Effects of substrate acidity and UV-B radiation on photosynthesis of radishes

2011 ◽  
Vol 6 (4) ◽  
pp. 624-631
Author(s):  
Irena Januskaitiene
Keyword(s):  
Gas Exchange ◽  
Water Use ◽  
Raphanus Sativus ◽  
Net Photosynthesis ◽  
Enzymatic Reactions ◽  
Growth Substrate ◽  
Gas Exchange Parameters ◽  
Raphanus Sativus L ◽  
Use Efficiency ◽  
Exchange Parameters

AbstractThe aim of this study was to assess the combined effect of substrate acidity (pH 4.8; pH 3.8) and 1 kJm−2d−1 UV-B radiation on photosynthesis and growth of radishes (Raphanus sativus L.). Radishes were sown in a neutral pH 6.5 peat substrate. When the second true leaf unfolded, the growth substrate was acidified using different concentration of H2SO4 and exposed to UV-B radiation for a period of ten days. Gas exchange parameters were measured with the LI-6400 portable photosynthesis system. Content of chlorophyll was evaluated spectrophotometrically. The results showed that the greatest inhibition of net photosynthesis was observed when radishes were grown in an acidified pH 3.8 substrate. The decrease of the photosynthesis of radish plants treated with both investigated factors (substrate acidity and UV-B) were lower compared to the effect of substrate acidity alone. UV-B radiation stimulated both enzymatic reactions of photosynthesis and water use efficiency of radish plants grown in acidified peat substrates. Also, investigated factors had higher impact on biomass of tuber than biomass of foliage.

scholarly journals Gas exchange and photosynthetic pigments in bell pepper irrigated with saline water

2017 ◽  
Vol 21 (1) ◽  
pp. 38-43 ◽  
Author(s):  
Hidelblandi F. de Melo ◽  
Edivan R. de Souza ◽  
Heitor H. F. Duarte ◽  
Jailson C. Cunha ◽  
Hugo R. B. Santos
Keyword(s):  
Electrical Conductivity ◽  
Gas Exchange ◽  
Water Use Efficiency ◽  
Chlorophyll A ◽  
Water Use ◽  
Photosynthetic Pigments ◽  
Saline Water ◽  
Net Photosynthesis ◽  
Gas Exchange Parameters ◽  
Use Efficiency

ABSTRACT The tools that evaluate the salinity effects on plants have great relevance as they contribute to understanding of the mechanisms of tolerance. This study aimed to evaluate gas exchanges and the contents of photosynthetic pigments in bell peppers cultivated with saline solutions (0, 1, 3, 5, 7 and 9 dS m-1) prepared using two sources: NaCl and a mixture of Ca, Mg, K, Na and Cl salts, in randomized blocks with a 6 x 2 factorial scheme and 4 replicates, totaling 48 experimental plots. The net photosynthesis (A), stomatal conductance (gs), transpiration (E), internal CO2 concentration (Ci), instantaneous carboxylation efficiency (A/Ci) and water use efficiency (WUE), besides chlorophyll a, b and carotenoids were evaluated. The gas exchange parameters were efficient to indicate the effects of salinity. All photosynthetic pigments decreased with increased electrical conductivity, and the chlorophyll a is the most sensitive to salinity, while the water use efficiency increased with the increment of electrical conductivity.

scholarly journals Estimation of Leaf Water Use Efficiency Threshold Values for Water Stress in Winter Wheat (Triticum aestivum L.)

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Qiu Xinqiang ◽  
Zhang Yushun ◽  
Qin Haixia ◽  
Wang Min ◽  
Wang Yanping ◽  
...  
Keyword(s):  
Water Stress ◽  
Gas Exchange ◽  
Winter Wheat ◽  
Water Use ◽  
Growth Stage ◽  
Severe Drought ◽  
Threshold Values ◽  
Gas Exchange Parameters ◽  
Use Efficiency ◽  
Exchange Parameters

