The effect of concurrent elevation in CO ₂ and temperature on the growth, photosynthesis, and yield of potato crops

Abstract

Global climate change accompanied by continuous increases in atmospheric carbon dioxide (CO ₂) concentration and temperature affects the growth and yield of important crops. The present study investigated the effect of elevated temperature and CO ₂ concentrations on the growth, yield, and photosynthesis of potato ( Solanum tuberosum L. cv. Superior) crops using Korean Soil-Plant-Atmosphere-Research chambers that allow the regulation of temperature and CO ₂ concentration under daylight conditions. Based on the average temperature from 1991 to 2010 in the Jeonju area, South Korea, potato plants were exposed to four different conditions: ambient weather (400 μmol mol ^-1, aCaT), elevated temperature (+4°C, aCeT), elevated CO ₂ concentration (800 μmol mol ^-1, eCaT), and concurrently elevated CO ₂ concentration and temperature (eCeT). Under aCeT conditions, the temperature exceeded the optimal growth temperature range towards the late growth phase that decreased stomatal conductance and canopy net photosynthetic rate and subsequently reduced biomass and tuber yield. Stomatal conductance and chlorophyll concentration were lower under eCaT conditions than under aCaT conditions, whereas late-growth phase biomass and tuber yield were greater. Compared to other conditions, eCeT yielded a distinct increase in growth and development and canopy net photosynthetic rate during tuber initiation and bulking. Consequently, biomass and canopy net photosynthesis increased, and tuber yield increased by 20.3%, which could be attributed to the increased tuber size, rather than increased tuber number. Elevated CO ₂ reduced chlorophyll, magnesium, and phosphorus concentrations; reducing nitrogen concentration (by approximately 39.7%) increased the C:N ratio. The data indicate that future climate conditions will likely change nutrient concentration and quality of crops. The present study shows that while elevated temperature may negatively influence the growth and yield of potato crops, especially towards the late-growth phase, the concurrent and appropriate elevation of CO ₂ and temperature could promote balanced development of source and sink organs and positively effect potato productivity and quality.