Physiological Performance Of Seeds Research Articles

OSMOPRIMING AND ITS RELATIONSHIP WITH THE QUALITY OF Urochloa decumbens SEEDS UNDER WATER DEFICIT

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

Effect of time of harvest at different moisture contents on physiological and storability attributes of pigeon pea (Cajanus cajan)

The physical quality and physiological performance of seeds can be influenced by numerous factors, including the moisture content at harvest and drying temperature. This study evaluated the effect of time of harvest at different moisture contents on physiological attributes and storability potential of pigeon pea in the tropics. The ten pigeon pea genotypes used for the experiment were sourced from International Institute of Tropical Agriculture (IITA) Ibadan, Oyo State, Nigeria. The field experiment was a Randomized Completely Block Design (RCBD) with three replications. The seeds were harvested at maturity on the field at 12, 15 and 17 % moisture content. Harvested seeds from each treatment were divided into three seed lots of 400g each with three (3) replicate each. Packaged seed lots of each treatment were stored under ambient environment. The temperature and relative humidity of the seed stores were monitored and maintained daily using hygrometers. Seed samples were taken from each packaged seed lot for evaluation at 30-days interval for a period of 240 days. The following physiological attributes were evaluated-;Standard germination, Seedling Vigor Index, Acceleration ageing and mean Germination index. Data collected from the above experiment on different characters were subjected to analysis of variance. The study concludes that the anticipation of harvest and drying seed at moisture content above 12 and 15 % in pigeon pea on the field resulted in low and poor physiological performance. Also, pigeon pea harvested with higher moisture (17%) are more susceptible to damage which cause lower viability and seedling vigour with corresponding higher mean germination time. The study showed that, best results across the evaluated attributes during the time of storage were associated with genotypes with the lowest and moderate percentage of moisture at harvest. Therefore, for better physiological performance, optimal harvest timing for pigeon pea seeds should be at 12 to 15% range of moisture content but preferably, 15% in other to reduce the rate of seed scattering and wastages through pod dehiscence.

Osmopriming, antioxidative action, and thermal stress in sunflower seeds with different vigor levels

The osmopriming technique can reduce the period between sowing and the emergence of seedlings in the field, as well as favor seed performance under stress conditions. This study aimed to evaluate the effect of osmopriming on the physiological performance and antioxidative enzymatic activity of sunflower seeds with different vigor levels and exposed to thermal stress. Three sunflower seed lots of the cultivar Hélio 250 were used. Initially, the seeds were evaluated by germination and vigor tests to characterize the lots. Subsequently, they were primed in a polyethylene glycol 6000 solution at -2.0 MPa and 15 °C for 8 h. Then, the primed and unprimed seeds were tested for physiological quality (germination, first germination count, percentage and emergence speed index of seedlings, and seedling dry matter) and determination of the activity of the enzymes superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and peroxidase (POX) under three temperatures: 15 °C (sub-optimal), 25 °C (optimal), and 35 °C (supra-optimal). The physiological tests allowed classifying lots 1, 2, and 3 into three different vigor levels, i.e., high, medium, and low, respectively. Osmopriming favored the performance of sunflower seeds in terms of germination and vigor at all the analyzed temperatures. This effect was more pronounced in lots of lower physiological quality at sub-optimal and supra-optimal temperatures. Sub-and supra-optimal temperatures led to a reduction in the physiological performance of seeds, mainly in less vigorous lots. In general, osmopriming favored an increase in the activity of the enzymes SOD, CAT, POX, and APX, mainly in low vigor seeds exposed to sub and supra-optimal temperatures. Osmopriming of sunflower seeds in PEG 6000 at -2.0 MPa for 8 hours is efficient to improve the performance of less vigorous lots under stress due to the sub- and supra-optimal temperatures, favoring an increase in the activity of enzymes of the antioxidative system.

