scholarly journals An in situ approach to characterizing photosynthetic gas exchange of rice panicle

2020 ◽  
Author(s):  
Tiangen Chang ◽  
Qing-Feng Song ◽  
Honglong Zhao ◽  
Shuoqi Chang ◽  
Changpeng Xin ◽  
...  
Keyword(s):  
Grain Yield ◽  
Pearson Correlation ◽  
Reproductive Organs ◽  
Photosynthetic Characteristics ◽  
Compensation Point ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Photosynthetic Gas Exchange ◽  
Cereal Breeding

Abstract Background: Photosynthesis of reproductive organs in C3 cereals is generally regarded as important to crop yield. Whereas, photosynthetic characteristics of reproductive organs are much less understood as compared to leaf photosynthesis, mainly due to methodological limitations. To date, many indirect methods have been developed to study photosynthesis of reproductive organs and its contribution to grain yield, such as organ shading, application of herbicides and photosynthetic measurement of excised organs or tissues, which might be intrusive and cause biases. Thus, a robust and in situ approach needs to be developed.Results: Here we report the development of a custom-built panicle photosynthesis chamber (P-chamber), which can be connected to standard infrared gas analyzers to study photosynthetic/respiratory rate of a rice panicle. With the P-chamber, we measured panicle photosynthetic characteristics of seven high-yielding elite japonica, japonica-indica hybrid and indica rice cultivars. Results show that, 1) rice panicle is photosynthetically active during grain filling, and there are substantial inter-cultivar variations in panicle photosynthetic and respiratory rates, no matter on a whole panicle basis, on an area basis or on a single spikelet basis; 2) among the seven testing cultivars, whole-panicle gross photosynthetic rates are 17 – 54 nmol s-1 5 days after heading under photon flux density (PFD) of 2000 μmol (photons) m-2 s-1, which represent some 20-38% of that of the corresponding flag leaves; 3) rice panicle photosynthesis has higher apparent CO2 compensation point, light compensation point and apparent CO2 saturation point, as compared to that of a typical leaf; 4) there is a strong and significant positive correlation between gross photosynthetic rate 5 days after heading on a single spikelet basis and grain setting rate at harvest (Pearson correlation coefficient r = 0.93, p-value < 0.0001). Conclusions: Rice panicle gross photosynthesis is significant, has great natural variation, and plays an underappreciated role in grain yield formation. The P-Chamber can be used as a tool to study in situ photosynthetic characteristics of irregular non-foliar plant organs, such as ears, culms, leaf sheaths, fruits and branches, which is a relatively less explored area in current cereal breeding community.

scholarly journals An in situ approach for characterizing photosynthetic gas exchange of rice panicle

2020 ◽  
Author(s):  
Tiangen Chang ◽  
Qing-Feng Song ◽  
Honglong Zhao ◽  
Shuoqi Chang ◽  
Changpeng Xin ◽  
...  
Keyword(s):  
Pearson Correlation ◽  
Grain Filling ◽  
Reproductive Organs ◽  
Photosynthetic Characteristics ◽  
Compensation Point ◽  
Photosynthetic Gas Exchange ◽  
Filling Stage ◽  
Cereal Breeding ◽  
Grain Filling Stage

