Carbon dioxide enrichment of the root zone of tomato seedlings

Abstract

SummaryThe root systems of five week old tomato plants (Lycopersicon esculentum Mill. cv. Vendor) growing in nutrient solution were treated for 12 h with various concentrations (between 0.5 and 50%) of carbon dioxide and 20% O2 in a balance of N2. Growth measured five days after treatment was influenced by the CO2 concentration. Stimulation of growth occurred at the lower CO2 concentrations (0.5–5%) while higher (25 and 50%) ones were inhibitory. When the application of CO2 was extended from 12 h to five days, even low CO2 concentrations inhibited growth. One centimeter excised root tips from five day old seedlings were treated with the same gas mixtures as the whole plants. The uptake of rubidium was promoted by 1% CO2, while higher concentrations either had no effect or were inhibitory. The uptake of phosphorus was unaffected by concentrations below 10% but was negatively modulated by concentrations above 10%. A 12 h application of 50% CO2 dramatically increased ion leakage from roots.