Yan Qiuxiao, Li Xiangying, Xiao Xuefeng, Chen Jingzhong, Liu Jiming, Lin Changhu, Guan Ruiting, Wang Daoping
Department of Ecology, College of Forestry Guizhou University Guiyang China.
The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences Guiyang China.
Ecol Evol. 2022 Jul 11;12(7):e9091. doi: 10.1002/ece3.9091. eCollection 2022 Jul.
Drought is the main limiting factor for plant growth in karst areas with a fragile ecological environment. H.W. Li is an endemic medicinal woody plant present in the karst areas of southwestern China, and it is endangered due to poor drought tolerance. Arbuscular mycorrhizal fungi (AMF) are known to enhance the drought tolerance of plants. However, few studies have examined the contribution of AMF in improving the drought tolerance of seedlings. Therefore, we conducted a series of experiments to determine whether a single inoculation and coinoculation of AMF ( and ) enhanced the drought tolerance of . Furthermore, we compared the effects of single inoculation and coinoculation with different inoculum sizes (20, 40, 60, and 100 g; four replicates per treatment) on mycorrhizal colonization rate, plant growth, photosynthetic parameters, antioxidant enzyme activity, and malondialdehyde (MDA) and osmoregulatory substance contents. The results showed that compared with nonmycorrhizal plants, AMF colonization significantly improved plant growing status; net photosynthetic rate; superoxide dismutase, catalase, and peroxidase activities; and soluble sugar, soluble protein, and proline contents. Furthermore, AMF colonization increased relative water content and reduced MDA content in cells. These combined cumulative effects of AMF symbiosis ultimately enhanced the drought tolerance of seedlings and were closely related to the inoculum size. With an increase in inoculum size, the growth rate and drought tolerance of plants first increased and then decreased. The damage caused by drought stress could be reduced by inoculating 40-60 g of AMF, and the effect of coinoculation was significantly better than that of single inoculation at 60 g of AMF, while the effect was opposite at 40 g of AMF. Additionally, the interaction between AMF and inoculum sizes had a significant effect on drought tolerance. In conclusion, the inoculation of the AMF ( and ) improved photosynthesis, activated antioxidant enzymes, regulated cell osmotic state, and enhanced the drought tolerance of , enabling its growth in fragile ecological environments.
干旱是生态环境脆弱的喀斯特地区植物生长的主要限制因素。华桑是中国西南喀斯特地区特有的药用木本植物，因其耐旱性差而濒危。丛枝菌根真菌（AMF）已知可增强植物的耐旱性。然而，很少有研究探讨AMF对提高幼苗耐旱性的贡献。因此，我们进行了一系列实验，以确定单一接种和联合接种AMF（ 和 ）是否能增强华桑的耐旱性。此外，我们比较了不同接种量（20、40、60和100克；每个处理四个重复）的单一接种和联合接种对菌根定殖率、植物生长、光合参数、抗氧化酶活性以及丙二醛（MDA）和渗透调节物质含量的影响。结果表明，与非菌根植物相比，AMF定殖显著改善了植物生长状况、净光合速率、超氧化物歧化酶、过氧化氢酶和过氧化物酶活性，以及可溶性糖、可溶性蛋白和脯氨酸含量。此外，AMF定殖增加了细胞相对含水量并降低了MDA含量。AMF共生这些综合累积效应最终增强了幼苗的耐旱性，且与接种量密切相关。随着接种量增加，植物生长速率和耐旱性先升高后降低。接种40 - 60克AMF可减轻干旱胁迫造成的损害，在60克AMF时联合接种效果显著优于单一接种，而在40克AMF时效果相反。此外，AMF与接种量之间的相互作用对耐旱性有显著影响。总之，接种AMF（ 和 ）改善了光合作用，激活了抗氧化酶，调节了细胞渗透状态，增强了华桑的耐旱性，使其能够在脆弱的生态环境中生长。
