Light response and photosynthesis in sorghum under field conditions

ABSTRACT. The diurnal variation of rate of photosynthesis (l') with photosynthetic photon flux density (PPFD) model of light response curves and the relationship between PPFD and P were studied for two postmonsoon (rabi) sorghum genotypes, viz.. M35- I and RSV-9R under field conditions at Pune. The half maximal values. i.e., PPFD level at which P=Pmax/2 obtained were 1251 and 937 umolm-2s-1 for M35-l and RSV.9R respectively. The potential rates of photosynthesis were 65,79 and 64.52 umolm-2S-1 whereas the observed maximum rates of photosynthesis were lower. 40.93 and 46.66 umolm-2s-1 in M35-1 and RSV-9R Respectively, due to effect of air temperatures under the field conditions, n1e maximum rate of photosynthesis determined from the model decreased with delay in the sowing of the crop. Correlation coefficients between PPFD and rate of photosynthesis were 0,794 and 0,708 for M35-1 and RSV-9R respectively. The PPFD received and rate of photosynthesis decreased significantly with delay in sorghum sowing.

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Photosynthetic Physiology of Blue, Green, and Red Light: Light Intensity Effects and Underlying Mechanisms

Frontiers in Plant Science ◽

10.3389/fpls.2021.619987 ◽

2021 ◽

Vol 12 ◽

Author(s):

Jun Liu ◽

Marc W. van Iersel

Keyword(s):

Blue Light ◽

Interactive Effect ◽

Red Light ◽

Green Light ◽

Photosynthetic Photon Flux Density ◽

Interactive Effects ◽

Photon Flux ◽

Photon Flux Density ◽

Light Spectrum ◽

Response Curves

Red and blue light are traditionally believed to have a higher quantum yield of CO2 assimilation (QY, moles of CO2 assimilated per mole of photons) than green light, because green light is absorbed less efficiently. However, because of its lower absorptance, green light can penetrate deeper and excite chlorophyll deeper in leaves. We hypothesized that, at high photosynthetic photon flux density (PPFD), green light may achieve higher QY and net CO2 assimilation rate (An) than red or blue light, because of its more uniform absorption throughtout leaves. To test the interactive effects of PPFD and light spectrum on photosynthesis, we measured leaf An of “Green Tower” lettuce (Lactuca sativa) under red, blue, and green light, and combinations of those at PPFDs from 30 to 1,300 μmol⋅m–2⋅s–1. The electron transport rates (J) and the maximum Rubisco carboxylation rate (Vc,max) at low (200 μmol⋅m–2⋅s–1) and high PPFD (1,000 μmol⋅m–2⋅s–1) were estimated from photosynthetic CO2 response curves. Both QYm,inc (maximum QY on incident PPFD basis) and J at low PPFD were higher under red light than under blue and green light. Factoring in light absorption, QYm,abs (the maximum QY on absorbed PPFD basis) under green and red light were both higher than under blue light, indicating that the low QYm,inc under green light was due to lower absorptance, while absorbed blue photons were used inherently least efficiently. At high PPFD, the QYinc [gross CO2 assimilation (Ag)/incident PPFD] and J under red and green light were similar, and higher than under blue light, confirming our hypothesis. Vc,max may not limit photosynthesis at a PPFD of 200 μmol m–2 s–1 and was largely unaffected by light spectrum at 1,000 μmol⋅m–2⋅s–1. Ag and J under different spectra were positively correlated, suggesting that the interactive effect between light spectrum and PPFD on photosynthesis was due to effects on J. No interaction between the three colors of light was detected. In summary, at low PPFD, green light had the lowest photosynthetic efficiency because of its low absorptance. Contrary, at high PPFD, QYinc under green light was among the highest, likely resulting from more uniform distribution of green light in leaves.

