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.

Using Tomato Analyzer software to determine embryo size in x-rayed seeds

A primary interest of image analysis of X-rayed seeds is to identify whether the extent of fill in the embryo cavity is associated with to seed physiological quality. The objective of this research was to verify the accuracy of the freely available Tomato Analyzer (TA) software developed at The Ohio State University to determine the ratio of embryo size over total seed area. Seeds of pumpkin, watermelon, cucumber and cotton were X-rayed and analyzed by the software which defines seed and embryo boundaries and automatically generates numerical values to quantify that ratio. Results showed that the TA has the sensitivity to evaluate the extent of embryo growth within the cucurbits and cotton seeds and is a promising alternative for this assessment in other seed species.

Alterations in the lipid and soluble sugar content of melanoxylon brauna seeds during natural and accelerated ageing

The decay of seeds is irreversible and at best can only be delayed by applying techniques that reduce the velocity of the metabolic reactions involved. There is little information on the biochemistry of tropical forest tree seeds related to their storability. It was investigated the influence of the composition of lipids and soluble sugars of two storage compartments, the cotyledons and the embryonic axis, of Melanoxylon brauna Schot. (Leguminosae- Caesalpinioideae), a hardwood known as black brauna, seeds stored at 20 ºC for 0, 3, 6, 9 and 12 months (natural ageing) and for 0, 24, 48, 72 and 96 hours at 40 ºC (accelerated ageing). The levels of fatty acids and monosaccharides varied differentially in each of the embryo storage compartments. Changes in oligosaccharide levels were similar for both types of ageing, diminishing in both compartments. Ageing can be attributed to the significant decrease of oligosaccharides and the increase of glucose in both types of ageing and both embryo compartments.

Reserve mobilization during imbibition of stored Gliricidia sepium (Jacq.) Steud. (Leguminosae - Papilionoideae) seeds

Gliricidia sepium is a drought-tolerant species, easily multiplied by seeds, and has been exploited by farmers as a source of forage in the semi-arid region of northeast Brazil. The objective of the present study was to evaluate the effect of seed storage on the mobilization of reserves during imbibition of "Gliricidia" seeds. Freshly-harvested seeds were packed in kraft paper bags and stored for three and six months in the laboratory under ambient conditions (25 º C ± 3 T and 75% ± 3 RH). Cotyledons were isolated from imbibed seeds and macerated for the extraction and quantification of total soluble sugars, reducing sugars, sucrose and starch, as well as of proteins, amino acids and for amylase activity. Storage under these conditions resulted in an increase in seed water content although germination remained at relatively high levels (86%). Seed macromolecule levels showed significant variation with the storage period and imbibition and these variations were associated with a loss in seed viability due to inadequate storage conditions.

Physiological quality evaluation of the radii Schinus terebinthifolius seeds

Schinus terebinthifolius is a native forest species which may be used in recuperating degraded areas and in urban afforestation. In order to evaluate the efficiency of methods for separating lots of S. terebinthifolius seeds into vigor levels, five lots of seeds were qualitatively evaluated for their moisture content, germination, first count, accelerated aging (the traditional and the saturated salt methods), germination speed index, average time of germination and seedling length and dry weight. The results showed that the tests of first germination count, accelerated aging at 41 ºC for 72 hours, average time of germination, seedling length and dry matter permitted the separation of S. terebinthifolius seeds into different vigor levels.

Partial characterization of genes from the embryonic axis of Melanoxylon brauna Schott. (Leguminosae-Caesalpinioideae) seeds

The objective of this study was to partially characterize some genes involved in the desiccation tolerance of the embryonic axis of Melanoxylon brauna seeds subjected, or not, to oven fast-drying. Seeds were initially dried rapidly in an oven at 40 ºC, 50 ºC, 60 ºC, 70 ºC, and 80 °C, for 24, 48 and 72 h and then subjected to germination tests and moisture content determination. Degenerate primers were designed for 19 genes. The CDNA was used as a template for PCR amplifications using the degenerate primers, and the PCR products obtained were purified, cloned and sequenced. The seeds showed a gradual reduction in percent germination with increasing temperature and drying time. Nucleotide sequences of the cloned fragments related to genes CAT1, SPS1, Abi5, Transk and PM25 were obtained. The similarity analysis with the sequences deposited in databases revealed similarities with genes CAT1, SPS1, Transk and PM25 from other plant species. The nucleotide sequences obtained from the respective genes will be used for designing specific primers for gene expression analyses during seed germination in order to understand the causes for loss of physiological quality of Melanoxylon brauna seeds.

