Key differences in photosynthetic characteristics of nine species of intertidal macroalgae are related to their position on the shore

2004 ◽  
Vol 82 (2) ◽  
pp. 177-184 ◽  
Author(s):  
Keith R Skene
Keyword(s):  
Net Photosynthetic Rate ◽  
Photosynthetic Rate ◽  
Rocky Shore ◽  
Dark Respiration ◽  
Algal Species ◽  
Physiological Processes ◽  
Fluorescence Characteristics ◽  
Use Efficiency ◽  
Kautsky Curve ◽  
Photosynthetic Efficiencies

A study of the fluorescence characteristics, net photosynthetic rate, and dark respiration of nine species of intertidal macroalgae, from three divisions and from different positions on a rocky shore on the east coast of Scotland, was carried out to address the following questions: (i) Do algae at different positions along the shore respond differently to the stresses at these positions in terms of photosynthetic efficiency, net photosynthetic rate, and respiration, when fully hydrated? (ii) Do algal species at different positions respond differently, in terms of function, to desiccation, and can these responses be correlated with tolerance or intolerance to desiccation in terms of recovery? The present study demonstrated that algal species that occur higher on the shore have greater photosynthetic rates, respiration rates, maximum fluorescence / initial fluorescence ratios, and photosynthetic efficiencies while fully hydrated than do species that live lower on the shore. These findings point towards an increase in time-use efficiency in species that have less time available for productivity or nutrient uptake, since species at a greater height on the shore spend less time in a state of sufficient hydration to photosynthesize. Furthermore, algae higher up the shore, which can recover from desiccation, have significantly different fluorescence characteristics from nonrecoverers, particularly in the area above the Kautsky curve between initial fluorescence and maximum fluorescence. This is the first biophysical evidence relating to a mechanism for desiccation tolerance in macroalgae, and it is discussed within the context of other examples of increasing rates of physiological processes with decreasing time.Key words: fluorescence, zonation, function, rocky shore, Fucus.

Analysis of the effects of the spotted tentiform leafminer (Phyllonorycter blancardella) on the photosynthetic characteristics of apple leaves

1982 ◽  
Vol 60 (12) ◽  
pp. 2734-2740 ◽  
Author(s):  
J. T. A. Proctor ◽  
J. M. Bodnar ◽  
W. J. Blackburn ◽  
R. L. Watson
Keyword(s):  
Photosynthetic Rate ◽  
Dark Respiration ◽  
Photochemical Efficiency ◽  
Photosynthetic Apparatus ◽  
Light Response ◽  
Apple Leaves ◽  
Economic Thresholds ◽  
Fluorescence Reading ◽  
Use Efficiency ◽  
High Fluorescence

Infestation of apple leaves with the spotted tentiform leafminer (STLM) reduced their net photosynthetic rate (Pn) over a range of light intensities. At a saturating irradiance level of 1240 μE∙m−2∙s−1 and 20 mines per leaf, 32.9% of the leaf area was injured but Pn was decreased by only 23.2%. Examination of parameters in a model for leaf photosynthesis showed a reduction in maximum photosynthetic rate (asymptotic value of the light-response curve) and mesophyll conductance but not in photochemical efficiency or dark respiration. The STLM injury had no effect on transpiration, stomatal conductance, and a slight effect on internal CO2 concentration and water-use efficiency. Mining reduced chlorophyll content of the leaves and this reduced the chlorophyll fluorescence of the mined areas. Tissue around the mines had a relatively high fluorescence reading confirming the Pn measurements and suggesting that this technique was suitable for these and similar studies. Mining by the STLM disrupts the photosynthetic apparatus of the leaf and affects a number of mechanisms in the photosynthetic process. Correlating these effects with field observations will help in determining economic thresholds for this insect.

scholarly journals Orange Rust Effects on Leaf Photosynthesis and Related Characters of Sugarcane

Plant Disease ◽  
2011 ◽  
Vol 95 (6) ◽  
pp. 640-647 ◽  
Author(s):  
Duli Zhao ◽  
Neil C. Glynn ◽  
Barry Glaz ◽  
Jack C. Comstock ◽  
Sushma Sood
Keyword(s):  
Stomatal Conductance ◽  
Quantum Yield ◽  
Net Photosynthetic Rate ◽  
Photosynthetic Rate ◽  
Transpiration Rate ◽  
Carbon Fixation ◽  
Dark Respiration ◽  
Western Hemisphere ◽  
Maximum Quantum Yield ◽  
Leaf Photosynthesis

