温室CO2施肥对黄瓜幼苗根系生长及分泌物和伤流液组成的影响

为探讨温室蔬菜CO2施肥的根际效应,以黄瓜幼苗为试材,研究了CO2施肥(上午施肥/上、下午施肥;施肥浓度/对照浓度(950±50)/(350±50)μmol/molCO2)对根系生长及分泌物和伤流液组成的影响。结果表明,CO2施肥明显促进黄瓜幼苗根系发育,根系生物量显著增加;单株根系分泌物中氨基酸、糖、有机酸和酚酸总量增加,但单位鲜重根系分泌量却呈现增幅减少、无变化甚至降低趋势,说明单株分泌量增加主要由根系生长量的增加所引起。CO2施肥促进幼苗对养分的吸收,伤流液中矿质元素、ZT浓度增加,但GA、ABA和IAA浓度降低;与上午CO2施肥相比,上、下午均CO2施肥的效果更明显。CO2施肥促进了黄瓜幼苗根系发育及其代谢活性,为地上部的旺盛生长创造了条件。

Effects of CO2 enrichment in greenhouse on root growth as well as root exudates and bleaching sap of cucumber seedlings

Development and the components of exudates and bleaching sap in the root of cucumber seedlings were examined to elucidate the response of the rhizosphere to CO2 enrichment treatments (one time in the morning and twice in the morning and afternoon). Results showed that: CO2 enrichment significantly promoted root development shown by higher fresh mass, and increased root secretion of sugars, amino acids, organic acids and phenolic acids. However, the root exudates per unit of root fresh mass did not increase so much, unchanged or even decreased in cases. This indicated that the increase in root exudates per plant was mainly attributed to the increase in root growth. CO2 enrichment improved nutrient uptake, which was indicated by increases in concentrations of minerals and ZT in the bleaching sap. However, the concentrations of GA, ABA and IAA decreased. Twice enrichments a day in the morning and afternoon proved more effective than the morning enrichment only. In conclusion, CO2 enrichment resulted in improvements in the root development, metabolic activities and the consequent shoot growth in cucumber seedlings.