Soil microbes alter seedling performance and biotic interactions under plant competition and contrasting light conditions

Abstract Background and Aims Growing evidence suggests that the net effect of soil microbes on plants depends on both abiotic and biotic conditions, but the context-dependency of soil feedback effects remains poorly understood. Here we test for interactions between the presence of conspecific soil microbes, plant competition and light availability on tree seedling performance. Methods Seedlings of two congeneric tropical tree species, Bauhinia brachycarpa and Bauhinia variegata, were grown in either sterilized soil or soil conditioned by conspecific soil microorganisms in a two-phase greenhouse feedback experiment. We examined the interactive effects of soil treatment (live, sterilized), light availability (low, high) and plant competition (no competition, intraspecific and interspecific competition) on tree seedling biomass. We also investigated the linkages between the outcomes of soil feedback effects and soil microbial community structure. Key Results The outcomes of soil feedback effects on seedling biomass varied depending on both competition treatment and light availability. Under low light conditions, soil feedback effects were neutral irrespective of competition treatment and plant species. Soil feedback effects were negative in high light for seedlings with interspecific competition, but positive for seedlings growing alone or with intraspecific competition. Soil feedback effects for seedlings were driven by variation in the Gram-positive:Gram-negative bacteria ratio. Light and conspecific soil microbes had interactive effects on the competitive environment experienced by tree species; in low light the presence of conspecific soil microbes decreased plant competition intensity, whereas in high light both the intensity and the importance of competition increased for seedlings in the presence of soil microbes, irrespective of plant species. Conclusions Our findings underline the importance of light and plant competition for the outcomes of soil feedback effects on young tree seedlings, and suggest that reduced light availability may reduce the influence of conspecific soil microbes on plant–plant interactions.

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Interactive effects of temperature and light during deep convection: a case study on growth and condition of the diatom Thalassiosira weissflogii

ICES Journal of Marine Science ◽

10.1093/icesjms/fsu218 ◽

2014 ◽

Vol 72 (6) ◽

pp. 2061-2071 ◽

Cited By ~ 11

Author(s):

B. Walter ◽

J. Peters ◽

J. E. E. van Beusekom ◽

M. A. St. John

Keyword(s):

Primary Production ◽

Deep Convection ◽

Growth Conditions ◽

Interactive Effects ◽

Light Conditions ◽

Thalassiosira Weissflogii ◽

Pulsed Light ◽

Low Light ◽

Chl A ◽

The North

Abstract Aim of this study was to expose phytoplankton to growth conditions simulating deep winter convection in the North Atlantic and thereby to assess changes in physiology enabling their survival. Growth rate, biochemical composition, and photosynthetic activity of the diatom Thalassiosira weissflogii were determined under two different light scenarios over a temperature range of 5–15°C to simulate conditions experienced by cells during winter deep convection. These metrics were examined under a low light scenario (20 µmol m−2 s−1, 12/12 h light/dark), and compared with a scenario of short light pulses of a higher light intensity (120 µmol m−2 s−1, 2/22 h light/dark). Both experimental light conditions offered the same daily light dose. No growth was observed at temperatures below 8°C. Above 8°C, growth rates were significantly higher under low light conditions compared with those of short pulsed light exposures, indicating a higher efficiency of light utilization. This could be related to (i) a higher content of Chl a per cell in the low light trial and/or (ii) a more efficient transfer of light energy into growth as indicated by constantly low carbohydrate levels. In contrast, pulsed intense light led to an accumulation of carbohydrates, which were catabolized during the longer dark period for maintaining metabolism. Light curves measured via Chl a fluorescence indicated low light assimilation for the algae exposed to short pulsed light. We postulate that our trial with short light pluses did not provide sufficient light to reach full light saturation. In general, photosynthesis was more strongly affected by temperature under pulsed light than under low light conditions. Our results indicate that model estimates of primary production in relation to deep convection, which are based on average low light conditions, not considering vertical transportation of algae will lead to an overestimation of in situ primary production.

