Photosynthetic Induction and Leaf Carbon Gain in the Tropical Understorey Epiphyte, Aspasia principissa

The high-yielding rice cultivar Takanari has fast photosynthetic induction owing to a high electron transport rate, stomatal conductance, and metabolic flux, leading to high daily carbon gain under fluctuating light.

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Drought stress delays photosynthetic induction and accelerates photoinhibition of photosystem I under fluctuating light

10.22541/au.163518994.43126980/v1 ◽

2021 ◽

Author(s):

Hu Sun ◽

Qi Shi ◽

Ning-Yu Liu ◽

Shi-Bao Zhang ◽

Wei Huang

Keyword(s):

Drought Stress ◽

Gas Exchange ◽

Photosystem I ◽

Co2 Fixation ◽

Electron Flow ◽

Photosynthetic Performance ◽

High Light ◽

Carbon Gain ◽

Photosynthetic Induction ◽

Fluctuating Light

Fluctuating light (FL) and drought stress usually occur concomitantly. However, whether drought stress affects photosynthetic performance under FL remains unknown. Here, we measured gas exchange, chlorophyll fluorescence, and P700 redox state under FL in drought-stressed tomato (Solanum lycopersicum) seedlings. Drought stress significantly affected stomatal opening and mesophyll conductance after transition from low to high light and thus delayed photosynthetic induction under FL. Therefore, drought stress exacerbated the loss of carbon gain under FL. Furthermore, restriction of CO2 fixation under drought stress aggravated the over-reduction of photosystem I (PSI) upon transition from low to high light. The resulting stronger FL-induced PSI photoinhibition significantly supressed linear electron flow and PSI photoprotection. These results indicated that drought stress not only affected gas exchange under FL but also accelerated FL-induced photoinhibition of PSI. Furthermore, drought stress enhanced relative cyclic electron flow in FL, which partially compensated for restricted CO2 fixation and thus favored PSI photoprotection under FL. Therefore, drought stress has large effects on photosynthetic dark and light reactions under FL.

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Drought stress imposes reversible photosynthetic damage under fluctuating light conditions in crops

10.22541/au.161281464.49728392/v1 ◽

2021 ◽

Author(s):

Kazuma Sakoda ◽

Kazuki Taniyoshi ◽

Wataru Yamori ◽

Yu Tanaka

Keyword(s):

Drought Stress ◽

Photosynthetic Capacity ◽

Crop Growth ◽

Growth And Yield ◽

Carbon Gain ◽

Limiting Factor ◽

Photosynthetic Induction ◽

Light Conditions ◽

Fluctuating Light ◽

Dynamic Photosynthesis

Drought stress is a major limiting factor for crop growth and yield. Water availability in the field can cyclically change between drought and rewatering conditions, depending on precipitation patterns. Concurrently, light intensity under field conditions can fluctuate, inducing dynamic photosynthesis and transpiration during crop growth period. The present study aimed to characterize carbon gain and water use in fluctuating light under drought and rewatering conditions by conducting gas exchange measurements in two major crops, namely rice and soybean. In both crops, drought stress reduced steady-state photosynthesis and/or photosynthetic capacity, and delayed photosynthetic induction even when it had relatively small impact on photosynthetic capacity, suggesting that the drought effects on photosynthesis should be evaluated based on induction, maximum, and steady states. This delayed photosynthetic induction resulted in a substantial loss of carbon gain under fluctuating light conditions, which can be a limiting factor for crop growth and yield in the field. Meanwhile, rewatering after drought conditions completely recovered photosynthetic capacity and induction in both crops, whereas drought experience would be memorized to slow down the stomatal opening. Therefore, the stability of photosynthetic induction can be a promising target to improve drought tolerance during crop breeding in the future.

