Effects of high CO2 concentration, drought, and their interaction on different stay-green wheat seedlings

Abstract

In this study, a pot experiment was carried out to examine the effects of high CO2 concentration, drought and interaction on seedling growth traits, biomass accumulation and physiological characteristics of different stay-green wheat seedlings, with a stay-green wheat variety Yannong 19 and a non stay-green wheat variety Hanxuan 3 as test materials. There were four treatments in the Open Top Chamber with factorial of CO2 concentration (370 μmol·mol-1 vs 550 μmol·mol-1) and drought (45%-55% vs. 75%-85% of field water-holding capacity). Drought significantly inhibited the growth and development of wheat seedlings, while CO2 concentration significantly increased the number of tillers and promoted the growth and development of wheat seedlings. Under drought condition, high CO2 concentration increased the number of tillers of Hanxuan 3 and Yannong 19 by 61.0% and 42.3%, respectively. Under both water conditions, high CO2 concentration significantly increased the biomass of wheat seedlings, and decreased the content of peroxidase and proline in leaves. Under drought condition, high CO2 concentration showed stronger "fertilizer effect". Furthermore, different varieties had different responses to high CO2 concentration, with higher sensitivity of Hanxuan 3 to enhancement of CO2 concentration. Under the scenario of increasing CO2 concentration, the amount of irrigation water applied to a field can be appropriately reduced for efficient use of water resources. Meanwhile, it is necessary to pay attention to the selection of suitable wheat varieties.