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1.
The aim of this research was to investigate the effect of arbuscular mycorrhizal (AM) colonisation on root morphology and nitrogen uptake capacity of carob ( Ceratonia siliqua L.) under high and low nutrient conditions. The experimental design was a factorial arrangement of presence/absence of mycorrhizal fungus inoculation ( Glomus intraradices) and high/low nutrient status. Percent AM colonisation, nitrate and ammonium uptake capacity, and nitrogen and phosphorus contents were determined in 3-month-old seedlings. Grayscale and colour images were used to study root morphology and topology, and to assess the relation between root pigmentation and physiological activities. AM colonisation lead to a higher allocation of biomass to white and yellow parts of the root. Inorganic nitrogen uptake capacity per unit root length and nitrogen content were greatest in AM colonised plants grown under low nutrient conditions. A better match was found between plant nitrogen content and biomass accumulation, than between plant phosphorus content and biomass accumulation. It is suggested that the increase in nutrient uptake capacity of AM colonised roots is dependent both on changes in root morphology and physiological uptake potential. This study contributes to an understanding of the role of AM fungi and root morphology in plant nutrient uptake and shows that AM colonisation improves the nitrogen nutrition of plants, mainly when growing at low levels of nutrients. 相似文献
2.
The responses of Acacia nilotica L. var. cupriciformis to phosphorus application and inoculation with the indigenous consortium of arbuscular mycorrhizal
(AM) fungi were evaluated in a nursery experiment using soil from a marginal wasteland. A positive growth response to mycorrhizal
inoculation was observed at an Olsen-P level of 20 ppm in the presence of the natural population of AM fungi. There was growth
stimulation by either inoculation or additional P at the highest soil P of 40 ppm. Colonization was negatively correlated
to soil P but P content of both shoot and root were positively correlated. Inoculation with the indigenous AM consortium significantly
increased the uptake of P at all levels of applied P. Acacia is moderately dependent upon the AM symbiosis and exhibited a maximal mycorrhizal dependence (MD) of 18.25% at 20 ppm Olsen-P
level under the conditions studied. A sharp and considerable reduction in MD and dry matter yield observed at 40 ppm P suggests
that the external P requirement for maximal production of biomass was met at approximately 20 ppm Olsen-P.
Accepted: 25 June 1996 相似文献
3.
The response of peanut to salt (NaCl) and acid (HCl) stress was studied in association with Glomus caledonium, an arbuscular mycorrhizal (AM) fungus. The plants were exposed to salt stress by irrigation on alternate days with 1% or
5% NaCl solutions, or with 0.1 N HCl to induce acid stress. Plant yield almost tripled in mycorrhizal plants compared with
nonmycorrhizal control plants. AM inoculation significantly increased plant yield and biomass at 1% NaCl, while at 5% NaCl
AM was less effective in alleviating salt stress. Percentage AM colonization was also lowest at 5% NaCl. AM inoculation was
found to promote the establishment of peanut plants under acid stress conditions.
Accepted: 2 October 1995 相似文献
4.
Broomsedge (Andropogon virginicus L.) is a dominant grass revegetating many abandoned coal-mined lands in West Virginia, USA. Residual soils on such sites are often characterized by low pH, low nutrients, and high aluminium. Experiments were conducted to assess the resistance of broomsedge to limited phosphorus (Pi) availability and to investigate the role that arbuscular mycorrhizal (AM) fungi play in aiding plant growth under low Pi conditions. Pregerminated mycorrhizal and non-mycorrhizal seedlings were grown in a sand-culture system with nutrient solutions containing Pi concentrations ranging from 10 to 100 microM for 8 weeks. Non-mycorrhizal plants exhibited severe inhibition of growth under Pi limitation (<60 microM). Colonization by AM fungi (combined Glomus clarum Nicolson & Schenck and Gigaspora gigantea (Nicol. & Gerd.) Gerd. & Trappe) greatly enhanced host plant growth at low Pi concentrations, but did not benefit growth when Pi was readily available (100 microM). In comparison to non-mycorrhizal plants, mycorrhizal plants had higher phosphorus use efficiency at low Pi concentrations and maintained nearly constant tissue nutrient concentrations across the gradient of Pi concentrations investigated. Manganese (Mn) and sodium (Na) accumulated in shoots of non-mycorrhizal plants under Pi limitation. Mycorrhizal plants exhibited lower instantaneous Pi uptake rates and significantly lower C(min) values compared to non-mycorrhizal plants. These patterns suggest that the symbiotic association between broomsedge roots and AM fungi effectively maintains nutrient homeostasis through changes in physiological properties, including nutrient uptake, allocation and use. The mycorrhizal association is thus a major adaptation that allows broomsedge to become established on infertile mined lands. 相似文献
5.
