Pan Jing, Peng Fei, Tedeschi Anna, Xue Xian, Wang Tao, Liao Jie, Zhang Wenjuan, Huang Cuihua
Drylands Salinization Research Station, Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, 320 West Donggang Road, Lanzhou, 730000, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Bot Stud. 2020 Apr 19;61(1):13. doi: 10.1186/s40529-020-00290-6.
Halophytes are better than glycophytes at employing mechanisms to avoid salt injury, but both types of plants can undergo damage due to high soil salinity. Arbuscular mycorrhizal fungi (AMF) can mitigate the damage from salt stress in both halophytes and glycophytes by enhancing salt tolerance and improving energy efficiency. However, variations in mycorrhizal symbiotic efficiency between halophytes and glycophytes were still poorly understood. Therefore, we evaluated the magnitude of AMF effects on plant growth and determined the mechanisms that regulate the growth response of halophytes and glycophytes by performing a meta-analysis of 916 studies (from 182 publications).
Arbuscular mycorrhizal fungi significantly enhance biomass accumulation, osmolytes synthesis (soluble sugar and soluble protein), nutrients acquisition (nitrogen, phosphorus, and potassium ion), antioxidant enzyme activities (superoxide dismutase and catalase), and photosynthetic capacity (chlorophyll and carotenoid contents, photosynthetic rate, stomatal conductance, and transpiration rate). AMF also substantially decreased sodium ion acquisition and malondialdehyde levels in both halophytes and glycophytes under salt stress conditions. Mycorrhizal halophytes deploy inorganic ions (potassium and calcium ions) and limited organic osmolytes (proline and soluble sugar) to achieve energy-efficient osmotic adjustment and further promote biomass accumulation. Mycorrhizal glycophytes depend on the combined actions of soluble sugar accumulation, nutrients acquisition, sodium ion exclusion, superoxide dismutase elevation, and chlorophyll synthesis to achieve biomass accumulation.
Arbuscular mycorrhizal fungi inoculation is complementary to plant function under salt stress conditions, not only facilitating energy acquisition but also redistributing energy from stress defence to growth. Glycophytes are more dependent on AMF symbiosis than halophytes under salt stress conditions.
盐生植物在运用避免盐害的机制方面比甜土植物更具优势，但两类植物都可能因土壤盐分过高而受到损害。丛枝菌根真菌（AMF）可通过提高耐盐性和改善能量效率来减轻盐生植物和甜土植物因盐胁迫造成的损害。然而，盐生植物和甜土植物之间菌根共生效率的差异仍知之甚少。因此，我们通过对916项研究（来自182篇出版物）进行荟萃分析，评估了AMF对植物生长的影响程度，并确定了调节盐生植物和甜土植物生长反应的机制。
丛枝菌根真菌显著提高生物量积累、渗透调节物质合成（可溶性糖和可溶性蛋白）、养分获取（氮、磷和钾离子）、抗氧化酶活性（超氧化物歧化酶和过氧化氢酶）以及光合能力（叶绿素和类胡萝卜素含量、光合速率、气孔导度和蒸腾速率）。在盐胁迫条件下，AMF还大幅降低了盐生植物和甜土植物中的钠离子获取量和丙二醛水平。菌根盐生植物利用无机离子（钾离子和钙离子）和有限的有机渗透调节物质（脯氨酸和可溶性糖）来实现节能的渗透调节，并进一步促进生物量积累。菌根甜土植物依靠可溶性糖积累、养分获取、钠离子排斥、超氧化物歧化酶升高和叶绿素合成的联合作用来实现生物量积累。
在盐胁迫条件下，接种丛枝菌根真菌与植物功能互补，不仅有助于获取能量，还能将能量从应激防御重新分配到生长方面。在盐胁迫条件下，甜土植物比盐生植物更依赖AMF共生。