Antioxidant activity and physiological performance of popcorn seed after saline stress and analysis of seedling images

ABSTRACT Salinity influences all germination stages and may adversely affect seedling establishment in the field. The objective of this research was to determine the relationship between the antioxidant activity and the physiological performance of seeds and to verify the efficacy of the imaging analysis of popcorn seedlings after seed exposure to saline stress. A completely randomized design was used that consisted of four replicates in a factorial scheme. This scheme comprised three popcorn hybrids (P618, AP6002, and AP8203) and five saline potential levels (0.0; -0.1; -0.3; -0.6, and -0.9 MPa) that were obtained from KCl solutions of different concentrations. First count germination, germination and seedling vigor classification (strong normal seedlings), and dry mass of seedlings were evaluated to determine the physiological quality of the seed. The images of seedlings were used to evaluate the coleoptile and root lengths, indices of vigor, uniformity, and growth using the Groundeye® software. The activities of the antioxidant enzymes superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT) were also determined. Saline stress compromises the physiological quality and antioxidant activity of seeds and the performance of popcorn seedlings. Computerized image analysis using Groundeye® was efficient in evaluating the popcorn seedlings after being subjected to salt stress. Hybrids AP6002 and AP8203 were more tolerant to salt stress than hybrid P618.

Influence of physiological and health quality on the vigor of cucumber seeds

ABSTRACT The physiological performance of seeds is related to their physiological quality and seed vigor, while their health quality may interfere with germination and early seedling establishment in the field due to the interaction of microorganisms associated with seeds. The study aimed to evaluate the physiological performance and health quality of cucumber seeds and to verify the relationship between these attributes. The physiological quality of cucumber seeds was evaluated by standard germination tests, first count of germination, controlled deterioration test, electrical conductivity test, seedling emergence, emergence speed index, and traditional accelerated aging and aging modified with saline for 48, 72, and 96 h. The health quality of cucumber seed lots was evaluated by blotter test. Stratification of cucumber seed lots by seedling emergence was similar to seedling emergence by controlled deterioration test, first count of germination, and electrical conductivity results. The cucumber seed lots evaluated showed high germination rates; however, lots 1 and 3 had a better performance in vigor tests than lots 2 and 4. Fungi detected in the blotter test were Alternaria sp., Aspergillus sp., Cladosporium sp., and Penicillium sp. Seed lots 2 and 4 had low vigor evaluated by seedling emergence and controlled deterioration, and showed a higher incidence of Penicillium sp. in the evaluation of health quality of seeds. The incidence of Penicillium sp. may negatively affect the vigor of cucumber seeds evaluated by seedling emergence and by controlled deterioration test.

Physiological maturity of Luffa cylindrica (L.) Roem. Seeds

Maturation of seeds involves a systematic sequence of physical and physiological alterations observed from fecundation until they become independent of the mother plant. These alterations comprehend a set of steps which prepare them for a successful germination in the future, characterized by the synthesis and accumulation of reserves. Thus, the objective was to evaluate the development and physiological quality of seeds of L. cylindrica accessions during maturation. Fruits of L. cylindrica accessions were harvested from the 10th day after anthesis (DAA) until the 50th DAA, at 10-day intervals. In each harvest, fruit fresh weight was determined, and then the seeds were manually extracted and subjected to the following evaluations: 100-seed weight, seed water content, seed dry matter content, seedling emergence and emergence speed index. The experiment was carried out in a completely randomized design, with four replicates, in a 3 x 4 factorial scheme (three L. cylindrica accessions and four harvest periods). At 10 DAA, no seeds were formed in the fruits harvested from any the accessions. The best physiological performance of seeds of the L. cylindrica accessions, under the studied conditions, was found at 50 DAA.

Production and performance of sugarcane seeds (caryopses) from different hybridizations involving RB92579.

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.

Treatment of soybean seeds of different levels of physiological quality with amino acids

Abstract: The aim of this study was to assess the effect of seed treatment at different levels of physiological quality with amino acids on the performance of seeds and plants in the field. The experimental design was a randomized complete block design with four replications involving a combination of two factors. Factor A consisted of seed lots of three levels of physiological quality (high, intermediate, and low) and factor B consisted of five doses of a commercial product based on amino acids used in seed treatment.Seeds of different levels of physiological quality were treated with a commercial product (C.P.) at doses of 0, 200, 400, 600, and 800 mL C.P. 100 kg−1 of seeds. After seed treatment, the physiological performance was assessed in the laboratory and then the seeds were sowed in the field aiming at assessing plant performance, yield components, and productivity. Seed treatment with amino acids does not promote the physiological performance of seeds and plants in the field. The productivity of isolated soybean plants from seed lots of a high physiological quality is 15% higher than that of plants from seed lots of a low physiological quality.