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Temperature response of photosynthesis and its interaction with light intensity in sweet orange leaf discs under non-photorespiratory condition

Ciência e Agrotecnologia ◽

10.1590/s1413-70542006000400012 ◽

2006 ◽

Vol 30 (4) ◽

pp. 670-678 ◽

Cited By ~ 15

Author(s):

Rafael Vasconcelos Ribeiro ◽

Eduardo Caruso Machado ◽

Ricardo Ferraz de Oliveira

Keyword(s):

Sweet Orange ◽

Photochemical Efficiency ◽

Temperature Response ◽

Light Response ◽

Photon Flux ◽

O2 Evolution ◽

Response Curves ◽

Leaf Discs ◽

Light Response Curves ◽

Heat Effects

This study aimed to evaluate the response of photosynthesis (A), given by photosynthetic O2 evolution, to increasing temperature from 25 to 50ºC in sweet orange (Citrus sinensis (L.) Osbeck) leaf discs under non-photorespiring conditions. In order to evaluate the response of gross photosynthesis to temperature and the balance between photosynthetic and respiratory activities, respiration (Rd) rates were also measured, i.e. the O2 uptake in each temperature. In addition, light response curves of photosynthesis were performed by varying the photosynthetic photon flux density (PPFD) from 0 to 1160 µmol m-2 s-1 at 25 and 40ºC. The highest A values were observed at 35 and 40ºC, whereas the highest Rd values were noticed at 50ºC. A higher relationship A/Rd was found at 30 and 35ºC, suggesting an optimum temperature of 35ºC when considering the balance between photosynthesis and respiration under non-photorespiring condition. Overall, heat effects on plant metabolism were more evident when evaluating the relationship A/Rd. In light response curves, higher A values were also found at 40ºC under PPFD higher than 300 µmol m-2 s-1. Light saturation point of photosynthesis was increased at 40ºC, without significant change of quantum efficiency under low PPFD. Respiration was also enhanced at 40ºC, and as a consequence, the light compensation point increased. The better photosynthetic performance at 35-40ºC was supported by higher photochemical efficiency in both light and temperature response curves. The temperature-dependence of photosynthesis was affected by growth temperature, i.e. a high air temperature during plant growth is a probable factor leading to a higher photosynthetic tolerance to heat stress.

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Effects of NIR Reflective Film as a High Tunnel-Covering Material on Fruit Cracking and Biomass Production of Tomatoes

Horticulturae ◽

10.3390/horticulturae8010051 ◽

2022 ◽

Vol 8 (1) ◽

pp. 51

Author(s):

Hiroko Yamaura ◽

Shinichi Furuyama ◽

Nobuo Takano ◽

Yuka Nakano ◽

Keiichi Kanno ◽

...

Keyword(s):

Near Infrared ◽

Morphological Changes ◽

Photosynthetic Photon Flux Density ◽

Photon Flux ◽

Photon Flux Density ◽

Slight Reduction ◽

High Tunnel ◽

Fruit Cracking ◽

Air Temperatures ◽

Covering Material

Tomatoes require higher irradiance, although the incidence of physiological disorders in fruit increases at high temperatures. Near-infrared (800–2500 nm) (NIR) reflective materials are effective tools to suppress rising air temperatures in greenhouses. We examined the physiological and morphological changes in tomato growth and fruit quality when grown in a high tunnel covered with NIR reflective film (NR) and in another covered with polyolefin film (PO; control). There was no relationship between the fruit cracking rate and mean daytime temperature under NR. The fruit temperature at the same truss was lower and the increase in air temperature was slow under NR. Fruit dry matter (DM) content under NR was also significantly decreased. These findings suggest that the reduction in fruit cracking under NR results from a decrease in fruit DM content as a consequence of lower fruit temperature and a decrease in total DM (TDM). Total fruit yield did not differ, whereas TDM was significantly decreased under NR. This was considered to result from a lower transmitted photosynthetic photon flux density (400–700 nm) (PPFD) and LAI, and lower photosynthetic capacity in single leaves because of a decrease in both total nitrogen and chlorophyll content. We conclude that NR film reduces fruit cracking in exchange for a slight reduction in TDM.

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Genotypic Variation in Light and Temperature Response of Photosynthesis in Nothofagus solandri Var. cliffortioides and N. menziesii

Functional Plant Biology ◽

10.1071/pp9960421 ◽

1996 ◽

Vol 23 (4) ◽

pp. 421 ◽

Cited By ~ 9

Author(s):

OJ Sun ◽

GB Sweet

Keyword(s):