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.

Sensibility of the PCR technique in the detection of Stenocarpella sp. associated with maize seeds

Maize seeds, infected by Stenocarpella species, are important sources of inoculum for the introduction and dissemination of stalk and ear rot and macrospore leaf spot diseases. The use of healthy seeds is an important strategy for the preventive control of these diseases. However, one of the difficulties in the health quality control programs for maize seeds is the availability of a reliable and quick method for detecting these fungi during routine seed analyses. Therefore, the objective of the present study was to investigate the possibility of using the PCR technique as an alternative method for accurately detecting these pathogens in maize seed samples. Maize seeds were kept in contact with S. maydis colonie developed in PDA media containing mannitol at -1.4 MPa for 72 h. The seed samples used in this study were prepared with infected seeds at incidences of 100, 20, 10, 2, 1 and zero %.The primers used were able to detect S. maydis fungi in association with seeds with a maximum of 2% , however those primers were not able to differentiate between the two species.

Physiological maturity of fruits and seeds of Poincianella pyramidalis (Tul.) L.P. Queiroz

The Leguminosae family is one of the most representative botanical families of the Caatinga, with 80 endemic species, highlighting the catingueira (Poincianella pyramidalis). The objective of this research work was to study the maturation process of P. pyramidalis seeds based on the physiological maturity. Five harvest of fruits and seeds were carried out, with 15 days interval each, in a period from July to September 2010. The harvests began 75 days after anthesis (d.a.a.) and lasted until 135 d.a.a. Fruits and seeds were subjected to the following assessments: size, moisture content, and dry mass of fruits and seeds; and germination and vigor of seeds (first count of germination, germination speed index, length and dry mass of seedling). Under the environmental conditions of municipality of Soledade, State of Paraiba, Northeast Brazil, the point of physiological maturity of P. pyramidalis seeds occurs at 125 d.a.a., when the maximum accumulation of dry mass is 1.993 g and moisture content is 21%. The ideal point of harvest is between 130 d.a.a and 135 d.a.a., before natural dehiscence, when the moisture content of seeds is between 13.0% and 5.0%.

Viability of recently harvested and stored Xylopia aromatica (Lam.) Mart. (Annonaceae) seeds

Xylopia aromatica is a native species from Brazil's "Cerrado", recommended for restoration ecology and also as a medicine. Its seeds have embryos with morphophysiological dormancy, making nursery propagation difficult. The objective of this study was to verify the efficiency of X-ray and tetrazolium tests for evaluating the viability of three seed lots, stored for different periods. All seeds were X-rayed (13 kV, 350 seconds) and samples used for tetrazolium and germination tests. In the tetrazolium test, seeds were submitted to six treatments at two temperatures (25 and 30 °C) with imbibition in distilled water and immersion in three concentrations of tetrazolium solution (0.5, 0.75 and 1%) at the two imbibition temperatures. Seeds for the germination test were placed for imbibition in distilled water and a 500 ppm Promalin® (6-Benzyladenine + GA4 + GA7) solution and later sown in sterilized sand. The embryo could not be observed with the X-ray test. However, those seeds observed with an undamaged endosperm did not differ in the percentages of seeds with firm and stained endosperms observed in the tetrazolium test for all the lots. The tetrazolium test is efficient for evaluating seed viability, principally if imbibed at 30 °C and immersed in a 0.5% solution at 30 °C.

Storage of Tabebuia caraiba (Mart.) Bureau seeds in different packaging and temperatures

Tabebuia caraiba (Mart.) Bureau, commonly known as Silver Trumpet Tree is a forestal species, belonging to Bignoniaceae family, which can be utilized as medicinal plant or in landscaping of urban and rural areas; besides producing large mechanical resistance wood. Despite its wide use and ecological importance, basic studies on storages of their seeds are scarce. This way, the objective of this study was to determine the most adequate packaging and the best temperatures, for storing seeds of T. caraiba. For this, seeds were stored in two types of packaging: Kraft paper bags and transparent polyethylene bags; which were then stored during 150 days under three different environments: laboratory normal environment (25±2 °C); cold chamber (8±2 °C); and refrigerator (6±2 °C). After periods of 0, 30, 60, 90, 120, and 150 days, seed moisture content, percentage of emergence, emergence speed index, and seedling length were evaluated. Seeds of T. caraiba kept in packaging of paper and polyethylene bags and stored at laboratory environmental condition, have lost more quickly their vigor along the storage period. For storage, it is recommended the maintenance of T. caraiba seeds in polyethylene bags into cold chamber; and/or polyethylene bags or Kraft paper bags into refrigerator.

