for function evaluation. Purified lunasin from salt-stress-germinated soybean (6 h-LSGS) exhibited stronger antioxidant activity than lunasin from water-treatment-germinated soybean (6 h-LWGS) and soybean seed without imbibition (DRY). The 6 h-LSGS presented anti-inflammatory activity on LPS-induced macrophage cells (p < 0.05) by suppressing the release of nitric oxide (NO) and proinflammatory cytokines, including IL-1 and IL-6. The gene expression of NOS, IL-1, IL-6, and TNF-α was significantly inhibited by 6 h-LSGS. Further, 6 h-LSGS exhibited superior antiproliferation activity on human breast-cancer cells MDA-MB-231 when compared to 6 h-LWGS and DRY. Overall, this study offers a feasible elicitation strategy for enhancing lunasin accumulation and its properties in soybean for possible use in functional food.

Aspectos físicos e fisiológicos em sementes de Mimosa ophthalmocentra Mart. ex Benth.

This study aimed to characterize jurema-de-embira fruits and seeds, the process of water absorption and set the best pre-germination treatment to overcome dormancy. To characterize the biometric parameters of 100 fruits and 100 seed. For the characterization of the seed hydration, the process was carried out soaking curve of seed lots with and without lopping. We also evaluated nine pre-germinating treatments to overcome seed dormancy: control; cutting with scissors and scarification with sandpaper 80, at the opposite end to the hilum; hot water at 80 °C for 3, 6 and 12 minutes and sulfuric acid (H2SO4) for 3, 6 and 12 minutes, and evaluated the percentage and speed of germination index, shoot length and root dry weight of shoot, root and total. The seeds of jurema-of-embira have low variation for biometric features and the larger variations occur from plant materials. Seed germination starts after 19 hours of imbibition, regardless of plant material. The scarification with sandpaper 80 or emerges with scissors at the opposite end to the hilum are the methods set out to overcome dormancy in jurema-de-embira seeds.

Adequação do teste de lixiviação de potássio em sementes de &lt;i&gt;Moringa oleifera&lt;/i&gt;

Os métodos que possibilitam a rápida avaliação do vigor são de grande interesse no controle de qualidade de sementes nas grandes empresas, visto que, o teste de lixiviação de potássio tem se mostrado uma ferramenta eficiente na avaliação dos lotes de espécies como a Moringa oleifera, que apresenta alto potencial nos diferentes subprodutos da planta, podendo ser empregado na agricultura e indústria farmacêutica. O objetivo do trabalho foi adequar a metodologia do teste de lixiviação de potássio em sementes de moringa. Os experimentos foram realizados em Laboratório de Sementes e em casa de vegetação, utilizando-se quatro lotes de sementes, submetidos aos testes de germinação, emergência de plântula, comprimento total e massa seca de plântulas e o teste de frio, para a caracterização fisiológica, além do teste de lixiviação de potássio. Este último foi realizado com amostras de 25 e 50 sementes, colocadas em copos plásticos contendo 70 e 100 mL de água destilada à 25 °C por períodos de 1, 2, 3, 4, 5 e 6 h. O delineamento foi em DIC com quatro repetições por tratamento, e os resultados submetidos a ANOVA, quando significativos pelo teste F, as médias comparadas pelo teste de Tukey a 5 %. Pode-se afirmar que, em todas as avaliações realizadas, apenas um lote se destacou em relação demais, pois, apresentou menor quantidade de lixiviados de potássio e maior potencial fisiológico em condições de laboratório e em campo. As combinações de amostras de 25 e os volumes 75 e 100 mL de água destilada, 50 sementes em um volume de 75 e 100 mL de água destilada por 5 e 6 horas de embebição, foi a metodologia do teste de lixiviação de potássio mais adequado para classificar lotes de sementes de M. oleifera, em função de sua qualidade fisiológica.

Investigating seed dormancy in cotton (Gossypium hirsutum L.): understanding the physiological changes in embryo during after-ripening and germination.

