Li Tao, Lin Ge, Zhang Xin, Chen Yongliang, Zhang Shubin, Chen Baodong
State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
Mycorrhiza. 2014 Nov;24(8):595-602. doi: 10.1007/s00572-014-0578-3. Epub 2014 Apr 18.
Both arbuscular mycorrhizal (AM) fungi and root hairs play important roles in plant uptake of water and mineral nutrients. To reveal the relative importance of mycorrhiza and root hairs in plant water relations, a bald root barley (brb) mutant and its wild type (wt) were grown with or without inoculation of the AM fungus Rhizophagus intraradices under well-watered or drought conditions, and plant physiological traits relevant to drought stress resistance were recorded. The experimental results indicated that the AM fungus could almost compensate for the absence of root hairs under drought-stressed conditions. Moreover, phosphorus (P) concentration, leaf water potential, photosynthetic rate, transpiration rate, stomatal conductance, and water use efficiency were significantly increased by R. intraradices but not by root hairs, except for shoot P concentration and photosynthetic rate under the drought condition. Root hairs even significantly decreased root P concentration under drought stresses. These results confirm that AM fungi can enhance plant drought tolerance by improvement of P uptake and plant water relations, which subsequently promote plant photosynthetic performance and growth, while root hairs presumably contribute to the improvement of plant growth and photosynthetic capacity through an increase in shoot P concentration.
丛枝菌根（AM）真菌和根毛在植物吸收水分和矿质养分方面都起着重要作用。为了揭示菌根和根毛在植物水分关系中的相对重要性，在水分充足或干旱条件下，对无毛根大麦（brb）突变体及其野生型（wt）进行接种或不接种AM真菌根内根孢囊霉的培养，并记录与抗旱性相关的植物生理性状。实验结果表明，在干旱胁迫条件下，AM真菌几乎可以弥补根毛缺失的影响。此外，除干旱条件下地上部磷浓度和光合速率外，根内根孢囊霉显著提高了磷（P）浓度、叶片水势、光合速率、蒸腾速率、气孔导度和水分利用效率，而根毛对这些指标没有显著影响。在干旱胁迫下，根毛甚至显著降低了根中的磷浓度。这些结果证实，AM真菌可以通过改善磷吸收和植物水分关系来增强植物的耐旱性，进而促进植物的光合性能和生长，而根毛可能通过提高地上部磷浓度来促进植物生长和光合能力。