In the eastern United States, broomsedge (Andropogon virginicus L.) is found growing on abandoned coal-mined lands that have extremely acidic soils with high residual aluminium (Al) concentrations. Broomsedge may be inherently metal-resistant and nutrient-efficient or may rely on the arbuscular mycorrhizal (AM) fungal association to overcome limitations on such sites. Broomsedge plants were grown with and without an acidic ecotype AM fungal consortium and exposed to controlled levels of Al in two experiments. The AM fungal consortium conferred Al resistance to broomsedge. Arbuscular mycorrhizal fungi reduced Al uptake and translocation in host plants, potentially reflecting measured reductions in inorganic Al availability in the rhizosphere of mycorrhizal plants. Mycorrhizal plants exhibited lower shoot P concentrations, higher phosphorus use efficiency, and lower root acid phosphatase rates than non-mycorrhizal plants. Aluminium significantly reduced calcium (Ca) and magnesium (Mg) tissue concentrations in both mycorrhizal and non-mycorrhizal plants. However, plant response to any change in nutrient acquisition was substantially less pronounced in mycorrhizal plants. The exclusion of Al and greater stability of tissue biomass accretion-tissue nutrient relationships in mycorrhizal broomsedge plants exposed to Al may be important mechanisms that allow broomsedge to grow on unfavourable acidic soils. 相似文献
6.
在温室盆栽条件下,分别模拟单作、间作和尼龙网分隔种植,比较接种丛枝菌根(arbuscular mycorrhizal, AM)真菌 Glomus intraradices和 Glomus mosseae对菌根植物玉米和非菌根植物油菜生长和磷吸收状况的影响,并分析土壤中各无机磷组分的变化。结果发现,接种AM真菌可以促进土壤中难溶性磷(Ca 10-P和O-P)向有效态磷转化,并显著降低总无机磷含量 ( P<0.05),显著提高菌根植物玉米的生物量和磷吸收量( P<0.05),特别是在间作体系中使玉米的磷营养竞争比率显著提高了45.0%-104.1% ( P<0.05),显著降低了油菜的生物量和磷吸收量( P<0.05),从而增强了了菌根植物的竞争优势,降低了非菌根植物与菌根植物的共存能力。揭示了石灰性土壤中AM真菌对植物物种多样性的影响,有助于更加全面地理解AM真菌在农业生态系统中的作用。 相似文献
7.
Arbuscular mycorrhizal (AM) fungi mediate interactions between plants and soils, and are important where nutrient or metal concentrations limit plant growth. Variation in fungal response to edaphic conditions may influence the effectiveness of the plant-mycorrhizal association in some soil environments. Andropogon virginicus (broomsedge) colonizes disturbed sites in the eastern United States, including acidic mine soils where aluminum (Al) is phytotoxic, and Al resistance in broomsedge has been associated with colonization by the AM fungus Glomus clarum. In the present study, inter- and intra-specific variation to confer Al resistance to broomsedge was assessed among selected species of AM fungi. Broomsedge seeds were grown in sand culture inoculated with one of five isolates of three species of fungi ( G. clarum, Acaulospora morrowiae, and Scutellospora heterogama). Plants were exposed to 0 or 400 µM Al in nutrient solution and harvested after 4 or 9 weeks of growth. Mean infection percentage, plant biomass, and plant tissue Al and phosphorus (P) concentrations were measured. G. clarum conferred the greatest Al resistance to broomsedge, with the lowest variability among isolates for colonization and growth inhibition by Al [tolerance indices (TI) between 22.4 and 92.7%]. Broomsedge plants colonized by A. morrowiae were consistently the most sensitive to Al, with little variation among isolates (TI between 1.6 and 12.1%). Al resistance by S. heterogama isolates was intermediate and wide-ranging (TI between 3.9 and 40.0%). Across all AM fungal isolates, resistance was associated with high rates of colonization and low tissue Al concentrations of broomsedge plants. The functional diversity in Al resistance displayed by these AM fungi reflect variation in acclimation mechanisms operating in the mycorrhizal symbiosis under environmental stress. 相似文献
8.