New Zealand ◽

Dark Respiration ◽

Genotypic Variation ◽

Temperature Response ◽

Light Response ◽

Net Photosynthesis ◽

Photosynthetic Photon Flux Density ◽

Ecosystem Dynamics ◽

Photon Flux ◽

Photon Flux Density

Responses of photosynthesis to light and temperature were studied in two Nothofagus species native to New Zealand: N. solandri var. cliffortioides (Hook. f.) Poole and N. menziesii (Hook. f.) Oerst.. Measurements of leaf photosynthesis were made in a controlled environment growth chamber at photosynthetic photon flux density between 0 and 700 μmol m-2 s-1 with temperatures set for 10, 20 and 25�C, on seedlings previously grown in a glasshouse from seed of three different origins. In both species, pronounced intraspecific variation was shown in dark respiration, light compensation point and light-saturated net photosynthesis (Amax). Seedlings of N. solandri showed higher dark respiration and light compensation levels than N. menziesii seedlings, but the two species did not differ in Amax. Change in temperature resulted in significant change in the response of photosynthesis to light in both N. solandri and N. menziesii. The differences between N. solandri and N. menziesii in light response of photosynthesis are discussed in terms of ecosystem dynamics of Nothofagus forests in New Zealand.

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Photosynthetic light and temperature responses of Eucalyptus cloeziana and Eucalyptus argophloia

Australian Journal of Botany ◽

10.1071/bt02092 ◽

2003 ◽

Vol 51 (5) ◽

pp. 573 ◽

Cited By ~ 2

Author(s):

Michael R. Ngugi ◽

Mark A. Hunt ◽

David Doley ◽

Paul Ryan ◽

Peter J. Dart

Keyword(s):

Quantum Yield ◽

Dark Respiration ◽

Temperature Response ◽

Net Photosynthesis ◽

Photosynthetic Photon Flux Density ◽

Photon Flux ◽

Photon Flux Density ◽

Response Curves ◽

Growth Environment ◽

Eucalyptus Cloeziana

Acclimation of gas exchange to temperature and light was determined in 18-month-old plants of humid coastal (Gympie) and dry inland (Hungry Hills) provenances of Eucalyptus cloeziana F.Muell., and in those of a dry inland provenance of Eucalyptus argophloia Blakely. Plants were acclimated at day/night temperatures of 18/13, 23/18, 28/23 and 33/28�C in controlled-temperature glasshouses for 4 months. Light and temperature response curves were measured at the beginning and end of the acclimation period. There were no significant differences in the shape and quantum-yield parameters among provenances at 23, 28 and 33�C day temperatures. Quantum yield [μmol CO2 μmol–1 photosynthetic photon flux density (PPFD)] ranged from 0.04 to 0.06 and the light response shape parameter ranged from 0.53 to 0.78. Similarly, no consistent trends in the rate of dark respiration for plants of each provenance were identified at the four growth temperatures. Average values of dark respiration for the plants of the three provenances ranged from 0.61 to 1.86 μmol m–2 s–1. The optimum temperatures for net photosynthesis increased from 23 to 32�C for the humid- and from 25 to 33�C for the dry-provenance E. cloeziana and from 21 to 33�C for E. argophloia as daytime temperature of the growth environment increased from 18 to 33�C. These results have implications in predicting survival and productivity of E. cloeziana and E. argophloia in areas outside their natural distribution.

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Growth, Carbon Acquisition, and Source-Sink Relationships in `Titan' Red Raspberry

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.119.6.1163 ◽

1994 ◽

Vol 119 (6) ◽

pp. 1163-1168 ◽

Cited By ~ 14

Author(s):

Gina E. Fernandez ◽

Marvin P. Pritts

Keyword(s):

Accumulation Rate ◽

Light Response ◽

Dry Weight ◽

Rubus Idaeus ◽

Field Conditions ◽

Partial Recovery ◽

Red Raspberry ◽

Response Curves ◽

Photosynthetic Rates ◽

Light Response Curves

Seasonal changes in growth, mean maximal photosynthetic rates, and the temperature and light response curves of `Titan' red raspberry (Rubus idaeus L.) were obtained from potted plants grown under field conditions. Primocane dry weight accumulation increased steadily at the beginning and the end of the season, but growth slowed midseason during fruiting. The slower midseason dry-weight accumulation rate coincided with an increase in root dry weight. Primocane net assimilation rate (NAR) was highest early in the season. Floricane photosynthetic rates (A) were highest during the fruiting period, while primocane A remained steady throughout the season. Primocane and floricane leaflets displayed a midday depression in A under field conditions, with a partial recovery in the late afternoon. Photosynthetic rates of primocane and floricane leaves were very sensitive to temperature, exhibiting a decline from 15 to 40C. Light-response curves differed depending on cane type and time of year. A temporal convergence of sink demand from fruit, primocanes, and roots occurs when plants experience high temperatures. These factors may account for low red raspberry yield.