Drought significantly threatens crop productivity and food security worldwide. However, the severity of drought is predicted to increasingly intensify in the future. To provide an antidrought strategy for farmers and breeders, the response of stomatal behavior of crops to water stress should be well studied. In this study, a lysimeter experiment was conducted to study the relationship between gas exchange parameters and grain yields of winter wheat. Light, moderate, and severe drought levels were imposed at seedling, jointing, heading, and filling stages. The results showed that crop evapotranspiration (ETc, mm) of winter wheat during the entire growing season was limited by drought imposed at any growth stage, and ETc under severe drought treatment was always the lowest. The stomatal limitation value had a significant linear correlation with the stomatal conductance (Gs, μmol mol H2O m–2 s–1) and transpiration rate (Tr, mmol H2O m–2 s–1). Light and moderate drought levels at the seedling stage did not generate irreversible physiological stress on wheat plants, while severe drought at any growth stage caused significant reduction in gas exchange parameters and grain yields. Theoretical threshold values of leaf water use efficiency (WUEl) for light, moderate, and severe drought levels were 2.62, 3.36, and 4.11 μmol mmol–1, respectively. The threshold values are useful to provide theoretical reference for achieving smart irrigation in the North China Plain.

Effects of exogenous ABA application on stomatal regulation of gas exchange parameters and calculated water use efficiency in major pulses of Tamil Nadu, India

2014 ◽  
Vol 48 (4) ◽  
pp. 324 ◽  
Author(s):  
Dhashnamurthi Vijayalakshmi ◽  
Sanchita Kukde Vijay ◽  
Prashanthi Ramakrishnan ◽  
Sathiakumar Periyasamy ◽  
Srividhya Sundaram ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Water Use Efficiency ◽  
Water Use ◽  
Tamil Nadu ◽  
Gas Exchange Parameters ◽  
Exogenous Aba ◽  
Stomatal Regulation ◽  
Use Efficiency ◽  
Exchange Parameters

scholarly journals Gas exchange efficiency in Cocoa – Spanish elm agroforestry system in the northwest Antioquia, Colombia

2020 ◽  
Vol 73 (3) ◽  
pp. 9283-9291
Author(s):  
Juan Pablo Gómez-Yarce ◽  
Edna Rocío Mompotes-Largo ◽  
Aníbal López-Castro ◽  
Juan David Hernández-Arredondo ◽  
Oscar De Jesús Córdoba-Gaona
Keyword(s):  
Gas Exchange ◽  
Environmental Conditions ◽  
Block Design ◽  
Area Under The Curve ◽  
Agroforestry System ◽  
Agroforestry Systems ◽  
Cordia Alliodora ◽  
Gas Exchange Parameters ◽  
Use Efficiency ◽  
Exchange Parameters

The cultivation of cocoa (Theobroma cacao L.) under agroforestry systems, generates beneficial environmental conditions for cocoa crop physiology. An experiment was conducted to evaluate the effect of shade trees (Spanish elm trees - Cordia alliodora (Ruiz & Pavon) Oken) planted along with cocoa (clone CCN51) under an agroforestry system on cocoa’s gas exchange parameters regarding the reduction of the light intensity over the cocoa-leaf canopy. The experiment was developed in the Centro de Investigación el Nus - Agrosavia, located in the municipality of San Roque, Antioquia. The experimental design used was a randomized complete block design for the cocoa planting distances from the first row of Spanish elm trees interfacing with the cocoa plantation (4 m, 7 m, 10 m, 13 m). The statistical analysis was performed by estimating the area under the curve (AUC) of each variable, using the trapezoid equation of the statistical environment SAS® 9.4, an analysis of variances was performed to determine if there were statistical differences between treatments, and Tukey’s test at 5% probability was used to estimated statistical differences between means. There were significant differences in the treatments regarding the net photosynthetic rate (A), stomatal conductance (gs), and transpiration rate (E). The highest values of gas exchange parameters were found in the plants located 13 m from elm trees, while the lowest values were presented at 4 m. Plants at 7 m and 10 m always showed intermediate values for all gas exchange parameters. In the same sense, plants at 13 m had a higher radiation use efficiency (RUE) compared to plants at 4 m. The arboreal component modified the environmental conditions on cocoa trees regarding its distribution, generating a differential response to the physiological behavior of cocoa plants.

