Augé RM, Kubikova E, Moore, JL. 2001. Foliar dehydration tolerance of mycorrhizal cowpea, soybean and bush bean. New Phytologist 151: 535-542.
Foliar dehydration tolerance of three mycorrhizal and nonmycorrhizal legumes is presented here.
Leaf water potential, osmotic adjustment and soil matric potential at the
end of a lethal drying episode were compared in soybean, cowpea and
bush bean colonized or uncolonized by Glomus intraradices.
Lethal leaf water potential were similar among treatments except in
soybean, for which nonmycorrhizal plants given low phosphorus
fertilization had values 0.3-0.4 MPa lower than mycorrhizal plants or
nonmycorrhizal plants given higher phosphorus fertilization. Mycorrhizal
symbiosis did not affect osmotic adjustment or lethal soil matric potential.
Nonmycorrhizal cowpeas given low phosphorus showed more osmotic
adjustment than nonmycorrhizal cowpeas given higher phosphorus.
Foliage of host species typically classified as drought avoiders, cowpea
and bush bean, survived to lower soil matric potentials than soybean,
although soybean foliage was more tolerant of dehydration.
Our findings support the idea that when arbuscular mycorrhizal plants
fare better than nonmycorrhizal plants during drought, it is probably due to
enhanced drought avoidance capabilities conferred by the symbiosis
rather than to changes in ability of foliage to withstand dehydration.
See also Mycorrhizal impact on osmotic adjustment in Ocimum basilicum during a lethal drying episode.