Physiological Performance of Seeds and Level of Herbicide Residues Depending on Application of 2.4-D in Wheat

ABSTRACT: Horseweed control through application of 2.4-D in the winter season is an alternative to manage biotypes resistant to herbicides that belong to other mechanisms of action. The objectives of this study were to assess the physiological quality of wheat seeds and determine the rate of 2.4-D residue, as function of application stages and herbicide rates. The treatments were arranged in factorial scheme, with three application stages (flowering, soft dough and hard dough), and four 2.4-D rates (0; 504; 1,008 and 2,015 g a.i. ha-1). The application of 2.4-D in the wheat crop changed physiological seed quality by increased the rate and total percentage of germination. The application of 2.4-D resulted in herbicide accumulation in seeds, especially when application was carried out at the soft dough stage. Also, the increase in herbicide rate increased the level of residue in the seeds. However, regardless of stage of application for 2.4-D and herbicide rate in use, the values of residue found in the seeds were below the allowed maximum limit.

Moisture content at harvest and drying temperature on bean seed quality

ABSTRACT The physical quality and physiological performance of seeds may be influenced by numerous factors, including the moisture content at harvest and drying temperature. This study aimed at evaluating the physical quality and physiological performance of black bean seeds (BRS Campeiro cultivar), depending on the moisture content at harvest and drying air temperature. The experiment was conducted under a completely randomized design, in a 3 x 5 (moisture content at harvest x drying air temperature) factorial arrangement, with four replications. The samples were collected when the seeds reached the moisture contents of 35.2 %, 25.2 % and 16.6 %. After harvesting, the seeds were subjected to drying at temperatures of 30 ºC, 35 ºC, 40 ºC, 45 ºC and 50 ºC. The physical quality of the seeds was evaluated by determining the 1,000-seed weight and hectoliter weight. The physiological performance was evaluated by the germination speed index, germination first count, accelerated aging, dry matter, seedling shoot and root length and electrical conductivity. The increase in the drying temperature, regardless of the moisture content at harvest, reduces the physical quality and physiological performance of the seeds. When subjected to drying temperatures lower than 40 ºC, the seeds obtained from the earliest harvests show a better physical quality and physiological performance.

Características físicas e germinação de sementes de Dyckia goehringii Gross & Rauh (Bromeliaceae) sob diferentes temperaturas

Dyckia goehringii Gross & Rauh é uma bromélia nativa do Cerrado, de alto potencial ornamental, devido à coloração prateada de suas folhas, e que ainda não foi explorada comercialmente, exigindo estudos para a sua conservação e aproveitamento agronômico. O presente estudo objetivou avaliar as características físicas e o comportamento fisiológico de sementes de D. goehringii, durante a embebição e a germinação, sob diferentes temperaturas, bem como determinar parâmetros de temperatura e de tempo para a realização de testes de germinação. Foram determinados os teores de água e massa de matéria fresca e seca de 100 sementes e avaliados a capacidade de embebição, germinação e vigor de sementes e de plântulas de sementes pequenas e grandes, sob temperaturas de 20ºC, 25ºC, 30ºC e 35ºC. Os resultados indicam que as sementes não apresentam impedimento à absorção de água e que esta é influenciada pelo tamanho das sementes. Sementes grandes apresentam maior germinação e vigor, originando plântulas mais vigorosas do que sementes pequenas, expressando melhor o seu potencial fisiológico à temperatura de 30ºC. As avaliações do teste de germinação devem ser realizadas no sétimo e décimo quarto dias após a semeadura.

CARACTERÍSTICAS FÍSICAS E GERMINAÇÃO DE SEMENTES DE Dyckia goehringii Gross & Rauh (BROMELIACEAE) SOB DIFERENTES TEMPERATURAS

Dyckia goehringii is a bromeliad native from Cerrado (Brazilian savannah). Despite its high ornamental value, because of the silvery appearance of its leaves, it is not yet commercialized due to lack of information on its conservation and agronomic employment. The present investigation aimed to appraise the physical and physiological performance of seeds, during the imbibition and germination period, under several temperatures, as well as to establish temperature parameters for germination tests. The moisture content and the fresh and dry mass content of one hundred seeds were determined. The imbibition capacity, germination and vigour of seeds and seedlings of large and small seeds were observed under temperatures of 20°C, 25°C, 30°C, and 35°C. The results showed that there are no obstructions to water absorption and that this feature is influenced by seeds size. The best vigour and germination rate were observed to large seeds, which produce more vigorous seedlings than small seeds, mainly at 30°C, and germination tests should be carried out on the 7th and 14th days after sowing. KEY-WORDS: Dyckia goehringii; seed vigour and size; imbibition.