The dormancy of seeds of upland cotton can be broken during dry after-ripening, but the mechanism of its dormancy release remains unclear. Freshly harvested cotton seeds were subjected to after-ripening for 180days. Cotton seeds from different days of after-ripening (DAR) were sampled for dynamic physiological determination and germination tests. The intact seeds and isolated embryos were germinated to assess effects of the seed coat on embryo germination. Content of H2 O2 and phytohormones and activities of antioxidant enzymes and glucose-6-phosphate dehydrogenase were measured during after-ripening and germination. Germination of intact seeds increased from 7% upon harvest to 96% at 30 DAR, while embryo germination improved from an initial rate of 82% to 100% after 14 DAR. Based on T50 (time when 50% of seeds germinate) and germination index, the intact seed and isolated embryo needed 30 and 21 DAR, respectively, to acquire relatively stable germination. The content of H2 O2 increased during after-ripening and continued to increase within the first few hours of imbibition, along with a decrease in abscisic acid (ABA) content. A noticeable increase was observed in gibberellic acid content during germination when ABA content decreased to a lower level. Coat removal treatment accelerated embryo absorption of water, which further improved the accumulation of H2 O2 and changed peroxidase content during germination. For cotton seed, the alleviation of coat-imposed dormancy required 30days of after-ripening, accompanied by rapid dormancy release (within 21 DAR) in naked embryos. H2 O2 acted as a core link between the response to environmental changes and induction of other physiological changes for breaking seed dormancy.

Effect of Nitric Oxide on Seed Germination and Dormancy in Empress Trees

Freshly harvested empress tree (Paulownia elongata) seeds have physiologic dormancy. The aim of this study was to investigate the effects of exogenous and endogenous nitric oxide (NO) on the dormancy and germination of empress tree seeds. After treatment with different concentrations of sodium nitroprusside (an NO-releasing compound) solution, the germination percentage of seeds under 12 h of continuous light was significantly greater. Seed germination percentage was promoted significantly by 10–4 M sodium nitroprusside plus cold stratification compared with seeds treated with cold stratification only. At different hours during imbibition, empress tree seeds treated with 2-(4-carboxyphenyl)-4, 4, 5, 5- tetramethylimidazoline -1-oxyl-3-oxide potassium salt (c-PTIO), NG-nitro-L-arginine methyl ester (L-NAME), and sodium tungstate showed reduced seed germination percentages. During the early hours of imbibition, c-PTIO or sodium tungstate treatment inhibited seed germination significantly. The results showed that both exogenous and endogenous NO can release empress tree seed dormancy. Endogenous NO oxide was involved in dormancy release and germination of seeds during the early stages of imbibition. Wider application of NO may be used for breaking seed dormancy in other species.

The interplay of PsABAUGT1 with other abscisic acid metabolic genes in the regulation of ABA homeostasis during the development of pea seeds and germination in the presence of H2O2

Inactivation of abscisic acid (ABA) in vitro may be catalyzed either by ABA 8′-hydroxylase (ABA8′OH) or by ABA uridine diphosphate glucosyltransferase (ABAUGT), which conjugates ABA with glucose. However, the involvement of these enzymes in the control of ABA content in vivo, especially ABAUGT, has not been fully elucidated. In pea seeds, both PsABAUGT1 and PsABA8′OH1 contribute to the reduction of ABA content during seed maturation and imbibition; however, during the first hours of imbibition, a high expression of only PsABAUGT1 was observed. Imbibition of seeds with H2O2 increased the ABA content despite the oxygen availability and altered the expression of metabolic genes. The expression of the biosynthetic gene 9-cis-epoxycarotene dioxygenase (PsNCED2) was increased, while that of PsABAUGT1 was decreased in each H2O2 experiment despite O2 availability. Under hypoxia, only seeds imbibed with H2O2 germinated, while under nonlimiting oxygen conditions, the germination rate was not altered by H2O2. Under hypoxia, the germination rate of H2O2-imbibed seeds seemed to not depend on the absolute ABA content and rather on the balance between ABA and gibberellins (GA), as H2O2 increased the expression of GA synthesis genes.Overexpression of PsABAUGT1 in Arabidopsis decreases seed ABA content, accelerates germination and reduces seed sensitivity to exogenously applied ABA, confirming the ability of PsABAUGT1 to inactivate ABA. Thus, PsABAUGT1 is a new player in the regulation of ABA content in maturating and imbibed pea seeds, both under standard conditions and in response to H2O2.

