Leaf tissue pigments and chlorophyll fluorescence parameters vary among sweet corn genotypes of differential herbicide sensitivity

Herbicide applications are meant to eliminate weed competition; however, herbicides may also impose abiotic stress on registered crops. Leaf tissue carotenoid pigments play vital roles in the photoprotection of photosynthetic membranes and contribute to non-photochemical quenching (NPQ) of excitation energy, both important to plant environmental stress tolerance. Our research objectives were to characterize leaf tissue pigments and chlorophyll fluorescence parameters following post-emergence herbicide applications (simulating an abiotic stress) to sweet corn (Zea mays var. rugosa) genotypes of differential herbicide sensitivities. Post-emergence herbicide applications of combinations of mesotrione (105 g ai/ha) and atrazine (560 g ai/ha) were applied to ‘Merit’ (sensitive), ‘Temptation’ (tolerant), and ‘Incredible’ (moderately sensitive) sweet corn genotypes. Leaf tissues were sampled after herbicide applications and measured for chlorophyll fluorescence parameters, and the same tissues were analyzed for carotenoid and chlorophyll pigments. Leaf pigments and chlorophyll fluorescence were not affected by any herbicide treatment; however, data revealed significant differences between genotypes for leaf tissue antheraxanthin, β-carotene, zeaxanthin, chlorophyll a/b ratios, and for values of Fo, Fm, Fv, and NPQ, with ‘Merit’ leaf tissue having higher values than the other two genotypes evaluated. Results demonstrate that genotypic sensitivities to certain post-emergence herbicides may be related to concentrations of photo-protective carotenoids in sweet corn leaf tissues.

This manuscript is a study in which we established a link between the concentrations of protective leaf tissues pigments and chlorophyll fluorescence parameters as they relate to environmental stress sensitivity in three different sweet corn genotypes. Our research objectives were to characterize leaf tissue xanthophyll cycle pigments and chlorophyll fluorescence parameters following post-emergence herbicide applications to sweet corn (Zea mays var. rugosa) genotypes of differential herbicide sensitivities. Data revealed that genotype contributed significantly to leaf tissue pigments of antheraxanthin, β-carotene, zeaxanthin, chlorophyll a/b ratios, and for chlorophyll fluorescence values of Fo, Fm, Fv, and NPQ. Results demonstrate that genotypic sensitivities may be related to concentrations of photo-protective carotenoids in sweet corn leaf tissues. This work sheds new light on the role that protective xanthophyll cycle pigments may be playing in sweet corn.Figure optionsDownload as PowerPoint slideResearch highlights
► Sweet corn genotype contributed significantly to leaf tissue pigments.
► Genotype contributed significantly to leaf tissue chlorophyll fluorescence values.
► Genotypic sensitivities may be related to photo-protective carotenoids in leaves.
► Xanthophyll cycle pigments serve protective roles in corn with low P450 metabolism.