Influence of Low Light on the Growth and Development of Vallisneria natans Seedlings

2013 ◽  
Vol 295-298 ◽  
pp. 62-68 ◽  
Author(s):  
Qiang Li ◽  
Yun Cheng Xie
Keyword(s):  
Weight Ratio ◽  
Photochemical Quenching ◽  
Low Light ◽  
Vallisneria Natans ◽  
Relative Electron Transport Rate ◽  
Leaf Formation ◽  
Relative Electron ◽  
Macrophyte Growth ◽  
Non Photochemical Quenching ◽  
Photochemical Quantum Yield

To research influence of low light on macrophyte growth, seedlings of Vallisneria natans were transplanted into the waters with 5%, 1%, 0.5% and 0.1% full sunlights, respectively. The results show that germination rates are significantly inhibited with the experiment. In first 20 days leaf formation of new plants aren’t inhibited, and their leaf elongation are promoted. Since then, them of old plants and new plants are remarkably inhibited with the experiment. Though maximum photochemical quantum yield (Fv/Fm), relative electron transport rate (ETR) and non-photochemical quenching (NPQ) of old plants reduce significantly on low light conditions, but V. natans still hsa a certain degree of photoasynthetic capacity on the 80th day. Fresh weight ratio of roots and stems increase with decreasing light intensity. However, it exhibits an opposite trend for leaves. Thus, V. natans has a strong ability of low-light (≤1% full sunlight) tolerance.

scholarly journals Growth under Fluctuating Light Reveals Large Trait Variation in a Panel of Arabidopsis Accessions

Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 316 ◽  
Author(s):  
Elias Kaiser ◽  
Dirk Walther ◽  
Ute Armbruster
Keyword(s):  
Photosystem Ii ◽  
Chemical Potential ◽  
Genomic Variation ◽  
Operating Efficiency ◽  
Photochemical Quenching ◽  
Low Light ◽  
Trait Variation ◽  
Light Regimes ◽  
Fluctuating Light ◽  
Non Photochemical Quenching

The capacity of photoautotrophs to fix carbon depends on the efficiency of the conversion of light energy into chemical potential by photosynthesis. In nature, light input into photosynthesis can change very rapidly and dramatically. To analyze how genetic variation in Arabidopsis thaliana affects photosynthesis and growth under dynamic light conditions, 36 randomly chosen natural accessions were grown under uniform and fluctuating light intensities. After 14 days of growth under uniform or fluctuating light regimes, maximum photosystem II quantum efficiency (Fv/Fm) was determined, photosystem II operating efficiency (ΦPSII) and non-photochemical quenching (NPQ) were measured in low light, and projected leaf area (PLA) as well as the number of visible leaves were estimated. Our data show that ΦPSII and PLA were decreased and NPQ was increased, while Fv/Fm and number of visible leaves were unaffected, in most accessions grown under fluctuating compared to uniform light. There were large changes between accessions for most of these parameters, which, however, were not correlated with genomic variation. Fast growing accessions under uniform light showed the largest growth reductions under fluctuating light, which correlated strongly with a reduction in ΦPSII, suggesting that, under fluctuating light, photosynthesis controls growth and not vice versa.

scholarly journals The role of coccoliths in protecting <i>Emiliania huxleyi</i> against stressful light and UV radiation

2016 ◽  
Vol 13 (16) ◽  
pp. 4637-4643 ◽  
Author(s):  
Juntian Xu ◽  
Lennart T. Bach ◽  
Kai G. Schulz ◽  
Wenyan Zhao ◽  
Kunshan Gao ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Uv Radiation ◽  
Growth Rates ◽  
Emiliania Huxleyi ◽  
Photochemical Quenching ◽  
Visible Radiation ◽  
Light Levels ◽  
Relative Electron ◽  
Non Photochemical Quenching

