Photosynthetic light response of the C4 grasses Brachiaria brizantha and B. humidicola under shade

Scientia Agricola

Moacyr Bernardino Dias-filho¹ 

[1] ,Embrapa Amazônia OrientalBelém PA

关键词: carbon assimilation;    chlorophyll content;    light compensation point;    pasture;    assimilação de carbono;    conteúdo de clorofila;    ponto de compensação de luz;    pastagem;   

DOI  :  10.1590/S0103-90162002000100009

来源: SciELO

【 摘 要 】

Forage grasses in tropical pastures can be subjected to considerable diurnal and seasonal reductions in available light. To evaluate the physiological behavior of the tropical forage grasses Brachiaria brizantha cv. Marandu and B. humidicola to low light, the photosynthetic light response and chlorophyll contents of these species were compared for plants grown outdoors, on natural soil, in pots, in full sunlight and those shaded to 30 % of full sunlight, over a 30-day period. Both species showed the ability to adjust their photosynthetic behavior in response to shade. Photosynthetic capacity and light compensation point were lower for shade plants of both species, while apparent quantum yield was unaffected by the light regime. Dark respiration and chlorophyll a:b ratio were significantly reduced by shading only in B. humidicola. B. humidicola could be relatively more adapted to succeed, at least temporarily, in light-limited environments.

【 授权许可】

CC BY   
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