Flooded native pastures of the northern region of the Pantanal of Mato Grosso: biomass and primary productivity variations

Pozer, C. G.; Nogueira, Flávia

doi:10.1590/s1519-69842004000500016

Cited by 28 publications

(15 citation statements)

References 16 publications

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“…In the rainy season, plants in the sun have a higher net photosynthetic rate than shaded plants, possible due to a higher sink demand (growth) and leaf acclimation. Greater growth rates and carbon absorption were observed during the rainy season, characterized by higher temperatures, as previously reported in the literature, including studies from Brazil (Pozer and Nogueira, 2004;Silva et al, 2004). In coffee plants, Silva et al (2004) found an increased growth rate of plants, higher net carbon absorption during the months of October to March (rainy season) and a reduction in during the months of April to September (dry season).…”

Section: Discussionsupporting

confidence: 80%

Photosynthetic performance and anatomical adaptations in Byrsonima sericea DC. under contrasting light conditions in a remnant of the Atlantic forest

Silva

Oliveira

Cunha

et al. 2010

Braz. J. Plant Physiol.

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The photosynthetic dynamics of the tropical pioneer species, Byrsonima sericea DC., were studied during the regeneration process of a native forest by evaluating ecophysiological (gas exchange, chlorophyll a fluorescence and photosynthetic pigment contents) and anatomical parameters of plants in sunny and shady environments. Ecophysiological evaluations were carried out monthly for one year, encompassing both a dry and a rainy season. Byrsonima sericea DC. presents anatomical plasticity that enables it to establish in environments with contrasting light regimes. In sunny conditions, it produced a thicker leaf (about 420 mm) and flat adaxial epidermis, whilst in the shade, leaves had a thinner convex adaxial epidermis (about 395 mm). No differences were found in the compositions of the pigments in the different environments, however, during the dry season, the plants presented a significantly higher concentration of photosynthetic pigments. In the sun, plants showed decreases in Fv/F0 ratio (in the rainy season) and NPQ (in the dry season), but no difference was observed between plants that were in the sun or in the shade. A significantly higher net photosynthetic rate was found only in the rainy season in the plants in the sun, compared to shaded plants (9.9±0.8 and 7.4±0.3 μmol m -2 s -1 , respectively). Significant increase in transpiration was observed in plants in the shade during the dry season, but no alterations were observed in the water use efficiency. Ecophysiological data suggest that mainly plants overexposed to the sun underwent water limitations during the dry season and that, in the rainy season, these plants increased their net photosynthetic rate, possibly due to the greater drainage force resulting from increased growth during this period. Data suggest that anatomic alterations, namely the convex adaxial epidermis, could aid in the supply of light to shaded plants during both seasons, precluding changes in the pigments, such as the increase in chlorophyll b usually observed in shaded plants, but not detected in the present study. Another consequence of the greater quantity of light captured by these shade plants is that during the dry season their net photosynthetic rate was not different from that of plants in a sunny environment. However, when water was not a limiting factor, a better photosynthetic performance was observed in this pioneer specie in open spaces.Key words: Atlantic forest species; photosynthetic adaptation; leaf anatomy; sun overexposure; shaded plants. RESUMOA dinâmica fotossintética da espécie pioneira tropical Byrsonima sericea DC. foi estudada durante o processo de regeneração de uma mata nativa por avaliações ecofisiológicas (trocas gasosas, fluorescência da clorofila a e conteúdo de pigmentos fotossintéticos) e parâmetros anatômicos das plantas em ambientes ensolarados e sombreados. As avaliações ecofisiológicas foram feitas mensalmente por um ano e os dados foram agrupados em estação seca e chuvosa. Byrsonima sericea DC. apresentou plasticidade anatômica que a ...

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Section: Discussionsupporting

confidence: 80%

Photosynthetic performance and anatomical adaptations in Byrsonima sericea DC. under contrasting light conditions in a remnant of the Atlantic forest

Silva

Oliveira

Cunha

et al. 2010

Braz. J. Plant Physiol.

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“…The DW values are expressed in grams per square meter (g DW.m -2 ). Net primary production (NPP) was determined according to Tieszen (1989) and Pozer and Nogueira (2004). According to this method, macrophyte productivity is calculated by determining the biomass difference between two consecutive samples and dividing this difference by the time in days between the two samples.…”

Section: Resultsmentioning

confidence: 99%

Temporal variation in the biomass and nutrient status of Azolla filiculoides Lam. (Salviniaceae) in a small shallow dystrophic lake

