Effects of growth irradiance on photosynthesis and photorespiration of Phoebe bournei leaves

2020 ◽  
Vol 47 (12) ◽  
pp. 1053
Author(s):  
Xinglin Tang ◽  
Guangzheng Liu ◽  
Jiang Jiang ◽  
Changju Lei ◽  
Yunxing Zhang ◽  
...  
Keyword(s):  
Co2 Concentration ◽  
Growth And Survival ◽  
Light Reduction ◽  
Co2 Diffusion ◽  
Growth Irradiance ◽  
Leaf Photosynthetic Rate ◽  
Shade Leaves ◽  
Co2 Release ◽  
Phoebe Bournei ◽  
Effect Of Light

Light intensity is a major environmental factor affecting the growth and survival of trees in a forest. The effect of light reduction on photosynthesis and photorespiration of an evergreen broad-leaved tree, Phoebe bournei (Hemsley) Yang was examined with three levels of full light, 50.5% light, and 21.8% light. The results showed that shading led to significant increase in plant height and crown diameter. Light-saturated leaf photosynthetic rate (Amax), maximal carboxylation activity (Vcmax), maximum electron transfer rate (Jmax), stomatal conductance (gs), mesophyll conductance (gm) and chloroplast CO2 concentration (Cc) significantly increased in response to shade. Photorespiratory CO2 release rate (PR) was higher in plants grown under shade conditions than under full light. The relative limitations of gm (lm) was higher than the relative limitations of gs (ls) and the relative limitations of biochemical factors (lb) in leaves of P. bournei grown under full light, whereas lm was lower than ls and lb under shade. Our results suggest that increase of photosynthesis in P. bournei leaves grown under shade is associated with enhanced CO2 diffusion and biochemistry. And we propose that enhancement of the photorespiratory is essential for shade leaves to improve photosynthesis.

Ammonium application mitigates the effects of elevated carbon dioxide on the carbon/nitrogen balance of Phoebe bournei seedlings

2021 ◽  
Author(s):  
Xiao Wang ◽  
Xiaoli Wei ◽  
Gaoyin Wu ◽  
Shengqun Chen
Keyword(s):  
Carbon Dioxide ◽  
Enzyme Activities ◽  
Atmospheric Carbon Dioxide ◽  
Global Climate ◽  
Co2 Concentration ◽  
Rubisco Activase ◽  
Plant Responses ◽  
N Metabolism ◽  
C And N ◽  
Phoebe Bournei

Abstract The study of plant responses to increases in atmospheric carbon dioxide (CO2) concentration is crucial to understand and to predict the effect of future global climate change on plant adaptation and evolution. Increasing amount of nitrogen (N) can promote the positive effect of CO2, while how N forms would modify the degree of CO2 effect is rarely studied. The aim of this study was to determine whether the amount and form of nitrogen (N) could mitigate the effects of elevated CO2 (eCO2) on enzyme activities related to carbon (C) and N metabolism, the C/N ratio, and growth of Phoebe bournei (Hemsl.) Y.C. Yang. One-year-old P. bournei seedlings were grown in an open-top air chamber under either an ambient CO2 (aCO2) (350 ± 70 μmol•mol−1) or an eCO2 (700 ± 10 μmol•mol−1) concentration and cultivated in soil treated with either moderate (0.8 g per seedling) or high applications (1.2 g per seedling) of nitrate or ammonium. In seedlings treated with a moderate level of nitrate, the activities of key enzymes involved in C and N metabolism (i.e., Rubisco, Rubisco activase and glutamine synthetase) were lower under eCO2 than under aCO2. By contrast, key enzyme activities (except GS) in seedlings treated with high nitrate or ammonium were not significantly different between aCO2 and eCO2 or higher under eCO2 than under aCO2. The C/N ratio of seedlings treated with moderate or high nitrate under eCO2was significantly changed compared with the seedlings grown under aCO2, whereas the C/N ratio of seedlings treated with ammonium was not significantly different between aCO2 and eCO2. Therefore, under eCO2, application of ammonium can be beneficial C and N metabolism and mitigate effects on the C/N ratio.

scholarly journals Effects of different treatments of pH on growth and photosynthesis of Phoebe bournei seedlings

2021 ◽  
Vol 8 (4) ◽  
pp. 11-21
Author(s):  
BAO Haiyue ◽  
ZHOU Mingqin ◽  
WU Yuemiao ◽  
FEI Yongjun
Keyword(s):  
Ph Value ◽  
Intercellular Co2 Concentration ◽  
Acid Stress ◽  
Co2 Concentration ◽  
Alkaline Stress ◽  
Sod Activity ◽  
Alkaline Environment ◽  
Acid Environment ◽  
Physiological Indexes ◽  
Phoebe Bournei

