Yield and kernel nutritional quality in normal maize and quality protein maize cultivars exposed to ozone

Abstract

BACKGROUND: Tropospheric ozone (O 3 ) is phytotoxic and therefore impacts global food security. In the present study yield responses and kernel quality traits of two maize cultivars [DHM117: normal maize (NM)] and [HQPM1: quality protein maize (QPM)] are investigated. Cultivars were exposed to two doses of elevated O 3 , namely NFC + 15 and NFC + 30 ppb O 3 above ambient level (NFC, non-filtered chambers) while filtered chambers served as control. RESULTS: Test weight (thousand kernel weight), weight of kernels per square meter and kernel starch content reduced more in NM than QPM due to elevated O 3 exposure. Total soluble and reducing sugars increased in both the cultivars being more in NM. Though, endosperm protein showed comparatively more increase in QPM than NM, decline in essential amino acids tryptophan and lysine was higher in QPM. Majority of nutrient elements increased after O 3 treatment, while reductions in oil content as well as saturated fatty acids were observed in both test cultivars. Of the two essential fatty acids, omega 3 fatty acid reduced while omega 6 fatty acid contents increased in QPM. Oil became more unsaturated (increase in polyunsaturated fatty acids) upon O 3 exposure, thus increasing its reactivity and hence became more prone to auto-oxidation. CONCLUSIONS: Elevated O 3 caused losses in yield of maize cultivars and NM showed higher sensitivity than QPM. Kernel quality analysis revealed significant changes in nutritional parameters. Carbohydrate content reduced more in NM, while essential amino acids and saturated fatty acids showed more decline in QPM.

Effects of combined abiotic stresses on nutrient content of European wheat and implications for nutritional security under climate change

“…Ozone is one of the most damaging tropospheric air pollutant affecting plant growth and productivity 31 , 32 and tropospheric O 3 concentrations have more than doubled since pre-industrial times 33 . Wheat is sensitive to elevated O 3 levels, causing differences in grain yields and nutrient content 17 .…”

“…Ozone had particularly interesting effects on micronutrient accumulation. Elevated O 3 (as a single stress) has been shown to affect nutrient content of grains 17 , 18 , 32 , and there is a high variability of sensitivity to tropospheric ozone among species and cultivars 17 , 34 . Ozone enters in the plant through the stomata of the underside of the leaf, and most likely reacts with molecules in the cell wall, and due to its strong oxidative property, it triggers production of reactive oxygen species (ROS).…”

Aphid-Triggered Changes in Oxidative Damage Markers of Nucleic Acids, Proteins, and Lipids in Maize (Zea mays L.) Seedlings

“…Maize ( Zea mays L.; Poaceae) has emerged as an important crop of increasing significance in several agronomic, pharmaceutical, nutraceutical and industrial areas [1,2]. In addition, it is a commonly used model plant in a variety of biochemical, molecular and genetic experiments [3,4].…”

Identifying Quality Protein Maize Inbred Lines for Improved Nutritional Value of Maize in Southern Africa

“…Maize kernels consist of 61 to 78% starch, 6 to 12% protein, and 3 to 6% fat [ 4 , 5 ]. Maize protein exists largely in the form of zein proteins, subdivided into β-, γ-, and α-zein fractions based on amino acid sequences [ 5 , 6 ], with α-zein being the most abundant fraction.…”

“…Maize kernels consist of 61 to 78% starch, 6 to 12% protein, and 3 to 6% fat [ 4 , 5 ]. Maize protein exists largely in the form of zein proteins, subdivided into β-, γ-, and α-zein fractions based on amino acid sequences [ 5 , 6 ], with α-zein being the most abundant fraction. The zein storage proteins are deficient in lysine and tryptophan, which are essential amino acids for human and other monogastric animals, thus negatively affecting the crop’s nutritional value [ 7 , 8 ].…”