Chlorophyll fluorescence and chlorophyll content in field-grown potato as affected by nitrogen supply, genotype, and plant age

2006 ◽  
Vol 44 (1) ◽  
Author(s):  
G. Mauromicale ◽  
A. Ierna ◽  
M. Marchese
Keyword(s):  
Chlorophyll Fluorescence ◽  
Chlorophyll Content ◽  
Nitrogen Supply ◽  
Plant Age

The Bioindicators of Forest Condition Project: A physiological, remote sensing approach

2000 ◽  
Vol 76 (6) ◽  
pp. 941-952 ◽  
Author(s):  
Paul H. Sampson ◽  
Gina H. Mohammed ◽  
Thomas L. Noland ◽  
Denzil Irving ◽  
Stephen J. Colombo ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Chlorophyll Fluorescence ◽  
Chlorophyll Content ◽  
Spectral Signatures ◽  
Condition Rating ◽  
Forest Condition ◽  
Operational Testing ◽  
Level Information ◽  
Intensive Sampling ◽  
Compact Airborne Spectrographic Imager

Objective measures of forest ecosystem condition are needed to gauge the effects of management activities and natural phenomena on sustainability. The Bioindicators of Forest Condition Project seeks to develop a Forest Condition Rating (FCR) system using a physiological, remote sensing approach. In particular, the goal of the project is to test whether hyperspectral remote sensing may be used to infer stand-level information about pigment concentration, chlorophyll fluorescence, and other physiological features of condition. The project spans a four-year period of intensive sampling in tolerant hardwood forests in Ontario using the Compact Airborne Spectrographic Imager (CASI). For each airborne campaign, concurrent ground-based sampling for leaf physiological features was performed. Controlled laboratory and greenhouse studies were also conducted to derive relationships between leaf-based spectral measurements and physiology in the presence of environmental stresses. The project has identified several promising bioindicators of strain that are discernible from hyperspectral images and related to ground-based physiology. The most promising remote indicator for semi-operational testing is estimation of chlorophyll content, which can be used to classify maple stands on a five-stage scale of health. Chlorophyll fluorescence has also been discerned from spectral signatures, but our studies indicate it may be confounded by chlorophyll content. The intent here is to update the forestry community on progress made, insights gained, and the practical implications of the research. Keywords: chlorophyll fluorescence, hyperspectral, indices, pigments, reflectance, tolerant hardwoods

scholarly journals Effects of Drought and Rehydration on the Physiological Responses of Artemisia halodendron

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 793
Author(s):  
Juanli Chen ◽  
Xueyong Zhao ◽  
Yaqiu Zhang ◽  
Yuqiang Li ◽  
Yongqing Luo ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Drought Stress ◽  
Membrane Permeability ◽  
Chlorophyll Content ◽  
Physiological Responses ◽  
Severe Drought ◽  
Native Plant ◽  
Chlorophyll Fluorescence Parameters ◽  
Artemisia Halodendron ◽  
Effects Of Drought

Artemisia halodendron is a widely distributed native plant in China’s Horqin sandy land, but few studies have examined its physiological responses to drought and rehydration. To provide more information, we investigated the effects of drought and rehydration on the chlorophyll fluorescence parameters and physiological responses of A. halodendron to reveal the mechanisms responsible for A. halodendron’s tolerance of drought stress and the resulting ability to tolerate drought. We found that A. halodendron had strong drought resistance. Its chlorophyll content first increased and then decreased with prolonged drought. Variable chlorophyll fluorescence (Fv) and quantum efficiency of photosystem II (Fv/Fm) decreased, and the membrane permeability and malondialdehyde increased. When plants were subjected to drought stress, superoxide dismutase (SOD) activity degraded under severe drought, but the activities of peroxidase (POD) and catalase (CAT) and the contents of soluble proteins, soluble sugars, and free proline increased. Severe drought caused wilting of A. halodendron leaves and the leaves failed to recover even after rehydration. After rehydration, the chlorophyll content, membrane permeability, SOD and CAT activities, and the contents of the three osmoregulatory substances under moderate drought began to recover. However, Fv, Fv/Fm, malondialdehyde, and POD activity did not recover under severe drought. These results illustrated that drought tolerance of A. halodendron resulted from increased enzyme (POD and CAT) activities and accumulation of osmoregulatory substances.

scholarly journals Effects of simulated nitrogen deposition and a stable isotopic assessment for the neotropical epiphytic orchid Laelia speciosa

2014 ◽  
Author(s):  
Edison A. Díaz-Álvarez ◽  
Roberto Lindig-Cisneros ◽  
Casandra Reyes-García ◽  
Erick de la Barrera
Keyword(s):  
Chlorophyll Fluorescence ◽  
Nitrogen Deposition ◽  
Chlorophyll Content ◽  
Biodiversity Loss ◽  
Oak Forest ◽  
Epiphytic Orchid ◽  
Field Assessment ◽  
Stable Isotopic ◽  
The City ◽  
Laelia Speciosa