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Potential Photosynthetic Advantages of Cucumber (Cucumis sativus L.) Seedlings Grown under Fluorescent Lamps with High Red:far-red Light

HortScience ◽

10.21273/hortsci.45.4.553 ◽

2010 ◽

Vol 45 (4) ◽

pp. 553-558 ◽

Cited By ~ 12

Author(s):

Toshio Shibuya ◽

Ryosuke Endo ◽

Yuki Kitamura ◽

Yoshiaki Kitaya ◽

Nobuaki Hayashi

Keyword(s):

Cucumis Sativus ◽

Morphological Changes ◽

Red Light ◽

Light Response ◽

Photosynthetic Photon Flux Density ◽

Photon Flux ◽

Photon Flux Density ◽

Cucumis Sativus L ◽

Fluorescent Lamps ◽

Metal Halide Lamps

To evaluate the effect of fluorescent lamps with a high red:far-red (R:FR) light on the potential photosynthesis of transplants, we investigated the photosynthetic light responses of cucumber (Cucumis sativus L.) seedlings grown under fluorescent lamps with high R:FR light (FLH) and compared them with the responses of the seedlings grown under metal-halide lamps (ML) that provided a spectrum similar to that of natural light and under a fluorescent lamp with low R:FR light (FLL). The seedlings were grown under FLH (R:FR = 7.0), ML (R:FR = 1.2), or FLL (R:FR = 1.1) at a photosynthetic photon flux density (PPFD) of 350 μmol·m−2·s−1. The gross photosynthetic rate (Pg), quantum yield of photosystem II (ΦPSII), and photosynthetic electron transfer rate (ETR) of the foliage leaves were then evaluated at PPFDs ranging from 0 to 1000 μmol·m−2·s−1. The photosynthetic light response of FLH seedlings was similar to those of sun leaves, and the responses of ML and FLL seedlings were similar to those of shade leaves. The Pg, ETR, and ΦPSII of FLH seedlings at PPFD of 1000 μmol·m−2·s−1 was 1.38, 1.32, and 1.28 times, respectively, those of ML seedlings, and was 1.40, 1.23, and 1.22 times, respectively, those of FLL seedlings. The Pg was closely correlated with ETR in each treatment. FLH seedlings had thicker leaf and greater chlorophyll content per leaf area than ML and FLL seedlings. The greater Pg of FLH seedlings than in the other two groups of seedlings at high PPFD was probably the result of the improved ETR resulting from physiological and morphological changes in response to the high R:FR light.

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Green light reduces elongation when partially replacing sole blue light independently from cryptochrome 1a

10.21203/rs.3.rs-53294/v1 ◽

2020 ◽

Author(s):

Xue Zhang ◽

Mehdi bisbis ◽

Ep Heuvelink ◽

Weijie Jiang ◽

Leo F. M Marcelis

Keyword(s):

Leaf Area ◽

Blue Light ◽

Stem Elongation ◽

Green Light ◽

Light Response ◽

Biomass Accumulation ◽

Photosynthetic Photon Flux Density ◽

Stem Length ◽

Photon Flux ◽

Photon Flux Density

Abstract Although green light is often neglected it can have several effects on plant growth and development. Green light is probably sensed by cryptochromes (crys), one of the blue light photoreceptor families. The aim of this study is to investigate the possible interaction between green and blue light and the involvement of crys in the green light response of plant photomorphogenesis. We hypothesize that green light effects on morphology only occur when crys are activated by the presence of blue light. Wild-type Moneymaker (MM), cry1a mutant (cry1a) and two CRY2 overexpressing transgenic lines (CRY2-OX3 and CRY2-OX8) of tomato (Solanum lycopersicum) were grown in a climate chamber without or with green light (30 µmol m− 2 s− 1) on backgrounds of sole red, sole blue and red/blue mixture, with all treatments having the same photosynthetic photon flux density of 150 µmol m− 2 s− 1. Green light showed no significant effect on biomass accumulation, nor on leaf photosynthesis and leaf characteristics such as leaf area, specific leaf area, and chlorophyll content. However, in all genotypes, green light significantly decreased stem length on a sole blue background, whereas green light did not affect stem length on sole red and red/blue mixture background. MM, cry1a and CRY2-OX3/8 plants all exhibited similar responses of stem elongation to green light, indicating that cry1a, and probably cry2, is not involved in this green light effect. We conclude that partially replacing blue light by green light reduces elongation and that this is independent of cry1a.