Summary Arbuscular mycorrhizal (AM) fungi significantly improve plant growth in soils with low phosphorus availability and cause many changes in root morphology, similar to those produced by increased P nutrition, mainly depending on root apex size and activity. The aim of this work was to discriminate between the morphogenetic role of AM fungi and P in leek ( Allium porrum L.) by feeding mycorrhizal and nonmycorrhizal plants with two nutrient solutions containing 3.2 or 96 M P and examining specific parameters related to adventitious root apices (apex size, mitotic cycle, and RNA synthesis). The results showed that AM fungi blocked meristem activity as indicated by the higher percentages of inactive apices and metaphases in the apical meristem of mycorrhizal plants, whereas the high P supply lengthened the mitotic cycle without blocking the apices, resulting in steady, slow root growth. The possible involvement of abscisic acid in the regulation of root apex activity is discussed.Abbreviations ABA
abscisic acid
- AM
arbuscular mycorrhizae
- CI and CII
nonmycorrhizal control plants grown with low or high phosphorus concentration
- MI and MII
mycorrhizal plants grown with low or high phosphorus concentration
- PGR
plant growth regulator 相似文献
9.
Seedlings of Lotus glaberMill., were grown in a native saline-sodic soil in a greenhouse for 50 days and then subjected to waterlogging for an additional
period of 40 days. The effect of soil waterlogging was evaluated by measuring plant growth allocation, mineral nutrition and
soil chemical properties. Rhizobiumnodules and mycorrhizal colonisation in L. glaberroots were measured before and after waterlogging. Compared to control plants, waterlogged plants had decreased root/shoot
ratio, lower number of stems per plant, lower specific root length and less allocation of P and N to roots. Waterlogged plants
showed increased N and P concentrations in plant tissues, larger root crown diameter and longer internodes. Available N and
P and organic P, pH and amorphous iron increased in waterlogged soil, but total N, EC and exchangeable sodium were not changed.
Soil waterlogging decreased root length colonised by arbuscular mycorrhizal (AM) fungi, arbuscular colonisation and number
of entry points per unit of root length colonised. Waterlogging also increased vesicle colonisation and Rhizobium nodules on roots. AM fungal spore density was lower at the end of the experiment in non-waterlogged soil but was not reduced
under waterlogging. The results indicate that L. glaber can grow, become nodulated by Rhizobium and colonised by mycorrhizas under waterlogged condition. The responses of L. glaber may be related its ability to form aerenchyma. 相似文献
10.
Plant ability to withstand acidic soil mineral deficiencies and toxicities can be enhanced by root-arbuscular mycorrhizal
fungus (AMF) symbioses. The AMF benefits to plants may be attributed to enhanced plant acquisition of mineral nutrients essential
to plant growth and restricted acquisition of toxic elements. Switchgrass ( Panicum virgatum L.) was grown in pH Ca (soil:10 mM CaCl 2, 1 : 1) 4 and 5 soil (Typic Hapludult) inoculated with Glomus clarum, G. diaphanum, G. etunicatum, G. intraradices, Gigaspora
albida, Gi. margarita, Gi. rosea, and Acaulospora
morrowiae to determine differences among AMF isolates for mineral acquisition. Shoots of mycorrhizal (AM) plants had 6.2-fold P concentration
differences when grown in pH Ca 4 soil and 2.9-fold in pH Ca 5 soil. Acquisition trends for the other mineral nutrients essential for plant growth were similar for AM plants grown in
pH Ca 4 and 5 soil, and differences among AMF isolates were generally higher for plants grown in pH Ca 4 than in pH Ca 5 soil. Both declines and increases in shoot concentrations of N, S, K, Ca, Mg, Zn, Cu, and Mn relative to nonmycorrhizal
(nonAM) plants were noted for many AM plants. Differences among AM plants for N and Mg concentrations were relatively small
(<2-fold) and were large (2- to 9-fold) for the other minerals. Shoot concentrations of mineral nutrients did not relate well
to dry matter produced or to percentage root colonization. Except for Mn and one AMF isolate, shoot concentrations of Mn,
Fe, B, and Al in AM plants were lower than in nonAM plants, and differences among AM plants for these minerals ranged from
a low of 1.8-fold for Fe to as high as 6.9-fold for Mn. Some AMF isolates were effective in overcoming acidic soil mineral
deficiency and toxicity problems that commonly occur with plants grown in acidic soil.
Accepted: 14 June 1999 相似文献
11.