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Drought stress delays photosynthetic induction and accelerates photoinhibition of photosystem I under fluctuating light

10.1101/2021.10.07.463522 ◽

2021 ◽

Author(s):

Hu Sun ◽

Qi Shi ◽

Ning-Yu Liu ◽

Shi-Bao Zhang ◽

Wei Huang

Keyword(s):

Drought Stress ◽

Gas Exchange ◽

Photosystem I ◽

Co2 Fixation ◽

Electron Flow ◽

Photosynthetic Performance ◽

High Light ◽

Carbon Gain ◽

Photosynthetic Induction ◽

Fluctuating Light

Fluctuating light (FL) and drought stress usually occur concomitantly. However, whether drought stress affects photosynthetic performance under FL remains unknown. Here, we measured gas exchange, chlorophyll fluorescence, and P700 redox state under FL in drought-stressed tomato (Solanum lycopersicum) seedlings. Drought stress significantly affected stomatal opening and mesophyll conductance after transition from low to high light and thus delayed photosynthetic induction under FL. Therefore, drought stress exacerbated the loss of carbon gain under FL. Furthermore, restriction of CO2 fixation under drought stress aggravated the over-reduction of photosystem I (PSI) upon transition from low to high light. The resulting stronger FL-induced PSI photoinhibition significantly supressed linear electron flow and PSI photoprotection. These results indicated that drought stress not only affected gas exchange under FL but also accelerated FL-induced photoinhibition of PSI. Furthermore, drought stress enhanced relative cyclic electron flow in FL, which partially compensated for restricted CO2 fixation and thus favored PSI photoprotection under FL. Therefore, drought stress has large effects on photosynthetic dark and light reactions under FL.

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Elevated CO2 Enhances Dynamic Photosynthesis in Rice and Wheat

Frontiers in Plant Science ◽

10.3389/fpls.2021.727374 ◽

2021 ◽

Vol 12 ◽

Author(s):

Huixing Kang ◽

Ting Zhu ◽

Yan Zhang ◽

Xinran Ke ◽

Wenjuan Sun ◽

...

Keyword(s):

Light Intensity ◽

Carbon Gain ◽

Substrate Effect ◽

Sudden Increase ◽

Photosynthetic Induction ◽

Crop Species ◽

Relative Contribution ◽

Dynamic Photosynthesis ◽

Photosynthetic Carbon ◽

Time Required

Crops developed under elevated carbon dioxide (eCO2) exhibit enhanced leaf photosynthesis under steady states. However, little is known about the effect of eCO2 on dynamic photosynthesis and the relative contribution of the short-term (substrate) and long-term (acclimation) effects of eCO2. We grew an Oryza sativa japonica cultivar and a Triticum aestivum cultivar under 400 μmol CO2 mol−1 air (ambient, A) and 600 μmol CO2 mol−1 air (elevated, E). Regardless of growth [CO2], the photosynthetic responses to the sudden increase and decrease in light intensity were characterized under 400 (a) or 600 μmol CO2 mol−1 air (e). The Aa1, Ae2, Ea3, and Ee4 treatments were employed to quantify the acclimation effect (Ae vs. Ee and Aa vs. Ea) and substrate effect (Aa vs. Ae and Ea vs. Ee). In comparison with the Aa treatment, both the steady-state photosynthetic rate (PN) and induction state (IS) were higher under the Ae and Ee treatments but lower under the Ea treatment in both species. However, IS reached at the 60 sec after the increase in light intensity, the time required for photosynthetic induction, and induction efficiency under Ae and Ee treatment did not differ significantly from those under Aa treatment. The substrate effect increased the accumulative carbon gain (ACG) during photosynthetic induction by 45.5% in rice and by 39.3% in wheat, whereas the acclimation effect decreased the ACG by 18.3% in rice but increased it by 7.5% in wheat. Thus, eCO2, either during growth or at measurement, enhances the dynamic photosynthetic carbon gain in both crop species. This indicates that photosynthetic carbon loss due to an induction limitation may be reduced in the future, under a high-CO2 world.

