Semi-hypogeal germination in Pachyrhizus ahipa (Wedd.) parodi (Fabaceae: Phaseoleae): seedling and sapling morphology

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

Seed with and without Partial Tegument Removal and Substrate Affect Germination of Castanea sativa

Portuguese chestnut (Castanea sativa) is used for forest products, raw nuts and processed flour, paste, and candy. We studied the influence on germination efficiency of seed with and without partial tegument removal combined with different substrate composition (coconut fiber, pine compost and vermiculite) at São Paulo State University, Campus of Botucatu, São Paulo, Brazil. Randomized blocks were used in a factorial scheme 3x2 (three substrates x two seed types) consisting of six treatments with five replications (twelve seeds). Seeds were sowed in expanded polystyrene trays, with 72 cells, and maintained at 25 C under controlled environment. Rate, time elapsed and speed of seed germination was submitted to ANOVA and the average compared using Tukey's 5% test of probability and curves adjusted based on Gompertz regression. Coconut fiber or vermiculite associated with seed without partial tegument removal showed the highest germination rate, and coconut fiber with or without partial tegument removal displayed the fastest speed of seed germination.

Imbibition phases and germination response of Mimosa bimucronata (Fabaceae: Mimosoideae) to water submersion

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influence of light quality on germination and initial growth of canephori seedlings Peltophorum dubium (Sprenge) Taub.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A standard protocol for obtaining fish chromosomes under post-mortem conditions

In order to improve cytogenetical analyses on fish, especially focusing on delicate and rare species, we have adopted a new in vitro methodology using dead animals. The results obtained from 24 neotropical freshwater and marine fish species demonstrate that chromosomes can be obtained under post-mortem conditions. Significantly, the samples analyzed provided reliable cytogenetical data in nearly all cases. Other advantages of this new methodology are also discussed. (c) 2006 Elsevier Ltd. All rights reserved.

Improved germination of soybean seed treated with thiamethoxam under drought conditions

The effect of thiamethoxam on germination of soybean (Glycine max L.) seeds cv. Pintado under water deficit was studied. When used as insecticide at the recommended level (100/100 kg seeds) in the treatment of soybean seeds. thiamethoxam accelerated germination. Soybean germination was delayed under lower water availability: however pretreatment of seeds with thiamethoxam reduced the negative effects of water deficit on such process.

Germination of Ocotea pulchella (Nees) Mez (Lauraceae) seeds in laboratory and natural restinga environment conditions

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

Cytogenetics of four Omophoita species (Coleoptera, Chrysomelidae, Alticinae): A comparative analysis using mitotic and meiotic cells submitted to the standard staining and C-banding technique

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Leaf-cutting ant faecal fluid and mandibular gland secretion: effects on microfungi spore germination

The mandibular gland secretion (MGS) and the faecal fluid (FF) of the leaf-cutting ant Atta sexdens rubropilosa Forel affected the spore germination of selected microfungi isolated from nests of this insect. MGS was more effective than the FF, completely inhibiting the spore germination of four out of six microfungi species.

Effects of different environmental stresses on seed germination

In this paper, the hypothesis was that different environmental stresses may show similar responses in a biological system, as exemplified by the kinetic of germination of Eucalyptus grandis W. Hill ex Maiden seeds. It was observed that the kinetic of germination depends on environmental factors, and different treatments induced similar germination responses. The treatments with PEG 6000 and NaCl suggest that germination depends on solute used, since NaCl exhibit both ionic and osmotic effects. The analysis of the results showed that different external disturbances may lead, perhaps through different physiological ways, to similar responses related to the germination process.

Seed size variation in the palm Euterpe edulis and the effects of seed predators on germination and seedling survival

Intraspecific variation in seed size is common in wild plant populations and has important consequences for the reproductive success of individual plants. Multiple, often conflicting evolutionary forces mediated by biotic as well as abiotic agents may maintain such a variation. In this paper we assessed seed size variation in a population of the threatened, commercially important palm Euterpe edulis in southeast Brazil. We investigated (i) how this variation affects the probability of attack by vertebrate and invertebrate post-dispersal seed predators, and (ii) if seed size influences the outcome of seeds damaged by beetles in terms of seed germination and early survival of seedlings. Euterpe edulis seeds varied in diameter from 8.3 to 14.1 mm. Neither insects nor rodents selected the seeds they preyed upon based on seed size. Seed germination and total, shoot and root biomasses of one-year seedlings were significantly and positively affected by seed size. Root biomass and seedling survival were negatively affected by seed damage caused by a scolytid beetle (Coccotrypes palmarum) whose adults bore into seeds to consume part of the endosperm, but do not oviposit on them. Seed size had a marginally significant effect on seedling survival. Therefore, if any advantage is accrued by E. edulis individuals producing large seeds, this is because of greater seed germination success and seedling vigor. If this is so, even a relatively narrow range of variation in seed size as observed in the E. edulis population studied may translate into differential success of individual plants. (c) 2006 Elsevier SAS. All rights reserved.

Effect of light and temperature on seed germination in guava (Psidium guajava L. Myrtaceae)

The germination of seeds of Psidium guajava L. (Myrtaceae) is controlled by phytochrome. Guava seeds can germinate with at least one hour per day of irradiation of high red:far-red ratio light preceeded or followed by shade light, indicating that phytochrome B controls germination in these conditions. Under alternating temperatures, in a range of at least 5degreesC, seeds will germinate in darkness, suggesting that in gaps of the canopy, when seeds are covered by a thin layer of soil they will germinate once the alternating temperatures are experienced. Under these conditions phytochrome A is responsible for the control of guava seed germination.

The role of the seed coat in phytochrome-controlled seed germination in Lactuca sativa L. cv. Grand Rapids

The effect of scarification with sodium hypochloride on light sensitivity in seeds of Lactuca sativa L. cv. Grand Rapids is presented in the paper. Light-requiring lettuce seeds germinated in both dark and continuous light after scarification and 36 degrees C pre-incubation restored light sensitivity at 25 degrees C. Curves of dose-response indicated that chemical scarification induced a change in the control of seed germination from Low Fluence Response to the Very Low Fluence Response. Pre-incubation at 36 degrees C return the control to the Low Fluence Response of phytochrome action.

Interaction of temperature and light on seed germination in Tecoma stans L. Juss. ex Kunth (Bignoniaceae)

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

Influence of light and temperature on seed germination of Cereus pernambucensis Lemaire (Cactaceae)

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