Leaf gas exchange, chlorophyll fluorescence and pigment indexes of Eugenia uniflora L. in response to changes in light intensity and soil flooding

Ultraviolet B (UV-B) (280–315 nm) and ultraviolet A (UV-A) (315–400 nm) radiation comprise small portions of the solar radiation but regulate many aspects of plant development, physiology and metabolism. Until now, how plants respond to UV-B in the presence of different light qualities is poorly understood. This study aimed to assess the effects of a low UV-B dose (0.912 ± 0.074 kJ m–2 day–1, at a 6 h daily UV exposure) in combination with four light treatments (blue, green, red and broadband white at 210 μmol m–2 s–1 Photosynthetically active radiation [PAR]) on morphological and physiological responses of cucumber (Cucumis sativus cv. “Lausanna RZ F1”). We explored the effects of light quality backgrounds on plant morphology, leaf gas exchange, chlorophyll fluorescence, epidermal pigment accumulation, and on acclimation ability to saturating light intensity. Our results showed that supplementary UV-B significantly decreased biomass accumulation in the presence of broad band white, blue and green light, but not under red light. UV-B also reduced the photosynthetic efficiency of CO2 fixation (α) when combined with blue light. These plants, despite showing high accumulation of anthocyanins, were unable to cope with saturating light conditions. No significant effects of UV-B in combination with green light were observed for gas exchange and chlorophyll fluorescence parameters, but supplementary UV-B significantly increased chlorophyll and flavonol contents in the leaf epidermis. Plants grown under red light and UV-B significantly increased maximum photosynthetic rate and dark respiration compared to pure red light. Additionally, red and UV-B treated plants exposed to saturating light intensity showed higher quantum yield of photosystem II (PSII), fraction of open PSII centres and electron transport rate and showed no effect on the apparent maximum quantum efficiency of PSII photochemistry (Fv/Fm) or non-photochemical quenching, in contrast to solely red-light conditions. These findings provide new insights into how plants respond to UV-B radiation in the presence of different light spectra.

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Leaf gas exchange, chlorophyll fluorescence and growth responses of Genipa americana seedlings to soil flooding

Environmental and Experimental Botany ◽

10.1016/s0098-8472(03)00036-4 ◽

2003 ◽

Vol 50 (3) ◽

pp. 221-231 ◽

Cited By ~ 121

Author(s):

Marcelo S. Mielke ◽

Alex-Alan F. de Almeida ◽

Fábio P. Gomes ◽

Marco Antonio G. Aguilar ◽

Pedro Antonio O. Mangabeira

Keyword(s):

Chlorophyll Fluorescence ◽

Gas Exchange ◽

Leaf Gas Exchange ◽

Growth Responses ◽

Soil Flooding

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Leaf gas exchange, chlorophyll fluorescence, non-structural carbohydrate content and growth responses of Distylium chinense during complete submergence and subaerial re-emergence

Aquatic Botany ◽

10.1016/j.aquabot.2015.04.003 ◽

2015 ◽

Vol 124 ◽

pp. 70-77 ◽

Cited By ~ 13

Author(s):

Zebin Liu ◽

Ruimei Cheng ◽

Wenfa Xiao ◽

Quanshui Guo ◽

Yanhui Wang ◽

...

Keyword(s):

Chlorophyll Fluorescence ◽

Gas Exchange ◽

Leaf Gas Exchange ◽

Carbohydrate Content ◽

Growth Responses ◽

Structural Carbohydrate

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Variations in leaf gas exchange, chlorophyll fluorescence and membrane potential of Medicago sativa root cortex cells exposed to increased salinity: The role of the antioxidant potential in salt tolerance

Archives of Biological Sciences ◽

10.2298/abs171019001f ◽

2018 ◽

Vol 70 (3) ◽

pp. 413-423 ◽

Cited By ~ 2

Author(s):

Mohamed Farissi ◽

Mohammed Mouradi ◽

Omar Farssi ◽

Abdelaziz Bouizgaren ◽

Cherki Ghoulam

Keyword(s):

