Growth, phosphorus uptake, and water relations of safflower and wheat infected with an arbuscular mycorrhizal fungus

Abstract

SafHower (Carthamus tinctorius L. cv. S5S5) and spring wheat {Triticiim aestivum L. cv. Anza) were grown with or without the arbuscular mycorrhizal fungus Glortius ettinicatum Becker & Gerd., under environmentally controlled conditions. Soil phosphate concentrations were adjusted before planting to produce mycorrhizal (M) and non-mycorrhizal (NM) plants that had similar leaf areas and root length densities at the same stage of development before initiating drought stress treatments. Drought did not afTect the amount of mycorrhizal infection in safflower or wheat. Interactions between water stress treatments and mycorrhizal infection on plant growth and phosphorus uptake were limited and only occurred in wheat. NM wheat plants had 28 °o greater shoot d. wt, slightly greater root length densities, and 39 °" greater P acquisition than M plants when grown under well watered conditions, but under droughted conditions plant size and tissue P contents of M and NM wheat plants were similar. Mycorrhizas did not afTect stomatal behaviour during drought stress in either safflower or wheat, i.e., transpiration and stomatal conductance declined independently of infection as soil water was depleted and leaf water potentials declined. Therefore, mycorrhizal infection did not alter the intrinsic hydraulic properties of the plant/soil system. Whilst wheat maintained turgor of recently expanded leaves during severe drought and safflower did not, mycorrhizal infection had no effect on leaf turgor during drought in either plant species.

Improved tolerance of wheat plants (Triticum aestivum L.) to drought stress and rewatering by the arbuscular mycorrhizal fungus Glomus claroideum: effect on growth and cell membrane stability

“…However, arbuscles formation did not recover in rewatered plants, probably because arbuscles are assimilated by root cells and their contents are absorbed by the host more rapidly under stress conditions (Kaspari, 1973). While some authors found that water stress affects mycorrhizal symbiotic establishment (Davies et al, 2002;Goicoechea et al, 2005), others such as Bryla and Duniway (1997) reported that drought stress (Ψ s = -1.5 to -2 MPa) does not affect mycorrhizal colonization rates in wheat. Braunberger et al (1994) determined that the hyphae network of AMF , moderate water stress (MoSt), severe water stress (SeSt), moderate water stress followed by rewatering (MoRw) or severe water stress followed by rewatering (SeRw).…”

Rôle des champignons mycorhiziens à arbuscules de zones arides dans la résistance du trèfle (Trifolium alexandrinum L.) au déficit hydrique

“…Aucune différence significative n'a été enregistrée au niveau du potentiel osmotique chez les plantes témoins et celles qui ont été inoculées. Ces résultats sont similaires à ceux obtenus par plusieurs auteurs [6,12,17,18] [7,43]. Les teneurs en K, Mg et en Na ne sont cependant pas améliorées chez les plantes mycorhizées par rapport à celles non mycorhizées, ce qui pourrait être dû à la forte stimulation de la production de la matière sèche des trèfles mycorhizées.…”

Osmotic solute responses of mycorrhizal citrus (Poncirus trifoliata) seedlings to drought stress

“…Although the benefit of colonization by AMF to plant-water relations has been supported by many studies, the debate still continues. For instance, Bryla and Duniway (1997) observed no AMF effects on osmotic adjustment of DS plants. A similar result was also found by Augé et al (1992) and Goicoechea et al (1997b).…”