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Low Light Availability Reduces the Subsurface Sediment Carbon Content in Halophila beccarii From the South China Sea

Frontiers in Plant Science ◽

10.3389/fpls.2021.664060 ◽

2021 ◽

Vol 12 ◽

Author(s):

Chanaka Premarathne ◽

Zhijian Jiang ◽

Jialu He ◽

Yang Fang ◽

Qiming Chen ◽

...

Keyword(s):

Carbon Content ◽

Light Availability ◽

Seagrass Beds ◽

Biomass Carbon ◽

Light Conditions ◽

Above Ground Biomass ◽

Low Light ◽

Subsurface Sediment ◽

Light Intensities ◽

Sediment Carbon

Eutrophication, dredging, agricultural and urban runoffs, and epiphyte overgrowth could reduce light availability for seagrass. This may affect “blue carbon” stocks in seagrass beds. However, little research is available on the effect of light intensities on carbon sequestration capacity in seagrass beds, especially small-bodied seagrasses. The dominant seagrass Halophila beccarii, a vulnerable species on the IUCN Red List, was cultured in different light intensities to examine the response of vegetation and sediment carbon in seagrass beds. The results showed that low light significantly reduced leaf length and above-ground biomass, while carbon content in both above-ground and below-ground tissues were not affected. Low light reduced both the above-ground biomass carbon and the total biomass carbon. Interestingly, while under saturating light conditions, the subsurface and surface carbon content was similar, under low light conditions, subsurface sediment carbon was significantly lower than the surface content. The reduction of subsurface sediment carbon might be caused by less release flux of dissolved organic carbon from roots in low light. Taken together, these results indicate that reduced light intensities, to which these meadows are exposed to, will reduce carbon sequestration capacity in seagrass beds. Measures should be taken to eliminate the input of nutrients on seagrass meadows and dredging activities to maintain the “blue carbon” storage service by enhancing light penetration into seagrass.

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Do mycorrhizas improve tropical tree seedling performance under water stress and low light conditions? A case study with Dicorynia guianensis (Caesalpiniaceae)

Journal of Tropical Ecology ◽

10.1017/s0266467405002348 ◽

2005 ◽

Vol 21 (4) ◽

pp. 375-381 ◽

Cited By ~ 6

Author(s):

Moïse Béreau ◽

Damien Bonal ◽

Eliane Louisanna ◽

Jean Garbaye

Keyword(s):

Water Stress ◽

Carbon Allocation ◽

Stomatal Closure ◽

Phosphorus Uptake ◽

Carbon Assimilation ◽

Mycorrhizal Symbiosis ◽

Light Conditions ◽

Tree Seedling ◽

Low Light ◽

Dicorynia Guianensis

We tested the response of seedlings of Dicorynia guianensis, a major timber tree species of French Guiana, to mycorrhizal symbiosis and water limitation in a semi-controlled experiment under natural light conditions. Under well-watered conditions, mycorrhizal colonization resulted in an increase of net photosynthesis, growth and phosphorus uptake. When submitted to water stress, no growth reduction of mycorrhizal seedlings was observed. Mycorrhizal seedlings were more sensitive to drought than non-mycorrhizal ones in terms of carbon assimilation, but not with regard to stomatal closure. In contrast to previous studies on temperate tree seedlings, this result precludes a mycorrhizal effect on the hydraulic properties of this species. Furthermore, our results suggest that below a specific threshold of soil moisture, carbon assimilation of D. guianensis seedlings was decreased by the mycorrhizal symbiosis. This is probably related to the competition between the plant and its host fungus for carbon allocation under low light intensity, even though it did not seem to have a significant effect on mortality in our experiment.

