Achene dimorphism in Bidens pilosa L. (Asteraceae) as determined by germination test

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of foliar fertilization with manganese on germination, vigor and storage time of RR soybean seeds

ABSTRACTThis study aimed to evaluate the influence of foliar fertilizer doses containing Mn of phenological stages of suggested application in RR soybeans, to recover management damages with glyphosate at postemergence application on seed vigor in post-harvest and post six months storage. The seeds originated from a field experiment conducted , which included two applications of glyphosate, concomitant with foliar fertilizer in growth stages V4 and V6, with 0.00, 113.50 and 227.00 mg ha-1doses of Mn2+. Germination, GSI (Germination Speed Index), electrical conductivity tests and the first count of seeds were conducted. The application of Mn did not affect the physiological quality of RR soy in postharvest. However, in post-storage, higher doses of Mn had a negative effect on tests of abnormal seedlings, GSI and electrical conductivity. The applications of Mn, regardless of the developmental stage, did not interfere in the germination and first count tests, with and without storage. The electrical conductivity test showed a higher correlation with the seed germination test in the post-harvest treatment.

Soluble sugars and germination of Annona emarginata (Schltdl.) H. Rainer seeds submitted to immersion in GA3 up to different water contents

The objective of this study was to evaluate the effect of different water contents achieved by Annona emarginata (Schltdl.) H. Rainer seeds during immersion in GA3 solutions, in variation of soluble sugars levels and germination. Seeds with 10% of initial water content were submitted to imbibition in GA3 solutions with concentrations of 0; 250; 500; 750 and 1000 mg L-1 and when they reached the water content of 15%, 20%, 25%, 30% and 35%, the quantification of soluble sugars levels and germination test were performed. Seeds immersed up to they reach 15% of water with GA3 and immersed up to the water acquisition of 20% without GA3, presented higher soluble sugars levels and germination percentage, which were decreased when the seeds reached 30% and 35% of water, independently of the presence of the plant growth regulator. It was conclude that different water contents reached by the seeds in immersion treatments with GA3 affect the soluble sugars levels and germination percentage of Annona emarginata seeds. Thus, in treatments with Annona emarginata, the seeds must remain immersed in water without GA3 up to they reach 20% of water, as higher water contents (35%) reduce the soluble sugars levels and the seed germination percentage.

Primary metabolite mobilization during germination in rosewood (Aniba rosaeodora Ducke) seeds

This study aimed to characterize protein, oil, starch and soluble sugar mobilization as well as the activity of alpha-amylase during rosewood seed germination. Germination test was carried out at 25°C and the following parameters were analyzed: percentage of germination, initial, average, and final germination time. Seed reserve quantification was monitored in quiescent seeds and during different stages of radicle growth. Starch mobilization was studied in function of a-amylase activity. Germination reached 87.5% at the initial, average, and final time of 16, 21 and 30 days, respectively. Oil mobilization showed a negative linear behavior, decreasing 40% between the first and the last stage analyzed, whereas protein levels increased 34.7% during the initial period of germination. Starch content (46.4%) was the highest among those of the metabolites analyzed and starch mobilization occurred inversely to the observed for soluble sugars; alpha-amylase activity increased until the 15th day, a period before radicle emission and corresponding to the highest starch mobilization. The high percentage of rosewood seed germination may be related to the controlled condition used in the germination chamber as well as to high seed reserve mobilization, in special oil and starch.

Germination of Caesalpinia leiostachya (benth.) ducke seeds classified by size and shape

Caesalpinia leiostachya (Benth.) Ducke (Caesalpiniaceae) is a Brazilian legumenous tree whose seeds present different sizes and shapes, with dormancy imposed by a waterproof coat. In order to improve that quality of lot, seeds were classified by width in sieves of circular meshes (13, 14, 15, 16 and 17) and manually separated by shape in elongate, round and angular. Masses of 1000 seeds were determined and the thickness of each width and shape seedclass was measured, and coat permeability of the seeds classified by the width was investigated. Seeds were scarified in concentrated sulphuric acid and submitted to the germination test. Both final percentage and speed of germination index were evaluated. The classification of the seeds improved the quality of the lot, and the coat permeability was not affected by seed width. Elongated-flat seeds are of low physiological quality and should be discarded. Masses of 1000 seeds, percentage final and speed of germination increased with the width of the seeds. Both elongated and angular seeds had similar germinative behavior, and round seeds are of greater thickness and of superior physiological quality.

