Higher Germination Speed Index Research Articles

Thermal optima for seed germination of 30 tree species from Central Amazonia: a comparison of approaches and a new proposal

This study compared the seed germination of 30 tree species from Central Amazonia using a wide temperature range (5-40°C with 12 hours of light daily). Seeds were submitted to pre-germination treatments, whenever necessary, sown on vermiculite or germitest paper, and normal seedling development was assessed until stabilisation. With the same data set, seeds' optimal germination temperature (Topt ) was determined by comparing the following approaches: (i) 2-step, the temperature with the highest germination and the shortest time to seed population reach 50% of germination was chosen; (ii) the highest Germination Speed Index (GSI); (iii) using the formula developed by Olff and collaborators (Olff's approach); (iv) three species were evaluated with Covell's approach; and (v) new formulas for Topt calculation are proposed, based on germination success and five different variables of germination rate (Cipriani's approach). Comparing the results, Topt differed between 0.6-10.0°C. GSI and 2-step indicated generally higher values than Olff's formula. The minimum and maximum Topt differences between Cipriani's approaches were between 0.1-2.2°C. Our study showed that Toptshould be determined for each species as, even the 30 Amazonian tree species of the same habitat, Topt ranged between 22.5 and 32.5°C.

Diaspores biometry, temperatures and light regime on seed germination of Ptychosperma macarthurii (Arecaceae)

This work aimed to analyze diaspores biometric characteristics, the effect of different temperatures and light regimes on seed germination and on the initial seedlings’ growth of Ptychosperma macarthurii. The experiment was performed at the Horticulture Seed Laboratory, UNESP/FCAV, Jaboticabal, SP. The individual diaspores biometric analysis was performed by measuring the length, diameter, mass and weight of a thousand diaspores, the data were subjected to descriptive statistical analysis. It was adopted a completely randomized design in a 5 × 2 factorial with four replications of 25 seeds per treatment. Five temperatures (25; 30; 35; 20-30 and 25-35 ºC) and two light regimes (presence and total absence of light) were evaluated. The variables analyzed were germination, germination speed index, average length of the primary root and shoot, diameter of the stem and seedlings total dry mass. The length, diameter and average weight of the diaspores were 12.54 mm, 6.05 mm and 0.1610 g, respectively. The seeds of Ptychosperma macarthurii germinated in a wide temperature range, reaching a higher germination percentage at 25 ºC and a higher germination speed index at 30 ºC, being classified as neutral photoblastics. The constant temperature of 30 ºC provided higher mean values ​​for all seedlings’ biometric characteristics.

In Vitro Germination and Propagation of Dyckia brevifolia, An Ornamental and Endangered Bromeliad

Dyckia brevifolia is an endangered plant used for ornamental purposes. As no references to the in vitro propagation of the species exist, the present study aims at investigating the possibility of an efficient micropropagation protocol. Seeds collected from mother plants were germinated at high percentages (84–86%) at a range of 15–25 °C, without any pre-treatment, and demonstrated their highest germination speed index (191.51) at 25 °C. In vitro-grown seedlings were used as the starting material for micropropagation on solid, or liquid, MS medium, supplemented with a variety of concentrations of cytokinins (BA, KIN or 2IP). Shoots and leaves were used as starting explants. Liquid media supplemented with BA or 2IP at 1.0 mg L−1 led to high multiplication rate and 2.7, or 2.3, lateral shoots were regenerated while on 2IP a high percentage (77.5%) of rooting occurred at the same time. Rooted microshoots were acclimatised ex vitro at 100% and acclimatised plants were transplanted in pots where they grew with a survival rate of 100% after two months. The in vitro propagation protocol presented in this study could enhance the large-scale propagation use of D. brevifolia as an ornamental plant and, simultaneously, contribute to the ex-situ conservation of the species.

