Phytotoxicity of organic extracts of Turnera ulmifolia L. and Turnera diffusa Willd. ex Schult. in cucumber seeds

We evaluated the phytotoxic effects that the hexane, ethyl acetate and methanol extracts from leaves and branches of the species Turnera ulmifolia L. and Turnera diffusa Willd. ex Schult. (Turneraceae), at concentrations of 1.25, 2.50, 3.75 and 5.00 mg ml-1, have on seed germination and seedling development in cucumber (Cucumis sativus L.). None of the extracts tested prevented germination, although the ethyl acetate extracts of T. diffusa, at 3.75 and 5.00 mg ml-1, reduced the mean germination speed and time to germination. Hexane extracts of both species reduced the main root length, number of secondary roots and hypocotyl length. In the ethyl acetate and methanol extracts, the number of secondary roots and hypocotyl length varied by species and concentration. Ethyl acetate extracts of T. ulmifolia at ≤ 2.50 mg ml-1stimulated growth of the main root and hypocotyl, as did T. ulmifolia methanol extracts at 1.25 and 3.75 mg ml-1; all other extract/concentration combinations had an inhibitory effect on those parameters. The hexane and ethyl acetate extracts of T. diffusa inhibited the formation of secondary roots and of the main root, although significant inhibition of hypocotyl growth was observed only at ≥ 2.50 mg ml-1. Comparatively, T. diffusa extracts inhibited development to a greater degree, thus presenting greater allelopathic potential, than did T. ulmifolia extracts.

Morphology and initial growth in the germination of dictyosperma album (bory) h. wendl. & drude ex scheffer (Arecaceae) seeds

Dictyosperma album, commonly known as Princess Palm, due to its graceful appearance and its ability to withstand strong hurricane force winds is largely used in landscaping areas. The aim of this work was to describe the diaspores (seeds with the stuck endocarp) morphology and the stages of the D. album germination process. Therefore we concluded that the species germination is of the tubular remote type and begins with the opening of a circular operculum in the fruit endocarp, through which emerges a bulbous and hollow structure, named cotyledonal petiole or embryophore. With the embryo growth, the endosperm is being gradually consumed. The embryo grows approximately up to 10 cm, when the dilation begins in its extremity. Starting from this extensive area, it begins the growth of the primary root and the opening of a longitudinal rift, through which emerges the aerial part that is composed by two sheaths that cover the first juvenile leaf. In this phase, the emergence of secondary roots is observed. The first leaves are simple and lance-shaped.

Temperature and scarification on seeds germination of copernicia prunifera (Mill) H.E. Moore (Arecaceae)

Copernicia prunifera, known as carnauba, is native to Brazil and presents great potential to be used in gardens and cultivation in pot. Palms species, with relatively few exceptions, can only be propagated by seeds; even so, there are no reports in the literature about the germination of this palm seeds. Several species of the Arecaceae family present seed physical dormancy in varying degrees, demanding treatments to improve germination. The objective of this work was to study the effects of temperature and mechanical scarification on seed germination of C. prunifera. The experimental design was entirely randomized in a factorial arrangement 6 x 2 (six conditions of temperature with or without mechanical scarification) with 4 replications and 25 seeds each. In accordance with the treatment, lateral scarifications were made on the seeds until appearance of the endosperm. Seeds were sown in moist fine vermiculite. Germination (%) and germination rate (GR) were evaluated. Germination data were arcsine (x/100)1/2 transformed before analysis of variance and germination rate data were not transformed. The means of the resulting values were then compared by the Scott-Knott test at 1% confidence level. It was concluded that the biggest germination percentage were obtained at alternated temperature of 25-35°C (92%) and at constant temperature of 25°C (87%). Seeds germinated faster at alternated temperature of 25- 35°C. Germination percentage was similar for the scarified and non-scarified seeds; however, scarified seeds germinated faster.

Seed germination of two Syagrus species native to Brazil

Palm species native to Brazil such as Syagrus picrophylla and S. schizophylla have great ornamental value and for this reason are much demanded for use in landscape. Its propagation is by seeds and often presents considerable problems to nursery managers because their seed has a hard and impermeable shell. Temperature is one of the factors that influence the seed germination process; however, the information for these species is scarce. Thus, this work aimed to study the effects of temperature regimes on the germination of S. picrophylla and S. schizophylla seeds and develop some recommendations in which temperature will obtain high rates of seed germination. The experimental design was entirely randomized with six temperatures and four replications of 25 seeds for each species. Germination and germination rate were evaluated. Higher and faster germination of S. picrophylla and S. schizophylla seeds were verified at constant temperature of 30°C and 35°C; and alternated temperature at 25-35°C.

