Marli A. Ranal

Calculating germination measurements and organizing spreadsheets

Com o objetivo de minimizar as dificuldades dos iniciantes, estamos propondo o uso de planilhas eletronicas convencionais para o calculo das principais medidas de germinacao (ou emergencia), a organizacao dos dados finais para a analise estatistica e alguns comandos eletronicos envolvidos nesses passos.

Fertilizantes e espaçamento entre plantas na produtividade da couve-da-Malásia

As brassicas tem sido objeto constante de pesquisa devido a sua importância na alimentacao humana, seja pela quantidade consumida, pelo alto valor nutricional ou por sua elevada produtividade. Brassica chinensis var. parachinensis foi introduzida no Brasil, Uberlândia, em 1992, destacando-se em relacao a outras brassicas por seu alto teor de vitaminas A e C, calcio e ferro, estando pronta para consumo em aproximadamente 30 dias. A produtividade biologica e agronomica dessa variedade foi analisada utilizando-se tres tipos de fertilizantes e tres espacamentos entre plantas, visando subsidiar sua producao em escala comercial. A area foliar, massa da materia seca e taxa de crescimento absoluto foram significativamente maiores com adubacao mineral em relacao a adubacao orgânica. Os maiores valores referentes a taxa de crescimento relativo e taxa assimilatoria liquida foram registrados em plantas mantidas nos maiores espacamentos (30x20 e 30x30 cm). A maior produtividade agronomica foi alcancada no menor espacamento (30x10 cm), com adubacao mineral, sendo registrados 21,5 t ha-1, valor muito proximo ao registrado na Malasia e China onde essa hortalica e cultivada em larga escala.

Germinação de diásporos recém-colhidos de Myracrodruon urundeuva Allemão (Anacardiaceae) ocorrente no cerrado do Brasil Central

Myracrodruon urundeuva occurs in Northeast, Southeast, and West Center Brazilian regions, being considered as a vulnerable species to extinction. Diaspores collected in the Araguari River valley, MG, were used in three experiments, in a completely randomized design, with five replications of 50 diaspores each one. In the first and second experiments, germination boxes with vermiculite moistened with distilled water, GA3 and cytokinin at 1, 10, 100 µg mL-1, and 0.2% KNO3 were used as treatments. The first experiment was conducted under continuous fluorescent white lamps and the second in darkness. In the third experiment the diaspores were moistened with distilled water and stratified during one to six days at 45 oC in darkness. Control treatment was constituted by diaspores moistened with water, without stratification. For the experiments conducted under light conditions, data were collected observing the embryo protrusion every 24 hours; in darkness conditions counting was processed after seven days from the beginning of the experiment. Under continuous light, diaspores treated with 1 µg.mL1 GA3 were more homogeneous (CVt = 17.13%) and synchronized (Z = 0.64) in relation to the other treatments. The germinability ranged from 52.8% to 60% and occurred between two and three days. In darkness condition, germinability ranged from 50.4% to 58.8% and under stratification, from 49.6% to 61.2%. For the experiment testing stratification, the lowest mean time, the highest rate and germination uniformity were registered for diaspores stratified during six days. Although the germination process had been fast, low germinability indicates that new investigations are necessary to the sustainable exploration of this species.

Multiple dormancy and maternal effect on Miconia ferruginata (Melastomataceae) seed germination, Serra de Caldas Novas, Goiás, Brazil

Species with mostly asexual reproduction are interesting subjects for germination studies since variation would be more easily linked to environmental factors. Miconia ferruginata DC. is an apomictic treelet in Brazilian cerrado areas on rocky outcrops. Germination of seeds collected from individuals occurring in the Serra de Caldas Novas State Park, Goias, was studied in three experiments under controlled conditions. Germination characteristics differed among individuals and were correlated with altitude and soil Al content. Seeds from plants growing at lower altitudes, with lower soil aluminium content, presented malformed seeds with absence of embryo which rendered lower, but better synchronized germination. The nested analysis showed that from the total variance, 78.14% for germinability, 54.56% for uncertainty of the germination process, and 68.30% for the quantity of seeds without embryo was attributed to the altitudinal effect. Individuals nested within altitude contributed up to 16.93% for the total variance. It means that there is low variability among individuals of the same altitude and high variability among individuals from different points of the slope, making clear that for the studied population the environmental effect is stronger than the genetic component to determine the seed quality. The testa of the seeds provides a mechanical dormancy which seems to be associated also with phenolic compounds, which help to disperse germination through time. Photoblastism was also registered for seeds of this species.

Emergência de plântulas oriundas de sementes recém colhidas e armazenadas de Copaifera langsdorffii Desf. (caesalpinioideae), triângulo mineiro, Brasil

Copaifera langsdorffii is a threatened species that presents seeds with multiple dormancy and low resistance to storage. Thus, it is interesting to know if the seeds lose viability from the physiological maturity point and if they resist to desiccation during the storage period. Four experiments were conducted using seeds from the Araguari River Valley, MG (matrix 1, July and matrix 2, August 2005). Two of them had newly-collected seeds and the other two used seeds stored in cold chamber. The loss of 31% of water from the seeds collected from the soil in relation to the seeds collected from the tree reduced the percentage of emergence in about 10%. The presence of aril increased the value of the coefficient of variation of the emergence, indicating the presence of germination inhibitors in this part of the seeds. The seeds had lost viability after storage, reducing significantly the percentages of emergence. This characteristic indicates that seeds of this species have some degree of recalcitrance. To obtain a high number of seedlings in short time, with high synchrony, seeds collected from newly-opened fruits, directly of the tree, without aril, and scarified are recommended.