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Two-year response of American chestnut (Castanea dentata) seedlings to shelterwood harvesting and fire in a mixed-oak forest ecosystem

Canadian Journal of Forest Research ◽

10.1139/x05-002 ◽

2005 ◽

Vol 35 (3) ◽

pp. 740-749 ◽

Cited By ~ 38

Author(s):

Corinne L McCament ◽

Brian C McCarthy

Keyword(s):

Light Availability ◽

Optimal Growth ◽

Castanea Dentata ◽

American Chestnut ◽

Site Quality ◽

Eastern United States ◽

Light Conditions ◽

Management Regime ◽

Seedling Biomass ◽

Texture Parameters

The American chestnut (Castanea dentata (Marsh.) Borkh.) was once an important tree species in the eastern United States prior to its devastation by the chestnut blight. The American Chestnut Foundation will soon release seeds that are blight resistant. However, the necessary site requirements for restoration efforts have not yet been explored. The goal of this study was to evaluate the survival and growth of chestnut seedlings within a diverse forest management regime. Seedlings were experimentally grown for 2 years in three mixed-oak forests subjected to thinning, burning, thinning followed by burning, and an untreated control. Seedling biomass parameters were most influenced by treatments that increased light availability. Soil chemistry and texture parameters were also correlated (p < 0.05) with chestnut biomass. Thus, site fertility should also be considered in reintroduction efforts. While site quality may influence growth, light conditions appear to be overwhelmingly important. Therefore, we recommend that American chestnut seeds be planted in areas with moderate to high light conditions (recently disturbed), with low surrounding competing vegetation (possibly after a burn) for optimal growth benefits.

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EFFECTS OF ROOT DEFORMATION AND LIGHT AVAILABILITY ON GROWTH AND BIOMASS ALLOCATION OF Senna multijuga SEEDLINGS (Rich) H. S. Irwin & Barneby

Revista Árvore ◽

10.1590/1806-908820200000018 ◽

2020 ◽

Vol 44 ◽

Author(s):

Emile Caroline Silva Lopes ◽

Ândrea Carla Dalmolin ◽

Ivan Bezerra Allama ◽

Karine Ferreira Pereira ◽

William Martin Aitken II ◽

...

Keyword(s):

Biomass Allocation ◽

Growth Rates ◽

Forest Restoration ◽

Light Availability ◽

Tropical Tree ◽

Interactive Effects ◽

Low Light ◽

Relative Growth ◽

Root Deformation ◽

Senna Multijuga

ABSTRACT The effects of root deformation caused by errors in the pricking-out process in forest nurseries are still unknown for tropical tree seedlings. We analyzed the effects of light availability and root deformation on growth and biomass allocation in seedlings of Senna multijuga, a pioneer tropical tree commonly used in forest restoration programs. Our hypotheses were: (a) as a typical light-demanding species, the seedlings of S. multijuga may have their growth compromised by low light availability; (b) root deformation impairs growth rates and induces changes in biomass allocation; and (c) the effects of low light availability on growth and biomass allocation are increased by root deformation. Seedlings with and without root deformation were cultivated for 43 days under three levels of total daily photosynthetically active radiation (PAR) (28, 12, and 1 mol photons m-2 day-1). Seedlings of S. multijuga had their growth rates severely affected by values of PAR at about 1 mol photons m-2 day-1, but root deformation did not affect the relative growth rates of the whole plant. Instead, root deformation caused a decrease in the relative growth rate of roots in all light availabilities. The changes in root growth affected biomass allocation to the roots. The interactive effects of light availability and root deformation on the allocation of biomass to leaves are more pronounced at low light availability. Root deformations may lead to the production of seedlings with a low competitiveness capacity regardless of light conditions.

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Interactive effects of light, CO2 and temperature on growth and resource partitioning by the mixotrophic dinoflagellate, Karlodinium veneficum

PLoS ONE ◽

10.1371/journal.pone.0259161 ◽

2021 ◽

Vol 16 (10) ◽

pp. e0259161

Author(s):

Kathryn J. Coyne ◽

Lauren R. Salvitti ◽

Alicia M. Mangum ◽

Gulnihal Ozbay ◽

Christopher R. Main ◽

...

