Data/hora: 11/06/2024 14:14:55

Biblioteca(s): | Embrapa Cerrados.
Data corrente: | 06/03/1998
Data da última atualização: | 06/03/1998
Autoria: | FELIPPE, G. M.; DALE, J. E.
Título: | The effects of phosphate supply on growth of plants from the Brasilian Cerrado: experiments with seedlings of the annual weed, Bidens gardneri Baker (Compositeae) and the tree, Qualea grandiflora (Mart.) (Vochysiaceae).
Ano de publicação: | 1990
Fonte/Imprenta: | Oecologia, Berlin, v.82, p.81-86, 1990.
Idioma: | Inglês
Conteúdo: | Plants of the Cerrado tree species Qualea grandiflora and the annual herb Bidens gardneri were grown from seed in controlled environment rooms at 30/20 C and 12 hour photoperiod. Seedlings were grown in pots or small tubes containing sand and provided with various amounts of mineral solutions based on the formulatin of Hoagland and Arnon but with the phosphate content modified in some cases. In a long-term experiment lasting 213 days, plants supplied with full strength Hoagland's solution all died but plants of Qualea given 1/10 strength solution survived, although they grew very slowly. Low relative growth rates (0.008-0.036 d-1) were also a feature of other experiments with Qualea and calculated rates of net assimilation rate gave values of 3-7 mg CO2 dm-2 h-1. Expansion of the photosynthetic surface proceeded slowly and the cotyledons were the main site of photosynthesis for more than 40 days. The low rates of growth occurred despite significant uptake of phosphorus by young plants and short-term experiments growth was independent of the amount of phosphate supplied and accumulated. In contrast, the values of R found for plants of Bidens reached 0.24 d-1. Growth of young plants was dependent on the external supply of phosphorus, being reduced when this was low and also when it was very high. Growth of the photosynthetic surface was also much more rapid than for Qualea and varied with supply of phosphorus. The results are discussed in the context of the occurrence of species in the Cerrado.
Palavras-Chave: | Bidens gardneri; Brasil; Mineral nutrients; Pau-terra.
Thesagro: | Cerrado; Fósforo; Nutriente Mineral; Qualea Grandiflora.
Thesaurus Nal: | Brazil; phosphorus.
Categoria do assunto: | --
Registro original: | Embrapa Cerrados (CPAC)
Exemplares: | CPAC - (10997-1) - ADD - SP - -- - CRI4499 -  - CRI4499 - DIS