To provide theoretical basis for the cultivation and landscape application of Phoebe bournei seedlings, the photosynthetic and physiological characteristics of the seedlings were determined in the experience. In this study, the growth, photosynthesis and physiological indexes of P. bournei seedlings under different pH conditions were tested every 15 days for a total of 45 days by using 2-year-old seedlings with different solutions with ph of 4.0, 5.0, 6.0, 7.0, 8.0, 8.5 and 9.0 as 7 different irrigation treatments. The results showed that the growth of P. bournei seedlings grew significantly in acid environment and inhibited in alkaline environment, and the growth rate of plant height in acid environment is significantly higher than natural condition of ph7.0. The chlorophyll and carotenoid contents increase with the increase of acid, and decrease in alkaline environment above ph8.0, which indicate that P. bournei seedlings has better adaptability to acid environment than alkaline environment. The net photosynthetic rate (Pn) and transpiration rate (Tr) of P. bournei seedlings reach the highest level at pH6.0, and the stomatal conductance (Gs) and intercellular CO2 concentration (Ci) reach the highest level at pH 4.0. However, these indicators are low in alkaline environment above pH 8.0. Under acid stress, all physiological indexes of P. bournei are increased; under alkaline stress, the superoxide dismutase (SOD) activity and the soluble protein (SP) content show a trend of increasing, and the peroxidase (POD) activity, MDA content and proline (Pro) show a trend of decreasing later under the treatment of pH 8.5 ~ 9.0. According to all the above, P. bournei seedlings has good tolerance to acid environment, and the suitable pH value of solution for P. bournei seedlings growth is pH 5.0-8.0.

scholarly journals Larval growth and survival in Indian Butter Catfish, Ompok bimaculatus (Bloch): effect of light intensity and photoperiod

2019 ◽  
Author(s):  
Kalpana Arambam ◽  
Pradyut Biswas ◽  
Soibam Khogen Singh ◽  
A. B. Patel ◽  
Alok Kumar Jena ◽  
...  
Keyword(s):  
Light Intensity ◽  
Larval Growth ◽  
Maximum Growth ◽  
Continuous Darkness ◽  
Growth And Survival ◽  
Light Intensities ◽  
Randomized Design ◽  
Significant Difference ◽  
Ompok Bimaculatus ◽  
Effect Of Light

AbstractTwo sequential indoor rearing trials each of 21 days duration were conducted to investigate the effect of light intensity and photoperiod respectively on the growth and survival of Ompok bimaculatus larvae. In first trial, five different light intensities viz. 0, 300, 500, 900, 1200 lx were applied randomly to 800 larvae (0.003 g; 0.51 cm) stocked in triplicate following a completely randomized design into aquarium (30.0 x 15.0 x 15.0 cm) tanks. Sequentially, in second trial, five photoperiod cycles (light: dark, L: D) namely, 24L: 0D, 16L: 8D, 12L: 12D, 8L: 16D and 0L: 24D in combination with the best performing light intensity (300 lx) as observed from the first trial were employed in triplicates in similar set up. From the first trial, significantly higher survival was observed in 0 and 300 lx, whereas growth was highest in 900 lx (P < 0.05). In the second trial, survival was higher in continuous darkness (0L: 24D), whereas, maximum growth was recorded in 24L: 0D and 16L: 8D groups (P < 0.05). Performance index (PI) showed no significant difference (P > 0.05) among 0 and 300 lx light intensities, but were reduced at higher light intensities. The lowest PI was found in 12L: 12D and 8L: 16D condition but did not have any effect in other photoperiod cycles. Overall, from the present study it can be concluded that growth of the larvae is found to be higher in higher light intensity (900lx) and longer photoperiodic cycles (24L: 0D and 16L: 8D), however, better survival was recorded in total dark conditions suggesting that continuous dark condition is recommended for better hatchery performance of the larvae.

scholarly journals Nutrition by Design: Boosting Selenium Content and Fresh Matter Yields of Salad Greens With Preharvest Light Intensity and Selenium Applications

2022 ◽  
Vol 8 ◽  
Author(s):  
Xudong Zhu ◽  
Tianbao Yang ◽  
Charles A. Sanchez ◽  
Jeffrey M. Hamilton ◽  
Jorge M. Fonseca
Keyword(s):  
Light Intensity ◽  
Food Composition ◽  
Fresh Matter ◽  
Light Reduction ◽  
Growing Medium ◽  
The Usa ◽  
Basin Region ◽  
Salad Greens ◽  
Se Uptake ◽  
Effect Of Light