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Photosynthetic induction upon transfer from low to high light is affected by leaf nitrogen content in tomato

10.1101/2021.10.18.464921 ◽

2021 ◽

Author(s):

Hu Sun ◽

Yu-Qi Zhang ◽

Shi-Bao Zhang ◽

Wei Huang

Keyword(s):

Electron Flow ◽

Co2 Assimilation ◽

High Light ◽

Carbon Gain ◽

Leaf Nitrogen Content ◽

Photosynthetic Induction ◽

N Content ◽

Fluctuating Light ◽

Leaf N Content ◽

Leaf N

The response of photosynthetic CO2 assimilation to changes of illumination affects plant growth and crop productivity under natural fluctuating light conditions. However, the effects of nitrogen (N) supply on photosynthetic physiology after transition from low to high light are seldom studied. To elucidate this, we measured gas exchange and chlorophyll fluorescence under fluctuating light in tomato (Solanum lycopersicum) seedlings grown with different N conditions. After transition from low to high light, the induction speeds of net CO2 assimilation (AN), stomatal conductance (gs) and mesophyll conductance (gm) delayed with the decline in leaf N content. The times to reach 90% of maximum AN, gs and gm were negatively correlated to leaf N content. This delayed photosynthetic induction in plants grown under low N concentration was mainly caused by the slow induction response of gm rather than that of gs. Furthermore, the photosynthetic induction upon transfer from low to high light was hardly limited by photosynthetic electron flow. These results indicate that decreased leaf N content declines carbon gain under fluctuating light in tomato. Increasing the induction kinetics of gm has the potential to enhance the carbon gain of field crops grown in infertile soil.

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Water deficit affects photosynthetic induction in Bauhinia forficata Link (Fabaceae) and Esenbeckia leiocarpa Engl. (Rutaceae) growing in understorey and gap conditions

Brazilian Journal of Plant Physiology ◽

10.1590/s1677-04202006000400007 ◽

2006 ◽

Vol 18 (4) ◽

pp. 491-502 ◽

Cited By ~ 9

Author(s):

Maria T. Portes ◽

Thiago H. Alves ◽

Gustavo M. Souza

Keyword(s):

Water Deficit ◽

Field Measurements ◽

Co2 Assimilation ◽

Carbon Gain ◽

Photosynthetic Induction ◽

Forest Gap ◽

Light Utilization ◽

Bauhinia Forficata ◽

Role Of Light

In tropical forests, light is considered the most limiting resource for plant growth and reproduction. Besides light, water deficit leads invariably to a decrease in photosynthesis. Thus, despite of the unquestionable role of light in CO2 assimilation (A), it is expected that water deficit affects and limits the light utilization by plants. In this study, we investigated how water deficit influenced the photosynthetic induction of the early successional tree Bauhinia forficata (Fabaceae) and the late successional Esenbeckia leiocarpa (Rutaceae) in the understorey and in the forest gap. Field measurements were carried out in June and August 2006 in plants of approximately two-years-old. In August, the plants were subjected to a period of 45 d without rain characterizing a water deficit situation. Leaf water potential was significantly lower in August, both in forest gap and understorey (-2.5 and -3.8 MPa, respectively), than in June (-0.6 and -1.6 MPa, respectively). In June, both species presented a rapid increase in A after a saturating light pulse under gap conditions. However, in the understorey the increase in A was slower in B. forficata than in E. leiocarpa. In August water deficit limited the increase in Amax in both species, indicating that potential utilization of increasing irradiance was reduced by water deficit conditions. The constrain in Amax was less pronounced in the understorey where plants at least reached the irradiance compensation point, whereas carbon gain by photosynthesis of the plants grown in the gap did not compensate the carbon loss by respiration.

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Drought stress reduces crop carbon gain due to delayed photosynthetic induction under fluctuating light conditions

Physiologia Plantarum ◽

10.1111/ppl.13603 ◽

2021 ◽

Author(s):

Kazuma Sakoda ◽

Kazuki Taniyoshi ◽

Wataru Yamori ◽

Yu Tanaka

Keyword(s):

Drought Stress ◽

Carbon Gain ◽

Photosynthetic Induction ◽

Light Conditions ◽

Fluctuating Light

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Effects of moisture supply in the dry season and subsequent defoliation on persistence of the savanna grasses Themeda triandra, Heteropogon contortus and Panicum maximum

Australian Journal of Agricultural Research ◽

10.1071/ar9920241 ◽

1992 ◽

Vol 43 (2) ◽

pp. 241 ◽

Cited By ~ 27

Author(s):

JJ Mott ◽

MM Ludlow ◽

JH Richards ◽

AD Parsons

Keyword(s):

