GAS EXCHANGE AND PHOTOCHEMICAL EFFICIENCY IN LIMA BEAN GENOTYPES GROWN IN COMPACTED SOILS

Authors

  • Renato Francisco da Silva Souza Universidade Federal da Paraíba/Centro de Ciências Agrárias http://orcid.org/0000-0001-8213-1722 (unauthenticated)
  • Djail Santos Departament Soils and Rural Engineering, Universidade Federal da Paraíba, Areia, PB
  • Walter Esfrain Pereira Departament of Fundamental and Social Science, Universidade Federal da Paraíba, Areia, PB
  • Fabrício Lopes de Macedo Centre for The Research and Technology of Agro-Environmental and Biological, Universidade de Trás-os-Montes e Alto Douro, Vila Real, VR
  • Jhony Vendruscolo Universidade Federal da Paraíba, Areia, PB

DOI:

https://doi.org/10.1590/1983-21252018v31n206rc

Keywords:

Phaseolus lunatus L.. Physical impediment. Photosynthetic rate.

Abstract

The effects of soil compaction on crop growth and productivity have been well studied in recent years, however, studies on the physiological responses of crops to compaction are scarce. The objective of this study was to evaluate the effect of soil compaction on gas exchange, and photochemical efficiency of lima bean (Phaseolus lunatus L.) genotypes of different growth habits. The experimental design was a randomized block in a 3×4 factorial arrangement, with three lima bean genotypes (Branca-Pequena, Orelha-de-Vó and Roxinha) and four compaction levels (soil densities of 1.1, 1.3, 1.5 and 1.7 g cm-3), with four replications. The following variables were evaluated at 38 days after sowing: photosynthetic rate (A), leaf transpiration (E), stomatal conductance (gs), internal CO2 concentration (Ci), instantaneous water use efficiency (WUE), intrinsic water use efficiency (iWUE), instantaneous carboxylation efficiency (iCE) and photochemical efficiency (Fo, Fm, Fv and Fv/Fm). The data were subjected to analysis of variance at 5% probability by the F test. The genotypes showed a reduction in the photosynthetic rate with increasing soil compaction. The soil compaction affected the photochemical efficiency of the genotype Orelha-de-Vó, with the Fm and Fv fitting to the linear model, and the Fv/Fm fitting to the quadratic model. The genotype Orelha-de-Vó had the highest rate of E and gs at the soil densities of 1.24 and 1.29 g cm-3, respectively. Regarding the photosynthetic rate, the genotype Roxinha is more efficient than Branca-Pequena at the soil density of 1.7 g cm -3.

Author Biography

  • Renato Francisco da Silva Souza, Universidade Federal da Paraíba/Centro de Ciências Agrárias
    Engenheiro Agrônomo, Mestre Agronomia (UFPB)

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Published

06-04-2018

Issue

Section

Agronomy