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

2005 ◽  
Vol 21 (4) ◽  
pp. 375-381 ◽  
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.

scholarly journals Growth and carbon assimilation limitations in Ricinus communis (Euphorbiaceae) under soil water stress conditions

2010 ◽  
Vol 24 (3) ◽  
pp. 648-654 ◽  
Author(s):  
Tanise Luisa Sausen ◽  
Luís Mauro Gonçalves Rosa
Keyword(s):  
Water Stress ◽  
Soil Water ◽  
Drought Resistance ◽  
Ricinus Communis ◽  
Stomatal Closure ◽  
Carbon Assimilation ◽  
Stress Conditions ◽  
Carbon Gain ◽  
Resistant Species ◽  
Ricinus Communis L

Water availability may influence plant carbon gain and growth, with large impacts on plant yield. Ricinus communis (L.), a drought resistant species, is a crop with increasing economic importance in Brazil, due to its use in chemical industry and for the production of biofuels. Some of the mechanisms involved in this drought resistance were analyzed in this study by imposing progressive water stress to pot-grown plants under glasshouse conditions. Water withholding for 53 days decreased soil water gravimetric content and the leaf water potential. Plant growth was negatively and significantly reduced by increasing soil water deficits. With irrigation suspension, carbon assimilation and transpiration were reduced and remained mostly constant throughout the day. Analysis of A/Ci curves showed increased stomatal limitation, indicating that limitation imposed by stomatal closure is the main factor responsible for photosynthesis reduction. Carboxylation efficiency and electron transport rate were not affected by water stress up to 15 days after withholding water. Drought resistance of castor bean seems to be related to a pronounced, early growth response, an efficient stomatal control and the capacity to keep high net CO2 fixation rates under water stress conditions.

scholarly journals Far-Red Chlorophyll Fluorescence Radiance Tracks Photosynthetic Carbon Assimilation Efficiency of Dark Reactions

2021 ◽  
Vol 11 (22) ◽  
pp. 10821
Author(s):  
Zhunqiao Liu ◽  
Chenhui Guo ◽  
Yanwen Bai ◽  
Nina Zhang ◽  
Qiang Yu ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Carbon Fixation ◽  
Stomatal Closure ◽  
Assimilation Efficiency ◽  
Carbon Assimilation ◽  
Pulse Amplitude ◽  
Light Conditions ◽  
Photosynthetic Carbon ◽  
Pam Fluorescence ◽  
Photosynthetic Carbon Assimilation

Solar-induced chlorophyll fluorescence (SIF) observations from space have shown close relationships with terrestrial photosynthesis rates. SIF originates from the light reactions of photosynthesis, whereas carbon fixation takes place during the dark reactions of photosynthesis. Questions remain regarding whether SIF is able to track changes in the efficiency of the dark reactions in photosynthesis. Using concurrent measurements of leaf-scale gas exchange, pulse amplitude-modulated (PAM) fluorescence, and fluorescence spectral radiances, we found that both far-red fluorescence radiances and PAM fluorescence yields responded rapidly to changes in photosynthetic carbon assimilation due to changes in environmental factors or induced stomatal closure under constant light conditions. Uncertainties in outgoing and incoming irradiance mismatch for SIF measurements may very likely obscure the contributions of the dark reactions, thereby causing the inconsistent findings previously reported, which were no change in far-red SIF and PAM fluorescence yields after clear reductions in the photosynthetic carbon assimilation efficiency of dark reactions. Our results confirm that high-quality SIF measurements have the potential to provide insights into the dark reactions of photosynthesis. This study is particularly relevant for better interpreting satellite SIF observations that are obtained under roughly constant overpass times and relatively stable light intensities.

Assimilate Movement in Lolium and Sorghum Leaves. Iii. Carbon Dioxide Concentration Effects on the Metabolism and Translocation of Photosynthate.

1982 ◽  
Vol 9 (6) ◽  
pp. 705 ◽  
Author(s):  
IF Wardlaw
Keyword(s):  
Water Stress ◽  
Stomatal Closure ◽  
Carbon Dioxide Concentration ◽  
Co2 Concentration ◽  
Co2 Exchange ◽  
Co2 Uptake ◽  
Concentration Effects ◽  
Low Light ◽  
Low Co2 ◽  
Before And After

Raising the CO2 concentration of air to 720 �l I-� increased the rate of net CO2 uptake by the leaf of Lolium temulentum, a C*3 species, more than in Sorghum sudanense, a C*4 species. In Lolium, but not in Sorghum, high CO2 over a 6 h period resulted in relatively more of the additional leaf photosynthate being partitioned into storage rather than to translocation. Removing CO2 from the air passing over a 5 cm length of leaf before and after a pulse application of 14CO2 resulted in a reduced labelling of sucrose and a slower rate of export of 14C-labelled photosynthate in both species. With the fall in net CO2 exchange by the leaf section deprived of CO2 there was a compensating increase within this section in retention of photosynthate derived from the distal part of the leaf. Evidence provided by 14CO2 pulse chase experiments and CO2 exchange studies confirmed the relative enhancement of photorespiration under low CO2 concentrations in Lolium, but not in Sorghum. The CO2 depletion experiments provide a useful base for comparison with the effect of low light and water stress on photosynthate metabolism and translocation in that both these conditions reduce CO2 uptake. There is support for the suggestion that the change in photosynthate metabolism under water stress in C*3 species may result from reduced CO2 entry into the leaf due to stomatal closure.

