Abstract: Forest plays very important roles in global system with about 35% land area producing about 70% of total land net production. It is important to consider both elevated CO₂ concentrations and different soil moisture when the possible effects of elevated CO₂ concentration on trees are assessed. In this study, we grew Cinnamomum camphora seedlings under two CO₂ concentrations (350 μmol/mol and 500 μmol/mol) and three soil moisture levels [80%, 60% and 40% FWC (field water capacity)] to focus on the effects of exposure of trees to elevated CO₂ on underground and aboveground plant growth, and its dependence on soil moisture. The results indicated that high CO₂ concentration has no significant effects on shoot height but significantly impacts shoot weight and ratio of shoot weight to height under three soil moisture levels. The response of root growth to CO₂ enrichment is just reversed, there are obvious effects on root length growth, but no effects on root weight growth and ratio of root weight to length. The CO₂ enrichment decreased 20.42%, 32.78%, 20.59% of weight ratio of root to shoot under 40%, 60% and 80% FWC soil water conditions, respectively. And elevated CO₂ concentration significantly increased the water content in aboveground and underground parts. Then we concluded that high CO₂ concentration favours more tree aboveground biomass growth than underground biomass growth under favorable soil water conditions. And CO₂ enrichment enhanced lateral growth of shoot and vertical growth of root. The responses of plants to elevated CO₂ depend on soil water availability, and plants may benefit more from CO₂ enrichment with sufficient water supply.

Key words: Cinnamomum camphora, CO₂ concentration, Soil moisture, Plant growth, Root to shoot ratio

Please provide your name, email address and a comment

Your Name: Affili: E-Mail Address:

Comment (Please comment in English):


Verification Code(click to change a pic):