HIGHLIGHTS:
Irrigation water salinity limits growth and photochemical efficiency of purple basil.
The foliar fertilization at N improves photochemical efficiency of basil.
The Photochemical efficiency of basil is stimulated by nitrogen foliar application.
ABSTRACT
Salinity can have detrimental effects on plant development. To minimize this damage, strategies such as balanced maintenance of plants’ nutritional status have been proposed previously. The objective of this study is to investigate whether the optimization of foliar nitrogen fertilization can promote the growth and photochemical efficiency of purple basil subjected to salt stress. The experiment was performed using a randomized block design with an incomplete 5 × 5 factorial arrangement generated through experimental matrix Central Composite Design with two parameters: salinity of irrigation water at 0.5, 0.81, 2.75, 4.69, and 5.50 dS m-1; and nitrogen doses at 0, 58.58, 200, 341.42, and 400 mg L-1. It was found that an increase in the salinity of irrigation water reduced the growth and photochemical efficiency of purple basil. However, the foliar application of nitrogen at the concentration of 400 mg L-1 attenuated the harmful effects of salinity on both the absolute and relative growth rates of stem diameter, the relative growth of plant height, and chlorophyll A fluorescence. These results showed that foliar nitrogen fertilization is a suitable strategy to help mitigate salt stress in basil plants.
Key words:
Ocimum basilicum; abiotic stress; photochemical efficiency; foliar nitrogen fertilization; salt stress
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*, ** - Significant at p ≤ 0.05 and p ≤ 0.01, respectively; ns - Not significant, by F test
*, ** - Significant at p ≤ 0.01 and p ≤ 0.05, respectively, ns - Not significant, by F test
*, ** - Significant at p ≤ 0.01 and p ≤ 0.05, respectively; ns - Not significant, by F test
*, ** - Significant at p ≤ 0.05 and p ≤ 0.01, respectively, ns - Not significant, by F test