Elevated and super-elevated CO₂ differ in their interactive effects with nitrogen availability on fruit yield and...

Area of Science:

• Agricultural Science
• Plant Physiology
• Environmental Science

Background:

• Investigates the interactive effects of elevated carbon dioxide (CO2) and nitrogen (N) availability on cucumber (Cucumis sativus L.) yield and fruit quality.
• Cucumber plants were subjected to three CO2 concentrations (400, 800, and 1200 µmol mol⁻¹) and two N application rates (low and high) in paddy soil.

Purpose of the Study:

• To elucidate the mechanisms behind CO2- and N-driven yield increases in cucumbers.
• To determine the impact of varying CO2 and N levels on cucumber fruit quality attributes.

Main Methods:

• Controlled environment study with factorial design of CO2 concentrations and N availability.
• Analysis of plant biomass, carbon allocation patterns, and fruit nutritional composition.

Main Results:

• Elevated CO2 (800 µmol mol⁻¹) increased cucumber yield by 106% under high N, mainly through enhanced carbon translocation from source leaves to fruits.
• Super-elevated CO2 (1200 µmol mol⁻¹) reduced yield gains (71%) and altered carbon allocation.
• Elevated CO2 improved fruit quality by increasing fructose and glucose, maintaining essential minerals, but decreasing nitrate and protein content in high N conditions.

Conclusions:

• Elevated CO2 significantly enhances cucumber yield in high N environments by redirecting carbon resources to fruits.
• Fruit quality is influenced by carbon allocation, carbohydrate transformation, and nutrient uptake under elevated CO2.
• Optimal CO2 concentrations are crucial for maximizing both yield and quality, with super-elevated levels potentially being detrimental.