Abstract Background: Photosynthesis of reproductive organs in C 3 cereals is generally regarded as important to crop yield. Whereas, photosynthetic characteristics of reproductive organs are much less understood as compared to leaf photosynthesis, mainly due to methodological limitations. To date, many indirect methods were developed to study photosynthesis of reproductive organs and its contribution to grain yield, such as shading, application of herbicides or photosynthetic measurement of excised organs or tissues, which might be intrusive and cause biases. Thus, a robust and in situ approach needs to be developed. Results: Here we report the development of a custom-built panicle chamber (P-chamber), which can be connected to a standard infrared gas analyzer to study photosynthetic/respiratory rate of a rice panicle. With this P-chamber, we measured photosynthetic characteristics of panicles for seven high-yielding elite japonica , japonica-indica hybrid and indica rice cultivars. Results show that, 1) rice panicle is photosynthetically active during grain filling, and there are substantial inter-cultivar variations in panicle photosynthetic and respiratory rates, both for a whole panicle and on a single spikelet basis; 2) among the seven testing cultivars, light saturated whole-panicle gross photosynthetic rates at early grain filling stage are 17 – 54 nmol s -1 , which are estimated to be 20-38% of the corresponding flag leaves; 3) rice panicle photosynthesis has higher apparent CO 2 compensation point, light compensation point and apparent CO 2 saturation point, as compared to that of a typical leaf; 4) there is a strong and significant positive correlation between gross photosynthetic rate at early grain filling stage on a single spikelet basis and grain setting rate at harvest (Pearson correlation coefficient r = 0.93, p -value < 0.0001). Conclusions: Overall, the P-Chamber can be used as a tool to study in situ photosynthetic characteristics of irregular non-foliar plant organs, which is a relatively less explored area in current cereal breeding community.

Leaf photosynthetic characteristics and net primary production of the polar willow (Salix polaris) in a high arctic polar semi-desert, Ny-Ålesund, Svalbard

2002 ◽  
Vol 80 (11) ◽  
pp. 1193-1202 ◽  
Author(s):  
Hiroyuki Muraoka ◽  
Masaki Uchida ◽  
Masako Mishio ◽  
Takayuki Nakatsubo ◽  
Hiroshi Kanda ◽  
...  
Keyword(s):  
Primary Production ◽  
Net Primary Production ◽  
Natural Habitat ◽  
Leaf Age ◽  
High Arctic ◽  
Photosynthetic Characteristics ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Salix Polaris ◽  
Temperature Conditions

Photosynthetic characteristics and their leaf-age dependence were examined to estimate ecophysiological effects on net primary production (NPP) of a polar willow (Salix polaris), a dominant dwarf shrub species in a polar semi-desert area of Ny-Ålesund, Svalbard. Leaves of S. polaris emerged just after snowmelt in early July in 2000; flowers were initiated within 1 week, and fruits in late July. Light-saturated rate of photosynthesis and stomatal conductance to water vapor increased rapidly to their maximum values within 1 week after leaf emergence and then decreased gradually. Depending on the leaf age, photosynthetic rates saturated at photosynthetically active photon flux density (PPFD) of 200–400 µmol·m–2·s–1, which is the light level usually available in the natural habitat. Optimum leaf temperature of photosynthesis ranged from 10 to 18°C, while air temperature in the habitat ranged from 8 to 20°C. These light and temperature responses of photosynthesis of S. polaris would be suitable for efficient carbon gain in the natural habitat characterized by highly variable light and temperature conditions. Using the photosynthetic and respiratory characteristics, biomass distribution, and meteorological data, NPP of S. polaris in the current year was estimated to be 26.1 g C·m–2. A model simulation of rising temperature conditions predicted a reduction of NPP because of a large increase in respiration. It was suggested that temperature condition and leaf phenological aspects strongly influence the carbon fixation by plants in the high arctic area studied.Key words: arctic semi-desert, climate change, net ecosystem production (NEP), net primary production (NPP), Salix polaris, photosynthesis.

scholarly journals Photosynthetic and Agronomic Traits of Winter Barley (Hordeum vulgare L.) Varieties

Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1999
Author(s):  
József Csajbók ◽  
Péter Pepó ◽  
Erika Kutasy
Keyword(s):  
Hordeum Vulgare ◽  
Grain Yield ◽  
Protein Content ◽  
Winter Barley ◽  
Yield Potential ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Photosynthetic Parameters ◽  
Assimilation Rate ◽  
Hordeum Vulgare L

