Produção e germinação de sementes de "capim dourado", Syngonanthus nitens (Bong.) Ruhland (Eriocaulaceae): implicações para o manejo

Abstract

RESUMO -(Produção e germinação de sementes de "capim dourado", Syngonanthus nitens (Bong.) Ruhland (Eriocaulaceae): implicações para o manejo). A venda de artesanato feito com escapos de S. nitens é uma importante fonte de renda na região do Jalapão, TO. Conhecer a época de produção e dispersão das sementes, bem como seu potencial germinativo, é essencial para propor formas de manejo que garantam a sustentabilidade econômica e ecológica deste extrativismo. Com o intuito de caracterizar a época de produção de sementes foram coletados capítulos entre agosto e dezembro/2003. Foram realizados experimentos de germinação em câmara a 22-30 ºC, sob foto e termoperíodo de 12 horas, e também em condições de escuro. Caracterizou-se também a germinação em condições de hipóxia (imersão em água) e acidez (pH 4 e 5). A produção de sementes iniciou-se em setembro e a maior parte da dispersão ocorreu entre outubro e novembro. A germinação das sementes coletadas entre setembro e outubro foi de 92 ± 7% (média ± DP), sementes coletadas a partir de novembro tiveram germinação significativamente menor. A acidez e a hipóxia não afetaram negativamente a germinação em relação ao controle. As sementes são fotoblásticas positivas e mantêm a germinação após congelamento a -20 ºC. A colheita de escapos após a frutificação (a partir do final de setembro) e a dispersão manual das sementes pelos próprios extrativistas no momento da colheita são estratégias importantes para o manejo da espécie e não prejudicam a atividade artesanal que está focada nos escapos e não nas flores, como ocorre para outras sempre-vivas. Palavras-chave: extrativismo vegetal, sempre-vivas, campos úmidos, Cerrado, produtos florestais não madeireirosABSTRACT (Production and germination of "capim dourado" seeds, Syngonanthus nitens (Bong.) Ruhland (Eriocaulaceae): implications for management). The sale of handcraft made from S. nitens' scapes is an important source of income in the Jalapão region, Tocantins state. Understanding seed production and dispersal periods, and germination potential is essential to management strategies that guarantee the ecological and economic sustainability of this activity. To characterize the seed production period, capitula were collected from August to December 2003. Germination experiments were conducted in a germination chamber at 22-30 °C, under white light (12-hour photoperiod) and darkness. Germination was also studied under conditions of hypoxia and acidity (pH 4 and 5). Seed production began in September and most dispersal occurred from October to November. The germination of seeds collected in September and October was 92 ± 7% (m ± SD). Seeds collected after November had significantly lower germination capacity. Acidity and hypoxia did not affect seed germination. The seeds are positive photoblastic and maintain high germination even after freezing (-20 °C). Harvesting and manual seed dispersal by the harvesters just after harvesting are important management strategies to guarantee the sustainability of this important economic acti...

Germination characteristics of Syngonanthusseeds (Eriocaulaceae) incampos rupestresvegetation in south-eastern Brazil

“…The seeds showed a light requirement for germination, a characteristic generally associated with small seeds (Thompson and Grime, 1983;Bewley and Black, 1994;Milberg et al, 2000) and open habitats Milberg et al, 2000). Small and positively photoblastic seeds have been reported in other studies with species of Eriocaulaceae, Xyridaceae and Velloziaceae -families typical of campos rupestres vegetation and open environments exposed to highintensity solar illumination (Mercier and GuerreiroFilho, 1989;Sá e Carvalho and Ribeiro, 1994a, b;Scatena et al, 1996;Garcia and Diniz, 2003;Abreu and Garcia, 2005;Oliveira and Garcia, 2005;Garcia et al, 2007;Schmidt et al, 2008).…”

Harvest times of Comanthera elegans, a worldwide traded Brazilian species of everlasting flower: implications on seed production, germination, and on species management

“…Although there are no studies approaching the effects of extraction on the species population dynamics, precocious harvest (i.e., prior to either production or complete maturation of seeds) may well interfere negatively on it due to decreased seedling recruitment via seeds, as reported to C. elegantula and S. nitens (Bedê 2006;Schmidt et al 2007Schmidt et al , 2008. In practice, however, C. elegans population decline occurs even in areas that have been kept free of anthropic intervention (i.e., with no harvesting and/or no use of fire) for several consecutive years, indicating that non-anthropic factors might be contributing to such decrease (pers.…”

“…S. nitens phenological traits and habitat differ from those of C. elegans. While the former occurs in wetlands and the plant part economically used consists in the scape alone (Schmidt et al 2007(Schmidt et al , 2008Oliveira et al 2014b), the latter occurs in dry soil lands and the commercialized plant part is the whole inflorescence. In S. nitens, uprooting usually occurs in precocious harvests (i.e., before seed production), not in late ones.…”

Quantification of Flavonoids, Naphthopyranones and Xanthones in Eriocaulaceae Species by LC-PDA

“…Ruhland is a grass-like species of Eriocaulaceae [3], a pantropical, predominantly herbaceous monocotyledonous family that comprises around 1100 species in 11 genera [1,2]. The plants are clonal, and fertile rosettes can annually produce from 1 to 10 scapes (flower stalks or stems), with each scape bearing a capitulum flower [4]. The flower stems of S. nitens are bright and assume a beautiful golden color when dried, acquiring a phenomenal aesthetic similarity to spun gold, hence their common name "capim dourado" (golden grass).…”

“…The flower stems of S. nitens are bright and assume a beautiful golden color when dried, acquiring a phenomenal aesthetic similarity to spun gold, hence their common name "capim dourado" (golden grass). This grass-like species occurs throughout the Brazilian Cerrado, in areas of intermediate humidity within the humid grasslands [4].…”