Mycorrhizal Enhancement of Water Transport in Soybean

Safir, Gene R.; Boyer, John S.; Gerdemann, J. W.

doi:10.1126/science.172.3983.581

Cited by 132 publications

(46 citation statements)

References 25 publications

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“…For example, ectomycorrhizal symbiosis has been reported to have negative or no effects on root hydraulic conductance (K R ) of Douglas fir seedlings [12]. This finding is in contrast with the classical interpretation suggesting that ectomycorrhizal infection of tree roots enhances root water uptake [24,32].…”

Section: Introductioncontrasting

confidence: 55%

“…Most of our understanding of mycorrhizal symbiosis comes from work on VAM (vescicular-arbuscular mycorrhizae) whose benefits to the host in terms of phosphorus uptake [1] and nutrition have recently been reviewed [10]. Considerable uncertainty still exists in the evaluation of many other aspects of the VAM-host interaction [10] among which the influence of mycorrhizae on host hydraulics and water relations which would be favoured by VAM, according to Safir et al [32], Sands et al [36], Huang et al [20], Ruiz-Lozano and Azcòn [31], Gemma et al [17] or would be independent on mycorrhizae, according to Graham et al [19], Andersen et al [7], Steudle and Heydt [40].…”

Section: Introductionmentioning

confidence: 99%

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Influence of the ectomycorrhizas formed by Tuber melanosporum Vitt. on hydraulic conductance and water relations of Quercus ilex L. seedlings

et al. 2000

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-The physiological impact of ectomycorrhizal infection was investigated in the association between Tuber melanosporumVitt. and Quercus ilex L. A number of physiological parameters were investigated on 2-year-old seedlings inoculated for 22 months (I-seedlings) compared to non-inoculated plants (NI-seedlings). I-seedlings had a 100% infection rate in root tips compared to a 25% infection rate in root tips of NI-seedlings. I-seedlings had higher values of net assimilation and stomatal conductance than NIseedlings. Root hydraulic conductance per unit root surface area of I-seedlings was much reduced to 0.44× that of NI-seedlings but had 2.5× more fine root surface area than NI-seedlings. When root conductance was scaled by leaf area, the I-seedlings had 1.27× the root conductance per unit leaf area compared to NI-seedlings. I-seedlings also had significantly higher hydraulic conductances of shoots with leaves, of shoots without leaves and lower leaf blade hydraulic resistances.hydraulic conductance / water relations / ectomycorrhiza / Quercus ilex L. / HPFM Résumé -Influence sur la conductance hydraulique et les relations hydriques des semis de Quercus ilex L. des ectomycorrhizes formées par Tuber melanosporum Vitt. L'impact physiologique dû à l'infection d'ectomycorrhizes a été étudié dans l'association Tuber melanosporum Vitt. et Quercus ilex L. Un certain nombre de paramètres physiologiques ont été mesurés sur des semis de 2 ans inoculés pendant 22 mois (semis-i) en comparaison avec des cultures saines (semis-ni). Les semis-i présentent 100 % de taux d'infection des racines, tandis que les semis-ni atteignent un taux de 25 %. Les semis-i ont des niveaux d'assimilation nette plus élevés par rapport aux semis-ni. La conductance hydraulique des racines par unité de surface des racines pour les semis-i est réduite de plus de 0,44 fois par rapport aux semis-ni, mais comporte une surface de racines 2,5 fois inférieure à celle des semis-ni. En rapportant la conductance des racines à la surface des feuilles, la conductance des racines par unité de surface des feuilles des semis-i est 1,27 fois plus élevée que celle des semis-ni. Les semis-i présentent également une conductance hydraulique des rameaux avec feuilles et sans feuilles bien plus élevée, ainsi qu'une moindre résistance hydraulique des feuilles.conductance hydraulique / relations hydriques / ectomycorrhize / Quercus ilex L. / HPFM Abbreviations PAR: photosyntetically active radiation Ψ L : leaf water potential g L : leaf conductance to water vapor Pn: net photosynthesis A L : total leaf surface area A R : total root surface area Ann. For. Sci. 57 (2000) [305][306][307][308][309][310][311][312] 305

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Section: Introductioncontrasting

confidence: 55%

Section: Introductionmentioning

confidence: 99%

Influence of the ectomycorrhizas formed by Tuber melanosporum Vitt. on hydraulic conductance and water relations of Quercus ilex L. seedlings

et al. 2000

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“…The vesicular-arbuscular mycorrhizal relationship, one of the most common forms of symbiosis, increases the growth of many host plant species (1-3, 10, 15, 16, 20, 25, 29) including soybean (30,31). The increased growth has been attributed to an enhanced nutrient uptake by the host plant (2,12,15,(18)(19)(20)26).…”