Sporophytic apomixis in polyploid Anemopaegma species (Bignoniaceae) from central Brazil

Apomixis and polyploidy have been important in the evolution of the angiosperms, and sporophytic apomixis has been associated with polyembryony and polyploidy in tropical floras. We studied the occurrence of polyembryony in populations of tetraploid Anemopaegma acutifolium, A.arvense and A.glaucum from the Brazilian cerrados, and histological features of sexual and apomictic processes were investigated in A.acutifolium. All populations and species were polyembryonic (68.9-98.4% of seeds). Normal double fertilization occurred in most ovules, with exceptions being that 3% of ovules were penetrated but not fertilized and in 4% of ovules both synergids were penetrated. The penetration of both synergids suggests a continuous attraction of pollen tubes and polyspermy. Adventitious embryo precursor cells (AEPs) arose from nucellar and integumental cells of the ovule in pollinated and unpollinated A.acutifolium, indicating sporophytic apomixis. However, further embryo and endosperm development required pollination and fertilization. This pseudogamy also allows concurrent sexual embryo development. Similar polyembryony rates and polyploidy indicated that A.arvense and A.glaucum are also apomictic, forming an agamic complex similar to that observed for some species of confamilial, but not closely related Handroanthus. The co-occurrence of apomixis and polyploidy in different groups of Bignoniaceae indicates homoplasious origin of these agamic complexes. © 2013 The Linnean Society of London.

Micropropagation of Maclura tinctoria L.: an endangered woody species

Algumas espécies nativas produzem sementes com baixa porcentagem de germinação e, na maioria dos casos, dormência que pode dificultar o aparecimento de novos indivíduos, por meio da propagação sexuada. A Maclura tinctoria tem sido considerada como ameaçada de extinção devido ao uso indiscriminado de sua madeira e à baixa taxa de germinação de suas sementes. Nesse contexto, o objetivo deste estudo foi estabelecer uma metodologia de propagação in vitro para a espécie. Combinações de ANA + BAP, diferentes concentrações de GA₃ e combinações de AIB + carvão ativado foram avaliadas na indução de brotações, alongamento caulinar e indução de enraizamento, respectivamente. Os resultados indicaram que a máxima formação de brotações foi obtida quando 5,37 mM NAA + 4,45 mM BAP foram utilizados. O crescimento das brotações foi observado com 5,48 mM GA₃. Para a formação de raízes, foi indicado o uso do meio WPM, com pH ajustado para 7,0, suplementado com 23,62 mM AIB e 4,7 g L^-1 de carvão ativado. O uso de sombrite 70% por sete dias, seguido da utilização de sombrite 50 e 30%, também por sete dias cada, promoveu 97% de sobrevivência de plantas.

Water uptake by Annona diversifolia Saff. and A. purpurea Moc. & sessé ex dunal seeds (Annonaceae)

Annonaceae seeds are known by presenting dormancy mechanisms, whose reports ranging from coating impermeable to the physiological dormancy. By this way, the present study aimed to evaluate water uptake in Annona diversifolia Saff and Annona purpurea Moc & Sessé ex Dunal seeds. For this study, seeds were placed under immersion in distilled water, and used four replicates of 25 seeds of each species, which were weighed during the 480 hours that were immersed. To determine the place of purchase of water, Annona diversifolia seeds were sealed with paraffin at different locations. Based on the results, seeds from both species reached the phases I and II of water uptake, which indicates they are not hard; however, germination (Phase III) was not reached. Annona diversifolia seeds completed Phase I with, 50h and Annona purpurea with 70h from imbibitions begin, which shows that even slowly, water is acquire.

Assessment of the physiological potential of spinach seeds (Tetragonia tetragonoides (Pall.) Kuntze)

The efficiency of vigor tests in assessing the physiological potential of seeds depends on their standardization for different species. In this context, the research aimed to study specific methodologies to evaluate the vigor of spinach seeds (Tetragonia tetragonoides). For this purpose, five lots of spinach seed cv. New Zealand were submitted to germination, first count of germination, seedling emergence in the field, accelerated aging (with and without use of saturated solution of NaCl at 41and 45 ºC for 24,48 and 72 hours), controlled deterioration (18,21 and 24% seed water content adjustments for 24 hours at 45 ºC) and electrical conductivity tests with variations inwater volume (25, 50 and 75 mL), seed quantity (25 and 50) and soaking period (1, 2, 4, 8,12, 16 and 24 hours) at 25 ºC. The first count test allowed obtaining preliminary information about seed vigor, and other tests in general showed similarity with seedling emergence in the field. Thus, it was concluded that traditional accelerated aging test 24 h /41 ºC and accelerated aging test with saturated salt solution for 24 h at 41 ºC and 45 ºC, and controlled deterioration test with 21% seed water content / 24 h / 45 ºC were all efficient for evaluating the physiological potential of spinach seeds.

