接种AM真菌对甘薯光合作用及碳磷代谢酶活性的影响

Effects of Arbuscular Mycorrhizal Fungi on Photosynthetic Characteristics and Metabolic Enzyme Activities of Carbon and Phosphorus of Sweetpotato

为探讨丛枝菌根真菌和磷水平对甘薯生长特性的影响,采用盆栽试验方法,设置3个P水平(P_0,P_(50),P_(150)mg/kg),研究了接种AM真菌对甘薯生长、光合特性和叶片酶活性的影响。结果表明:接种AM真菌显著增加了甘薯根系侵染率、丛枝丰度、根内菌丝丰度和泡囊丰度。不同磷水平间甘薯的侵染率、丛枝丰度均差异显著,中磷的总体侵染情况显著高于低磷和高磷水平(P<0.05)。低磷和中磷条件下,接种处理显著提高了甘薯的生物量和氮磷吸收量(P<0.05),其中在磷50mg/kg水平下,接种菌根真菌后甘薯氮磷养分吸收量显著高于未接种处理,地上地下部生物量分别提高了28.6%和73.3%,而高磷条件下接种处理甘薯地上和地下部的生长显著降低。在低磷和中磷水平下,接种AM真菌显著提高了甘薯的净光合速率、气孔导度和蒸腾速率;在中磷水平下接种AM真菌甘薯叶片的蒸腾速率和气孔导度达到最大值,之后随着磷水平的升高而降低;当土壤磷素供应过高时,接种AM真菌属非气孔限制因素导致的光合速率降低(P<0.05)。在低磷和中磷水平下,接种菌根真菌显著提高了甘薯叶片中蔗糖合成酶、6-磷酸葡萄糖酸脱氢酶、蔗糖磷酸合成酶和磷酸酶的活性;在高磷水平下,接种后甘薯叶片代谢酶活性明显降低。不同磷水平下的菌根效应表现为P_(50)>P_0>P_(150),说明接种菌根的效果受土壤磷水平的影响。

In order to explore the effects of arbuscular mycorrhizal fungi and phosphorus levels on the growth characteristics of sweetpotato,apot experiment was conducted to investigate the effects of arbuscular mycorrhizal fungi on the growth,photosynthetic characteristics and metabolic enzyme activities of sweetpotato at different P Levels（0,50,150 mg/kg）.The results showed that the inoculation with AM fungi significantly increased the colonization rate,arbuscular frequency,hyphae frequency and vesicle frequency of sweetpotato roots.AMF had a significant influence on colonization rate and arbuscular frequency,and the overall colonization rate of medium phosphorus level was higher than those of low and high phosphorus levels（P〈0.05）.At low and medium phosphorus levels,inoculation treatment significantly increased the biomass and the content of nitrogen and phosphorus uptake（P〈0.05）,and sweetpotato inoculated with AMF at 50 mg/kg phosphorus level was significantly higher than no inoculation treatment in N and P content and biomass of sweetpotato,and aboveground and belowground biomass increased by 28.6% and 73.3%,respectively,while inoculation significantly reduced the growth of aboveground and belowground sweetpotato under high P level.AM fungi significantly improved the net photosynthetic rate,stomata conductance and transpiration rate at low and medium phosphorus levels.Under the medium phosphorus level,the stomata conductance and transpiration rate reached the maximum,and then reduced with the increase of P.When the soil phosphorus supply was too high,AM fungi led to the lower-photosynthetic rate due to non-stomatal limitation（P〈0.05）.Under low and medium phosphorus levels,arbuscular mycorrhizal fungi significantly increased leaf enzyme activities including sucrose synthase,6-phosphaogluconate dehydrogenase,sucrose phosphate synthase and phosphatase.The AMF inoculation significantly decreased the metabolic enzyme activities of sweetpotato leaves under thehigh phosphorus level.The mycorrhizal effect of different phosphorus levels showed P0P（150）P（50） tendency,indicating that the effect of mycorrhizal inoculation was affected by soil phosphorus supply.