根际CO_2浓度升高对网纹甜瓜矿质营养吸收的影响

Effect of Elevated Rhizosphere CO_2 Concentration on Mineral Nutrient Absorption of Muskmelon

为探讨根际CO2浓度对网纹甜瓜生育和矿质营养吸收的影响,采用雾培植株根际通CO2处理方式,在果期对网纹甜瓜进行不同浓度根际CO2处理,研究根际CO2浓度升高对网纹甜瓜矿质营养吸收的影响。结果表明:根际高浓度CO2(2500μL·L-1和5000μL·L-1)处理同对照(350μL·L-1)相比,植株各部分矿质营养吸收受到不同程度抑制。根中氮含量先增后降,磷、钾、钙和镁含量随CO2浓度升高而下降。茎中氮、磷、钾、钙和镁的含量均低于对照。叶中氮和钾含量显著低于对照,磷含量在处理10d时显著低于对照,5000μL·L-1CO2处理的钙含量显著低于对照,镁含量较对照先增后降。5000μL·L-1CO2处理果实中氮、磷、钾和钙含量显著低于对照。伤流液中矿质元素含量随CO2浓度的升高而减少,2500μL·L-1CO2处理磷含量显著降低,5000μL·L-1CO2处理氮、磷、钾和钙含量均显著低于对照。表明在网纹甜瓜果实发育期间根际CO2浓度长期达到2500μL·L-1以上时,植株对矿质营养的吸收和运输均不同程度减少,当根际CO2浓度达到5000μL·L-1时受到的抑制作用显著。

The objective of the experiments to investigate the effect of rhizosphere CO2 concentration on growth and mineral nutrient absorption of muskmelon. By the geoponics culture system, the effects of rhizosphere different CO2 concentrations on mineral nutrient absorption of muskmelon were studied during the fruiting periods. The results showed that in treatments of high concentration CO2 （2500 and 5000μL·L^-1） as compared to the control （350μL·L^-1）, the absorption and transportation of nutrition were restricted. The content of nitrogen in roots was increased first and then decreased, the contents of P, K, Ca and Mg in roots were decreased with increasing CO2 concentration. The contents of N, P, K, Ca and Mg in stems were lower than the control. The contents of N and K in leaves decreased significantly. The content of P was affected significantly at 10d of treatment. The content of Ca was significantly lower than the control in treatment of 5000μL·L^-1 CO2 concentration. The content of Mg in leaves was increased first and then decreased. The contents of N, P, K and Ca in fruit were significantly lower than the control in treatment of 5000μL·L^-1 CO2 concentration. The content of mineral nutrient in root xylem sap reduced to different degree with the increasing of the root-zone CO2 concentration. The content of P decreased significantly in treatment of 2500μL·L^-1 CO2. The contents of N, P, K and Ca in root xylem sap were significantly lower than the control in treatment of 5000μL·L^-1 CO2. It was concluded that the uptake and transporation of mineral nutrient were inhibited in plant when the rhizosphere CO2 concentration reached 2500μL·L^-1 in fruit development period of muskmelon. The restrain effect was more serious when CO2 concentration reached 5000μL·L^-1.