Orange rust of sugarcane (Saccharum spp. hybrids), caused by Puccinia kuehnii, is a relatively new disease in the Western Hemisphere that substantially reduces yields in susceptible sugarcane genotypes. The objective of this study was to determine the physiological mechanisms of orange rust–induced reductions in sugarcane growth and yield by quantifying effects of the disease on leaf SPAD index (an indication of leaf chlorophyll content), net photosynthetic rate, dark respiration, maximum quantum yield of CO2 assimilation, carbon fixation efficiency, and the relationships between these leaf photosynthetic components and rust disease ratings. Plants growing in pots were inoculated with the orange rust pathogen using a leaf whorl inoculation method. A disease rating was assigned using a scale from 0 to 4 with intervals of 0.5. At disease ratings ≥2, the rust-infected leaf portion of inoculated plants showed significant reductions in SPAD index, maximum quantum yield, carbon fixation efficiency, stomatal conductance, leaf transpiration rate, and net photosynthetic rate; but the rusted portion of the infected leaves had increased intercellular CO2 concentration and leaf dark respiration rate. Although leaf SPAD index, photosynthetic rate, stomatal conductance, and transpiration rate at the rust-infected portion decreased linearly with increased rust rating, the effect of orange rust on photosynthetic rate was much greater than that on stomatal conductance and transpiration. Unlike earlier reports on other crops, reduction in leaf photosynthesis by orange rust under low light was greater than that under high light conditions. These results help improve the understanding of orange rust etiology and physiological bases of sugarcane yield loss caused by orange rust.

High Nitrogen Use Efficiency in Rice Genotypes is Associated with Higher Net Photosynthetic Rate at Lower Rubisco Content

2003 ◽  
Vol 46 (2) ◽  
pp. 251-256 ◽  
Author(s):  
Debabrata Ray ◽  
M.S. Sheshshayee ◽  
K. Mukhopadhyay ◽  
H. Bindumadhava ◽  
T.G. Prasad ◽  
...  
Keyword(s):  
Net Photosynthetic Rate ◽  
Photosynthetic Rate ◽  
Nitrogen Use Efficiency ◽  
High Nitrogen ◽  
Nitrogen Use ◽  
Use Efficiency ◽  
Rice Genotypes

Significant relationships among frost tolerance and net photosynthetic rate, water use efficiency and dehydrin accumulation in cold-treated winter oilseed rapes

2013 ◽  
Vol 170 (18) ◽  
pp. 1600-1608 ◽  
Author(s):  
Milan Oldřich Urban ◽  
Miroslav Klíma ◽  
Pavel Vítámvás ◽  
Jakub Vašek ◽  
Alois Albert Hilgert-Delgado ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Net Photosynthetic Rate ◽  
Water Use ◽  
Photosynthetic Rate ◽  
Frost Tolerance ◽  
Significant Relationships ◽  
Use Efficiency

Diurnal Variation of Instantaneous CO2 and H2O Gas-Exchange over Canopy and Leaf Level of Spring Maize in Arid Area

2013 ◽  
Vol 807-809 ◽  
pp. 1829-1838 ◽  
Author(s):  
Jia Xuan Guo ◽  
Xu Rong Mei ◽  
Yu Zhong Li
Keyword(s):  
Water Stress ◽  
Water Use Efficiency ◽  
Net Photosynthetic Rate ◽  
Water Use ◽  
Photosynthetic Rate ◽  
Arid Area ◽  
Theory And Practice ◽  
Filling Stage ◽  
Leaf Level ◽  
Use Efficiency

Information on the relationship between crop photosynthetic rate and water use efficiency at the leaf level and these at the canopy level is important on the study of theory and practice of high efficiency and water-saving agriculture. We simultaneous made instantaneous CO2 and H2O exchange rate, and instantaneous water use efficiency measurement at both leaf and canopy level in a rain-fed cropping system with spring corn during filling stage by Li-6400 infrared gas analysis meter and eddy correlation system. The results showed that in arid area water stress was the mainly factor influencing the net photosynthesis rate and water use efficiency. At the diurnal course, when soil relative moisture was about 40% at 0-100 cm soil layer, the maximum of net photosynthetic rate at leaf level occurred at about 10:00 under soil water stress, and at about 12:00 at canopy level on sunny days, the maximum leaf photosynthetic rate reached 1.3 mgm-2s-1 , almost close to those of irrigation corn at similar latitude area, and the maximum canopy assimilation rate were 0.9 mgm-2s-1 , reached 54.5% of those of irrigation corn at similar latitude area during filling stage, respectively;The maximum values of instantaneous water use efficiency at leaf and canopy level were 0.16 g (CO2)/ g (H2O) and 0.06 g (CO2)/ g (H2O), and ranged between 0.0055g (CO2)/ g (H2O) and 0.0123 g (CO2)/ g (H2O), 0.0113 g (CO2)/ g (H2O) and 0.0197 g (CO2)/ g (H2O) around noon, respectively. Instantaneous net photosynthetic rate and water use efficiency at leaf level were higher than those at canopy level after 10:00.

