干旱胁迫条件下AM真菌对蓝莓光合特性及矿质元素含量的影响

Arbuscular Mycorrhizal Fungus Affects the Photosynthetic Characteristics and Mineral Element Concentration of Blueberry Under Drought Stress

旨在进一步明确丛枝菌根(arbuscular mycorrhizal, AM)真菌摩西球囊霉(Glomus mosseae)提高蓝莓抗旱性的机制。采用盆栽实验研究了在中度干旱胁迫条件下AM真菌对南高丛蓝莓"奥尼尔"叶片光合特性及矿质元素含量的影响。结果表明:中度干旱显著降低了蓝莓菌根侵染率、净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)、PSII原初光能转化效率(Fv/Fm)以及叶片磷(P)、镁(Mg)及铁(Fe)含量;在中度干旱胁迫条件下,AM真菌接种显著提高了蓝莓叶片叶绿素和类胡萝卜素含量、Pn、Tr、Gs、胞间CO2浓度(Ci)、Fv/Fm以及P、Mg和Fe含量,而对钾(K)和锰(Mn)含量并无显著性影响。可见中度干旱胁迫主要通过降低PSII光能转化效率等非气孔因素来抑制蓝莓的光合速率;但在中度干旱胁迫条件下,AM真菌则通过气孔因素和非气孔因素来提高蓝莓的光合效率,进而有利于提高其抗旱性。

For further clarifying the drought-resistant mechanism of blueberry improved by the arbuscular mycorrhizal(AM)fungus Glomus mosseae,a pot experiment was conducted to study the effects of AM fungus on the photosynthetic characteristics and mineral element concentrations in the leaves of southern highbush blueberry‘O’Neal’(Vaccinium corymbosum)under moderate drought stress.The results showed that moderate drought treatment significantly decreased the mycorrhizal colonization rate,net photosynthetic rate(Pn),transpiration rate(Tr),stomatal conductance(Gs),original light energy conversion efficiency of PSII(Fv/Fm),phosphorus(P),magnesium(Mg)and iron(Fe)concentration in the leaves of blueberry.Under moderate drought stress,AM inoculation significantly enhanced leaf chlorophyll and carotenoid concentrations,Pn,Tr,Gs,intercellular CO2 concentration(Ci),Fv/Fm,concentration of P,Mg and Fe,but it had no significant effect on potassium(K)and manganese(Mn)concentration in the leaves of blueberry.Thus,moderate drought stress treatment inhibits the rate of photosynthesis in blueberry mainly through the non-stomatal factors such as decreasing the light energy conversion efficiency of PSII.However,under moderate drought stress,AM inoculation enhances photosynthetic efficiency of blueberry through both non-stomatal and stomatal factors,which are beneficial to enhance blueberry’s drought resistance.