关键词: 土壤种子库, 植被恢复工程, 响应面优化法

Abstract: To estimate the effects of elevated \[CO₂\] on the mineral nutrition of brown rice as well as the differences of effect between indica and japonica cultivars (Oryza sativa L.), the concentrations and accumulations of Fe, Mn, Cu, Zn, Ni and Se in brown rice of indica IIY084 and japonica WYJ23 were investigated at a free-air CO₂ enrichment (FACE) experimental facility in eastern China during 2013 and 2014. The target \[CO₂\] of the FACE plots was 200 μmol·mol^-1 higher than the ambient. The results showed that there were significant CO₂ effects on grain and brown rice yields in both years. Average grain yield of two years increasedby 33.1% (IIY084) and 14.3% (WYJ23), and the average brown rice yield enhanced by 34.3% (IIY084) and 16.3% (WYJ23) respectively under elevated \[CO₂\]. The average brown rice Fe, Mn, Cu, Zn, Ni and Se concentrations of two years in IIY084 decreased by 10.4%, 13.4%, 15.5%, 11.7%, 25.7% and 3.2%, respectively, while the change trend of those in WYJ23 were inconsistent. Especially, there were negative CO₂ effects on Mn, Cu, Zn and Ni (P<0.05) concentrations in 2014. In addition, there were significant differences in Fe (P<0.1, 2014), Mn (P<0.01, 2013 and 2014), Cu (P<0.1, 2014), Zn (P<0.01, 2013 and 2014), Ni (P<0.01, 2014) and Se (P<0.05, 2013; P<0.01, 2014) concentrations in brown rice between the two cultivars. Fe, Mn, Cu, Zn, Ni and Se accumulations in both cultivars were affected by \[CO₂\] enrichment. Compared to the ambient, the average mineral nutrient accumulations of two years at elevated \[CO₂\] were increased by 2.1%-29.2% (IIY084) and 12.8%-19.3% (WYJ23), respectively. In short, concentrations of Fe, Mn, Cu, Zn, Ni and Se in the brown rice of II084 had greater reduction than that of WYJ23 under elevated \[CO₂\]. Taking into account the health of mankind who depend on rice, feeding on IIY084 may cause a greater risk of Fe, Mn, Cu, Zn, Ni and Se deficiency than WYJ23 under the global elevated \[CO₂\] scenario. In the future, more attentions should be paid on rice cultivars that can alleviate the nutrient deficiency due to the decline of mineral nutrition when screening and breeding of yield-increasing cultivars to ensure grain security.

Key words: soil seed bank, vegetation recovery project, response surface methodology.