Ortiz N, Armada E, Duque E, Roldán A, Azcón R
Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, CSIC, Prof. Albareda 1, 18008 Granada, Spain.
Departamento de Proteccion Ambiental, Estación Experimental del Zaidín, CSIC, Prof. Albareda 1, 18008 Granada, Spain.
J Plant Physiol. 2015 Feb 1;174:87-96. doi: 10.1016/j.jplph.2014.08.019. Epub 2014 Oct 20.
Autochthonous microorganisms [a consortium of arbuscular-mycorrhizal (AM) fungi and Bacillus thuringiensis (Bt)] were assayed and compared to Rhizophagus intraradices (Ri), Bacillus megaterium (Bm) or Pseudomonas putida (Psp) and non-inoculation on Trifolium repens in a natural arid soil under drought conditions. The autochthonous bacteria Bt and the allochthonous bacteria Psp increased nutrients and the relative water content and decreased stomatal conductance, electrolyte leakage, proline and APX activity, indicating their abilities to alleviate the drought stress. Mycorrhizal inoculation significantly enhanced plant growth, nutrient uptake and the relative water content, particularly when associated with specific bacteria minimizing drought stress-imposed effects. Specific combinations of autochthonous or allochthonous inoculants also contributed to plant drought tolerance by changing proline and antioxidative activities. However, non-inoculated plants had low relative water and nutrients contents, shoot proline accumulation and glutathione reductase activity, but the highest superoxide dismutase activity, stomatal conductance and electrolyte leakage. Microbial activities irrespective of the microbial origin seem to be coordinately functioning in the plant as an adaptive response to modulated water stress tolerance and minimizing the stress damage. The autochthonous AM fungi with Bt or Psp and those allochthonous Ri with Bm or Psp inoculants increased water stress alleviation. The autochthonous Bt showed the greatest ability to survive under high osmotic stress compared to the allochthonous strains, but when single inoculated or associated with Ri or AM fungi were similarly efficient in terms of physiological and nutritional status and in increasing plant drought tolerance, attenuating and compensating for the detrimental effect of water limitation.
在干旱条件下，对天然干旱土壤中的白三叶草进行了本地微生物（丛枝菌根真菌和苏云金芽孢杆菌的组合）的测定，并与根内根孢囊霉、巨大芽孢杆菌或恶臭假单胞菌进行比较，同时设置了不接种处理。本地细菌苏云金芽孢杆菌和外来细菌恶臭假单胞菌增加了养分和相对含水量，降低了气孔导度、电解质渗漏、脯氨酸和抗坏血酸过氧化物酶活性，表明它们具有缓解干旱胁迫的能力。接种菌根显著促进了植物生长、养分吸收和相对含水量，特别是当与特定细菌结合时，可将干旱胁迫的影响降至最低。本地或外来接种剂的特定组合也通过改变脯氨酸和抗氧化活性来提高植物的耐旱性。然而，未接种的植物相对含水量和养分含量较低，地上部脯氨酸积累和谷胱甘肽还原酶活性较低，但超氧化物歧化酶活性、气孔导度和电解质渗漏最高。无论微生物来源如何，微生物活动似乎在植物中协同发挥作用，作为对调节水分胁迫耐受性和最小化胁迫损伤的适应性反应。本地丛枝菌根真菌与苏云金芽孢杆菌或恶臭假单胞菌以及外来根内根孢囊霉与巨大芽孢杆菌或恶臭假单胞菌接种剂均增强了水分胁迫的缓解。与外来菌株相比，本地苏云金芽孢杆菌在高渗透胁迫下的存活能力最强，但在单独接种或与根内根孢囊霉或丛枝菌根真菌结合时，在生理和营养状况以及提高植物耐旱性、减轻和补偿水分限制的有害影响方面同样有效。