We tested six winter barley (Hordeum vulgare L.) cultivars in a small plot field experiment, measuring photosynthesis and other parameters three times during the growing season. Four genotypes—Andoria, Jakubus, Paradies and Zophia—are new, promising varieties with requirements of intensive technology, high yield potential and very good disease resistance. The two popular Hungarian varieties (KG Apavár and KG Puszta) are relatively old but they have good tolerance to extreme ecological conditions and outstanding resistance and winter hardiness. The aim of our research was to test the new varieties’ performance. Several recent studies found close connections among various photosynthetic parameters in barley, and we confirmed that in our research. There were significant differences between the varieties in the assimilation rate—the highest values were measured at the BBCH 47–49 stage (end of booting), except Jakubus and Zophia, where the highest values were at BBCH 73–75 (milk ripe). The cultivars’ response to irradiation change varied, especially at higher photosynthetic photon flux density (PPFD) levels. In April and May, the plants were in drought stress according to the intercellular CO2 level and the total conductance to carbon dioxide. The differences between the air and leaf temperature were also low, indicating water stress, but the assimilation rate was relatively high (9.07–14.09 µmol m−2 s−1).We found a close connection between normalized difference vegetation index (NDVI) values and grain protein content in each of the tested barley cultivars. The correlation was significant, at p = 0.01 level. The protein yield per hectare was determined rather by grain yield than protein content. The relationship between the NDVI values and grain yield was moderate, but NDVI values and protein content are in strong correlation.

Effects of periodic fluctuations of photon flux density on anatomical and photosynthetic characteristics of soybean leaves

1987 ◽  
Vol 13 (1) ◽  
pp. 81-89 ◽  
Author(s):  
J. P. Gaudillere ◽  
J. J. Drevon ◽  
J. P. Bernoud ◽  
F. Jardinet ◽  
M Euvrard
Keyword(s):  
Flux Density ◽  
Photosynthetic Characteristics ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Periodic Fluctuations ◽  
Soybean Leaves

Blue Light Induction of in situ Nitrate Reductase Activity in the Marine Green Alga Ulva rigida

1992 ◽  
Vol 19 (6) ◽  
pp. 625 ◽  
Author(s):  
A Corzo ◽  
X Niell
Keyword(s):  
Nitrate Reductase ◽  
Flux Density ◽  
Blue Light ◽  
Time Course ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Ulva Rigida ◽  
Light Enhancement ◽  
Nr Activity

The regulation by light (especially blue light) and NO3- of the nitrate reductase (NR) activity was studied in the marine green macroalga Ulva rigida C. Agardh. NR activity was measured in situ as no available in vitro method exists for Ulva rigida. The effectiveness spectrum of NR-enhancement by light was determined. Blue light was clearly the most effective wavelength, being more effective than white or red light. Blue light enhancement of NR was strictly dependent on photosynthesis since it was inhibited by 95% in presence of 5 × 10-5 M DCMU. The time course of NR enhancement by blue light was hyperbolic in shape, the semimaximal level of increase was reached in 24 min in N-sufficient algae. Blue light activation of NR is dependent upon photo flux density in a sigmoidal manner; 95% of the maximum increase was reached at 137 μmol m-2 s-1. Blue light enhancement of NR is linearly dependent on the amount of KNO3 available in the medium at the beginning of the experiment. Increase in NO3- by itself, in dark or without a concomitant increase in photon flux density, only increases NR activity by 12% (darkness) or 25% (white light, 4 μmol m-2 s-1) with respect to a blue light control. The blue light enhancement of NR was inhibited by actinomycin D (33%), rifampicin (32%) and cycloheximide (88%). Therefore, in Ulva rigida the blue light enhancement of NR occurs mainly by induction of de novo synthesis.

Gas Exchange Properties of Jointed Goatgrass (Aegilops cylindrica)

Weed Science ◽  
1987 ◽  
Vol 35 (4) ◽  
pp. 482-489 ◽  
Author(s):  
David R. Gealy
Keyword(s):  
Dark Respiration ◽  
Stomatal Density ◽  
Photosynthetic Photon Flux Density ◽  
Compensation Point ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Aegilops Cylindrica ◽  
Jointed Goatgrass ◽  
Diffusive Resistance ◽  
Leaf Surfaces