Abstract. Coccolithophores are a group of phytoplankton species which cover themselves with small scales (coccoliths) made of calcium carbonate (CaCO3). The reason why coccolithophores form these calcite platelets has been a matter of debate for decades but has remained elusive so far. One hypothesis is that they play a role in light or UV protection, especially in surface dwelling species like Emiliania huxleyi, which can tolerate exceptionally high levels of solar radiation. In this study, we tested this hypothesis by culturing a calcified and a naked strain under different light conditions with and without UV radiation. The coccoliths of E. huxleyi reduced the transmission of visible radiation (400–700 nm) by 7.5 %, that of UV-A (315–400 nm) by 14.1 % and that of UV-B (280–315 nm) by 18.4 %. Growth rates of the calcified strain (PML B92/11) were about 2 times higher than those of the naked strain (CCMP 2090) under indoor constant light levels in the absence of UV radiation. When exposed to outdoor conditions (fluctuating sunlight with UV radiation), growth rates of calcified cells were almost 3.5 times higher compared to naked cells. Furthermore, the relative electron transport rate was 114 % higher and non-photochemical quenching (NPQ) was 281 % higher in the calcified compared to the naked strain, implying higher energy transfer associated with higher NPQ in the presence of calcification. When exposed to natural solar radiation including UV radiation, the maximal quantum yield of photosystem II was only slightly reduced in the calcified strain but strongly reduced in the naked strain. Our results reveal an important role of coccoliths in mitigating light and UV stress in E. huxleyi.

scholarly journals Effects of Different Shading Rates on the Photosynthesis and Corm Weight of Konjac Plant

2019 ◽  
Vol 47 (3) ◽  
Author(s):  
Yaoguo QIN ◽  
Zesheng YAN ◽  
Honghui GU ◽  
Zhengxiang WANG ◽  
Xiong JIANG ◽  
...  
Keyword(s):  
Photosynthetic Efficiency ◽  
Daily Variation ◽  
Photochemical Efficiency ◽  
High Yield ◽  
Photochemical Quenching ◽  
Digital Object Identifier ◽  
Chlorophyll Fluorescence Parameters ◽  
Relative Electron ◽  
Comprehensive Comparison ◽  
Non Photochemical Quenching

To study the effects of shading level on the photosynthesis and corm weight of konjac plant, the chlorophyll fluorescence parameters, daily variation of relative electron transport rate (rETR), net photosynthetic rate (Pn), and corm weight of konjac plants under different treatments were measured and comparatively analyzed through covered cultivation of biennial seed corms with shade nets at different shading rates (0%, 50%, 70%, and 90%). The results showed that with the increase in shading rate, the maximum photochemical efficiency, potential activity, and non-photochemical quenching of photosystem Ⅱ (PSⅡ) of konjac leaves constantly increased, whereas the actual photosynthetic efficiency, rETR, and photochemical quenching of PSⅡ initially increased and then decreased. This result indicated that moderate shading could enhance the photosynthetic efficiency of konjac leaves. The daily variation of rETR in konjac plants under unshaded treatment showed a bimodal curve, whereas that under shaded treatment displayed a unimodal curve. The rETR of plants with 50% treatment and 70% treatment was gradually higher than that under unshaded treatment around noon. The moderate shading could increase the Pn of konjac leaves. The stomatal conductance and transpiration rate of the leaves under shaded treatment were significantly higher than those of the leaves under unshaded treatment. Shading could promote the growth of plants and increase corm weight. The comprehensive comparison shows that the konjac plants had strong photosynthetic capacity and high yield when the shading rate was 50%-70% for the area.   ********* In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 3, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue. *********

Responses of Rainforest Understorey Plants to Excess Light during Sunflecks

1997 ◽  
Vol 24 (1) ◽  
pp. 17 ◽  
Author(s):  
Jenny R. Watling ◽  
Sharon A. Robinson ◽  
Ian E. Woodrow ◽  
C. Barry Osmond
Keyword(s):  
Tropical Rainforest ◽  
Photon Flux ◽  
Photochemical Quenching ◽  
Photon Flux Density ◽  
Leaf Angle ◽  
Low Light ◽  
Fourth Species ◽  
Excess Light ◽  
Understorey Plants ◽  
Non Photochemical Quenching