Common bean seed germination and seedling emergence under inoculation with biostimulators

Biostimulating microorganisms have protector effect against pathogenic agents, affect the stand formation, promote plant growth, and increase yield of agricultural crops. Thus, the objective of this work was to evaluate the seed germination and seedling emergence of different common bean cultivars as a function of treatments with Bacillus subtilis BV02 and Trichoderma asperellum BV10. Germination tests in paper rolls and sand were conducted in a completely randomized design, with a 2×4 factorial arrangement consisted of two cultivars, namely Campos Gerais (CG) and Estilo (ES), and four microorganism treatments, namely B. subtilis BV02 (BS), T. asperellum BV10 (TA), B. subtilis BV02 + T. asperellum BV10 (BS+TA), and Control. The variables analyzed were: germination speed index (GSI), emergence speed index (ESI), germination percentage, emergence percentage, root length, seedling height, and root and shoot fresh and dry weights. The CG cultivar had higher GSI, ESI, root length, seedling height, shoot fresh weight, root fresh weight, and shoot dry weight than the ES cultivar in the paper roll and sand tests. The common bean seed inoculation with BS+TA increased seedling height, shoot fresh weight, shoot dry weight, and root length in the ES cultivar. The CG cultivar had higher GSI, ESI, root length, root fresh weight, and root and shoot dry weights than the ES cultivar. The treatment of seeds with BS+TA is recommended to improve the performance of common bean seedlings of the ES cultivar.

Calidad fisiológica de semilla de tomate de cáscara (Physalis ixocarpa Brot. ex Horm.) en dos condiciones de almacenamiento

In order to evaluate the physiological quality of tomatillo seeds over time and the effect of two environments, seeds of four varieties produced in 2013 were stored for three years under ambient conditions (23.43 ± 0.64 °C and 23 % RH) and at the Germplasm Bank (-20 °C and 13 % RH) of the Universidad Autónoma Chapingo, Mexico. They were sampled every year from October 2013 to November 2016. Germination and vigor tests were performed in each sampling under a completely randomized experimental design with six replications. Germination percentage was determined at 30 °C for 21 days in a germination chamber. Vigor was evaluated by means of the germination speed index (GSI), seedling length (SL), seedling dry weight (SDW) and percentage of normal seedlings (NS). After three years of storage, germination decreased 4.3 %, where the highest percentages were obtained with the Diamante and Tecozautla 04 varieties. However, the four varieties evaluated showed more than 90 % germination. No significant effect of storage environments on germination was observed, although the highest GSI and NS values were obtained under the storage conditions of the Germplasm Bank. The Diamante variety showed the highest germination percentage and GSI values. In the vigor variables (GSI, SL and SDW) a negative influence was observed due to the effect of storage time.

Leaf morpho-anatomy of Jatropha curcas in vitro: Response to light conditions and temperature

Jatropha curcas L. plant is adapted to diverse climatic conditions with high requirement of heat stroke and drought resistant, having a special position among the attractive crops to biofuel program. This species has been studied from the perspectives of plant breeding, biotechnology and development of production systems. However, there are few reports of research regarding its anatomical characteristics . Thus, the objective of this study was to evalu­ate the effects of different conditions of light and temperature on the germination in vitro of J. curcas embryo and describe the leaf structure of seedlings through anatomical and micromorphological parameters. Embryos were excised and cultured in test tubes containing 15 ml of MS medium and grown in different temperature (25 °C and 30 °C) and light conditions (white, red, far red, and absence of light). The cultures were kept in BOD germinators chambers, with a 16 h photoperiod. Phytotechnical, anatomical and micromorphological (via electron scanning microscopy) characteristics were measured. The species J. curcas has a higher germination speed index when grown at 30 oC. There is an increased of number of normal seedlings in white light and this point characterizes the species as neutral photoblastic. J. curcas presents uniseriate epidermis, palisade unistratified parenchyma, and spongy parenchyma composed of irregular cells. It is an amphistomatic species, with more stomata on the abaxial surface.