Net (apparent) photosynthesis rate (Pn) of jointed goatgrass (Aegilops cylindricaHost # AEGCY) leaves in the greenhouse became light saturated at a photosynthetic photon flux density (PPFD) of about 1000 μE·m–1-2·s–1with a maximum Pn of 27 mg CO2·dm–2·h–1. Diffusive resistance to water vapor (rl) of adaxial leaf surfaces was 43% that of abaxial surfaces, in part, because stomatal density was 50% greater on adaxial leaf surfaces than on abaxial surfaces. Dark respiration rate (Rd) was 1.6 mg CO2·dm−2·h−1. Light compensation point (CPl) was 21 μE·m−2·s−1and CO2compensation point (CPc) was 32 ppmv. In the field, where light intensity and temperature were greater than in the greenhouse, leaves became light saturated for Pn at a higher intensity, and Rd and CPl were three times greater than in the greenhouse. Pn and Rd of spikes at anthesis were at least 30% less and 200% greater, respectively, than the values for leaves.

Photosynthetic Productivity of Mayweed Chamomile (Anthemis cotula)

Weed Science ◽  
1991 ◽  
Vol 39 (1) ◽  
pp. 18-26 ◽  
Author(s):  
David R. Gealy ◽  
Sheila A. Squier ◽  
Alex G. Ogg
Keyword(s):  
Pacific Northwest ◽  
Dark Respiration ◽  
Cropping Systems ◽  
Net Photosynthesis ◽  
Compensation Point ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Photosynthetic Photon Flux ◽  
Photosynthetic Productivity ◽  
Maximum Net Photosynthesis

Photosynthetic productivity parameters were determined for mayweed chamomile, a troublesome annual weed of the cropping systems in the Pacific Northwest. At a photosynthetic photon flux density of 1800 μE m−2s–1, maximum net photosynthetic rate of greenhouse-grown plants was 35 mg CO2dm−2h–1and maximum transpiration rate was 6.7 μg H2O cm−2s–1. Dark respiration rate was 1.4 mg CO2dm−2h–1and the light compensation point was 17.5 μE m−2s–1. Carbon dioxide compensation point increased from 25 ppm at 15 C to 43 ppm at 30 C. At saturating photosynthetic photon flux densities, optimum leaf temperature for net photosynthesis was about 25 C. Maximum net photosynthesis of leaves of field-grown plants averaged 15.8 mg CO2dm−2h–1. After a 24-h exposure to 0.075 kg ha–1metribuzin, maximum net photosynthesis and transpiration were reduced 85 and 40%, respectively. Soil water deficits reduced maximum net photosynthesis about 50%.

scholarly journals Promotive effects of 5-aminolevulinic acid on photosynthesis and chlorophyll fluorescence of tomato seedlings under suboptimal low temperature and suboptimal photon flux density stress – Short communication

2012 ◽  
Vol 39 (No. 2) ◽  
pp. 97-99 ◽  
Author(s):  
Guo Xiaoqing ◽  
Li Yansu ◽  
Yu Xianchang
Keyword(s):  
Flux Density ◽  
Short Communication ◽  
Transformation Efficiency ◽  
Aminolevulinic Acid ◽  
Compensation Point ◽  
Photon Flux ◽  
Photochemical Quenching ◽  
Photon Flux Density ◽  
Tomato Seedlings ◽  
Maximum Quantum Efficiency

Effects of 5-aminolevulinic acid (ALA) on photosynthetic characteristics of tomato grown under suboptimal conditions were investigated to evaluate the potential value of ALA spraying in vegetables. The net photosynthetic rate (Pn), stomatal conductance (Gs), maximum quantum efficiency of photosystem II (Fv/Fm), coefficient of photochemical quenching (qP), antenna transformation efficiency (Fv'/Fm'), light compensation point (LCP), CO<sub>2 </sub>compensation point (CCP) and chlorophyll (chl) contents of tomato stressed by suboptimal temperature (17&deg;C/12&deg;C) and suboptimal photon flux density (250 &mu;mol/m<sup>2</sup>s) were decreased, but intercellular CO<sub>2 </sub>concentration (Ci) was increased distinctly. Compared with the parameters of tomato pretreated with water, Pn, Gs, Fv/Fm, qP, Fv'/Fm' and chl content of tomato pretreated with ALA were increased, and the Ci, LCP and CCP were decreased obviously. These results indicate that the inhibition of photosynthesis induced by suboptimal stress can be alleviated by ALA spraying.

