The aim of this work was to correlate changes of photosynthesis activity vs. growth in Chlorella vulgaris R-117 (CCALA 1107), fast-growing and robust microalga cultured in an internally illuminated ...10-L photobioreactor (PBR). The cultures were grown at high output irradiance provided by four LED light sources submerged in the culture when the light path was short, between 25-30 mm. The culture of Chlorella R-117 grown under 2,500 µmol(photon) m-2 s-1 attained a doubling time of 3.5 d and biomass density of 3.5 g(DM) L-1 after about 10-d period. When grown under 3,500 µmol(photon) m-2 s-1, the culture reached a doubling time of 1.7 d, and biomass density of ~5.5 g L-1 before entering the stationary phase. Electron transport rate changes correlated well with the culture growth demonstrating the usefulness of chlorophyll fluorescence for photosynthesis monitoring. This can be crucial for potential scale-up to large indoor PBRs to optimise culture growth.
•Short-listing of 22 contrasting set of genotypes (CSG) for growth from the diverse mulberry germplasam.•Analysis of growth in CSG based on important morphological and gas exchange ...parameters.•Prediction the mulberry growth by logistic and linear regression analysis using marpho-physiological traits.
Plant growth is key determinant for leaf yield and biomass accumulation in mulberry. Accurate prediction of yield ensures brushing of right quantum of silkworms for silk production. Repeated harvesting of leaves/shoots leads to stress with physiological and biochemical changes. This necessitates in-depth analysis of growth attributes leading to rejuvenation and biomass production. A total of 22 contrasting genotypes for growth (CSG) were shortlisted from a diverse set of germplasm based on Number of Days required for Bud Sprouting (NDBS), Shoot Elongation Rate (SER) and Number of Branches (NB) in two distinct seasons. The logistic regression analysis of CSG expressed in odds ratio showed positive regression coefficients for important traits viz., inter-nodal distance (2.71), NB (1.31), Total Shoot Length (TSL, 1.38), Length of the Longest Shoot (LLS, 1.17) and Number of Leaves on the Longest Shoot (NLLS, 1.18) for high growth in August 2016. The growth curve estimates for SER was significantly (P < 0.0001) higher among High Growth Genotypes (HGG; 4–6.2 cm/day) compared to Low Growth Genotypes (LGG; 2.6–4.1 cm/day). Repeated measure ANOVA showed significance A (P < 0.0001), gs (P < 0.01), IWUE (P < 0.01) between three growth periods. A, Tr, and gs were higher among HGG compared to LGG and opposite was true in case of IWUE. Similarly, Amax and AQL were higher in HGG whereas Vcmax and Jmax were higher in LGG. Significant linear relationship of Tr, gs and IUWE was observed with NB, TSL and LLS. The study concludes that mulberry growth can be predicted using important morpho-metric traits and gas exchange parameters as supported by logistic and linear regression analysis.
•There were fundamental differences in the light response of SIF and GPP•SIF responded to light earlier in the year than the spring onset of GPP•SIF did not exhibit a parallel response to temperature ...and moisture controls on GPP•In summer SIF was not correlated with canopy conductance
The phenology of montane conifer forests is likely to shift in response to climate change and altered seasonal dynamics of light, temperature, and moisture. Solar-induced fluorescence (SIF) is expected to provide substantial improvement for mapping temporal changes in evergreen gross primary production (GPP) over greenness-based remote sensing indices. The utility of SIF to monitor seasonal changes in the phenology of conifer photosynthesis depends on the degree to which GPP and SIF respond in synchrony to key environmental drivers. However, to what extent SIF and GPP become decoupled by responding differently to the combined effects of light and other environmental conditions remains unknown. The goal of this study was to characterize the responses of GPP and SIFred to a suite of environmental drivers at the half-hour time scale and determine how these relationships change across seasons. We analyzed one year of tower-based SIFred and eddy covariance-derived GPP data from a conifer forest at Niwot Ridge, Colorado. We compared the light responses of GPP and SIFred across the year, finding that SIFred increased in response to light earlier in the year than did GPP. The light response of GPP had a positive temperature dependence in spring, and this dependency reversed in summer due to increased evaporative demand, while the light response of SIFred was less temperature dependent. Using artificial neural network ensemble analysis, we found that from spring to summer, SIFred did not exhibit a parallel response to the seasonally dynamic temperature and moisture controls on GPP. In summer SIFred was not correlated with canopy conductance, suggesting that SIF is less sensitive to stomatal control than GPP. Our results suggest that, in conifers, photosystems begin to activate in spring prior to when water becomes available for photosynthesis, presenting a challenge for the use of SIF as a phenological indicator in conifer forests.
