Photosynthetic Pigments and Photochemical Efficiency in Soursop under Saline Water Irrigation and Nitrogen Sources

  •  Evandro Silva    
  •  Geovani Lima    
  •  Hans Gheyi    
  •  Reginaldo Nobre    
  •  Francisco Vanies Sá    
  •  Leandro Souza    
  •  Lauriane Soares    
  •  Pedro Fernandes    


The Studies have shown that nitrogen fertilization can mitigate the effects of saline stress on plants, however, the efficiency may vary according to the source of nitrogen used, specifically on the photosynthetic activity. In this context, the objective of this work was to evaluate the effect of different nitrogen sources on photosynthetic pigments and photochemical efficiency in soursop plants irrigated with distinct salinities. A randomized complete block design was used in a 4 × 4 factorial scheme, with the treatments corresponding to four levels of irrigation water salinity - ECw (0.5, 1.5, 2.5 and 3.5 dS m-1) and four sources of nitrogen (urea, ammonium sulfate, calcium nitrate and potassium nitrate), with three replications. The irrigation with saline water from 0.5 dS m-1 inhibits the concentration of photosynthetic pigments and promotes damages in the photochemical efficiency of photosynthesis at 110 days after transplanting. The different sources of nitrogen do not cause changes in the levels of photosynthetic pigments, however, the fertilization with potassium nitrate mitigates the effect of saline stress on the photochemical efficiency, mainly in the water salinity of 3.5 dS m-1.

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