SEEDS ECOPHYSIOLOGY IN AN ALTITUDE MARSH IN PARAÍBA STATE, BRAZIL, AIMING THE CONSERVATION OF THE AUTOCHTHONOUS BIODIVERSITY

The altitude swamps in northeast Brazil are areas with divergent microclimates from the context that they are located; their forest formations are disjunctions of the Atlantic Forest, marooned by the ‘Caatinga’ vegetation, a condition that makes these remaining areas with high biodiversity. Botanical research in remnants forests of Paraíba state, particularly with regard to the redemption of germplasm, are relevant. The aim of this study was to evaluate the ecophysiology of seeds from native species of the Fabaceae family selected in the CCHSA forest fragment, submitted to thermal stress and monitor their reproductive phenophases. The experiment was conducted at the Seed Laboratory of the CCHSA/UFPB and with the aid of B.O.D germinators, with 8 hours of photoperiod in a randomized experiment design with constant temperatures of 20, 25, 30 and 40°C. The seeds were distributed on a paper towel moistened with distilled water equivalent to three times the weight of the dry paper. Four replicates of 25 seeds were used per treatment. Data of germination and Germination Speed Index (GSI) were submitted to analysis of variance and polynomial regression. The germination of Pterogyne nitens Tul. was affected by the studied temperatures and the temperature range that promoted higher germination percentage between 25 and 40°C. The higher temperature (40°C) markedly increased the germination and vigor of Senegalia tenuifolia L. Britton and Rose. The higher GSI was observed for Enterolobium contortisiliquum (Vell.) with the use of 40°C of temperature. The results can indicate the optimum temperature and range temperature for germination and early seedling development of the species studied in its habitat.

Germination and seedling structure of Ruprechtia laxiflora Meissn. (Polygonaceae)

Germination of diaspores and the seedling structure of Ruprechtia laxiflora Meissn. (Polygonaceae) which is a secondary species frequent in forest remnants are described. Seedlings were embedded in hydroxymethacrylate and sectioned in a rotary microtome according to usual techniques in plant anatomy. For bioassays of germination, the experimental design was completely randomized in a 3x2 bifactorial arrangement, corresponding to three temperatures (20, 25 and 30°C) and two light conditions (photoperiod and continuous darkness) for the diaspores newly harvested and in a 4x2 bifactorial arrangement, corresponding to four temperatures (15, 20, 25 and 30°C) and two light conditions (photoperiod and continuous darkness) for diaspores analyzed after storage. There was no interaction between the factors light condition and temperature for germination parameters analyzed. However, the temperature affected the germination and diaspores maintained at 25°C showed a shorter mean time and higher germination speed index. Seedlings are phanerocotylar and epigeal with tetrarch root, intermediate-low type of root-stem transition and trilacunar cotyledonary node.

Efeitos de diferentes substratos e temperaturas na germinação de sementes de Foeniculum vulgare

RESUMO O funcho (Foeniculum vulgare) é uma espécie medicinal nativa da Europa e amplamente cultivada em todo o Brasil. Possui propriedades carminativas, digestivas e diuréticas. Dada a grande importância dessa espécie no âmbito medicinal, objetivou-se com este trabalho avaliar o efeito de diferentes substratos e temperaturas na germinação de sementes de funcho. Os tratamentos foram compostos de duas temperaturas sendo uma constante de 20ºC e outra alternada de 25-30 °C e três diferentes substratos: papel mata borrão (Germitest), areia e vermiculita, em esquema fatorial 3 x 2, com 4 repetições de 25 sementes. Foi avaliado o índice de velocidade de germinação (IVG), porcentagem de germinação (PG), comprimento da radícula (CR), massa fresca (MF) e seca (MS) de plântulas. A temperatura de 20 ºC proporcionou maiores IVG, porcentagens de germinação, comprimento de radícula e massa seca. A germinação de sementes de funcho não foi influenciada pelos diferentes substratos testados. Pelos resultados, conclui-se que a condição que permitiu maior porcentagem de germinação das sementes de funcho foi a temperatura de 20 °C atingindo 91% de germinação.