Physiological acclimation of Pinus flexilis to drought stress on contrasting slope aspects in Waterton Lakes National Park, Alberta, Canada

2009 ◽  
Vol 39 (3) ◽  
pp. 629-641 ◽  
Author(s):  
Matthew G. Letts ◽  
Kevin N. Nakonechny ◽  
K. Eric Van Gaalen ◽  
Cyndi M. Smith
Keyword(s):  
Gas Exchange ◽  
Water Use ◽  
Isotope Composition ◽  
Stable Carbon Isotope ◽  
Vapour Pressure Deficit ◽  
Net Photosynthesis ◽  
Pinus Flexilis ◽  
Limber Pine ◽  
Use Efficiency ◽  
Physiological Acclimation

Photosynthetic gas-exchange characteristics were measured in Pinus flexilis James (limber pine) during two drought years in a xeric, subalpine ecosystem of the Rocky Mountains. Limber pine exhibited conservative water-use traits, including low specific leaf area, leaf nitrogen, stomatal conductance, transpiration (E), and light-saturated net photosynthesis (Amax), but exhibited high needle longevity, water-use efficiency (Amax/E), and stable carbon isotope composition. Net photosynthesis declined strongly with leaf-to-air vapour pressure deficit, resulting in a bimodal seasonal pattern of Amax. Although very little gas exchange was observed in late summer, photosynthetic activity extended into October. The avoidance of gas exchange during high atmospheric demand maximized whole-season water-use efficiency. Leaf temperature and leaf-to-air vapour pressure deficit were higher on south-facing slopes during both moderate (2006) and severe (2007) drought. Severe drought caused lower stomatal conductance and E on the southeast-facing slope, but neither Amax nor canopy reflectance indices differed among slope aspects. Although Amax was lower in 2007 than 2006, branch-length increment did not differ. Foliar stable carbon isotope composition was higher in needles produced in dry years but did not vary among slope aspects. These results indicate that physiological acclimation to water stress prevented among-aspect differences in Amax and that shoulder-season photosynthesis may become increasingly important in a warmer climate.

scholarly journals Effect of fertigation with potassium and nitrogen on gas exchange and biomass accumulation in eggplant1

2017 ◽  
Vol 47 (3) ◽  
pp. 345-352
Author(s):  
Álvaro Henrique Cândido de Souza ◽  
Roberto Rezende ◽  
Marcelo Zolin Lorenzoni ◽  
Fernando André Silva Santos ◽  
André Maller
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Water Use ◽  
Biomass Accumulation ◽  
Net Photosynthesis ◽  
Dry Weight ◽  
Co2 Concentration ◽  
Internal Co2 ◽  
Use Efficiency ◽  
Total Dry Weight

ABSTRACT Adequate crop fertilization is one of the challenges for agriculture. Measuring gas exchange and biomass accumulation may be used to adjust crop management. The effect of fertigation with potassium (0 kg ha-1, 54 kg ha-1, 108 kg ha-1 and 216 kg ha-1) and nitrogen (0 kg ha-1, 67 kg ha-1, 134 kg ha-1 and 268 kg ha-1) on gas exchange and biomass accumulation in eggplant was assessed under greenhouse conditions. The net photosynthesis, stomatal conductance, transpiration, internal CO2 concentration, instantaneous carboxylation efficiency, water-use efficiency and total dry weight were evaluated. With the exception of K for water-use efficiency and N for internal CO2 concentration, all the other gas exchange parameters were significantly affected by the K and N doses. There was an interaction between N and K doses for net photosynthesis, stomatal conductance, transpiration and instantaneous carboxylation efficiency. The highest values for net photosynthesis, stomatal conductance, transpiration rate, carboxylation instantaneous efficiency and total dry weight were found in the range of 125-185 kg ha-1 of K and 215-268 kg ha-1 of N.

scholarly journals A Field Study on the Influence of Verticillium dahliae and Pratylenchus penetrans on Gas Exchange of Potato

Plant Disease ◽  
2007 ◽  
Vol 91 (12) ◽  
pp. 1531-1535 ◽  
Author(s):  
Ibrahim A. M. Saeed ◽  
Ann E. MacGuidwin ◽  
Douglas I. Rouse ◽  
Chris Malek
Keyword(s):  
Gas Exchange ◽  
Verticillium Dahliae ◽  
Field Experiments ◽  
Leaf Gas Exchange ◽  
Pratylenchus Penetrans ◽  
Gas Exchange Parameters ◽  
Pathogen Control ◽  
Use Efficiency ◽  
The Impact ◽  
Exchange Parameters

