Data/hora: 16/06/2024 20:16:39

Biblioteca(s): 	Embrapa Amazônia Oriental; Embrapa Unidades Centrais.	
Data corrente: 	04/08/1999	
Data da última atualização: 	25/01/2021	
Autoria: 	DIAS FILHO, M. B.	
Afiliação: 	MOACYR BERNARDINO DIAS FILHO, CPATU.	
Título: 	Physiological responses of two tropical weeds to shade. II. Leaf gas exchange and nitrogen content.	
Ano de publicação: 	1999	
Fonte/Imprenta: 	Pesquisa Agropecuária Brasileira, Brasília, DF, v. 34, n. 6, p. 953-961, jun. 1999.	
Idioma: 	Inglês	
Conteúdo: 	Ipomoea asarifolia (Desr.) Roem. & Schultz (Convolvulaceae) and Stachytarpheta cayennensis (Rich) Vahl. (Verbenaceae), two weeds found in pastures and crop areas in the Brazilian Amazonia, Brazil, were grown in controlled environment cabinets under high (800-1000 umol m-2 s-1) and low (200-350 umol m-2 s-1) light regimes during a 40-day period. The objective was to determine the effect to shade on photosynthetic features and leaf nitrogen content of I. asarifolia and S. cayennensis. High-irradiance grown I. asarifolia leaves had significantly higher dark respiration and light satured rates of photosynthesis than low-irradiance leaves. No significant differences for these traits, between treatments, were observed in S. cayennensis. Low-irradiance leaves of both species displayed higher CO2 assimilation rates under low irradiance. High-irradiance grown leaves of both species had less nitrogen per unit of weight. Low-irradiance S. cayennensis had more nitrogen per unit of leaf area than high-irradiance plants; however, I. asarifolia showed no consistent pattern for this variable through time. For S. cayennensis, leaf nitrogen content and CO2 assimilation were inversely correlated to the amount of biomass allocated to developing reproductive structures. These results are discussed in relation to their ecological and weed management implications.	
Palavras-Chave: 	Brasil; Fertilizer applications; Impoea asarifolia; Ipomoea asarifolia; Leaf nitrogen; Nitrogenio foliar; Tese.	
Thesagro: 	Adubação Foliar; Fisiologia Vegetal; Fotossíntese; Nitrogênio; Stachytarpheta Cayennensis.	
Thesaurus Nal: 	Amazonia; nitrogen; photosynthesis; plant physiology.	
Categoria do assunto: 	--	
URL: 	http://ainfo.cnptia.embrapa.br/digital/bitstream/AI-SEDE/11431/1/pab395_96i.pdf	
Registro original: 	Embrapa Amazônia Oriental (CPATU)	
Exemplares: 	AI-SEDE - (11431-1) - UPE - AP - PP - 630.72081 - P474 -  - DIS
CPATU - (3304-1) - UPC - AP - PP - 630.5 - P472 - 101 - DIS