Influência da temperatura e substrato na germinação e vigor de sementes de Jacaranda micrantha Cham.

The caroba (Jacaranda micrantha Cham.) is a forest species belonging to the family Bignoniaceae, with the potential for landscaping and commercial plantations, as well as recovering degraded areas. Due to limited information of listed species, the present study aimed to evaluate the effect of temperature and substrate suitable for seed germination. The experimental design was completely randomized in a 4 x 4 factorial, consisting of combinations of four temperatures (20, 25, 30 and 25-30 °C) and four substrates (sand, commercial substrate, vermiculite and Germitest® paper), with four replicates of 25 seeds each. The parameters evaluated were speed index of germination, first count germination, germination, length of seedlings, fresh weight and dry weight of normal seedlings. There was no difference between the substrates and temperatures tested in this study, for seed germination of J. micrantha. The 25 °C temperature, 30 °C and 25-30 °C combined with the substrates, sand and Germitest® paper are suitable for the germination of Jacaranda micrantha seeds, providing, in general, higher germination speed index values and seedling development.

Effect Of Soil Waterlogging Stress On The Physiological Performance Of Seeds And On The Productivity Of Rye Plants

The objectives of this study were to evaluate the effect of waterlogging on seed physiological performance and plant productivity in rye. Our study consisted of three treatments: 1) no waterlogging, 2) a single waterlogging period, and 3) double waterlogging period. Plant productivity was evaluated from the number of spikes per plant, the number of seeds per plant, the number of seeds per spike, and seed yield. Seeds were exposed to a germination test and seed physiological quality was evaluated from the seed germination rate, initial germination rate, germination speed index, electric conductivity, shoot length, primary root length, shoot dry matter and primary root dry matter, and weight per 1000 seeds. The seeds derived from plants not exposed to waterlogging showed a higher germination rate in a shorter period of time and higher germination speed index than those derived from plants that were exposed to waterlogging; however, the weight per 1000 seeds was lower and seedlings had longer shoots and primary roots. The plants that were not exposed to waterlogging had a higher number of spikes per plant, higher number of seeds per plant, higher number of seeds per spike, and better seed yield per plant. Therefore, it was concluded that waterlogging has a negative effect on seed physiological performance in rye and that plant productivity is reduced under long-term waterlogging.

The effect of temperature regulation on seed germination of the tropical tree Myrsine parvifolia A. DC near its southern limit

Myrsine parvifolia A. DC. (Myrsinoideae, Primulaceae) is a native pioneer tree on the Brazilian coastal plain that occupies a diversity of sunny and wet sandy habitats. This study evaluated the germination of three seed batches of this species, collected near its southern limit in South America (Rio Grande, RS, Brazil) during two different years (2008 and 2009), with or without cold storage. The seeds were incubated for 30days at four constant temperatures (15°C, 20°C, 25°C and 30°C) and one thermoperiod (20/30°C, 12h:12h). Pooled data from the three batches showed higher final germination (~75%) at temperatures of 15°C and 20°C, whereas significantly lower germination (between 20% and 30%) occurred at 25°C, 30°C and during a 20/30°C thermoperiod. Inhibition at 25°C, 30°C and 20/30°C was completely reversed (resulting in ≥90% germination) by transferring the seeds to 20°C and incubating them for an additional 30days, or it was partially reversed (rose to 50–65%) by mechanical abrasion of the seed testa or gibberellic acid application. A higher germination speed index was also observed at a constant temperature of 20°C than the other temperature regimes tested. Cold storage did not significantly affect the final germination percentage, but it resulted in higher germination synchrony. The seeds of the southern population of M. parvifolia are non-dormant and orthodox and denote a marked adaptation to the local warm-temperate climate.