The effect of root exudates from onions differing in P status on spore germination and hyphal growth of arbuscular mycorrhizal
fungi was investigated. Onion ( Allium cepa) was grown in solution culture at different phosphorus concentrations (0, 0.1, 1.0, 8.0 and 24.0 mg P l –1) and root exudates were collected. When spores of the arbuscular mycorrhizal fungus, Gigaspora margarita were incubated with these root exudates, spore germination was only slightly affected but hyphal growth was greatly affected,
particularly with exudates from P-deficient plants. This suggests that the P nutrition of host plants influences the composition
of root exudates and thereby the hyphal growth of arbuscular mycorrhizal fungi.
Accepted: 25 June 1995 相似文献
12.
Oxygen and CO 2 fluxes were measured in hydroponically grown mycorrhizal and non-mycorrhizal Triticum aestivum L. cv. Hano roots. The NO 3
– uptake of the plants was used to estimate the amount of root respiration attributable to ion uptake. Plants were grown at
4 mM N and 10 μM P, where a total and viable mycorrhizal root colonisation of 48% and 18%, respectively, by Glomus mosseae (Nicol. and Gerd.) Gerd. and Trappe (BEG 107) was observed. The O 2 consumption and NO 3
– uptake rates were similar and the CO 2 release was higher in mycorrhizal than in non-mycorrhizal wheat. This resulted in a significantly higher respiratory quotient
(RQ, mol CO 2 mol –1 O 2) in mycorrhizal (1.27±0.13) than in non-mycorrhizal (0.79±0.05) wheat. As the biomass and N and P concentrations in mycorrhizal
and non-mycorrhizal wheat were the same, the higher RQ resulted from the mycorrhizal colonisation and not differences in nutrition
per se.
Accepted: 26 March 1999 相似文献
13.
Mycorrhizal plants often have greater tolerance to drought than nonmycorrhizal plants. This study was conducted to determine the effects of arbuscular mycorrhizal (AM) fungi inoculation on growth, grain yield and mineral acquisition of two winter wheat ( Triticum aestivum L.) cultivars grown in the field under well-watered and water-stressed conditions. Wheat seeds were planted in furrows after treatment with or without the AM fungi Glomus mosseae or G. etunicatum. Roots were sampled at four growth stages (leaf, tillering, heading and grain-filling) to quantify AM fungi. There was negligible AM fungi colonization during winter months following seeding (leaf sampling in February), when soil temperature was low. During the spring, AM fungi colonization increased gradually. Mycorrhizal colonization was higher in well-watered plants colonized with AM fungi isolates than water-stressed plants. Plants inoculated with G. etunicatum generally had higher colonization than plants colonized with G. mosseae under both soil moisture conditions. Biomass and grain yields were higher in mycorrhizal than nonmycorrhizal plots irrespective of soil moisture, and G. etunicatum inoculated plants generally had higher biomass and grain yields than those colonized by G. mosseae under either soil moisture condition. The mycorrhizal plants had higher shoot P and Fe concentrations than nonmycorrhizal plants at all samplings regardless of soil moisture conditions. The improved growth, yield and nutrient uptake in wheat plants reported here demonstrate the potential of mycorrhizal inoculation to reduce the effects of drought stress on wheat grown under field conditions in semiarid areas of the world. 相似文献
14.
Psidium guajava L.) plantlets was determined during acclimatization and plant establishment. Guava plantlets were asexually propagated through
tissue culture and grown in a glasshouse for 18 weeks. Half of the plantlets were inoculated with a mixed endomycorrhiza isolate
from Mexico, ZAC-19, containing Glomus diaphanum, G. albidum and G. claroides. Plantlets were fertilized with modified Long Ashton nutrient solution that supplied 11 μg P ml −1. Gas exchange measurements were taken at 2, 4, 8, and 18 weeks after inoculation using a portable photosynthesis system.
All micropropagated guava plantlets survived transplant shock. After 6 weeks, mycorrhizal plantlets had greater shoot growth
rates and leaf production than non-mycorrhizal plantlets. This also corresponded with increased photosynthetic rates and stomatal
conductance of mycorrhizal plants. By 18 weeks, mycorrhizal plantlets had greater shoot length, leaf area, leaf, stem, and
root dry mass. However, gas exchange was comparable among treatments, in part because the container size was restricting growth
of the larger mycorrhizal plantlets. Non-mycorrhizal plantlets had greater leaf area ratios and specific leaf areas than mycorrhizal
plantlets. Increased leaf tissue mineral levels of P, Mg, Cu, and Mo also occurred with mycorrhizal plantlets. Roots of inoculated
guava plantlets were heavily colonized with arbuscules, vesicles and endospores. Guava plantlets were highly mycotrophic with
a mycorrhizal dependency index of 103%.