Selenium (Se) is an essential mineral in multiple human metabolic pathways with immune modulatory effects on viral diseases including the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and HIV. Plant-based foods contain Se metabolites with unique functionalities for the human metabolism. In order to assess the value of common salad greens as Se source, we conducted a survey of lettuce commercially grown in 15 locations across the USA and Canada and found a tendency for Se to accumulate higher (up to 10 times) in lettuce grown along the Colorado river basin region, where the highest amount of annual solar radiation of the country is recorded. In the same area, we evaluated the effect of sunlight reduction on the Se content of two species of arugula [Eruca sativa (E. sativa) cv. “Astro” and Diplotaxis tenuifolia (D. tenuifolia) cv. “Sylvetta”]. A 90% light reduction during the 7 days before harvest resulted in over one-third Se decline in D. tenuifolia. The effect of light intensity on yield and Se uptake of arugula microgreens was also examined under indoor controlled conditions. This included high intensity (HI) (160 μ mol−2 s−1 for 12 h/12 h light/dark); low intensity (LI) (70 μ mol m−2 s−1 for 12 h/12 h light/dark); and HI-UVA (12 h light of 160 μ mol m−2 s−1, 2 h UVA of 40 μ mol m−2 s−1, and 10 h dark) treatments in a factorial design with 0, 1, 5, and 10 ppm Se in the growing medium. HI and HI-UVA produced D. tenuifolia plants with 25–100% higher Se content than LI, particularly with the two higher Se doses. The addition of Se produced a marked increase in fresh matter (&gt;35% in E. sativa and &gt;45% in D. tenuifolia). This study (i) identifies evidence to suggest the revision of food composition databases to account for large Se variability, (ii) demonstrates the potential of introducing preharvest Se to optimize microgreen yields, and (iii) provides the controlled environment industry with key information to deliver salad greens with targeted Se contents.

scholarly journals The Light Dependence of Mesophyll Conductance and Relative Limitations on Photosynthesis in Evergreen Sclerophyllous Rhododendron Species

Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1536
Author(s):  
Ying-Jie Yang ◽  
Hong Hu ◽  
Wei Huang
Keyword(s):  
Light Intensity ◽  
Negative Relationship ◽  
Light Response ◽  
Co2 Concentration ◽  
Limiting Factor ◽  
Mesophyll Conductance ◽  
Co2 Diffusion ◽  
Rate Limiting Step ◽  
Internal Cavities ◽  
Rate Limiting

Mesophyll conductance (gm) limits CO2 diffusion from sub-stomatal internal cavities to the sites of RuBP carboxylation. However, the response of gm to light intensity remains controversial. Furthermore, little is known about the light response of relative mesophyll conductance limitation (lm) and its effect on photosynthesis. In this study, we measured chlorophyll fluorescence and gas exchange in nine evergreen sclerophyllous Rhododendron species. gm was maintained stable across light intensities from 300 to 1500 μmol photons m−2 s−1 in all these species, indicating that gm did not respond to the change in illumination in them. With an increase in light intensity, lm gradually increased, making gm the major limiting factor for area-based photosynthesis (AN) under saturating light. A strong negative relationship between lm and AN was found at 300 μmol photons m−2 s−1 but disappeared at 1500 μmol photons m−2 s−1, suggesting an important role for lm in determining AN at sub-saturating light. Furthermore, the light-dependent increase in lm led to a decrease in chloroplast CO2 concentration (Cc), inducing the gradual increase of photorespiration. A higher lm under saturating light made AN more limited by RuBP carboxylation. These results indicate that the light response of lm plays significant roles in determining Cc, photorespiration, and the rate-limiting step of AN.

scholarly journals Effect of Light on the Photosynthesis, Pigment Content and Stomatal Density of Sun and Shade Leaves of Vernonia Amygdalina

2018 ◽  
Vol 7 (4.30) ◽  
pp. 209 ◽  
Author(s):  
Aisha Idris ◽  
Alona C. Linatoc ◽  
Aisha M. Aliyu ◽  
Surayya M. Muhammad ◽  
Mohd Fadzelly Bin Abu Bakar
Keyword(s):  
Gas Exchange ◽  
Light Intensity ◽  
Stomatal Density ◽  
Photosynthetic Pigment ◽  
Vernonia Amygdalina ◽  
Sun And Shade Leaves ◽  
Sun And Shade ◽  
Shade Leaves ◽  
Sun Leaves ◽  
Effect Of Light

Light affects the growth and development of plants by influencing the physical appearance of one leaf as well as the appearance of the whole plant. Plant photosynthesis, stomata density, and pigment contents are all influenced by light The objective of this research is to determine the effect of light on the photosynthesis, pigment content and stomatal density of Sun and Shade Leaves of Vernonia amygdalina. Gas exchange was measured using Li-6400 and the data obtained was used to create a light response curve where parameters including light saturation point (LSP), light compensation point (LCP) and apparent quantum yield were estimated. Photosynthetic pigment were quantified spectrophotometrically.  Moreover, the stomatal density was counted under light microscope, after making a nail polish impression of the leaf. The results discovered shows that as the light intensity increases, the gas exchange and stomatal density increases while the photosynthetic pigment of the studied plant decreases (P<0.05). In addition, LSP and LCP increases with increasing light intensity. Besides, statistically significant negative correlation (P<0.05) was achieved among stomatal density and transpiration rate thereby leading to a conclusion that sun leaves of Vernonia amygdalina contribute the highest assimilation rate to the plant than shade leaves. Yet, the higher stomatal density of sun leaves provides water saving to the plant.

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