Field experiments were conducted for three consecutive years to study the effects of low populations of Verticillium dahliae and Pratylenchus penetrans on leaf gas exchange of Russet Burbank potato. Treatments were P. penetrans, V. dahliae, the combination of the nematode with the fungus, and a no-pathogen control. Gas exchange was measured nondestructively on young, fully expanded, asymptomatic leaves one to three times per week starting the ninth week after planting. Infection with either pathogen alone had little or no effect on leaf gas exchange parameters. However, co-infection by both pathogens resulted in reduced leaf light use efficiency (mole of CO2 fixed per mole of photon), lower leaf stomatal conductance, lower leaf water use efficiency (mole of CO2 fixed per mole of water used), and increased intercellular CO2 compared with the no-pathogen control. These effects, additive relative to the impact of each pathogen alone, were first observed 9 weeks after inoculation in the first 2 years of the study and 15 weeks after inoculation in the third year.

scholarly journals Effect of a long chain aliphatic alkohols on growth. gas exchange and assimilate parlitioning in radish plant

2013 ◽  
Vol 51 (1-2) ◽  
pp. 5-10 ◽  
Author(s):  
Zbyszek K. Blamowski ◽  
Edward Borowski ◽  
Maria Blamowska
Keyword(s):  
Gas Exchange ◽  
Total Mass ◽  
Physiological Activity ◽  
Net Photosynthesis ◽  
Assimilate Partitioning ◽  
Gas Exchange Parameters ◽  
Radish Plant ◽  
Storage Organs ◽  
Long Chain ◽  
Exchange Parameters

In pot experiments the influence of long chain aliphatic alcohols (hexacosanol - HEXA, octacosanol - OCTA and triacontanol - TRIA), which were used in concentration O.00l mg·dm<sup>3</sup> , on growth, assimilate partitioning and gas exchange of radish plants cv. "Krakowianka" and "Sopel lodu" were studied. The received results showed that triacontanol was characterized by higher physiological activity than remaining alcohols. TRIA significantly increased yield of mass, as well as it changed the pattern of distribution of assimilates in plants. Under its influence the rate of mass of leaves to mass of storage organs decreased as well as the share of mass of leaves in the total mass of both plant cultivars. TRIA stimulated the rate of net photosynthesis (P<sub>n</sub>), howewer, it did not influence the other detennined gas exchange parameters: substomatal concentration of CO<sub>2</sub> (c<sub>i</sub>), stomatal conductance for water vapour (g<sub>s</sub>) and rate of transpiration (T<sub>r</sub>). Remaining alcohols (HEXA and OCFA) did not any influence on growth of plants and their gas exchange but only on distribution of biomass.

scholarly journals Effects of Planting Density on Morphological and Photosynthetic Characteristics of Leaves in Different Positions on Cunninghamialanceolata Saplings

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 853
Author(s):  
Zhijun Huang ◽  
Qingqing Liu ◽  
Bo An ◽  
Xiaojian Wu ◽  
Linjun Sun ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Leaf Morphology ◽  
Leaf Gas Exchange ◽  
Photosynthetic Pigment ◽  
Net Photosynthesis ◽  
Economic Benefits ◽  
Planting Density ◽  
Gas Exchange Parameters ◽  
Pigment Contents ◽  
Exchange Parameters

The improvement of the stand yield and economic benefits of Cunninghamialanceolata (Lamb.) Hook, one of the most important plantation trees in China, has always been a concern. An appropriate planting density plays an important role in increasing productivity. To determine the optimum planting density of C. lanceolata, we measured leaf morphology, gas exchange parameters, and photosynthetic pigments in replicate leaves on 4-year-old saplings grown in four canopy positions under a low (D1), medium (D2), and high (D3) planting density (approximately 900, 2505, and 6660 trees·ha−1, respectively). We then ranked trait variations using the coefficient of variation to explore the influence of planting density. Planting density significantly influenced the leaf morphology, gas exchange parameters, and the photosynthetic pigment contents of C. lanceolata. Medium planting density (D2) resulted in a larger leaf area and specific leaf areas, a higher net photosynthesis rate, and higher photosynthetic pigment contents. The responses of leaf gas exchange parameters had the most plastic traits that responded to planting density. An appropriate planting density and leaf position might improve C. lanceolata leaf morphology and physiological attributes, which in turn would facilitate growth.

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