School of Life Science, Devi Ahilya University, Indore, 452017, India.
Photosynth Res. 2019 Mar;139(1-3):227-238. doi: 10.1007/s11120-018-0538-4. Epub 2018 Jul 7.
Drought stress (DS) is amongst one of the abiotic factors affecting plant growth by limiting productivity of crops by inhibiting photosynthesis. Damage due to DS and its protection by Arbuscular Mycorrhizal fungi (AMF) was studied on photosynthetic apparatus of wheat (Triticum aestivum) plants in pot experiments. DS was maintained by limiting irrigation to the drought stressed (DS) and AMF + DS plants. Relative Water content (RWC) was measured for leaf as well as soil to ensure drought conditions. DS plants had minimum RWC for both leaf and soil. AMF plants showed increased RWC both for leaf and soil indicating that AMF hyphae penetrated deep into the soil and provided moisture to the plants. In Chl a fluorescence induction curve (OJIP), a declined J-I and I-P phase was observed in DS plants. Efficacy of primary photochemistry declined in DS plants as result of DS, while AMF plants showed maximum photochemistry. DS leads to declined quantum efficiency of PSI and PSII in DS plants while it was restored in AMF + DS plants. Electron transport (ETRI and ETRII) decreased while quantum yield of non-photochemical quenching Y(NPQ) increased as a result of drought stress. CEF around PSI increased in DS-stressed plants. Efficient PSI complexes decreased in DS plants while in case of AMF plants PSI complexes were able to perform PSI photochemistry significantly. Thus, it is concluded that drought stress-induced damage to the structure and function of PSII and PSI was alleviated by AMF colonization.
干旱胁迫（DS）是影响植物生长的非生物因素之一，通过抑制光合作用来限制作物的生产力。在盆栽实验中，研究了 DS 对小麦（Triticum aestivum）植物光合作用装置的破坏及其被丛枝菌根真菌（AMF）的保护作用。通过限制对干旱胁迫（DS）和 AMF+DS 植物的灌溉来维持 DS。测量叶片和土壤的相对水含量（RWC）以确保干旱条件。DS 植物的叶片和土壤的 RWC 均最低。AMF 植物的 RWC 均增加，表明 AMF 菌丝深入土壤并为植物提供水分。在 Chl a 荧光诱导曲线（OJIP）中，DS 植物的 J-I 和 I-P 相下降。由于 DS，初级光化学的功效下降，而 AMF 植物显示出最大的光化学活性。DS 导致 DS 植物 PSI 和 PSII 的量子效率下降，而在 AMF+DS 植物中则得到恢复。电子传递（ETRI 和 ETRII）减少，而非光化学猝灭量子产额 Y（NPQ）增加，这是由于干旱胁迫的结果。PSI 周围的 CEF 在 DS 胁迫植物中增加。DS 植物中有效的 PSI 复合物减少，而 AMF 植物中的 PSI 复合物能够显著进行 PSI 光化学。因此，可以得出结论，AMF 定殖缓解了干旱胁迫对 PSII 和 PSI 的结构和功能的损伤。
