การคัดเลือกแบคทีเรียทนแล้ง
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.