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Light distribution within forest edges in relation to forest regeneration

Journal of Forest Science ◽

10.17221/4538-jfs ◽

2012 ◽

Vol 51 (No. 1) ◽

pp. 1-5 ◽

Cited By ~ 3

Author(s):

I. Schmid ◽

K. Klumpp ◽

M. Kazda

Keyword(s):

Net Photosynthesis ◽

Forest Edge ◽

Quercus Petraea ◽

Photosynthetic Photon Flux Density ◽

Photon Flux ◽

Photon Flux Density ◽

Carbon Gain ◽

Acer Pseudoplatanus ◽

Response Curves ◽

Clear Cut

Light conditions were measured along six transects from 35 m inside of a mixed Norway spruce/Scots pine forest to an adjoining clear-cut in NW-Austria. Photosynthetic photon flux density (PFD) was recorded every minute of the day from 5:00 a.m. to 8:00 p.m. for three weeks in July. PFD decreases exponentially from the clear-cut to the interior of the forest following the gap fraction. Low light intensity classes (< 50 µmol photons m<sup>2</sup>/s) decrease from the stand towards the open, whereas the clear-cut receives light of higher intensities (> 200 µmol photons m<sup>2</sup>/s) for most of the day. PFD values assessed during the day were compared with photosynthetic light response curves measured on advanced planting of broadleaf species in the same stand. The high light compensation point of Quercus petraea enables carbon gain in deep shade for about 60% of the day. The other shade tolerant species Fagus sylvatica and Acer pseudoplatanus can perform net photosynthesis at 80% and 90% of the time, respectively. This reduces the possibility of advanced planting of light demanding species to the first few meters of the inner part of the forest edge. 

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Cannabis Yield, Potency, and Leaf Photosynthesis Respond Differently to Increasing Light Levels in an Indoor Environment

Frontiers in Plant Science ◽

10.3389/fpls.2021.646020 ◽

2021 ◽

Vol 12 ◽

Author(s):

Victoria Rodriguez-Morrison ◽

David Llewellyn ◽

Youbin Zheng

Keyword(s):

Indoor Environment ◽

Treatment Effects ◽

Cannabis Sativa ◽

Light Response ◽

Photon Flux ◽

Photon Flux Density ◽

Plant Responses ◽

Production Environment ◽

Response Curves ◽

Leaf Level

Since the recent legalization of medical and recreational use of cannabis (Cannabis sativa) in many regions worldwide, there has been high demand for research to improve yield and quality. With the paucity of scientific literature on the topic, this study investigated the relationships between light intensity (LI) and photosynthesis, inflorescence yield, and inflorescence quality of cannabis grown in an indoor environment. After growing vegetatively for 2 weeks under a canopy-level photosynthetic photon flux density (PPFD) of ≈425 μmol·m−2·s−1 and an 18-h light/6-h dark photoperiod, plants were grown for 12 weeks in a 12-h light/12-h dark “flowering” photoperiod under canopy-level PPFDs ranging from 120 to 1,800 μmol·m−2·s−1 provided by light emitting diodes. Leaf light response curves varied both with localized (i.e., leaf-level) PPFD and temporally, throughout the flowering cycle. Therefore, it was concluded that the leaf light response is not a reliable predictor of whole-plant responses to LI, particularly crop yield. This may be especially evident given that dry inflorescence yield increased linearly with increasing canopy-level PPFD up to 1,800 μmol·m−2·s−1, while leaf-level photosynthesis saturated well-below 1,800 μmol·m−2·s−1. The density of the apical inflorescence and harvest index also increased linearly with increasing LI, resulting in higher-quality marketable tissues and less superfluous tissue to dispose of. There were no LI treatment effects on cannabinoid potency, while there were minor LI treatment effects on terpene potency. Commercial cannabis growers can use these light response models to determine the optimum LI for their production environment to achieve the best economic return; balancing input costs with the commercial value of their cannabis products.

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