Responses of Alocasia macrorrhiza (L.) G. Don, Castanospora alphandii (F. Muell.) F. Muell. and Alpinia hylandii R. Smith, growing in a tropical rainforest understorey, to excess light during sunflecks were investigated using chlorophyll fluorescence techniques and by analysing xanthophyll cycle activity. A fourth species, the pioneerOmalanthus novo-guineensis (Warb.) Schum., growing in a small gap, was also studied. In all three understorey species there were large and rapid decreases in the proportion of open Photosystem II (PSII) centres, as indicated by qP, on illumination with saturating light and a concurrent increase in non-photochemical quenching. qP remained low (< 0.4) throughout the period of illumination (~15 min), although it did increase gradually, probably reflecting photosynthetic induction. Sustained declines (up to 120 min) in quantum yield, indicated by Fv/Fm, occurred in all three understorey species following exposure to saturating Photon flux density (PFD) during sunflecks. When ?PSII was monitored during sunflecks it was found to be very sensitive to changes in PFD, declining rapidly with even modest rises in the latter. There was rapid and continuing net conversion of violaxanthin (V) to antheraxanthin plus zeaxanthin (A+Z) on exposure of A. macrorrhiza and C. alphandii to saturating sunflecks. On returning to low light A. macrorrhiza retained its high levels of A+Z for up to 60 min, while C. alphandii rapidly converted back to V. O. novo- guineensis responded to high light by changing its leaf angle to reduce interception and showed no indication of photoinhibition during or after exposure.

scholarly journals Photoprotective energy dissipation is greater in the lower, not the upper, regions of a rice canopy: a 3D analysis

2020 ◽  
Vol 71 (22) ◽  
pp. 7382-7392 ◽  
Author(s):  
Chuan Ching Foo ◽  
Alexandra J Burgess ◽  
Renata Retkute ◽  
Pracha Tree-Intong ◽  
Alexander V Ruban ◽  
...  
Keyword(s):  
Three Dimensional ◽  
High Light ◽  
Photochemical Quenching ◽  
3D Analysis ◽  
Low Light ◽  
Gene Encoding ◽  
Light Intensities ◽  
Dimensional Reconstruction ◽  
Non Photochemical Quenching

Abstract High light intensities raise photosynthetic and plant growth rates but can cause damage to the photosynthetic machinery. The likelihood and severity of deleterious effects are minimised by a set of photoprotective mechanisms, one key process being the controlled dissipation of energy from chlorophyll within PSII known as non-photochemical quenching (NPQ). Although ubiquitous, the role of NPQ in plant productivity is important because it momentarily reduces the quantum efficiency of photosynthesis. Rice plants overexpressing and deficient in the gene encoding a central regulator of NPQ, the protein PsbS, were used to assess the effect of protective effectiveness of NPQ (pNPQ) at the canopy scale. Using a combination of three-dimensional reconstruction, modelling, chlorophyll fluorescence, and gas exchange, the influence of altered NPQ capacity on the distribution of pNPQ was explored. A higher phototolerance in the lower layers of a canopy was found, regardless of genotype, suggesting a mechanism for increased protection for leaves that experience relatively low light intensities interspersed with brief periods of high light. Relative to wild-type plants, psbS overexpressors have a reduced risk of photoinactivation and early growth advantage, demonstrating that manipulating photoprotective mechanisms can impact both subcellular mechanisms and whole-canopy function.

scholarly journals Variation in relaxation of non-photochemical quenching in a soybean nested association mapping panel as a potential source for breeding improved photosynthesis