Keyword(s):

Elevated Temperature ◽

Nitrogen Content ◽

Resource Partitioning ◽

Interactive Effects ◽

Light Conditions ◽

Ambient Conditions ◽

Low Light ◽

Carbon And Nitrogen ◽

Karlodinium Veneficum ◽

Carbon And Nitrogen Content

There is little information on the impacts of climate change on resource partitioning for mixotrophic phytoplankton. Here, we investigated the hypothesis that light interacts with temperature and CO2 to affect changes in growth and cellular carbon and nitrogen content of the mixotrophic dinoflagellate, Karlodinium veneficum, with increasing cellular carbon and nitrogen content under low light conditions and increased growth under high light conditions. Using a multifactorial design, the interactive effects of light, temperature and CO2 were investigated on K. veneficum at ambient temperature and CO2 levels (25°C, 375 ppm), high temperature (30°C, 375 ppm CO2), high CO2 (30°C, 750 ppm CO2), or a combination of both high temperature and CO2 (30°C, 750 ppm CO2) at low light intensities (LL: 70 μmol photons m-2 s-2) and light-saturated conditions (HL: 140 μmol photons m-2 s-2). Results revealed significant interactions between light and temperature for all parameters. Growth rates were not significantly different among LL treatments, but increased significantly with temperature or a combination of elevated temperature and CO2 under HL compared to ambient conditions. Particulate carbon and nitrogen content increased in response to temperature or a combination of elevated temperature and CO2 under LL conditions, but significantly decreased in HL cultures exposed to elevated temperature and/or CO2 compared to ambient conditions at HL. Significant increases in C:N ratios were observed only in the combined treatment under LL, suggesting a synergistic effect of temperature and CO2 on carbon assimilation, while increases in C:N under HL were driven only by an increase in CO2. Results indicate light-driven variations in growth and nutrient acquisition strategies for K. veneficum that may benefit this species under anticipated climate change conditions (elevated light, temperature and pCO2) while also affecting trophic transfer efficiency during blooms of this species.

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Changes in the Stoichiometry of Photosystem II Components as an Adaptive Response to High-Light and Low-Light Conditions during Growth

Zeitschrift für Naturforschung C ◽

10.1515/znc-1986-5-618 ◽

1986 ◽

Vol 41 (5-6) ◽

pp. 597-603 ◽

Cited By ~ 33

Author(s):

Aloysius Wild ◽

Matthias Höpfner ◽

Wolfgang Rühle ◽

Michael Richter

Keyword(s):

Photosystem Ii ◽

Functional Organization ◽

Photosynthetic Apparatus ◽

High Light ◽

Molar Ratio ◽

Light Conditions ◽

Low Light ◽

Pigment System ◽

Transport Chain ◽

The One

The effect of different growth light intensities (60 W·m-2, 6 W·m-2) on the performance of the photosynthetic apparatus of mustard plants (Sinapis alba L.) was studied. A distinct decrease in photosystem II content per chlorophyll under low-light conditions compared to high-light conditions was found. For P-680 as well as for Oᴀ and Oв protein the molar ratio between high-light and low-light plants was 1.4 whereas the respective concentrations per chlorophyll showed some variations for P-680 and Oᴀ on the one and Oв protein on the other hand.In addition to the study of photosystem II components, the concentrations of PQ, Cyt f, and P-700 were measured. The light regime during growth had no effect on the amount of P-700 per chlorophyll but there were large differences with respect to PQ and Cyt f. The molar ratio for Cyt f and PQ between high- and low-light leaves was 2.2 and 1.9, respectively.Two models are proposed, showing the functional organization of the pigment system and the electron transport chain in thylakoids of high-light and low-light leaves of mustard plants.

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