Incremento de área em sementes de moringa durante a embebição por meio da análise de imagens

A morfologia das sementes e as modificações físicas sofridas por elas durante a germinação podem estar associadas ao vigor. Por isso, objetivou-se com este trabalho monitorar o incremento de área em sementes de moringa durante a embebição, por meio da análise de imagens, com o intuito de se determinar a sua qualidade fisiológica a partir deste incremento. Utilizaram-se sementes de quatro lotes de moringa com e sem tegumento, fotografadas antes e durante a embebição, nos períodos de 8, 16 e 24 horas, nas temperaturas de 15 e 20 °C. Calculou-se o incremento de área (%) através da análise das imagens, utilizando-se o programa ImageJ. Os resultados de cada período avaliado foram comparados com os testes usualmente utilizados na avaliação do vigor de sementes. O delineamento foi inteiramente casualizado, com quatro repetições de 50 sementes por tratamento. Os dados foram submetidos a ANOVA e comparados pelo teste de Tukey. Os lotes 1, 2 e 4 foram considerados de melhor qualidade, enquanto que, o lote 3 apresentou qualidade inferior, quando comparado aos demais lotes testados. As sementes de moringa seguiram o padrão trifásico de embebição, com a protrusão da raiz primária ocorrendo em 72 horas. Foi possível avaliar o percentual de incremento de área por meio do programa ImageJ, sendo o período de 8 horas de embebição a 15 °C o que demonstrou maior eficiência para classificação dos lotes quanto a sua qualidade fisiológica.

Integrating proteomics and enzymatic profiling to decipher seed metabolism affected by temperature in seed dormancy and germination

Temperature is an important environmental factor affecting seed dormancy and germination. The mechanism by which temperature induces germination in dormant seeds is however still unclear. Proteomic study has been performed in dormant sunflower seeds during imbibition at permissive and non-permissive temperatures for germination, 20 and 10 °C, respectively. Proteome analysis showed an increase of proteins belonging to metabolism and energy from the first hours of imbibition followed by a decrease of proteins involved in protein metabolism and seed storage in germinating compared to non-germinating seeds. Proteomic study was completed by polysome and proteasome activity assessment and enzymatic profiling on several altered proteins involved in metabolism and energy. Results showed that 20 °C treatment induced the activation of both protein synthesis and degradation processes, the latter being related to proteasome activity during the germination sensu stricto, and to other degradation processes such as proteases during the post-germination. Interestingly, enzymatic profiles showed that TCA cycle and glycolysis were more active in non-germinating seeds in the phase I of the germination sensu stricto. This result suggests the regulation of central metabolism activity in germinating seeds. The control of energy production during imbibition seems to be involved in molecular networks controlling seed dormancy and germination.

The Seed Water Sorption Isotherm and Antioxidant-Defensive Mechanisms of &amp;lt;i&amp;gt;Hordeum vulgare&amp;lt;/i&amp;gt; L. Primed Seeds