2020 ◽  
Author(s):  
Steven J. Burgess ◽  
Elsa de Becker ◽  
Stephanie Cullum ◽  
Isla Causon ◽  
Iulia Floristeanu ◽  
...  
Keyword(s):  
Field Experiments ◽  
Genetic Manipulation ◽  
Photochemical Quenching ◽  
Low Light ◽  
Breeding Programs ◽  
Nested Association Mapping ◽  
Mapping Panel ◽  
Non Photochemical Quenching ◽  
Energy Dependent ◽  
Transgenic Manipulation

AbstractImproving the efficiency of crop photosynthesis has the potential to increase yields. Genetic manipulation showed photosynthesis can be improved in Tobacco by speeding up relaxation of photoprotective mechanisms, known as non-photochemical quenching (NPQ), during high to low light transitions. However, it is unclear if natural variation in NPQ relaxation can be exploited in crop breeding programs. To address this issue, we measured NPQ relaxation in the 41 parents of a soybean NAM population in field experiments in Illinois during 2018 and 2019. There was significant variation in amount and rate of fast, energy dependent quenching (qE) between genotypes. However, strong environmental effects led to a lack of correlation between values measured over the two growing season, and low broad-sense heritability estimates (< 0.3). These data suggest that either improvements in screening techniques, or transgenic manipulation, will be required to unlock the potential for improving the efficiency of NPQ relaxation in soybean.Table of Abbreviations

Photosynthesis, light energy partitioning, and photoprotection in the shade-demanding species Panax notoginseng under high and low level of growth irradiance

2016 ◽  
Vol 43 (6) ◽  
pp. 479 ◽  
Author(s):  
Jun-Wen Chen ◽  
Shuang-Bian Kuang ◽  
Guang-Qiang Long ◽  
Sheng-Chao Yang ◽  
Zhen-Gui Meng ◽  
...  
Keyword(s):  
Panax Notoginseng ◽  
High Light ◽  
Light Energy ◽  
Quantum Yields ◽  
Photochemical Quenching ◽  
Light Illumination ◽  
Low Light ◽  
Psii Photochemistry ◽  
Growth Irradiance ◽  
Non Photochemical Quenching

Partitioning of light energy into several pathways and its relation to photosynthesis were examined in a shade-demanding species Panax notoginseng (Burkill) F.H.Chen ex C.Y.Wu & K.M.Feng grown along a light gradient. In fully light-induced leaves, the actual efficiency of PSII photochemistry (ΔF/Fmʹ), electron transport rate (ETR), non-photochemical quenching (NPQ) and photochemical quenching (qP) were lower in low-light-grown plants; this was also the case in fully dark-adapted leaves under a simulated sunfleck. In response to varied light intensity, high-light-grown plants showed greater quantum yields of light-dependent non-photochemical quenching (ΦNPQ) and PSII photochemistry (ΦPSII) and smaller quantum yields of fluorescence and constitutive thermal dissipation (Φf,d). Under the simulated sunfleck, high-light-grown plants showed greater ΦPSII and smaller Φf,d. There were positive relationships between net photosynthesis (Anet) and ΦNPQ+f,d and negative relationships between Anet and ΦPSII in fully light-induced leaves; negative correlations of Anet with ΦNPQ+f,d and positive correlations of Anet with ΦPSII were observed in fully dark-adapted leaves. In addition, more nitrogen was partitioned to light-harvesting components in low-light-grown plants, whereas leaf morphology and anatomy facilitate reducing light capture in high-light-grown plants. The pool of xanthophyll pigments and the de-epoxidation state was greater in high-light-grown plants. Antioxidant defence was elevated by increased growth irradiance. Overall, the evidences from P. notoginseng suggest that in high-light-grown shade-demanding plants irradiated by high light more electrons were consumed by non-net carboxylative processes that activate the component of NPQ, that low-light-grown plants correspondingly protect the photosynthetic apparatus against photodamage by reducing the efficiency of PSII photochemistry under high light illumination, and that during the photosynthetic induction, the ΔpH-dependent (qE) component of NPQ might dominate photoprotection, but the NPQ also depresses the enhancement of photosynthesis via competition for light energy.