Seasonal variation in the fate of seeds under contrasting logging regimes

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

Maturity, Pulp Removal and Storage Effects on the Germination of Livistona rotundifolia Seeds

The Livistona rotundifolia species is native to Oceania, and has a high potential for landscaping use and as a pot plant. This work aimed to study the effects of the maturation stage, pulp removal and storage on the germination of L. rotundifolia seeds. The experimental design was entirely randomized in a factorial arrangement 5x2x2 (five storage periods: 15, 30, 45, 60 and 75 days; two maturation stages: green and ripe; and the presence or absence of the pulp - exocarp and mesocarp) with four replications of 25 seeds each. After sorting out the fruits by the maturity stage and removing the pulp out of half of the fruits from each plot, the seeds were placed in closed bottles, which were sealed and stored in a cold chamber at 10 degrees C. The seeds were removed from the cold chamber and left to germinate in plastic boxes (gerbox type) with sphagnum. The boxes were kept at 25-35 degrees C and photoperiod of 12 hours. The germination rate was determined when seed germination was steady. The highest germination rate was found when green fruits had their pulp removed. The germination rate gradually decreased with the increase of the storage period regardless the maturation stage and the presence or absence of the pulp.

Germination of Roystonea borinquena OF Cook (Arecaceae) Seeds

This work aimed to study the effect of the temperature on the seed germination and to describe the morphology and germination process of disseminules (seeds with stucked endocarp) of R. borinquena species. The fruits were harvested and had their pulp (exocarp and mesocarp) removed and the disseminules were shade dried. The experimental design was entirely randomized and six treatments were performed (temperature conditions: constant at 25, 30 and 35 degrees C; alternated at 25-35 and 20-30 degrees C; and room temperature) with four replications with 25 disseminules per plot, placed in plastic boxes (gerbox) containing vermiculite. The germination rate and germination speed index were calculated, and the data were submitted to the variance analysis, and the means compared by the Tukey test. For the morphological studies, the external and internal sides of the disseminules, the embryo and the representative germination stages were sketched. The samples were fixed in FAA (formalin - acetic acid - ethyl alcohol). It was concluded that the highest germination rate and faster germination were at the constant temperature of 35 degrees C and alternated of 25-35 degrees C. The seeds are albuminous, with a hard endosperm that takes almost the entire interior of the disseminules; the embryo is lateral, peripheral and poorly differentiated; the germination is adjacent.

Seed germination performances of Styrax species help understand their distribution in Cerrado areas in Brazil

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A New Species of Maytenus (Celastraceae) with Fleshy Fruits from Eastern Brazil, with Notes on the Delimitation of Maytenus

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

STORAGE OF Handroanthus umbellatus SEEDS

Seed storage under controlled environmental conditions represents one of the most important lines of research to be applied on short-lived forest species as Handroanthus. The present research aimed to identify the most suitable seed storage conditions and longevity behavior of Handroanthus umbellatus seeds subject to the following storage treatments: packaging permeable paper bags under a no-controlled laboratory temperature and humidity (control) and multiwall semipermeable bag at temperatures of -18 degrees C ,1 degrees C and 25 degrees C. Seeds were dried to 6.3% of water content. Stored seeds were evaluated every three months until 24 months for water content, germination percentage and vigor utilizing first counting test. Seeds of T. umbellata are orthodox, with low longevity under natural conditions, once they remain viable for less than 5 months. The best conditions of seed preservation of these species were obtained by storage at -18 degrees C in multiwall bags. Under these conditions physiological seed quality remains unchanged for a 24-month period.

Germination, vigor and pathogen incidence in broccoli seeds treated with Carboxin + Thiram

The purpose of treating seeds chemically is to eradicate their pathogens and/or protect them against soil pathogens, mainly by germination time. However, there is little research on vegetables investigating the effect of this treatment on seed quality. Therefore, this study evaluates the effects of Carboxin + Thiram doses on germination and vigor of three lots of broccoli seeds, as well as on the incidence of fungi in treated seed. The 15 treatments were evaluated in a factorial system (3x5), with the first factor consisting of three lots of 'Avenger' broccoli seeds (lots 82744, 82745 and 82749), and the second factor consisting of five doses (0, 0.04, 0.06, 0.10 and 0.12% of a.i.) of Carboxin + Thiram fungicide (commercial name Vitavax-Thiran). The germination and seed vigor were evaluated, in addition to the presence of pathogens in seeds after treatment (blotter test). All lots showed high levels of germination and vigor. The lot 82749, however, showed higher value in plug test in substrate emergence (99%) than lot 82745 (95%). Regarding the treatment with Carboxin + Thiram, no changes in germination average (98%) and vigor were noticed (average for the first germination count, length, and dry weight of seedling, plug test at 10 days after sowing of 97%, 4.9 cm, 4.0 mg and 96%, respectively), showing that this fungicide, in the evaluated doses, does not affect the quality of broccoli seeds. As to seeds health, the pathogens Alternaria spp. and Fusarium spp. were detected, in addition to saprophytic species such as Penicillium, Aspergillus, Trichoderma, and Rhizopus. The higher incidence of Fusarium spp. was noticed in lot 82744, and the lowest in lot 82749. As to Penicillium spp., lot 82479 was the most contaminated. Regarding other fungi, the general incidence was very low and there was no difference between lots and doses used.