Photosynthetic parameters of young Brazil nut (Bertholletia excelsa H. B.) plants subjected to fertilization in a degraded area in Central Amazonia
2009
Ferreira, M. J | Gonçalves, J. F. C | Ferraz, J. B. S
In an experimental site for reforestation of degraded area, three-year-old plants of Bertholletia excelsa Humb. & Bonpl. were subjected to different fertilization treatments: T0 = unfertilized control, T1 = green fertilization (branches and leaves) and T2 = chemical fertilization. Higher net photosynthetic rates (P N) were observed in T1 [13.2±1.0 μmol(CO₂) m⁻² s⁻¹] compared to T2 [8.0±1.8 μmol(CO₂) m⁻² s⁻¹] and T0 [4.8±1.3 μmol(CO₂) m⁻² s⁻¹]. Stomatal conductance (g s), transpiration rate (E) and water use efficiency (WUE) of individuals of T1 and T2 did not differ significantly, however, they were by 88, 55 and 63%, respectively, higher in T1 than in the control. The mean values of variable fluorescence (Fv), performance index (P.I.) and total chlorophyll [Chl (a+b)] were higher in T1. Our results indicate that green fertilization improves photosynthetic structure and function in plants of B. excelsa in young phase.
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