Section: Methodsmentioning

confidence: 99%

Nutrient Status and Mycorrhizal Enhancement of Water Transport in Soybean

1972

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MATERIALS AND METHODSMycorrhizal soybean (Glycine max L. Merr. var. plants have lower resistances to water transport than nonmycorrhizal plants after 4.5 weeks of growth. Although resistances of whole plants differ by 40 %, there were no differences in the resistances of stems plus leaves, indicating that the major effect of the mycorrhizae was to reduce the resistance of the roots. Since the fungitoxicant, p-chloronitrobenzene, had no effect on resistances to water transport, reduced resistances were probably not caused by a direct modification of the transport pathway by the fungus. Differences in resistance between mycorrhizal and nonmycorrhizal soybean were essentially eliminated by the application of nutrients to the soil. Thus, lowered resistances of mycorrhizal roots growing in soil with low levels of nutrients probably resulted from the enhanced nutrient status of the plant brought about by the fungus. Mycorrhizal infection increased growth at both low and high nutrient levels.The vesicular-arbuscular mycorrhizal relationship, one of the most common forms of symbiosis, increases the growth of many host plant species (1-3, 10, 15, 16, 20, 25, 29) including soybean (30, 31). The increased growth has been attributed to an enhanced nutrient uptake by the host plant (2,12,15,(18)(19)(20)26). Mycorrhizal plants take up more phosphorus than nonmycorrhizal controls when relatively unavailable sources of phosphorus are supplied to the roots (12,26). In most cases the addition of more readily available phosphorus eliminates differences in growth and phosphorus uptake (3,12,13,20,26).We have recently shown that VA3 mycorrhizae also decrease the resistance to water transport in whole soybean plants (31). The present study was undertaken to determine where the fungus acts and whether the lowered resistance to water transport can be attributed to increases in the nutrient status of the host brought about by the mycorrhizae.'This work was supported in part by The method used for determining resistance to water transport was that of Boyer (5, 6), which has previously given results that compare well with independent methods (6, 31) and provides consistent determinations of whole plant resistances in mycorrhizal and nonmycorrhizal soybean (31). The method involves measurement of the recovery in water potential of a moderately water-deficient leaf on an intact plant. The time required for recovery, which is determined when no transpiration is occurring, is dependent on the resistance to water transport.For measurement of the recovery of a whole plant, the blade of an intact soybean leaf which was moderately water deficient was sealed in a thermocouple psychrometer chamber that measures the water potential of intact leaves (4). The soil and root system were then submerged in degassed water, excess water was drained away, and the recovery in water potential of the leaf was recorded. After determining that the data conformed to the transfer equation for a plane sheet (5, 9, 1 1), the resistance of the whole plant was calc...

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“…This results primarily from improved uptake of soil phosphorus (P) through extraradical hyphae which increase the root absorptive-surface area (Hayman, 1983). VAM infection has also been shown to enhance transpiration flux of the host plant (Hardie & Leyton, 1981;Allen et a/., 1981;Nelson & Safir, 1982;Levy, Syvertsen & Nemec, 1983;Graham & Syvertsen, 1984), probably as a result of reduced stomatal resistance (Allen & Boosalis, 1983;Huang, Smith & Yost, 1984;Stahl & Smith, 1984) and increased root hydraulic conductivity (Safir, Boyer & Gerdemann, 1971;Hardie & Leyton, 1981;Nelson & Safir, 1982;Graham & Syvertsen, 1984). It was suggested by Safir et a/.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Removal of Extraradical Hyphae on Water Uptake by Vesicular‐arbuscular Mycorrhizal Plants

Hardie

1985

New Phytologist

127

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SUMMARYResults from experiments on clover (Trifoliumpratense L.) and leek (Alliumporrum L.) revealed that removal of extraradical hyphae from vesicular-arbuscular mycorrhizal (VAM) plants had a detrimental effect on transpiration flux. The advantage of comparisons between VAM plants with and without extraradical hyphae rather than between VAM and non-mycorrhizal plants is discussed in relation to this type of investigation. It is suggested that extraradical hyphae increase the root absorptive-surface area, independently of an enhanced nutrient status.

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Mycorrhizal Enhancement of Water Transport in Soybean

Abstract: Mycorrhizae produced by Endogone mosseae decrease the resistance to water transport in soybean (Glycine max L.). The decrease was associated with an increase in the growth of shoots but not of roots.

Cited by 132 publications

References 25 publications

Influence of the ectomycorrhizas formed by Tuber melanosporum Vitt. on hydraulic conductance and water relations of Quercus ilex L. seedlings

Influence of the ectomycorrhizas formed by Tuber melanosporum Vitt. on hydraulic conductance and water relations of Quercus ilex L. seedlings

Nutrient Status and Mycorrhizal Enhancement of Water Transport in Soybean

The Effect of Removal of Extraradical Hyphae on Water Uptake by Vesicular‐arbuscular Mycorrhizal Plants

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