Photosynthesis of ryegrass biotypes under different competition levels

Planta Daninha

Ferreira, E.A.¹  UFV¹  Universidade Federal de Viçosa, Viçosa¹  Reis, M.R.¹  Vargas, L.¹  Embrapa Trigo, Passo Fundo¹  Ferreira, F.A.¹  Concenço, G.¹  d'Antonino, L.¹  Galon, L.¹  Silva, L.V.B.D.¹  Silva, A.A.¹ 

关键词: photosynthetic activity;    Lolium multiflorum;    mass increase.;   

DOI  :  10.1590/S0100-83582008000300015

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 】

Characteristics associated with photosynthetic activity of ryegrass biotypes, susceptible and resistant to glyphosate, were evaluated under different competition levels. The experiment was installed in a factorial design, with two ryegrass biotypes, susceptible and resistant to glyphosate, growing in the plot center, surrounded by 0, 1, 2, 3, and 4 plants of the opposite biotype. Fifty days after emergence, stomatal gas flow rate (U µmol s 1), sub-stomatal CO2 concentration (Ci - µmol mol-1) and photosynthetic rate (A µmol m-2 s-1 ) were evaluated, with the CO2 used in photosynthesis (ΔC - µmol mol-1) being calculated as the difference between the reference CO2 and the CO2 in the evaluation chamber. Data were collected using an infrared gas analyzer (IRGA), model LCA4 (ADC Company), followed by building a correlation matrix between the variables. The ryegrass biotypes susceptible and resistant to glyphosate did not differ in relation to the photosynthetic activity in absence of competition. However, the photosynthetic rate was reduced in function of increasing competition with plants of the opposite biotype for both the resistant and susceptible biotypes, and for the resistant biotype when in competition with plants of the same biotype. This behavior was attributed to reciprocal shading and light competition.

【 授权许可】

Unknown