2012

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Aim: This study determined the temporal variation of the biomass and the concentrations of carbon, nitrogen and phosphorus in Azolla filiculoides Lam. in a small (0.5 ha) shallow dystrophic lake located in the city of Rio Grande (Rio Grande do Sul State, Brazil). Method: Sampling was conducted monthly between November 2000 and October 2001. The macrophytes were collected randomly in three replicates with a circular collector 0.3 m in diameter and subsequently washed with tap water and oven-dried at 60 °C for determination of the dry weight and the nutrient status (i.e., carbon, nitrogen and phosphorus). Primary productivity was estimated by the variation in biomass among successive samples. Results: A. filiculoides was present in the lake throughout the year and occupied between 50 and 80% of the surface area. The biomass values ranged from 34.2 g DW.m -2 , recorded in May (autumn), to 170.9 g DW.m -2 in January (summer). The highest rate of primary productivity was 3.3 g DW.m -2 .d -1 , observed in June. The concentrations of carbon, nitrogen and phosphorus in the plant ranged between 403 and 551 g.kg -1 , 13.4 and 25.7 g.kg -1 and 0.5 and 1.9 g.kg -1 , respectively. The water N:P ratio ranged between 19:1 and 368:1. Conclusion: The coverage of the surface of the lake by A. filiculoides throughout the study period and the nutritional status of the plant demonstrate the importance of the cycling of nutrients by macrophytes in this aquatic environment. The higher N:P ratio in the water column, compared with other neighboring environments without macrophytes, shows that the enrichment of the lake may result from the biological N-fixation activity produced by A. filiculoides.Keywords: primary production, floating macrophytes, carbon, phosphorus, nitrogen.Resumo: Objetivo: Este estudo determinou a variação temporal da biomassa e as concentrações de carbono, nitrogênio e fósforo de Azolla filiculoides Lam., em um pequeno lago raso distrófico situado no município do Rio Grande (Rio Grande do Sul, Brasil). Método: As amostragens foram realizadas mensalmente no período entre novembro de 2000 e outubro de 2001. As macrófitas foram coletadas aleatoriamente em três repetições, utilizando-se coletor circular de 0,3 m de diâmetro e posteriormente lavadas com água corrente e secas em estufa 60 °C para determinação do peso seco e dos nutrientes: carbono, nitrogênio e fósforo. A produção primária foi estimada pela variação de biomassa entre coletas sucessivas. Resultados: A. filiculoides esteve presente no lago durante todo o ano, ocupando sempre entre 50 e 80% da superfície do lago. Os valores de biomassa variaram entre 34,2 g PS.m -2 , registrado em maio (outono) e 170,9 g PS.m -2 em janeiro (verão). A maior taxa de produtividade primária foi 3,3 g PS.m -2 .d -1 foi registrada em Junho. As concentrações de carbono, nitrogênio e fósforo na planta variaram entre: 403 e 551 g. kg -1 , 13,4 e 25,7 g.kg -1 e 0,5 e 1,9 g.kg -1, respectivamente. Os valores da relação N:P na coluna de água variou entre 19:1 e 368:1. Conclus...

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“…A família com maior riqueza de espécies nos CM do PEA (Poaceae) vem sendo citada como importante no Bioma (Pozer & Nogueira 2004).…”

Section: Discussionunclassified

Florística dos campos de murundus do Pantanal do Araguaia, Mato Grosso, Brasil

et al. 2012

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ABSTRACT(Floristics of fl oodplain 'murundus' of the Pantanal of Araguaia, Mato Grosso, Brazil). Th is study aimed to compare angiosperm species richness and composition between fl oodplain 'murundus' (FM) of Araguaia State Park (ASP) in one of Brazil´s largest fl oodplains. ASP is located in Novo Santo Antônio, Mato Grosso state, and is bordered on the east by the Araguaia River, and on the west by Das Mortes River. Intensive fl oristic inventories were made on 11 hectares, and adjacent areas, of FM distributed over ASP. Environmental studies were performed by in situ descriptions. Th e soils are deep, mineral hydromorphic plinthosols, imperfectly to poorly drained, with low permeability. A total of 318 species, 193 genera and 66 families were collected, and FM values ranged from 51 to 135 species, 42 to 107 genera and 27 to 52 families. Erythroxylum suberosum is a typical species of Brazilian FM, Curatella americana typical of Mato Grosso FM and Byrsonima cydoniifolia typical of the ASP. Th e physical and spatial distribution pattern of the "murundus" (earthmounds) may refl ect the seasonal fl ood pulse, since the fl oristic composition of the FM varied between the areas under the infl uence of the rivers that border the park. Th is was the largest fl oristic inventory ever undertaken in FM, with a signifi cant increase in our knowledge and recording of typical species of the Cerrado Biome which occur in this phytophysiognomy.

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Flooded native pastures of the northern region of the Pantanal of Mato Grosso: biomass and primary productivity variations

Cited by 28 publications

References 16 publications

Photosynthetic performance and anatomical adaptations in Byrsonima sericea DC. under contrasting light conditions in a remnant of the Atlantic forest

Photosynthetic performance and anatomical adaptations in Byrsonima sericea DC. under contrasting light conditions in a remnant of the Atlantic forest

Temporal variation in the biomass and nutrient status of Azolla filiculoides Lam. (Salviniaceae) in a small shallow dystrophic lake

Florística dos campos de murundus do Pantanal do Araguaia, Mato Grosso, Brasil

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