scholarly journals Production and Postproduction Irradiance Affects Acclimatization and Longevity of Potted Chrysanthemum and Poinsettia

1990 ◽  
Vol 115 (2) ◽  
pp. 262-265 ◽  
Author(s):  
Terril A. Nell ◽  
Ria T. Leonard ◽  
James E. Barrett
Keyword(s):  
Flux Density ◽  
Dark Respiration ◽  
Photosynthetic Photon Flux Density ◽  
Compensation Point ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Euphorbia Pulcherrima ◽  
Total Chlorophyll ◽  
Photosynthetic Photon Flux ◽  
Light Compensation Point

Production irradiance levels on growth, light compensation point (LCP), dark respiration (DR), and interior longevity of potted chrysanthemum (Demfranthema grandiflora Tzvelev. cvs. Iridon and Mountain Peak) and poinsettia (Euphorbia pulcherrima Wind. cvs. Annette Hegg Dark Red and Gutbier V-10 Amy) were determined. LCP and DR were measured at anthesis and during acclimatization to interior conditions (10 μmol·s-1·m-2). Days to flowering, inflorescence diameter, total chlorophyll, and interior longevity of chrysanthemum increased when maintained at a mean maximum photosynthetic photon flux density (PPFD) of 500 μmol·s-1·m-2 compared to plants shifted to 300 or 100 μmol·s-1·m-2 8 weeks after planting. LCP and DR were highest at anthesis and were reduced 38% and 49%, respectively, for chrysanthemum and 19% and 42%, respectively, for poinsettia within 3 days in interior conditions. Chrysanthemum plants shifted to 300 μmol·s1·m-2 during production had lower LCP and DR rates at anthesis and throughout time in interior conditions compared to plants maintained at 500 μmol·s-1·m-2. The acclimatization of chrysanthemum to reduced production PPFD is of little significance because interior longevity is reduced. No differences were found in the LCP or DR of poinsettia or chrysanthemum cultivars that differ in interior performance, demonstrating that these physiological characteristics are not good indicators of interior longevity for chrysanthemum and poinsettia.

scholarly journals Rapid Excision Apparatus for Plants (REAPer): Design, Implementation, and Functionality

HortScience ◽  
2003 ◽  
Vol 38 (2) ◽  
pp. 207-211
Author(s):  
Gerard W. Wall ◽  
Guy McDonnell
Keyword(s):  
Water Vapor Pressure ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Personnel Cost ◽  
In Situ Studies ◽  
Uniform Sample ◽  
Discrete Interval ◽  
All Treatment

Net primary productivity of a botanical is often determined by monitoring gas exchange rates (i.e., CO2, H2O) in a controlled-environment cuvette. Because atmospheric conditions (i.e., incident photon flux density, air temperature, and water vapor pressure) change within a day, whereas edaphic (i.e., soil-water content and nutrient availability) conditions change across days, experimental results obtained between treatment variants can often be confounded within the sample interval. Consequently, in order to obtain a “snapshot” of the CO2 and H2O flux of a botanical across treatment variants, all in situ measurements must be made within a discrete interval. One approach would be to use multiple cuvettes to measure CO2 and H2O flux across all treatment variants simultaneously. But, this would be expensive in both equipment and personnel cost. A more economical approach would be to rapidly excise a botanical from each treatment variant within a discrete interval and store them under exacting steady-state laboratory conditions for in vivo rather than in situ studies. However, this too can be problematic, because in order to excise a botanical a standard operating procedure (SOP) is required. Hence, a need exists for a Rapid Excision Apparatus for Plants (REAPer). Following the SOP of the REAPer enables personnel to excise a botanical across all treatment variants within a discrete interval, while maintaining xylem conductance, minimizing mechanical damage, and providing a uniform sample for in vivo rather then in situ studies. This work describes the design, implementation, and functionality of the REAPer, its application in basic research and development, and its potential applications in the commercial floral and horticultural industries.

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