Dr. Bryla et Jm. Duniway, EFFECTS OF MYCORRHIZAL INFECTION ON DROUGHT TOLERANCE AND RECOVERY INSAFFLOWER AND WHEAT, Plant and soil, 197(1), 1997, pp. 95-103
The influence of arbuscular mycorrhizal fungi on drought tolerance and
recovery was studied in safflower (Carthamus tinctorius L.) and wheat
(Triticum aestivum L.). Plants were grown with and without the mycorr
hizal fungus, Glomus etunicatum Becker & Gerd., in nutrient-amended so
il under environmentally-controlled conditions to yield mycorrhizal an
d nonmycorrhizal with similar leaf areas, root length densities, dry w
eights, and adequate tissue phosphorus. When drought stress was induce
d, mycorrhizal infection did not affect changes in leaf water, osmotic
or pressure potentials, or osmotic potentials of leaf tissue rehydrat
ed to full turgor in either safflower or wheat. Furthermore, in safflo
wer, infection had little effect on drought tolerance as indicated by
the level of leaf necrosis. Mycorrhizal wheat plants, however, had les
s necrotic leaf tissue than uninfected plants at moderate levels of dr
ought stress (but not at severe levels) probably due to enhanced phosp
horus nutrition. To determine the effects of infection on drought reco
very, plants were rewatered at a range of soil water potentials from -
1 to -4 MPa. We found that although safflower tended to recover more s
lowly from drought after rewatering than wheat, mycorrhizal infection
did not directly affect drought recovery in either plant species. Dail
y water use after rewatering was reduced and was correlated to the ext
ent that leaves were damaged by drought stress in both plant species,
but was not directly influenced by the mycorrhizal status of the plant
s.