AUTHOR=Zhang Huihui , Xu Nan , Li Xin , Long Jinghong , Sui Xin , Wu Yining , Li Jinbo , Wang Jifeng , Zhong Haixiu , Sun Guang Y. 

TITLE=Arbuscular Mycorrhizal Fungi (Glomus mosseae) Improves Growth, Photosynthesis and Protects Photosystem II in Leaves of Lolium perenne L. in Cadmium Contaminated Soil

JOURNAL=Frontiers in Plant Science

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2018.01156

DOI=10.3389/fpls.2018.01156

ISSN=1664-462X

ABSTRACT=<p>In this study, the effects of inoculating arbuscular mycorrhizal fungi (<italic>Glomus mosseae</italic>) on the growth, chlorophyll content, photosynthetic gas exchange parameters, and chlorophyll fluorescence characteristics of <italic>Lolium perenne</italic> L. in cadmium (Cd) contaminated soil were investigated. The results showed that the root vigor of <italic>L. perenne</italic> declined, while the chlorophyll content significantly decreased with the increase of Cd content, especially the chlorophyll a content in leaves. The photosynthetic carbon assimilation capacity and PSII activity of <italic>L. perenne</italic> leaves were also significantly inhibited by Cd stress, especially the electron transfer at the receptor side of PSII, which was more sensitive to Cd stress. The infection level of <italic>G. mosseae</italic> on <italic>L. perenne</italic> roots was relatively high and inoculation with <italic>G. mosseae</italic> increased the mycorrhizal infection rate of <italic>L. perenne</italic> roots up to 50–70%. Due to the impact of the mycorrhizal infection, the Cd content in <italic>L. perenne</italic> roots was significantly increased compared to non-inoculated treatment; however, the Cd content in the aboveground part of <italic>L. perenne</italic> was not significantly different compared to the non-inoculated treatment. After inoculation with <italic>G. mosseae</italic>, the root vigor of <italic>L. perenne</italic> increased to some extent, alleviating the chlorophyll degradation in <italic>L. perenne</italic> leaves under Cd contaminated soil. Infection with <italic>G. mosseae</italic> can improve the stoma limitation of <italic>L. perenne</italic> leaves in Cd contaminated soil and increase the non-stomatal factors including the tolerance of its photosynthetic apparatus to Cd, to improve photosynthetic capacity. <italic>G. mosseae</italic> infection can improve the photosynthetic electron transport capacity of PSII in <italic>L. perenne</italic> leaves under Cd stress and promotes the activity of the oxygen-evolving complex to different degrees at the donor side of PSII and the electron transport capacity from Q<sub>A</sub> to Q<sub>B</sub> on the receptor side of PSII. Thus, this guarantees that <italic>L. perenne</italic> leaves inoculated with <italic>G. mosseae</italic> in Cd contaminated soil have relatively higher PSII activity. Therefore, inoculation with <italic>G. mosseae</italic> can improve the capacity of Cd tolerance of <italic>L. perenne</italic> with regard to various aspects, such as morphological characteristics and photosynthetic functions, and reduce the toxicity of Cd on <italic>L. perenne</italic>.</p>