scholarly journals PsaK2 Subunit in Photosystem I Is Involved in State Transition under High Light Condition in the Cyanobacterium Synechocystis sp. PCC 6803

2005 ◽  
Vol 280 (23) ◽  
pp. 22191-22197 ◽  
Author(s):  
Tamaki Fujimori ◽  
Yukako Hihara ◽  
Kintake Sonoike
Keyword(s):  
Energy Transfer ◽  
Photosystem I ◽  
State Transition ◽  
Light Condition ◽  
High Light ◽  
Photochemical Quenching ◽  
Wild Type ◽  
Low Light ◽  
High Light Condition ◽  
Non Photochemical Quenching

To avoid the photodamage, cyanobacteria regulate the distribution of light energy absorbed by phycobilisome antenna either to photosystem II or to photosystem I (PSI) upon high light acclimation by the process so-called state transition. We found that an alternative PSI subunit, PsaK2 (sll0629 gene product), is involved in this process in the cyanobacterium Synechocystis sp. PCC 6803. An examination of the subunit composition of the purified PSI reaction center complexes revealed that PsaK2 subunit was absent in the PSI complexes under low light condition, but was incorporated into the complexes during acclimation to high light. The growth of the psaK2 mutant on solid medium was inhibited under high light condition. We determined the photosynthetic characteristics of the wild type strain and the two mutants, the psaK1 (ssr0390) mutant and the psaK2 mutant, using pulse amplitude modulation fluorometer. Non-photochemical quenching, which reflects the energy transfer from phycobilisome to PSI in cyanobacteria, was higher in high light grown cells than in low light grown cells, both in the wild type and the psaK1 mutant. However, this change of non-photochemical quenching during acclimation to high light was not observed in the psaK2 mutant. Thus, PsaK2 subunit is involved in the energy transfer from phycobilisome to PSI under high light condition. The role of PsaK2 in state transition under high light condition was also confirmed by chlorophyll fluorescence emission spectra determined at 77 K. The results suggest that PsaK2-dependent state transition is essential for the growth of this cyanobacterium under high light condition.

scholarly journals Photosynthetic Parameters Show Specific Responses to Essential Mineral Deficiencies

Antioxidants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 996
Author(s):  
Miho Ohnishi ◽  
Riu Furutani ◽  
Takayuki Sohtome ◽  
Takeshi Suzuki ◽  
Shinya Wada ◽  
...  
Keyword(s):  
Electron Flux ◽  
Assimilation Efficiency ◽  
Primary Electron ◽  
Oxidation States ◽  
Photochemical Quenching ◽  
Photosynthetic Parameters ◽  
Mineral Deficiency ◽  
Primary Electron Acceptor ◽  
Relative Electron ◽  
Non Photochemical Quenching

In response to decreases in the assimilation efficiency of CO2, plants oxidize the reaction center chlorophyll (P700) of photosystem I (PSI) to suppress reactive oxygen species (ROS) production. In hydro-cultured sunflower leaves experiencing essential mineral deficiencies, we analyzed the following parameters that characterize PSI and PSII: (1) the reduction-oxidation states of P700 [Y(I), Y(NA), and Y(ND)]; (2) the relative electron flux in PSII [Y(II)]; (3) the reduction state of the primary electron acceptor in PSII, QA (1 − qL); and (4) the non-photochemical quenching of chlorophyll fluorescence (NPQ). Deficiency treatments for the minerals N, P, Mn, Mg, S, and Zn decreased Y(II) with an increase in the oxidized P700 [Y(ND)], while deficiencies for the minerals K, Fe, Ca, B, and Mo decreased Y(II) without an increase in Y(ND). During the induction of photosynthesis, the above parameters showed specific responses to each mineral. That is, we could diagnose the mineral deficiency and identify which mineral affected the photosynthesis parameters.

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