Antioxidant Enzymes ◽

Salt Stress ◽

Chlorophyll Fluorescence ◽

Membrane Potential ◽

Salt Tolerance ◽

Gas Exchange ◽

Medicago Sativa ◽

Leaf Gas Exchange ◽

Root Cortex ◽

Root Cortex Cells

Salinity is one of the most serious agricultural problems that adversely affects growth and productivity of pasture crops such as alfalfa. In this study, the effects of salinity on some ecophysiological and biochemical criteria associated with salt tolerance were assessed in two Moroccan alfalfa (Medicago sativa L.) populations, Taf 1 and Tata. The experiment was conducted in a hydro-aeroponic system containing nutrient solutions, with the addition of NaCl at concentrations of 100 and 200 mM. The salt stress was applied for a month. Several traits in relation to salt tolerance, such as plant dry biomass, relative water content, leaf gas exchange, chlorophyll fluorescence, nutrient uptake, lipid peroxidation and antioxidant enzymes, were analyzed at the end of the experiment. The membrane potential was measured in root cortex cells of plants grown with or without NaCl treatment during a week. The results indicated that under salt stress, plant growth and all of the studied physiological and biochemical traits were significantly decreased, except for malondialdehyde and H2O2 contents, which were found to be increased under salt stress. Depolarization of membrane root cortex cells with the increase in external NaCl concentration was noted, irrespective of the growth conditions. The Tata population was more tolerant to high salinity (200 mM NaCl) and its tolerance was associated with the ability of plants to maintain adequate levels of the studied parameters and their ability to overcome oxidative stress by the induction of antioxidant enzymes, such as guaiacol peroxidase, catalase and superoxide dismutase.

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Changes in Leaf Structural and Functional Characteristics when Changing Planting Density at Different Growth Stages Alters Cotton Lint Yield under a New Planting Model

Agronomy ◽

10.3390/agronomy9120859 ◽

2019 ◽

Vol 9 (12) ◽

pp. 859 ◽

Cited By ~ 2

Author(s):

Aziz Khan ◽

Jie Zheng ◽

Daniel Kean Yuen Tan ◽

Ahmad Khan ◽

Kashif Akhtar ◽

...

Keyword(s):

Chlorophyll Fluorescence ◽

Quantum Yield ◽

Gas Exchange ◽

Stomatal Density ◽

Leaf Gas Exchange ◽

High Density ◽

Lint Yield ◽

Planting Density ◽

Cotton Lint ◽

Cotton Lint Yield

Manipulation of planting density and choice of variety are effective management components in any cropping system that aims to enhance the balance between environmental resource availability and crop requirements. One-time fertilization at first flower with a medium plant stand under late sowing has not yet been attempted. To fill this knowledge gap, changes in leaf structural (stomatal density, stomatal length, stomata width, stomatal pore perimeter, and leaf thickness), leaf gas exchange, and chlorophyll fluorescence attributes of different cotton varieties were made in order to change the planting densities to improve lint yield under a new planting model. A two-year field evaluation was carried out on cotton varieties—V1 (Zhongmian-16) and V2 (J-4B)—to examine the effect of changing the planting density (D1, low, 3 × 104; D2, moderate, 6 × 104; and D3, dense, 9 × 104) on cotton lint yield, leaf structure, chlorophyll fluorescence, and leaf gas exchange attribute responses. Across these varieties, J-4B had higher lint yield compared with Zhongmian-16 in both years. Plants at high density had depressed leaf structural traits, net photosynthetic rate, stomatal conductance, intercellular CO2 uptake, quenching (qP), actual quantum yield of photosystem II (ΦPSII), and maximum quantum yield of PSII (Fv/Fm) in both years. Crops at moderate density had improved leaf gas exchange traits, stomatal density, number of stomata, pore perimeter, length, and width, as well as increased qP, ΦPSII, and Fv/Fm compared with low- and high-density plants. Improvement in leaf structural and functional traits contributed to 15.9%–10.7% and 12.3%–10.5% more boll m−2, with 20.6%–13.4% and 28.9%–24.1% higher lint yield averaged across both years, respectively, under moderate planting density compared with low and high density. In conclusion, the data underscore the importance of proper agronomic methods for cotton production, and that J-4B and Zhongmian-16 varieties, grown under moderate and lower densities, could be a promising option based on improved lint yield in subtropical regions.

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