Influence of Brachiaria brizantha in physiological characteristics related to photosynthesis and efficient use of water in sugarcane

Planta Daninha

Concenço, G¹  Rocha, P.R.R¹  UFV¹  Silva, A.F¹  Tironi, S.P¹  Borges, E.T¹  Universidade Federal dos Vales do Jequitinhonha e Mucuri, Diamantina¹  Ferreira, E.A¹  Universidade Federal de Viçosa¹  Galon, L¹  Embrapa Agropecuária Oeste, Dourados, Brasil¹  Aspiazú, I¹  Silva, A.A¹  Universidade Estadual de Montes Claros, Janaúba¹  Universidade Federal do Pampa, Itaqui¹ 

关键词: weeds;    Saccharum spp.;    photosynthesis;    transpiration;    competition.;   

DOI  :  10.1590/S0100-83582011000500010

学科分类：农业科学（综合）

来源: Sociedade Brasileira da Ciencia das Plantas Daninhas (S B C P D) / Brazilian Society of Herb Science

【 摘 要 】

The increase in density of weeds increases also its competitive ability, which affects the physiological aspects of crops. This study aimed to evaluate the interference of increasing densities of Brachiaria brizantha over sugarcane varieties RB72454, RB867515 and SP80-1816 based on physiological variables related to the photosynthesis rate. For this, a field was installed, being treatments composed by 12 densities of the competitor, ranging from 0 to 112 plants m-2, emerged simultaneously to the crop. At 120 days after crop emergence the substomatal CO2 concentration (Ci - µmol mol-1), photosynthetic activity (A - µmol m-2 s-1), stomatal conductance (gs - mol m-1 s-1), the transpiration rate (E), the water use efficiency (WUE) and the shoot dry mass (SDM - g per plant) of the crop were evaluated. All physiological variables and SDM of the variety RB72454 were affected by increasing the density of B. brizantha, as well as the transpiration rate of the variety RB867515. The variety RB72454 showed lower competitive ability with weeds and its photosynthetic ability is limited by factors that reduce the influx of CO2 into the leaf.

【 授权许可】

Unknown