Germination, initial growth and cotyledon protein content of bean cultivars under salinity stress

Excess salts in the root zone inhibit water uptake by plants, affect nutrient uptake and may result in toxicities due to individual salts in the soil solution. Excess exchangeable sodium in the soil may destroy the soil structure to a point where water penetration and root aeration become impossible. Sodium is also toxic to many plants. Beans (Phaseolus vulgaris L.) are consumed as protein source in northeastern Brazil, although little is known about common bean cultivar tolerance to salinity. The germination of bean cultivars under salt stress was studied. The cultivars 'Carioca' and 'Mulatinho' were submitted to germination test in a germinator at 25ºC, at the Seed Analysis Laboratory of the Brazilian Agricultural Research Corporation unit in the Semi- Arid region (Embrapa Semi Árido), Petrolina, Pernambuco State. These seeds were germinated on "germitest" papers imbibed in distilled water or in 10, 50, 100 e 200 mol.m-3sodium chloride (NaCl) solutions. At the first and second counts of the germination test, normal seedlings were counted, measured, weighed and dried, supplying data for vigor, total germination, fresh matter weight and dry matter weight and seedlings length. Total protein was quantified in cotyledons at 3, 6 and 9 days after sowing. The results indicated that the NaCl content influenced seed germination and concentrations above 50 mol.m-3 decreased germination and seedling growth.

Physical purity and germination of sugarcane seeds (caryopses) (Saccharum spp.)

Plant breeding is generally done through sexual reproduction even when the species is propagated asexually for commercial exploitation, as for example, in sugarcane. Therefore, the development of procedures to evaluate sugarcane seed viability is important for plant breeding programs. The objective of this research was to develop a methodology for analyzing the viability of sugarcane seeds (Saccharum spp.). Three crosses were used, two biparental crosses and one polycross. For the germination test study, two substrates (paper and sand) and three constant incubation temperatures (25 ºC, 30 ºC and 35 ºC), in the presence of constant light and also an alternating temperatures (20-30 ºC), with 8 hours light (30 ºC) and 16 hours darkness (20 ºC), were studied. Seedlings were evaluated every five days. The results demonstrated that temperature affected sugarcane seed germination with the most favorable conditions being the alternating temperature (20-30 ºC) and the constant temperature of 30 ºC on a paper substrate.

Viability of barley seeds by the tetrazolium test

The tetrazolium test is used to control seed quality of various plant species since it allows a rapid evaluation of viability. Freshly harvested barley seeds show dormancy that can make the germination test ineffective for an immediate evaluation. Therefore, the development of more efficient methods, such as the tetrazolium test, is necessary. The objective of this research work was to study various procedures for performing the tetrazolium test on barley seeds. Five lots of cv. BRS 195 barley seeds were used and subjected to the following treatments: two different methods of seed preconditioning (direct immersion in H2O and between sheets of moistened paper towels); two types of preparation for staining (longitudinal cross-section of the seed through the embryo with immersion of one half in a 2,3,5 triphenyl tetrazolium chloride solution or placing both halves on top of filter paper moistened with the tetrazolium salt solution); two methods of staining (on top of filter paper and direct immersion in the tetrazolium salt solution). Three concentrations of the tetrazolium salt solution (0.1%, 0.5%, and 1.0%) were used. It was concluded that the tetrazolium test on barley seeds may be accomplished with preconditioning by direct immersion in H2O and staining by immersing in a 0.1% or 0.5% concentration of tetrazolium salt solution or staining on top of filter paper moistened with such solution at a 1.0% concentration.

Test of exudates color hues for evaluating the physiological potential of coffee (Coffea arabica L.) seeds

Coffee seeds have slow and irregular germination, losing fast their viability during storage, and the standard germination test of these seeds requires at least 30 days. Besides, the results may not reflect the actual physiological quality of these seeds. The objective of this work was to develop a fast and practical test for evaluating the viability of coffee seeds, which is based on the interpretation of different color hues of exudates from seeds. Coffee seeds of the cultivar Catuai 44 from six lots were submitted to germination, accelerated aging, and electrical conductivity tests. In the exudates color hue test, coffee seeds without the parchment and the silvery pellicle (four replications of 10 seeds each) were distributed on top of paper towels moistened and then maintained into a germinator, at 25 ºC for 24, 48, 72, 96, and 120 h. Three classes of color hues were established: colorless, light color hue, and dark color hue, assigning the values of 0, 1, and 3, for each class, respectively. The proposed exudates color hue test can be recommended for the fast assessment of viability for coffee seeds. The most promising results were obtained for seeds with 12% moisture content, after imbibition periods of 72, 96, and 120 h; and with 30% moisture content, after imbibition periods of 72 and 120 h.

Floral biology and characterization of seed germination in physic nut (Jatropha curcas L.)

The objective of this study was to characterize morphologically the seed germination and floral biology of Jatropha curcas grown in Viçosa, Minas Gerais state. The floral biology study was made on fresh inflorescences of 20 plants. For the post-seminal development study, the seeds were submitted to laboratory and greenhouse germination test. J. curcas has flowers of both sexes within the same inflorescence, with each inflorescence having an average of 131 flowers, being 120 male and 10.5 female flowers. Low numbers of hermaphrodite flowers were also found, ranging from 0 to 6 flowers per inflorescence. The germination of J. curcas begins on the third day with radicle protrusion in the hilum region. The primary root is cylindrical, thick, glabrous and branches rapidly, with about 4-5 branches three days after protrusion, when the emergence of the secondary roots begins. Seed coat removal occurs around the 8th day, when the endosperm is almost totally degraded and offers no resistance to the cotyledons that expand between the 10th and 12th day. A normal seedling has a long greenish hypocotyl, two cotyledons, a robust primary root and several lateral roots. On the 12th day after sowing, the normal seedling is characterized as phanerocotylar and germination is epigeal.