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•Mixotrophic mode improved nutrient removal efficiency and biomass productivity.•FP-PBR performed better in terms of photosynthetic activity with SDWW.•Biochemical composition showed ...major proportion of carbohydrates.•FAME profile resulted in higher fraction of Heptadecanoic acid (C17:0)
Monoraphidium sp. SVMIICT6 was isolated and mixotrophically cultivated in a flat-panel photobioreactor (8 days) to treat synthetic dairy wastewater. COD, nitrates, and phosphates removal efficiencies were 75%, 85%, and 60% respectively. The nutrient removal supported the growth of microalgae in terms of biomass productivity (50 mg L-1d-1), and accumulation of carbohydrate (228.8 mg g-1), protein (88.8 mg g-1), and lipid content (25%). Elemental analysis of microalgal biomass revealed carbon (50.6%) as a major fraction. Quantum yield and electron transport rate (ETR) from PSII to PSI increased with time correlating well with chlorophyll pigments (89.53 mg g-1). The lipid profile resulted in a major fraction of Heptadecanoic acid (C17:0; 51.5%), followed by Myristoleic acid (C14:1; 24.3%) with potent nutraceutical properties. The isolated strain showed efficient treatment of dairy wastewater yielding biomass for diverse applications.
The phenology of montane conifer forests is likely to shift in response to climate change and altered seasonal dynamics of light, temperature, and moisture. Solar-induced fluorescence (SIF) is ...expected to provide substantial improvement for mapping temporal changes in evergreen gross primary production (GPP) over greenness-based remote sensing indices. The utility of SIF to monitor seasonal changes in the phenology of conifer photosynthesis depends on the degree to which GPP and SIF respond in synchrony to key environmental drivers. However, to what extent SIF and GPP become decoupled by responding differently to the combined effects of light and other environmental conditions remains unknown. The goal of this study was to characterize the responses of GPP and SIFred to a suite of environmental drivers at the half-hour time scale and determine how these relationships change across seasons. We analyzed one year of tower-based SIFred and eddy covariance-derived GPP data from a conifer forest at Niwot Ridge, Colorado. We compared the light responses of GPP and SIFred across the year, finding that SIFred increased in response to light earlier in the year than did GPP. The light response of GPP had a positive temperature dependence in spring, and this dependency reversed in summer due to increased evaporative demand, while the light response of SIFred was less temperature dependent. Using artificial neural network ensemble analysis, we found that from spring to summer, SIFred did not exhibit a parallel response to the seasonally dynamic temperature and moisture controls on GPP. In summer SIFred was not correlated with canopy conductance, suggesting that SIF is less sensitive to stomatal control than GPP. Furthermore, our results suggest that, in conifers, photosystems begin to activate in spring prior to when water becomes available for photosynthesis, presenting a challenge for the use of SIF as a phenological indicator in conifer forests.
Light response curves (LRCs) describe how the rate of photosynthesis varies as a function of light. They provide information on the maximum photosynthetic capacity, quantum yield, light compensation ...point and leaf radiation use efficiency of leaves. Light response curves are widely used to capture photosynthetic phenotypes in response to changing environmental conditions. However, models describing these are predominantly empirical and do not attempt to explain behaviour at a mechanistic level. Here, we use modelling to understand the metabolic changes required for photosynthetic acclimation to changing environmental conditions. Using a simple kinetic model, we predicted LRCs across the physiological temperature range of
Arabidopsis thaliana
and confirm these using experimental data. We use our validated metabolic model to make novel predictions about the metabolic changes of temperature acclimation. We demonstrate that NADPH utilization are enhanced in warm-acclimated plants, whereas both NADPH and CO
2
utilization is enhanced in cold-acclimated plants. We demonstrate how different metabolic acclimation strategies may lead to the same photosynthetic response across environmental change. We further identify that certain metabolic acclimation strategies, such as NADPH utilization, are only triggered when plants are moved beyond a threshold high or low temperature.
Insect herbivory is a dominant interaction across virtually all ecosystems globally and has dramatic effects on plant function such as reduced photosynthesis activity and increased levels of ...defenses. However, most previous work assessing the link between insect herbivory, photosynthesis and plant defenses has been performed on cultivated model plant species, neglecting a full understanding of patterns in natural systems. In this study, we performed a field experiment to investigate the effects of herbivory by a generalist foliar feeding insect (Lymantria dispar) and leaf mechanical damage on multiple leaf traits associated with defense against herbivory and photosynthesis activity on two sympatric oak species with contrasting leaf habit (the evergreen Quercus coccifera L. and the deciduous Quercus pubescens Willd). Our results showed that, although herbivory treatments and oak species did not strongly affect photosynthesis and dark respiration, these two factors exerted interactive effects. Insect herbivory and mechanical damage (vs control) decreased photosynthesis activity for Q. coccifera but not for Q. pubescens. Insect herbivory and mechanical damage tended to increase chemical (increased flavonoid and lignin concentration) defenses, but these effects were stronger for Q. pubescens. Overall, this study shows that two congeneric oak species with contrasting leaf habit differ in their photosynthetic and defensive responses to insect herbivory. While the evergreen oak species followed a more conservative strategy (reduced photosynthesis and higher physical defenses), the deciduous oak species followed a more acquisitive strategy (maintained photosynthesis and higher chemical defenses).
