HIGHLIGHTS:
Electrical conductivity of water (ECw) of 2.0 dS m-1 reduces growth and chlorophyll content in maize.
Hydrogen peroxide up to a concentration of 171.66 µmol L-1 increases leaf area and total biomass in maize.
Salt stress combined with high H2O2 concentrations inhibits stomatal conductance, transpiration, and CO2 assimilation rate.
ABSTRACT
The salinity of irrigation water or soil is the abiotic factor that most negatively impacts the yield of crops, including green maize, so it is necessary to find alternatives to ensure production. In this context, this study aimed to evaluate gas exchange, photosynthetic pigments, and growth of maize under salinity of irrigation water and application of hydrogen peroxide. The experiment was conducted at the Center of Sciences and Agrifood Technology, Pombal, PB, belonging to the Federal University of Campina Grande, in the period from January to February 2015, using the maize hybrid ‘AG 1051’. The treatments consisted of two salinity levels of irrigation water (0.3 and 2.0 dS m-1) and five concentrations of hydrogen peroxide (0, 40, 80, 160, and 320 µmol L-1) applied via irrigation water. The experimental design was completely randomized, in a 2 × 5 factorial scheme, with four replicates. ECw of 2.0 dS m-1 reduces transpiration, stomatal conductance, total chlorophyll, carotenoids, and initial growth, but does not affect the dry mass accumulation of maize plants. Application of H2O2 via soil varying from 0 to 320 µmol L-1 causes reductions in the CO2 assimilation rate and transpiration, as well as at concentrations from 0 to 160 µmol L-1 for stomatal conductance of plants irrigated with ECw of 2.0 dS m-1. Application of H2O2 via soil up to a concentration of 320 µmol L-1 increases the plant height, but reduces culm diameter of maize.
Key words:
Zea mays L.; saline water; mitigator
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* - Significant at p ≤ 0.05 by F test. Means of ECw compared by F teste at p ≤ 0.05. Means followed by the same letter for determined concentration of H2O2 indicate no significant difference between them. Vertical bars indicate standard error of mean (n = 4)
**, * significant at p ≤ 0.01, 0.05, respectively by F test. Means of ECw compared by F test at p ≤ 0.05. Means followed by the same letter for determined concentration of H2O2 indicate no significant difference between them. Vertical bars indicate standard error of mean (n = 4)
Means compared by F test at p ≤ 0.05. Means followed by same letter indicate no significant difference between them. Vertical bars indicate standard error of mean (n = 4)
Means compared by F test at p ≤ 0.05. Means followed by same letter indicate no significant difference between them. Vertical bars indicate standard error of mean (n = 4)
* and ** significant at p ≤ 0.05 and 0.01, respectively by F test. Vertical bars indicate standard error of mean (n = 4)