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

2020 ◽  
Vol 126 (6) ◽  
pp. 1089-1098
Author(s):  
Nianxun Xi ◽  
Juliette M G Bloor ◽  
Chengjin Chu
Keyword(s):  
Soil Microbes ◽  
Plant Competition ◽  
Light Availability ◽  
Interactive Effects ◽  
Light Conditions ◽  
Tree Seedling ◽  
Low Light ◽  
Feedback Effects ◽  
Seedling Biomass ◽  
Soil Feedback

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.

scholarly journals Xylem embolism in leaves does not occur with open stomata: evidence from direct observations using the optical visualization technique

2019 ◽  
Vol 71 (3) ◽  
pp. 1151-1159 ◽  
Author(s):  
Danielle Creek ◽  
Laurent J Lamarque ◽  
José M Torres-Ruiz ◽  
Camille Parise ◽  
Regis Burlett ◽  
...  
Keyword(s):  
Water Stress ◽  
Stomatal Closure ◽  
Safety Margin ◽  
Carbon Assimilation ◽  
Xylem Embolism ◽  
Growth And Survival ◽  
Direct Observations ◽  
Optical Visualization ◽  
Embolism Resistance ◽  
The One

Abstract Drought represents a major abiotic constraint to plant growth and survival. On the one hand, plants keep stomata open for efficient carbon assimilation while, on the other hand, they close them to prevent permanent hydraulic impairment from xylem embolism. The order of occurrence of these two processes (stomatal closure and the onset of leaf embolism) during plant dehydration has remained controversial, largely due to methodological limitations. However, the newly developed optical visualization method now allows concurrent monitoring of stomatal behaviour and leaf embolism formation in intact plants. We used this new approach directly by dehydrating intact saplings of three contrasting tree species and indirectly by conducting a literature survey across a greater range of plant taxa. Our results indicate that increasing water stress generates the onset of leaf embolism consistently after stomatal closure, and that the lag time between these processes (i.e. the safety margin) rises with increasing embolism resistance. This suggests that during water stress, embolism-mediated declines in leaf hydraulic conductivity are unlikely to act as a signal for stomatal down-regulation. Instead, these species converge towards a strategy of closing stomata early to prevent water loss and delay catastrophic xylem dysfunction.

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

1986 ◽  
Vol 41 (5-6) ◽  
pp. 597-603 ◽  
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.

scholarly journals Perceptually based tone mapping for low-light conditions

2011 ◽  
Vol 30 (4) ◽  
pp. 1-10 ◽  
Author(s):  
Adam G. Kirk ◽  
James F. O'Brien
Keyword(s):  
Tone Mapping ◽  
Light Conditions ◽  
Low Light

Inhibition of cambial activity in Abies balsamea by internal water stress: role of abscisic acid

1975 ◽  
Vol 53 (24) ◽  
pp. 3041-3050 ◽  
Author(s):  
C. H. A. Little
Keyword(s):  
Abscisic Acid ◽  
Water Stress ◽  
Indoleacetic Acid ◽  
Stomatal Closure ◽  
Abies Balsamea ◽  
Cambial Activity ◽  
Inhibitory Effect ◽  
Internal Water ◽  
Endogenous Aba

In experiments with attached and detached shoots of balsam fir, Abies balsamea L., synthetic (±)abscisic acid (ABA) (1) reduced photosynthesis and transpiration by inducing stomatal closure, (2) inhibited indoleacetic acid (IAA) - induced cambial activity in photosynthesizing and non-photosynthesizing shoots, and (3) inhibited the basipetal movement of [14C]IAA. Neither gibberellic acid nor kinetin counteracted the inhibitory effect of (±)ABA on IAA-induced cambial activity. In addition it was demonstrated that increasing the internal water stress increased the level of endogenous ABA in the phloem–cambial region of bark peelings and decreased the basipetal movement of [14C]IAA through branch sections. On the basis of these findings it is proposed that internal water stress inhibits cambial activity, partly through increasing the level of ABA; the ABA acts to decrease the provision of carbohydrates and auxin that are required for cambial growth.

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