Germinação de sementes de pinhão manso em diferentes temperaturas, luz e substratos

The physic nut crop (Jatropha curcas L.) has been gaining some importance in the last years due to its use as a raw material for biodiesel production. The Physic nut can be propagated through stakes and/ or seeds. In this context, it was developed this study in order to evaluate the effects of the substrate, temperature and light on the germination and germination speed index (GSI) of physic nut seeds. The experimental design used was a factorial 4x2x2 with temperature (25, 30, 35 and 40 °C) x substrate (sand and paper) x light (presence and absence) with three replicates per treatment. The best germination percentages were obtained with the temperatures of 25, 30 and 35 °C with light and 30 ºC in light absence for the sand substrate and at a temperature of 30°C, whether in presence or absence of light for the paper substrate. The sowing in sand without light at 30 °C was that best promoted the seedling development with higher GSI. The combination of substrate between sand, temperature of 30 °C and absence of light showed the best condition for evaluating germination and GSI of physic nut seeds.

Influência de temperatura, luz e giberelina na germinação de sementes de Thlaspi caerulescens J. Presl & C. Presl (Brassicaceae)

Thlaspi caerulescens é espécie hiperacumuladora de metais como Cd2+, Ni2+ e Zn2+, considerada como uma plantamodelo para estudar a acumulação e tolerância a metais pesados. No entanto, a baixa produção de sementes em nossas condições climáticas tornam necessária a determinação de condições que possam maximizar a germinação e o vigor de suas sementes. Para identificar as melhores condições para a germinação, sementes de T. caerulescens foram colocadas na presença (15 mmol.m-2.s-1, 8 h luz/16 h escuro) ou ausência de luz nas temperaturas de 10, 15, 20 e 25 ºC, em papel germitest previamente umedecido com solução de ácido giberélico (GA3) a 0,05% ou água destilada. Foram avaliados a porcentagem de germinação (%G) e o índice de velocidade de germinação (IVG). Maior porcentagem de germinação (66%) foi observada nos tratamentos com GA3 e temperaturas de 15 e 20 ºC, na presença de luz. Maiores valores do IVG foram obtidos com a utilização de GA3 nas temperaturas de 15 e 20 ºC, tanto na presença quanto na ausência de luz. Maiores germinação e IVG de T. caerulescens foram observados com uso de GA3 na presença de luz nas temperaturas de 15 e 20 ºC.

Micropropagação do maracujazeiro-do-sono

Em função da dificuldade de propagação de Passiflora setacea DC., técnicas de cultura de tecidos tornam-se alternativas viáveis. Objetivou-se estudar a germinação in vitro e determinar o melhor meio de cultivo na sua micropropagação. O presente trabalho constou de duas etapas, na primeira as sementes (sem escarificação, escarificadas na extremidade ou na parte mediana) na foram colocadas em % MS e 30 g L-1 de sacarose, distribuído em tubos de ensaio e suplementado com zero, 20 ou 40 mg L-1 de GA3. O pH do meio foi ajustado para 5,8 antes da adição de 6,0 mg L-1 de ágar. Após a inoculação das sementes nos meios de cultura, elas foram mantidas em sala de crescimento com luminosidade de 35 µmol.m-2.s-1, temperatura de 26 ± 1ºC e fotoperíodo de 16 horas. Assim que germinaram, as plântulas foram transferidas para tubos contendo meio MS, onde constituíram um segundo experimento, a fim de se testarem meios combinados com concentrações de sacarose. O delineamento experimental utilizado foi inteiramente casualizado, em esquema fatorial 3 x 3, quatro repetições e 15 sementes por parcela no primeiro experimento e 4 x 4, com quatro repetições e 3 plantas por parcela no segundo experimento. Melhores resultados na micropropagação foram obtidos em meio de cultivo MSM, associado a 28,51 e 28,74 g L-1 de sacarose. Maior índice de velocidade de germinação foi verificado com uso de 20 mg L-1 de GA3, associado à escarificação na ponta da semente.