菌根真菌对榉树光合特性的影响

【目的】探究丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)对木本植物生长和光合特性的影响以及樟树光响应模型的适用性。【方法】以自培无菌榉树(Zelkova serrata Thunb.)幼苗为试验材料,设置3个处理,分别为不接种菌根真菌(CK)、接种来自贵州毕节的摩西球囊霉(GM1)、接种来自云南楚雄的摩西球囊霉(GM2),测定榉树的光响应曲线,通过对5种常用的光响应曲线模型进行比较分析,探索菌根真菌对榉树光合特性的影响,并通过5种模型对光响应曲线进行拟合,评定5种模型的适用性。【结果】接种菌根真菌明显提高了榉树的一些形态指标,体现在苗高、地径的增加。接种菌根真菌提高了榉树的净光合速率(P_n)、气孔导度(G_s)、胞间CO₂浓度(C_i)。其中,GM1的效果要好于GM2,同时,GM1对榉树的蒸腾速率(T_r)也有提升效果。通过5种模型的拟合,发现模拟效果都很好,只有指数模型在拟合接种GM1的榉树光响应曲线时,R²为0.977,其余的都达到了0.99以上。从决定系数的均值分析,叶子飘模型的拟合效果最好,其次是非直线双线模型,拟合效果相对最差的是指数模型。相关性分析表示,叶绿素含量与侵染率呈负相关关系,苗高与侵染率无显著相关性,地径、C_i、G_s、P_n均与侵染率呈显著正相关。【结论】接种菌根真菌可以促进宿主植物的生长,对植物的光合特性也有一定的提升效果。5种光响应模型中,叶子飘模型的模拟效果最好,所以在对榉树的光响应情况的描述上,应该以叶子飘模型为主,其余几个模型可以作为参考。

Effects of mycorrhizal fungi on photosynthetic characteristics of Zelkova serrata Thunb

【Objective】Determine the effects of arbuscular mycorrhizal fungi(AMF)on the growth and photosynthetic characteristics of woody plants, and the applicability of light response models. 【Method】In this study, Zelkova serrata Thunb. was used as experimental material. Glomus mosseaefrom Guizhou, Bijie and Glomus mosseae from Yunnan, Chu-xiong were inoculated on self-seeding sterile seedlings of Z. serrata, recorded as GM1 and GM2 respectively, with no inoculation as control, it was recorded as CK. After successful induction of infection, light-response curves of Z. serrata were measured. Five common light-response curve models were analyzed and compared to explore the effects of AMF on photosynthetic characteristics of Z. serrata. Five models were used to simulate the light-response curve, and the applicability of the models was evaluated.【Result】The results show that AMF increased the growth of Z. serrata, as indicated by the increase in seedling height, ground diameter, and leaf number; however, the effect on total chlorophyll content was not obvious or even reduced. Mycorrhizal inoculation improved the net photosynthetic rate light of Z. serrata(P_n), stomatal conductance(G_s), and intercellular CO₂ concentration(C_i). The effect of inoculation with GM1 was better than that with GM2. The transpiration(T_r)rate of GM1 inoculation on Z. serrata was increased, but the transpiration efficiency of GM2 inoculation of Z. serrata was even lower than CK. Through the fitting of five models, the simulation results were found to be good, and the coefficient of determination(R²)was 0.9, only the exponential model in fitting with GM1 Z. serrata light-response curve, R² value is 0.977, the coefficient of determination of the other models are over 0.99. From the mean of coefficient of determination, the effect of Ye Zi-Piao model was found to be the best, followed by the non-linear double line model. The exponential model was found to be the least beneficial. Correlation analysis showed that chlorophyll content was negatively correlated with infection rate, while seedling height was not significantly correlated with infection rate. Ground diameter, C_i, G_s and P_n were positively correlated with infection rate.【Conclution】Inoculation with mycorrhizal fungi can promote the growth of host plant. In addition, the photosynthetic characteristics of the plant were enhanced. Five types of light-response models were used. The best simulation result was obtained for Ye Zi-Piao model. Therefore, When describing photoresponse of Z. serrata should mainly rely on Ye Zi-Piao model although other models can be used as reference.