Accepted: 27 December 1999 相似文献
15.
AimsArbuscular mycorrhizal (AM) fungi associate with the majority of terrestrial plants, influencing their growth, nutrient uptake and defence chemistry. Consequently, AM fungi can significantly impact plant-herbivore interactions, yet surprisingly few studies have investigated how AM fungi affect plant responses to root herbivores. This study aimed to investigate how AM fungi affect plant tolerance mechanisms to belowground herbivory. MethodsWe examined how AM fungi affect plant (Saccharum spp. hybrid) growth, nutrient dynamics and secondary chemistry (phenolics) in response to attack from a root-feeding insect (Dermolepida albohirtum). ResultsRoot herbivory reduced root mass by almost 27%. In response, plants augmented investment in aboveground biomass by 25%, as well as increasing carbon concentrations. The AM fungi increased aboveground biomass, phosphorus and carbon. Meanwhile, root herbivory increased foliar phenolics by 31% in mycorrhizal plants, and increased arbuscular colonisation of roots by 75% overall. AM fungi also decreased herbivore performance, potentially via increasing root silicon concentrations. ConclusionsOur results suggest that AM fungi may be able to augment plant tolerance to root herbivory via resource allocation aboveground and, at the same time, enhance plant root resistance by increasing root silicon. The ability of AM fungi to facilitate resource allocation aboveground in this way may be a more widespread strategy for plants to cope with belowground herbivory. 相似文献
16.
Seedlings of papaya ( Carica papaya L. var. Solo) were transplanted to pots with or without an arbuscular mycorrhizal (AM) fungus ( Gigaspora margarita Becker and Hall). After 3 months, half the plants were subjected to water stress by withdrawing irrigation. The leaf water
potential (LWP) was measured during 20 days of water-stress treatment and then the plants were harvested. Root ethylene and
1-aminocyclopropane-1-carboxylic acid (ACC) concentrations were measured and plant fresh weight determined. The LWP decreased
during the water-stress treatment and this decrease was more severe in the non-AM plants. Plant fresh weight was higher for
AM than non-AM plants under both conditions. Under well-irrigated conditions, the ethylene concentration in the roots was
increased by the presence of AM, although there was no significant difference between AM and non-AM roots in ACC levels. ACC
increased in both AM and non-AM roots under water-stress conditions. The water-stress treatment resulted in a marked increase
in ethylene concentration in non-AM roots but the concentration in AM roots was slightly lower than under normal conditions.
Accepted: 7 July 2000 相似文献
17.
A pot experiment was conducted to examine the effect of arbuscular mycorrhizal fungus, Glomus fasciculatum, and salinity on the growth of Acacia nilotica. Plants were grown in soil under different salinity levels (1.2, 4.0, 6.5, and 9.5 dS m −1). In saline soil, mycorrhizal colonization was higher at 1.2, 4.0, and 6.5 dS m −1 salinity levels in AM-inoculated plants, which decreased as salinity levels further increased (9.5 dS m −1). Mycorrhizal plants maintained greater root and shoot biomass at all salinity levels compared to nonmycorrhizal plants.
AM-inoculated plants had higher P, Zn, and Cu concentrations than uninoculated plants. In mycorrhizal plants, nutrient concentrations
decreased with the increasing levels of salinity, but were higher than those of the nonmycorrhizal plants. Mycorrhizal plants
had greater Na concentration at low salinity levels (1.2, 4.0 dS m −1), which lowered as salinity levels increased (6.5, 9.5 dS m −1), whereas Na concentration increased in control plants. Mycorrhizal plants accumulated a higher concentration of K at all
salinity levels. Unlike Na, the uptake of K increased in shoot tissues of mycorrhizal plants with the increasing levels of
salinity. Our results indicate that mycorrhizal fungus alleviates deleterious effects of saline soils on plant growth that
could be primarily related to improved P nutrition. The improved K/Na ratios in root and shoot tissues of mycorrhizal plants
may help in protecting disruption of K-mediated enzymatic processes under salt stress conditions. 相似文献
18.
