非饱和带二氧化碳入侵对表生植物及土壤的影响

非饱和带属于地球关键带，与人类生存环境及安全健康关系密切，而CO₂对生态环境及全球气候变化的影响至关重要。为了探索高浓度CO₂入侵非饱和带对生态环境可能带来的风险，基于长安大学水与环境原位试验场CO₂试验平台，向种植有5种典型植物（黑麦草、小麦、玉米、豌豆和苋菜）的土壤中长期注入浓度为5%、10%和15%的CO₂气体，评估CO₂入侵对植物和土壤的潜在影响。对表生植物及土壤样品（深度为20～30 cm）的理化性质分析表明:高浓度CO₂明显抑制了植物的生长，会导致植株高度、叶片数和果实重量下降；土壤矿相和理化性质也有微小变化，表现为土壤pH值的变化以及氮、有效钾、有效磷等的减少。通过分析植物的光合作用、渗透调节作用以及抗氧化系统的变化，不同的植物对CO₂胁迫表现出不同且复杂的响应，总体上C3单子叶植物黑麦草和C4单子叶植物玉米显示出比其他植物更高的敏感性，表明它们有潜力作为评估CO₂生态影响的指示植物。

Influence of carbon dioxide invasion in the unsaturated zone on vegetation and soil

The unsaturated zone is the critical zone of the earth, which is closely related to the human living environment and health safety. Carbon dioxide plays a crucial role in the ecological environment and global climate change. In order to explore the potential risk of high concentration CO₂ invasion into the unsaturated zone to the ecological environment, and based on CO₂ simulation platform of in situ research filed of water and environment of the Chang’an University, we present a controlled experiment, in which 5%, 10% and 15% pure CO₂ was respectively injected into the local soil planted with five typical plants (ryegrass, wheat, corn, pea and amaranth) to assess the potential impact of CO₂ invasion on the environment, specifically on soil and plants. Botanical investigation and chemical analyses of soil samples (at depth from 20 to 30 cm) shows a significant adverse impact of CO₂ injection on plant growth, including declining plant height, number of leaves and fruit weight. Small changes were observed in mineralogy and bulk chemistry, showing the change of soil pH and reduction of nitrogen, available potassium, available phosphorus, etc. Different plants show different and complicated responses to CO₂ stress, depending on plant life history, including photosynthetic pathways, osmoregulation and antioxidant systems. On the whole, C3 monocotyledon ryegrass and C4 monocotyledon corn show greater sensitivity than other plants, suggesting their potential as indicator plants for evaluation of CO₂ impact on ecological environment.