Influence of leaf retention on cutting propagation of Lavandula dentata L.

Vegetative propagation of lavender offers several advantages over sexual propagation, among them crop homogeneity and yield of higher quality essential oil. However, Lavandula species have been propagated mostly by seeds and are said to be recalcitrant to rooting when propagated by cuttings. During cutting propagation, one of the important variables that influence the rooting capacity of cuttings is the leaf retention. The objective of this work was to evaluate the influence of leaf retention on rooting of L. dentata cuttings. Apical cuttings of L. dentata of 10 cm in length, keeping approximately 1/3, 1/2 or 2/3 of their leaves were planted in commercial substrate Plantmax HT® under intermittent mist. After two months, averages of root number, length of the longest root, root fresh and dry weights, and the survival percentage were evaluated. Root length and fresh weight were statistically greater with 2/3 of leaf retention and when fewer leaves were kept on the cuttings, lower means of root dry weight was observed. Under the conditions applied in this study, greater leaf retention was better for rooting of L. dentata cuttings.

Drying kinetics of jatropha seeds

Given the necessity of developing jatropha cultivation equipment, this work adjusted different mathematical models to experimental data obtained from the drying of jatropha seeds submitted to different drying conditions and selected the best model to describe the drying process. The experiment was carried out at the Federal Institute of Goiás - Rio Verde Campus. Seeds with initial moisture content of approximately 0.50 (kg water/kg dry matter) were dried in a forced air-ventilated oven, at temperatures of 45, 60, 75, 90 and 105°C to moisture content of 0.10 ± 0.005 (kg water/kg dry matter). The experimental data were adjusted to 11 mathematical models to represent the drying process of agricultural products. The models were compared using the coefficient of determination, chi-square test, relative mean error, estimated mean error and residual distribution. It was found that the increase in the air temperature caused a reduction in the drying time of seeds. The models Midilli and Two Terms were suitable to represent the drying process of Jatropha seeds and between them the use of the Midili model is recommended due to its greater simplicity.

Species richness of anthophilous butterflies of an Atlantic Forest fragment in Southeastern Brazil

The objectives of this study were to identify anthophilous butterflies on psychophilous flowers of four Asteraceae species in an Atlantic Forest fragment in Viçosa, Minas Gerais State, Southeastern Brazil, and to determine whether there are species in common with other lepidopteran inventories of the Southeastern and Midwestern regions of Brazil. It is the first inventory of anthophilous butterflies of a semideciduous forest fragment in Zona da Mata, State of Minas Gerais. A total of 108 species were recorded, representing the fourth largest lepidopteran survey in this State. The results demonstrated that Asteraceae species may be important tools for monitoring anthophilous butterflies. The similarity with other inventories ranged from 1 to 92.55%. Fifteen species were reported for the first time in the State of Minas Gerais, and among them, Melanis alena and Thisbe irenea were observed in this study only.

Soybean growth and yield after single tillage and species mixture of cover plants

The use of cover crops is important for the agricultural crop and soil management in order to improve the system and, consequently, to increase yield. Therefore, the present study analyzed the effect of crop residues of black oat (Avena strigosa Schreb.) (BO) and a cocktail (CO) of BO, forage turnip (Raphanus sativus L.) (FT) and common vetch (Vicia sativa L.) (V) on the emergence speed index (ESI), seedling emergence speed (SES) plant height and soybean yield in different intervals between cover crop desiccation with glyphosate 480 (3 L ha-1) and BRS 232 cultivar sowing. Plots of 5 x 2.5 m with 1 m of border received four treatments with BO cover crops and four with CO as well as a control for each cover crop, at random, with five replications. The plots were desiccated in intervals of 1, 10, 20 and 30 days before soybean seeding. The harvest was manual while yield was adjusted to 13% of moisture content. The experimental design was completely randomized with splitplots and means compared by the Scott and Knott test at 5% of significance. The results showed that CO of cover crops can be recommended for soybean to obtain a more vigorous seedling emergence, from 10 days after cover crop desiccation.