A pot experiment was conducted to examine the effect of the arbuscular mycorrhizal (AM) fungus, Glomus mosseae, on plant biomass and organic solute accumulation in maize leaves. Maize plants were grown in sand and soil mixture with
three NaCl levels (0, 0.5, and 1.0 g kg −1 dry substrate) for 55 days, after 15 days of establishment under non-saline conditions. At all salinity levels, mycorrhizal
plants had higher biomass and higher accumulation of organic solutes in leaves, which were dominated by soluble sugars, reducing
sugars, soluble protein, and organic acids in both mycorrhizal and non-mycorrhizal plants. The relative abundance of free
amino acids and proline in total organic solutes was lower in mycorrhizal than in non-mycorrhizal plants, while that of reducing
sugars was higher. In addition, the AM symbiosis raised the concentrations of soluble sugars, reducing sugars, soluble protein,
total organic acids, oxalic acid, fumaric acid, acetic acid, malic acid, and citric acid and decreased the concentrations
of total free amino acids, proline, formic acid, and succinic acid in maize leaves. In mycorrhizal plants, the dominant organic
acid was oxalic acid, while in non-mycorrhizal plants, the dominant organic acid was succinic acid. All the results presented
here indicate that the accumulation of organic solutes in leaves is a specific physiological response of maize plants to the
AM symbiosis, which could mitigate the negative impact of soil salinity on plant productivity. 相似文献
19.
The effect of arbuscular mycorrhiza (AM) on white clover and ryegrass grown together in a soil spiked with polycyclic aromatic
hydrocarbons (PAH) was assessed in a pot experiment. The soil was spiked with 500 mg kg –1 anthracene, 500 mg kg –1 chrysene and 50 mg kg –1 dibenz( a, h)anthracene, representing common PAH compounds with three, four and five aromatic rings, respectively. Three treatments and
two harvest times (8 and 16 weeks) were imposed on plants grown in spiked soil: no mycorrhizal inoculation, mycorrhizal inoculation
( Glomus mosseae P2, BEG 69) and mycorrhizal inoculation and surfactant addition (Triton X-100). Pots without PAH were also included as a
control of plant growth and mycorrhizal colonization as affected by PAH additions. The competitive ability of clover vis-à-vis
ryegrass regarding shoot and root growth was enhanced by AM, but reduced by PAH and the added surfactant. This was reflected
by mycorrhizal root colonization which was moderate for clover (20–40% of total root length) and very low for ryegrass (0.5–5%
of total root length). Colonization of either plant was similar in spiked soil with and without the added surfactant, but
the PAH reduced colonization of clover to half that in non-spiked soil. P uptake was maintained in mycorrhizal clover when
PAH were added, but was reduced in non-mycorrhizal clover and in mycorrhizal clover that received surfactant. Similar effects
were not observed on ryegrass. These results are discussed in the context of the natural attenuation of organic pollutants
in soils.
Accepted: 12 June 2000 相似文献
20.
1. It has been hypothesised that the symbiosis with arbuscular mycorrhizal fungi (AMF) leads to a higher uptake of phosphorus (P) and nitrogen (N) in aquatic plants, but it has never been shown experimentally without the use of fungicides. In particular, the symbiosis may be important for nutrient uptake by isoetids in oligotrophic lakes, where low concentrations of inorganic N and P both in the water and in the sediment limit the growth of plants and where symbiosis facilitates the uptake of nutrients from the sediment. 2. Plants of the isoetid Littorella uniflora were propagated under the sterile conditions without an AMF infection. The plants were then grown for 60 days with and without re‐infection by AMF, and with either high (150 μm ) or low (ambient concentration approximately 15 μm ) CO 2 concentration. 3. The study proved that the symbiosis between AMF and L. uniflora had a positive impact on the retention of N and P in the plants at very low nutrient concentrations in the water and on biomass development. Shoot biomass and standing stocks of both P and N were significantly higher in re‐infected plants. 4. Raised CO 2 concentration resulted in a fivefold increase in hyphal infection, but had no impact on the number of arbuscules and vesicles in the cross sections. There were significantly higher biomass and lower tissue P and N concentrations in the plants from high CO 2 treatments. This resulted in similar standing stocks of P and N in plants from low and high CO 2 treatments. 5. The results from this study showed that the symbiosis between AMF and L. uniflora is an important adaptation enabling isoetids to grow on nutrient‐poor sediments in oligotrophic lakes. 相似文献
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