Xu Wenbo, Li Miaomiao, Lin Weihu, Nan Zhibiao, Tian Pei
State Key Laboratory of Grassland Agro-Ecosystems, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China.
Institute of Rural Development, Gansu Provincial Academy of Social Sciences, Lanzhou 730071, China.
Plants (Basel). 2021 Aug 11;10(8):1649. doi: 10.3390/plants10081649.
This study explored the effects of the endophyte on growth, photosynthesis, ionic content (K and Ca), phytohormones (abscisic acid-ABA, cytokinin-CTK, indolE-3-acetic acid-IAA, and gibberellin-GA), and elements-C, N, P (in the shoot and root) in two ecotypes of (ecotypes 111 and 141) under different soil water conditions (35% and 65% relative saturation moisture content (RSMC)). The results showed that 35% RSMC inhibited the plants' growth, and compared with 65% RSMC, there was a significant ( < 0.05) decrease in the growth and photosynthesis indices, the contents of CTK and GA, Ca concentration, and the contents of C, N, and P (in both the aboveground and underground parts) under 35% RSMC. had beneficial effects on host growth and stress tolerance. Under both 35% and 65% RSMC, the presence of significantly ( < 0.05) increased host plant height, tiller number, root length, root volume, shoot dry weight, chlorophyll content, and the rate of photosynthesis of both ecotypes. Furthermore, the shoot C, N, and P contents in plants infected with (E+) from the two ecotypes, under both conditions of RSMC, were significantly ( < 0.05) higher than those in corresponding plants that were not infected with (E-). Under 35% RSMC, the contents of ABA, K, Ca, and root P contents in E+ plants were significantly ( < 0.05) higher than those in corresponding E- plants in both ecotypes. However, under 65% RSMC, root C, N, and P contents in E+ plants of ecotype 111 and 141 were significantly ( < 0.05) higher than those in corresponding E- plants. In addition, the host ecotype also had effects on host growth and stress tolerance; the growth and photosynthetic indices of ecotype 141 were significantly ( < 0.05) higher than those of ecotype 111 under 35% RSMC, which suggested that ecotype 141 is more competitive than ecotype 111 under water deficiency conditions. These findings suggest that the endophyte improved the host plant resistance to water deficiency by maintaining the growth of the plant, improving photosynthesis, accumulating K and Ca, promoting nutrient absorption, and adjusting the metabolism of plant hormones.
本研究探讨了内生菌对两种生态型（生态型111和141）在不同土壤水分条件（相对饱和含水量（RSMC）分别为35%和65%）下生长、光合作用、离子含量（钾和钙）、植物激素（脱落酸 - ABA、细胞分裂素 - CTK、吲哚 - 3 - 乙酸 - IAA和赤霉素 - GA）以及地上部和根部碳、氮、磷元素含量的影响。结果表明，35%的RSMC抑制了植物生长，与65%的RSMC相比，在35%的RSMC条件下，生长和光合作用指标、CTK和GA含量、钙浓度以及地上部和地下部碳、氮、磷含量均显著（P < 0.05）下降。内生菌对宿主生长和胁迫耐受性具有有益影响。在35%和65%的RSMC条件下，内生菌的存在均显著（P < 0.05）增加了两种生态型宿主植物的株高、分蘖数、根长、根体积、地上部干重、叶绿素含量和光合速率。此外，在两种RSMC条件下，两种生态型中感染内生菌（E+）的植物地上部碳、氮、磷含量均显著（P < 0.05）高于未感染内生菌（E-）的相应植物。在35%的RSMC条件下，两种生态型中E+植物的ABA、钾、钙含量以及根部磷含量均显著（P < 0.05）高于相应的E-植物。然而，在65%的RSMC条件下，生态型111和141的E+植物根部碳、氮、磷含量均显著（P < 0.05）高于相应的E-植物。此外，宿主生态型对宿主生长和胁迫耐受性也有影响；在35%的RSMC条件下，生态型141的生长和光合指标显著（P < 0.05）高于生态型111，这表明在水分亏缺条件下，生态型141比生态型111更具竞争力。这些发现表明，内生菌通过维持植物生长、改善光合作用、积累钾和钙、促进养分吸收以及调节植物激素代谢来提高宿主植物对水分亏缺的抗性。