Thelypteris subg. Goniopteris e Meniscium (Thelypteridaceae) da Estação Ecológica do Panga, Uberlândia, Minas Gerais, Brasil

This paper presents the taxonomic treatment for the species of Thelypteris, subgenera Goniopteris and Meniscium, collected in the Ecological Station of Panga. Thelypteridaceae is one of the richest families in the area, with 14 species of Thelypteris segregated in four subgenera (Amauropelta, Cyclosorus, Goniopteris, and Meniscium). Two species of subgenus Goniopteris, Thelypteris biformata (Rosenst.) R.M. Tryon and T. jamesonii (Hook.) R.M. Tryon, and three species of subgenus Meniscium, T. chrysodioides (Fee) C.V. Morton var. goyazensis (Maxon & C.V. Morton) C.V. Morton, T. salzmannii (Fee) C.V. Morton, and T. serrata (Cav.) Alston were recorded. Descriptions and identifications keys, as well as geographical distribution and illustrations are included.

SEMENTES FLORESTAIS BRASILEIRAS: INÍCIO PRECÁRIO, PRESENTE INEBRIANTE E O FUTURO, PROMISSOR?

By analyzing the trajectory of forest seed sector, it is widely known the relationship between the studies on native species and the Brazilian Forest Legislation. The Brazilian market for forest seed species is mostly informal and there are only a few species with laboratory tests registered in the Rules for Seed Testing (RAS). However, Law number 10,711, when ruling as to the marketing of seeds and seedlings, granted legal subsidies to promote the formalization of the forest seeds industry. Compliance with this law is conditioned to standardized laboratory methodologies for evaluating seed quality. For this reason, the formulation of a supplement or specific RAS for native forest seeds seems to be near. This fact will certainly consolidate the national seed industry sector. However, what were the paths that native forest seed science had to walk down to reach this standardization? What are the prospects for the future relating to the native forest seed sector? These are just some of the questions this work intends to answer, based on the perspectives of forestry and environmental organizations, such as the Seeds Networks.

Allelopathic interference of Sapindus saponaria root and mature leaf aqueous extracts on diaspore germination and seedling growth of Lactuca sativa and Allium cepa

Sapindus saponaria (soapberry) is a species that presents a great diversity of chemical compounds, such as saponins; however, few studies have examined the allelopathic effect of this species. Therefore, this study provides an evaluation of the allelopathic potential of aqueous extracts of the roots and mature leaves of S. saponaria on the germination of diaspores and seedlings growth of lettuce (Lactuca sativa) and onion (Allium cepa). The aqueous extract was prepared in the proportion of 100 g of dry plant material in 1,000 mL of distilled water (a concentration of 10% w v-1), and diluted with distilled water to 7.5, 5.0 and 2.5% concentrations. The mature leaf extracts caused delay and decrease in the germination process of the lettuce and onion diaspores, with inhibitory effect concentration-dependent, while the root extracts showed no allelopathic effects on the germination process. Both extracts caused abnormalities and inhibited the growth of shoot and root seedlings.

Blechnaceae da Estação Ecológica do Panga, Uberlândia, Minas Gerais, Brasil

This paper provides the taxonomic treatment for the species of Blechnaceae of the Ecological Station of Panga. This Ecological Station covers an area of 409.5 hectares located about 30 km far from the city of Uberlândia, Minas Gerais State, Brazil. It is one of the few areas of the region with natural vegetation with different savannah physiognomies and forest formations. One genus and four species of Blechnaceae (Blechnum brasiliense Desv., B. lanceola Sw., B. occidentale L., and B. regnellianum (Kunze) C. Chr.) were found. Identification key, descriptions, illustrations of diagnostic characters of the species, geographical distribution, and comments are presented.

Doses de nitrogênio na produção de couve-da-Malásia

E recomendavel que a introducao de uma cultura em uma regiao passe por avaliacoes previas que demonstrem a produtividade das plantas nas condicoes edafo-climaticas do local, bem como suas exigencias nutricionais. Isto vem sendo feito com Brassica chinensis var. parachinensis, introduzida no Brasil, municipio de Uberlândia, em 1992. Avaliou-se o efeito de doses de nitrogenio na produtividade e na acumulacao de nutrientes na parte aerea das plantas, em experimento em delineamento de blocos casualizados, com cinco tratamentos incluindo quatro doses de N (105; 210; 315 e 420 kg ha-1) e a testemunha sem N, e quatro repeticoes. O nitrogenio foi aplicado parceladamente, sendo 30% da respectiva dose na semeadura, 35% aos 15 e 35% aos 30 dias apos a semeadura. Foram avaliados massa fresca e seca da parte aerea e das raizes, numero de folhas, diâmetro do caule e acumulacao de N, P, K, Ca, Mg, S, B, Cu, Fe, Mn e Zn pela parte aerea de plantas cultivadas em casa de vegetacao, em vasos de 5 dm3 contendo Latossolo Vermelho Distrofico tipico. A couve-da-Malasia respondeu significativamente a aplicacao de nitrogenio, sendo o maior crescimento, a maior produtividade e absorcao de nutrientes registrados na dose de 210 kg ha-1, exceto o N, Mn e Zn que aumentaram linearmente.