scholarly journals Characterization of coffee cultivars leaf rust-resistant subjected to framework pruning

2018 ◽  
Vol 13 (1) ◽  
pp. 63 ◽  
Author(s):  
Estevam Antonio Chagas Reis ◽  
Tainah Freitas ◽  
Milene Alves de Figueiredo Carvalho ◽  
Antônio Nazareno Guimarães Mendes ◽  
Tiago Teruel Rezende ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Net Photosynthetic Rate ◽  
Leaf Rust ◽  
Water Use ◽  
Photosynthetic Rate ◽  
Transpiration Rate ◽  
Agronomic Traits ◽  
High Yield ◽  
Area Index ◽  
Use Efficiency

The goal of our work was to evaluate physiological and agronomic traits, as well as the relationship between these traits in coffee cultivars coming from a germplasm supposedly resistant to leaf rust, and their response to framework pruning. The experiment was conducted at the Federal University of Lavras in randomized blocks with three replicates, with spacing of 3.5 x 0.7 m and plots of 12 plants. An amount of 25 coffee cultivars was evaluated, from which 23 were considered resistant and two susceptible to leaf rust. Traits analyzed were the plagiotropic branch length and number of nodes, net photosynthetic rate, transpiration rate, water use efficiency, fluorescence and chlorophyll index, leaf area index, leaf rust incidence and yield. Catucaí Amarelo 20/15 cv 479, Araponga MG1 and Tupi IAC 1669-33 cultivars show highly responsive to framework pruning. These cultivars have high yield associated to high net photosynthetic rate, water use efficiency and low transpiration rate. Moreover, the last two cultivars show a low incidence of leaf rust. The Acauã cultivar has a good response to framework pruning, showing high yield associated to lower incidence of leaf rust. Catucaí Vermelho 785/15 cultivar is not responsive to framework pruning because show lower yield, high incidence of leaf rust, low vegetative growth and low water use efficiency.

Diurnal variation in net photosynthetic rate and influencing environmentalfactors of Elaeagnus mollis Diels leaf

2009 ◽  
Vol 17 (3) ◽  
pp. 474-478
Author(s):  
Qun-Long LIU ◽  
Chan-Juan NING ◽  
Duo WANG ◽  
Guo-Liang WU ◽  
Hong-Mei ZHANG ◽  
...  
Keyword(s):  
Diurnal Variation ◽  
Net Photosynthetic Rate ◽  
Photosynthetic Rate ◽  
Elaeagnus Mollis

scholarly journals Changes in peanut canopy structure and photosynthetic characteristics induced by an arbuscular mycorrhizal fungus in a nutrient-poor environment

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yinli Bi ◽  
Huili Zhou
Keyword(s):  
Net Photosynthetic Rate ◽  
Leaf Area ◽  
Photosynthetic Rate ◽  
Mycorrhizal Fungus ◽  
Canopy Structure ◽  
Arbuscular Mycorrhizal ◽  
Photosynthetic Characteristics ◽  
Total Leaf Area ◽  
Tiller Angle ◽  
Amf Inoculation

AbstractA well-developed canopy structure can increase the biomass accumulation and yield of crops. Peanut seeds were sown in a soil inoculated with an arbuscular mycorrhizal fungus (AMF) and uninoculated controls were also sown. Canopy structure was monitored using a 3-D laser scanner and photosynthetic characteristics with an LI-6400 XT photosynthesis system after 30, 45 and 70 days of growth to explore the effects of the AMF on growth, canopy structure and photosynthetic characteristics and yield. The AMF colonized the roots and AMF inoculation significantly increased the height, canopy width and total leaf area of the host plants and improved canopy structure. AMF reduced the tiller angle of the upper and middle canopy layers, increased that of the lower layer, reduced the leaf inclination of the upper, middle and lower layers, and increased the average leaf area and leaf area index after 45 days of growth, producing a well-developed and hierarchical canopy. Moreover, AMF inoculation increased the net photosynthetic rate in the upper, middle and lower layers. Plant height, canopy width, and total leaf area were positively correlated with net photosynthetic rate, and the inclination angle and tiller angle of the upper leaves were negatively correlated with net photosynthetic rate. Overall, the results demonstrate the effects of AMF inoculation on plant canopy structure and net photosynthetic rate.

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