Light Response Curves in Land Plants Coe, Robert A; Lin, Hsiang-Chun
Methods in molecular biology (Clifton, N.J.),
2024, Letnik:
2790
Journal Article
Light is the driving force for photosynthesis. Two techniques are commonly employed to help characterize the relationship between the light environment and photosynthesis in plants.Chlorophyll a ...fluorescence analysis is used to examine both the capacity for and the efficiency of the conversion of absorbed light into energy for photosynthesis. Additionally, gas exchange analysis is used to assess the utilization of that energy for carbon fixation. These techniques are used either in isolation or in combination to acquire light response curves that measure the response of the plant to sequential changes in irradiance. Light response curves can help users understand photosynthetic mechanisms, evaluate how plants respond to light conditions, or assess the extent of physiological plasticity within plants. In this chapter, we provide a generalized method for acquiring light response curves suitable for both chlorophyll a fluorescence and gas exchange techniques using commercially available apparatus. Depending on the equipment available, these methods can be applied individually or combined to acquire data simultaneously. The methods are broadly applicable to most land plants but are ideally suited to help those that are unfamiliar with these techniques.
ABSTRACT
Field measurements of photosynthesis of Vitis vinifera cv. Semillon leaves in relation to a hot climate, and responses to photon flux densities (PFDs) and internal CO2 concentrations (ci) at ...leaf temperatures from 20 to 40 °C were undertaken. Average rates of photosynthesis measured in situ decreased with increasing temperature and were 60% inhibited at 45 °C compared with 25 °C. This reduction in photosynthesis was attributed to 15–30% stomatal closure. Light response curves at different temperatures revealed light‐saturated photosynthesis optimal at 30 °C but also PFDs saturating photosynthesis increased from 550 to 1200 µmol (photons) m−2 s−1 as temperatures increased. Photosynthesis under saturating CO2 concentrations was optimal at 36 °C while maximum rates of ribulose 1,5‐bisphosphate (RuBP) carboxylation (Vcmax) and potential maximum electron transport rates (Jmax) were also optimal at 39 and 36 °C, respectively. Furthermore, the high temperature‐induced reduction in photosynthesis at ambient CO2 was largely eliminated. The chloroplast CO2 concentration at the transition from RuBP regeneration to RuBP carboxylation‐limited assimilation increased steeply with an increase in leaf temperature. Semillon assimilation in situ was limited by RuBP regeneration below 30 °C and above limited by RuBP carboxylation, suggesting high temperatures are detrimental to carbon fixation in this species.
Semillon grapevines are grown in hot climates of Australia and this has a major effect on photosynthesis and, therefore, growth and development of the vines. A question arises as to whether the stomata or the physiology of photosynthesis is affected by the high temperatures. Our results showed stomata do limit photosynthesis by as much as 30% but the photosynthetic processes related to carboxylation of Ribulose 1, 5‐bisphosphate are the most important limitations to photosynthesis at high temperatures and impact on carbon fixation. Strategies to reduce leaf temperatures, therefore, are needed to maintain productivity in these and potentially future hotter climates.
The frequent occurrence of monsoon winds usually leads to the formation of inverted soybean leaves. However, the effect of leaf inversion on photosynthetic capacity remains unclear. The responses of ...leaf anatomical traits, chlorophyll fluorescence induction kinetics parameters, photosynthetic capacity, and nonstructural carbohydrates of fully expanded leaves to inversion of leaves in two soybean cultivars were studied. Leaf inversion decreased the stomatal size and thickness of developed leaves. The net photosynthetic rate was significantly reduced under leaf inversion, which resulted from reduced excitation energy trapping and electron transport of PSII reaction center. Leaf inversion increased leaf temperature 10 d after leaf inversion but reduced the instantaneous water-use efficiency compared to normally oriented leaves. Due to the decreased light-saturated net photosynthetic rate, the soluble sugars of light-sensitive cultivar decreased significantly. In summary, leaf inversion deactivated the PSⅡ reaction centers, reduced photosynthesis and nonstructural carbohydrates in upper canopy soybean leaves.
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