The key successful for seed priming technique was the management of seed imbibition process. This study was aimed to indicate the seed moisture sorption characteristics of Hordeum vulgare L. cv. Samerng 2 in relation to the seed priming technique and its effect on the seed qualities. The experiment was designed by Completely Randomized Design (CRD) with four replications. Seed hydro-priming technique was done under 25 degree Celsius, and 40% - 60% RH. Barley seed moisture content was determined every hour after imbibition for 24 hours. Then, primed barley seed qualities were evaluated at 6, 8, 10, 12, 14, and 16 hours of hydrotime. The results revealed that barley seeds were imbibed rapidly from 10.55% to 37.69% seed moisture content during 0 - 9 hours of imbibition. The constantly seed moisture content was continued until 17 hours of imbibition. Radicle was protruded with 42.74% seed moisture content. Seed moisture sorption characteristic equation was Y = 0.0055x3- 0.267x2 + 4.5931x + 13.348. Coefficient of determination (R2) was 0.916. Primed seed germination was not affected by hydrotime. Primed seeds were improved in speed of germination and seedling growth rate. The best primed barley seed vigorous was noted at 14 - 16 hours of hydrotime. In addition, catalase activity (CAT) and superoxide dismutase activity (SOD) were not significantly different for non-primed and 14 - 16 hours primed seeds. However, lipoxygenase activity (LOX) was increased and malondialdehyde (MDA) content was decreased for 14 - 16 hours primed seeds. Subsequently, 14 - 16 hours primed barley seeds can maintain high seed germination and vigor for 8 - 12 months under 5 degree Celsius. Thus, it could be concluded that hydro-priming for 14 - 16 hours enhances barley seed quality by reducing germination time, induced defenses mechanism, and could be stored for 8 - 12 months.

Germination behavior of Jatropha curcas L. after different imbibition times

Jatropha curcas is an important specie for production of biofuel. The specie can survive and produce fruits and seeds even in drought condition. For an adequate establishment in the field is necessary that seeds have a good quality in vigor and viability. In this study, we evaluated the seed water relation with different imbibition times, in deionized water, from 0 to 24 hours. Imbibed seeds were sown in polyethylene trays with 1,200 g of river sand. The germination was recorded every day for 25 days. Seeds with at least 10 mm radicle on the soil surface was considered as germinated. To determinate seed water content (SWC), 10 seeds were weighed in fresh (SFW), turgid (STW) and dry weight (SDW) at 105°C for 24 hours. After 24 hours of imbibition our results show a decrease in the germination rate from 85% to 47%, and an increase of the mean germination time from 4.8 to 7.1 days. The initial moisture of the seed used in this experiment was about 8% and after 24 hours of imbibition, the SWC was around 60%. The initial low moisture in the seeds produce imbibition damage because the tissue hydration takes place in a not controlled way so that the reconstruction of internal structures of the cells and organelles were affected. According to the PCA analysis the seed germination had a negative correlation with the imbibition time (r = -0.72, p < 0.05) and with the electrical conductive (r = -0.88, p < 0.05), variables related to the seed vigor. This study suggests that electrical conductivity may be useful in J. curcas for vigor test and their seeds do not need previously water imbibition to improve germination from seeds with initial moisture less than 8%.

Chemical composition and physiological quality of wheat seeds with the application of trinexapac-ethyl, a plant growth regulator

This study evaluated the effect of the plant growth regulator trinexapac-ethyl on chemical composition and physiological quality of wheat seeds produced under fertilization for high yield potential. The experiment was performed under completely randomized design with five treatments (0; 200; 400; 600; 800 mL ha-1 of the commercial product Moddus ) and four repetitions. The plant growth regulator was applied at elongation via foliar spraying. Seeds were harvested at the end of crop cycle. Variables evaluated were 1000 seeds weight, germination and first count of germination, speed of germination index, seedling dry matter, electrical conductivity, accelerated ageing and the contents of total soluble sugars, starch, amino acids and proteins. The first count of germination increased until the higher dose. Electrical conductivity after three hours of imbibition reduced at the doses of 600 mL ha-1 and 800 mL ha-1, indicating greater seed physiological quality. Starch showed a trend of increase until the dose of 448 mL ha-1; amino acids until the dose of 243 mL ha-1 and protein until the dose of 417 mL ha-1. The content of total soluble sugars decreased with the increasing dose of the plant growth regulator. Therefore, wheat seeds produced from plants in which trinexapac-ethyl is applied present higher vigor and greater contents of starch, protein and amino acids, but lower content of total soluble sugars. Our results demonstrate that trinexapac-ethyl can be used for wheat management in seed production fields in the recommended dose (400 mL ha-1) with benefits in seed quality and composition.

