Highlights

• Ethylenediurea protects ozone foliar injury in rice cultivars under elevated CO₂.
• Ethylenediurea treated PB-1 cultivar aggregated more biomass under elevated CO₂.
• Ethylenediurea and carbon dioxide treated PB-1 showed better grain yield.
• Grain nutrient contents varied in combined ethylenediurea and carbon dioxide treatment.

Abstract

The present field experiment assesses the individual and combined effects of ethylenediurea (EDU, 200 ppm) and elevated CO₂ (ECO₂, 550 ppm), on two rice (Oryza sativa L.) cultivars, Sarjoo-52 and Pusa Basmati-1(PB-1) under FACE (Free Air Concentration Enrichment) facility. During the experiment, the mean ambient ozone (AO₃) concentration was 60.3 ppb. EDU treated PB-1 cultivar under elevated CO₂ showed less discernible ozone (O₃) injury, better photosynthetic rate, photosynthetic pigments, and aggregated more plant biomass in comparison to the Sarjoo-52 cultivar. Non-EDU treated plants showed more O₃ induced injury symptoms. PB-1 cultivar was found to be more ozone sensitive than Sarjoo-52 under ambient environment. PB-1 responses to EDU for plant length, grains no plant⁻¹, grain weight plant⁻¹ were better than Sarjoo-52 cultivar under ambient CO_2. EDU+CO₂ treated PB-1 cultivar showed improved antioxidant capacity than the Sarjoo-52 cultivar. EDU treated PB-1 cultivar under elevated CO₂, had more economic yield as compared to the Sarjoo-52 cultivar. Essential human dietary nutrients such as Zn, Ca, and Fe were accumulated more in EDU treated grains of PB-1 as compared to a Sarjoo-52 under elevated CO₂ condition. EDU and CO₂ showed significant interactive effects on morphological, physiological, yield, and grain quality attributes of both rice varieties. EDU protected rice plants from ambient O₃ pollution, improved rice growth, and yield under both ambient and elevated CO₂ conditions.

The full article is available on the Environmental Advances website at https://www.sciencedirect.com/science/article/pii/S2666765720300259