Growing Season ◽

Close Correlation ◽

Dry Season ◽

Carbon Gain ◽

Panicum Maximum ◽

Wet Season ◽

Themeda Triandra ◽

Heteropogon Contortus ◽

Moisture Conditions ◽

Sheath Material

The close correlation between grazing-induced mortality and major climatic patterns in Australian savannas, led us to the hypothesis that moisture conditions during the dry, non-growing season could affect sensitivity to grazing in the subsequent growing season. Using three widespread savanna species (Themeda triandra, Heteropogon contortus and Panicum maximum), this hypothesis was tested experimentally and the mechanisms controlling this response examined and quantified. In T. triandra drought during the dry season led to major mortality in defoliated plants in the next growing season. This mortality was caused by a synchrony of tillering at the commencement of the wet season, leaving few buds for replacement once parent tillers were killed by defoliation. T. triandra was also the most sensitive species to defoliation. This sensitivity was due to the poor ability of the plant to maintain positive carbon gain after defoliation. Several factors contributed to this poor ability, including: low total photosynthetic rate, low specific leaf area, and a large proportion of sheath material with poor photosynthetic capacity remaining after cutting. Both H. contortus and P. maximum growing under irrigated and fertilized conditions did not display any effects of previous moisture treatments when defoliated during the next wet season and were much less sensitive to defoliation than T. triandra.

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Lichen carbon gain under tropical conditions: water relations and CO2 exchange of Lobariaceae species of a lower montane rainforest in Panama

The Lichenologist ◽

10.1017/s0024282904014392 ◽

2004 ◽

Vol 36 (5) ◽

pp. 329-342 ◽

Cited By ~ 34

Author(s):

Otto L. LANGE ◽

Burkhard BÜDEL ◽

Angelika MEYER ◽

Hans ZELLNER ◽

Gerhard ZOTZ

Keyword(s):

Water Relations ◽

Carbon Fixation ◽

Nitrogen Concentration ◽

Carbon Gain ◽

Carbon Loss ◽

Natural Conditions ◽

Low Light ◽

Green Algal ◽

Tropical Conditions ◽

Montane Rainforest

Diel (24-h) time courses of microclimate, water relations, and CO2 exchange were measured under quasi-natural conditions at a forest edge in a lower montane, tropical rainforest in Panama for six Lobariaceae (Lobaria crenulata, L. dissecta, Pseudocyphellaria aurata, P. intricata, Sticta sublimbata, S. weigelii). Responses to experimentally controlled water content (WC), photosynthetic photon fluence rate (PPFR), and temperature were studied in most detail with P. aurata.Photosynthesis was well adapted to high temperatures, and all species exhibited ‘shade plant’ characteristics with low light compensation points and low light saturation. Lobaria and Pseudocyphellaria species suffered from a strong depression of net photosynthesis (NP) at suprasaturating WC; suprasaturation depression was less in cyphellate Sticta species.Photosynthetic capacity correlated with thallus nitrogen concentration, and maximal NP rates of the cyanobacterial Sticta species was 4 to 5 times higher than that of the green algal Lobaria species. However, high rates of NP were uncommon and brief events under natural conditions; the different environmental factors were rarely optimal simultaneously. Similar to earlier observations with other rainforest lichens, NP ceased during the period of highest irradiation on most days due to desiccation. During moist periods low light often limited carbon fixation, and high thallus hydration was often detrimental to NP. In spite of these limitations the maximal daily integrated net photosynthetic carbon income (ΣNP) was quite high especially for the Sticta species [17·3 and 24·1 mgC (gC)−1 day−1 for S. sublimbata and S. weigelii, respectively]. High nocturnal carbon loss, due to high night temperatures and continuous hydration, resulted in frequent negative diel carbon balances (ΣC) in all species. The average nocturnal carbon loss amounted to 83 and 70% ΣNP for P. aurata and P. intricata, respectively and to 64 and 59% of ΣNP for S. sublimbata and S. weigelii, respectively. Their average diel ΣC was as high as 3·7 and 5·3 mgC (gC)−1 day−1. In contrast, ΣC was much lower for the other species, it amounted to only 0·18 mgC (gC)−1 day−1 for L. crenulata. Thus, the Sticta species stood out amongst the species studied for their most successful adaptation of photosynthetic productivity to the habitat conditions in the lower montane rainforest.

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