Progresses of free-air CO2 enrichment (FACE) researches on C4 crops: a review Effect of Free-air CO2 Enrichment on Root Activity of Japonica Rice (Oryza sativa L.) Cultivar Wuxiangjing 14 A simulation of growth duration in FACE rice Effect of Free-air CO2 Enrichment on Spikelet Differentiation and Degeneration of Japonica Rice (Oryza sativa L.) Cultivar Wuxiangjing 14 Effect of Free-air CO2 Enrichment on Root Growth Dynamics of Japonica Rice (Oryza sativa L.) Cultivar Wuxiangjing 14 Effects of Free-air CO2 Enrichment (FACE) on Growth Duration of Rice (Oryza sativa L.) and Its Cause Effects of Free-air CO2 Enrichment(FACE) on Nitrogen Nutrition at Different Growth Stages in Rice(Oryza sativa L.) Cultivar Wuxiangjing 14 Effects of Free-air CO2 Enrichment on Root System and Yield in Rice (Oryza sativa L.)