Desempenho fisiológico de sementes olerícolas em diferentes tempos de hidrocondicionamento

The production of high quality physiological seed is a major challenge for seed producers. In the search for lower cost conditioners arises the possibility of using hydropriming, which consists of a controlled hydration of seeds. The aim of this study was to evaluate the efficiency of this technique on lettuce, cabbage and tomato seeds, submitted to different times of imbibition in water. Eight periods of hydropriming in three vegetable crops were used, wherein for each of these was conducted a separate experiment. For lettuce and cabbage, periods tested were 0, 5, 10, 15, 20, 25, 30 and 35 hours and for tomato were of the periods 0, 24, 48, 72, 96, 120, 144 and 168 hours. The seeds of each treatment were submitted to the germination test and vigor to determine the physiological potential. For the tomato crop, the best answers to the average time of germination, emergence speed index and emergency field were found 72 hours of imbibition. As for the cabbage crop the best answers to these variables were obtained with 20 hours of imbibition. Lettuce did not respond positively to the imbibition times.

Ratio of seeds and sodium hypochlorite solution on the germination process of papaya seeds

Abstract: Sarcotesta, a mucilaginous layer found in papaya seeds, negatively affects the germination of papaya seeds and its removal has been manually performed. The use of sodium hypochlorite can be an alternative to manual removal of sarcotesta in papaya seeds. The objective of this study was to evaluate the effect of different active chlorine concentrations (0, 2, 4, 6 and 8%) during 24 hours of immersion, in different proportions (10:200, 50:200, 100:200, 200:200, 300:200, 400:200, 500:200 and 600:200) of seeds number and solution volume (mL) to identify the best combination for an effective remotion of sarcotesta to improve the germination process. Germination test and first count were performed. A completely randomized design with four replications was used. Regression analysis was performed for quantitative variables with significant effect by F-test at 5% probability. Papaya seeds immersion in the ratio of 10 seeds per 200 mL of NaOCl solution (10:200, i.e. 20 mL of solution per seed), at a 2% sodium hypochlorite concentration during 24 hours of imbibition, can be used as an alternative for sarcotesta remotion for freshly harvested papaya seeds, because besides the effective remotion of sarcotesta, this technique improves the germination process.

Metabolite profiling of the oilseed crop Ricinus communis during early seed imbibition reveals a specific metabolic signature in response to temperature

Seed imbibition is an important process in the plant life cycle and determines whether seed germination and plant growth will be successful or not. Ricinus communis is becoming an important crop for oil production, and therefore, studying the physiological and biochemical aspects of seed imbibition and germination may aid in the improvement of crop quality and yield. Metabolite profiling was performed in order to assess biochemical changes associated with the temperature during early seed imbibition. Changes in the metabolite profile were already detected within 2h of imbibition, but they were more prominent after 8h. An increased level of glycerol and fatty acids upon a few hours of imbibition suggests that lipid mobilization occurs shortly after water uptake begins. Fumarate and succinate levels increased after 2h of imbibition, suggesting that energy metabolism is reactivated relatively early in this species. Seeds imbibed at 20 and 25°C showed an overall accumulation of carbohydrates, while at 35°C increased levels of some amino acids were observed. Ascorbate content was 30-fold higher in seeds imbibed for 8h at 35°C as compared to seeds imbibed at 20°C, suggesting that 35°C is a stress condition for R. communis seeds. In this study, we have demonstrated that temperature plays an important role in water uptake rate, reserve mobilization and reactivation of metabolism during early seed imbibition. Additionally, we demonstrated that this species possess a specific metabolic signature which is not restricted to the imbibition period, but also during seedling establishment and plant growth.