Physiological responses of two tropical weeds to shade: I. Growth and biomass allocation

Resumo

Ipomoea asarifolia (Desr.) Roem. & Schultz (Convolvulaceae) and Stachytarpheta cayennensis (Rich) Vahl. (Verbenaceae), two weeds found in pastures and crop areas in Brazilian Amazonia, were grown in controlled environment cabinets under high (800-1000 µmol m-² s-¹) and low (200-350 µmol m-² s-¹) light regimes during a 40-day period. For both species leaf dry mass and leaf area per total plant dry mass, and leaf area per leaf dry mass were higher for low-light plants, whereas root mass per total plant dry mass was higher for high-light plants. High-light S. cayennensis allocated significantly more biomass to reproductive tissue than low-light plants, suggesting a probably lower ability of this species to maintain itself under shaded conditions. Relative growth rate (RGR) in I. asarifolia was initially higher for high-light grown plants and after 20 days started decreasing, becoming similar to low-light plants at the last two harvests (at 30 and 40 days). In S. cayennensis, RGR was also higher for high-light plants; however, this trend was not significant at the first and last harvest dates (10 and 40 days). These results are discussed in relation to their ecological and weed management implications.

Resumo conforme Crossref.

Palavras-chave

• Ipomoea asarifolia
• Stachytarpheta cayennensis
• tropical weeds
• shade tolerance
• light intensity
• biomass allocation
• leaf area
• root biomass
• relative growth rate
• reproductive tissues
• weed control
• pasture weeds
• Amazon basin

Termos atribuídos por OpenAlex.

Fontes bibliográficas

Esta publicação está registrada em 3 fontes de metadados.

• CrossrefDOI 10.1590/s0100-204x1999000600004 · ISSN 0100-204XAbrir registro em Crossref (nova aba)
• Currículo LattesISSN 0100204XAbrir registro em Currículo Lattes (nova aba)
• OpenAlexW2122088670 · DOI 10.1590/s0100-204x1999000600004 · ISSN 0100-204X · ISSN 1678-3921Abrir registro em OpenAlex (nova aba)