Relationship between eggplant seed morphology and germination

Structural differences such as abnormalities, damage and free spaces in seeds may affect germination. The aim of this study was to study the relationship between eggplant seed morphology and seed germination. Ten seed lots of the eggplant cultivar Embu were evaluated by X-ray image analysis and the germination test. Seed image analysis was performed by Image Pro Plus® software and the whole seed area and free space between the embryo and endosperm were measured. The internal seed area filled by the embryo and endosperm was calculated from the difference between the whole seed and free space areas. Based on these results and visual seed analysis, seeds were classified into three categories and information on germination was obtained for each one. X-ray image analysis provides a perfect view of the internal seed parts and for seed morphology studies. An increase in seed area filled by the endosperm and embryo does not improve seed germination. Mechanical seed damage and deteriorated tissues can adversely affect seed germination.

Germination of Albizia hassleri seeds at different temperatures, under laboratory conditions

The objective of this study was to analyze the germination of seeds of Albizia hassleri under different temperatures. A completely random design arranged as a split plot for temperatures regimes, with 11 seed lots and four replications of 15 seeds was used. The plot was represented by the various lots and the sub plots for different temperatures. The means were compared by Scott-Knott test at 5% probability. The temperatures used were: a) constant: 20, 25 and 30 degrees C, and b) alternating: 20-30 and 25-35 degrees C. For all 11 seed lots the mean germination was 90%, speed germination index (IVG) was 5.059, fresh matter of seedlings (MMF) was 0.0628 g and dry matter (MMS) 0.0499 g. The variation coefficient (CV) between plots ranged from 8.48% for germination to 51.71% for dry matter of seedlings and sub plot of 6.77% to 60.45% for germination and MMS. These high values of CV, tested for MMS and MMF, indicate low repeatability of results within each treatment. In general, the IVG obtained at temperatures of 20 and 25 degrees C was lower than those in temperatures of 30, 20-30 and 25-35 degrees C. The best temperature for IVG was the alternating 25-35 degrees C and constant 30 degrees C. The germination test can be conducted at 30, 20-30 and 25-35 degrees C for 19 days.

Electrical conductivity test in the evaluation of physiological quality in seeds of Zeyheria tuberculosa

The electrical conductivity test is still an excellent tool to evaluate the effect of seeds of various forest and agricultural species and recent studies have been conducted aiming at verifying its application in forest seeds. The objective of this study was to establish a specific methodology to test the electrical conductivity of forest seeds of Zeyheria tuberculosis. Four lots of seeds were used, which were submitted to the germination test, evaluating the percentage of germination, germination speed index and dry mass of seedlings. For the electrical conductivity test, five replicates of 20 seeds installed in three volumes of deionized water (75, 100 and 125 mL) were used and eight periods for seed imbibitions (2, 4, 6, 12, 18, 24, 48 and 72 hour) at 25 degrees C were allowed. The statistical design used was completely random; the comparison of means was performed by Tukey test at 5 % probability. Lot II showed higher germination percentage and speed. The electrical conductivity test allows discrimination of the same batch by the germination test under laboratory conditions. It was possible to separate the seed lot presenting better physiological quality (lot II) from among the other lots. It was recommended the use of 75 or 125 mL of deionized water at a temperature of 25 degrees C to perform the electrical conductivity test.

Seed maturation and effect of temperature regime on Trema micrantha (L.) Blume seed germination

T. micrantha (L.) Blume (Ulmaceae), a common pioneer tree species in Brazil, is used in the restoration of degraded areas. The fruits are fleshy and indehiscent, with only one water impermeable seed. During the fruiting period, fruits of different colours are found at the same time on the same branch. This research aimed to correlate fruit colour with other physical indicators of seed maturity and to Verify the effect of temperature regime on seed germination. Collected fruits were separated in to green, green-red and red colour and for each of these maturation stages, size, moisture content and dry matter of both fruits and seeds were determined. Seeds were scarified with sulphuric acid and submitted to a germination test conducted at constant (20 degreesC, 30 degreesC and 40 degreesC) and alternating (20-30 degreesC, 30-40 degreesC and 20-40 degreesC) temperatures for 15 weeks. Seed germination percentage and speed were analysed after five weeks and the fmal percentage of germinated and Viable seeds after 15 weeks. Seed maturity is attained when the fruits are green-red. At this stage, moisture content was about 64% for fruits and 10% for seeds. Alternating temperature was required for seed germination and 20-30 degreesC was the best option. Most seeds had germinated after five weeks, providing mature seeds, acid scarification and alternating temperature were used.

Soluble sugars and germination of Annona emarginata (Schltdl.) H. Rainer seeds submitted to immersion in GA3 up to different water contents

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)