The accelerated increase of nitrogen deposition is the third cause of biodiversity loss, as a result of saturation of ecosystems worldwide. The effects of nitrogen deposition on the endemic and endangered neotropical epiphytic orchid, Laelia speciosa, were evaluated via a dose-response experiment and a stable isotopic field assessment for individuals from a city and from an oak forest, in order to evaluate the potential risk facing this orchid, and record the history of the nitrogen deposition of series of consecutive annually produced pseudobulbs. Lower doses of nitrogen of up to 20 kg N ha yr–1 the dose that led to optimal performance of plants, acted as fertilizer. For instance, chlorophyll content and chlorophyll fluorescence (Fv/Fm) peaked at 0.66 ± 0.03 g m-2 and 0.85 ± 0.01, respectively. In contrast, toxic effects were observed at the higher doses of 40 and 80 kg N ha yr–1, leading a decrease of 38% of the chlorophyll content and 23% of the chlorophyll fluorescence. For the field assessment, a tissue nitrogen content of 1.2 ± 0.1% (dry mass basis) for the orchids suggested non-toxic deposition rates both at the city and the oak forest. However, their respective isotopic signatures revealed different sources of N at each site. Indeed, in the oak forest δ15N amounted –3.1 ± 0.3‰, typical of places with low industrial activities, while in the city the δ15N reached 5.6 ± 0.2‰, typical of sites with some degree of industrial and automobile activity. Laelia speciosa would be an adequate bioindicator of nitrogen deposition because its ability to take up nitrogen from the atmosphere while preserving its isotopic signature and showing a clear physiological response to increasing inputs of nitrogen. However, its limited geographical distribution precludes the orchid as an ideal candidate for biomonitoring. Thus other vascular epiphytes should be considered for this purpose.

scholarly journals Effect of exogenously application selected phytohormonal substances on the physiological and morphological indicators of Philadelphus x hybrid in containers

2012 ◽  
Vol 60 (8) ◽  
pp. 109-118
Author(s):  
Martin Jonáš ◽  
P. Salaš ◽  
T. Baltazár
Keyword(s):  
Abscisic Acid ◽  
Chlorophyll Fluorescence ◽  
Stomatal Conductance ◽  
Chlorophyll Content ◽  
Significant Influence ◽  
Woody Plants ◽  
Stress Factors ◽  
Morphological Parameters ◽  
Physiological Indicators ◽  
The Impact

The experiment was established in order to eliminate the effect of stress factors acting on woody plants cultivated in containers. The timber Philadelphus x hybrid ’Mont Blanc’. The timber was in 1.5 l containers. The experiment was evaluated effect of exogenouse application of phytohormonal substances on select physiological indicators (stomatal conductance, chlorophyll fluorescence and chlorophyll content), were measured three times during the vegetation. Morphological indicators (diameter of root neck, total length of shoots and number of shoots), were evaluated at the end of vegetation. Phytohormones affecting the impact of stress on plants were used for the purpose. Abscisic acid, 24- epibrassinolid, kinetin and spermine were applied by spraying the leaf in three concentrations (0.01 mg.l−1, 0.1 mg.l−1 a 1 mg.l−1). In the results were found highly significant differences compared to controls with other variants, especially in the evaluation of physiological parameters. The most significant influence on the stomatal conductance was observed in the variants treated with abscisic acid. Application 24- epibrassinolid significantly increased the chlorophyll content in comparison with control variant. Morphological parameters reached the best results in variants treated with 24- epibrassinolid and spermine.

scholarly journals Thermostability of Photosynthesis of Vitis aestivalis and V. vinifera

2006 ◽  
Vol 131 (4) ◽  
pp. 476-483 ◽  
Author(s):  
Sorkel Kadir
Keyword(s):  
Chlorophyll Fluorescence ◽  
High Temperature ◽  
Chlorophyll Content ◽  
High Temperatures ◽  
Prolonged Exposure ◽  
Strong Relationship ◽  
Cellular Level ◽  
Pinot Noir ◽  
Cabernet Sauvignon ◽  
Intact Leaves

High temperature adversely affects photosynthetic rates and thylakoid activities in many species, but photosynthesis response to heat stress is not well defined in grapes (Vitis L.). Genotypes within species respond differently to high temperatures, indicating a genetic variability for the trait. The objective of this study was to determine the physiological responses of two grape species to high temperature, at the whole-plant level and at the cellular level. Gas exchange, relative chlorophyll content, and chlorophyll fluorescence of intact leaves and thermostability of extracted thylakoids of the American (V. aestivalis Michx.) `Cynthiana' and European (V. vinifera L.) `Semillon', `Pinot Noir', `Chardonnay', and `Cabernet Sauvignon' wine grapes were evaluated. One-year-old vines were placed in controlled environmental chamber held at 20/15, 30/25, or 40/35 °C day/night for 4 weeks. Net CO2 assimilation (A) rate, stomatal conductance (gs), transpiration (E) rate, chlorophyll content, and chlorophyll fluorescence of intact leaves were measured at weekly intervals. Chlorophyll fluorescence of thylakoids extracted from V. aestivalis `Cynthiana' and V. vinifera `Pinot Noir' subjected to temperatures ranging from 20 to 50 °C was measured. Optimal temperatures for photosynthesis were 20/15 °C for `Cynthiana' and `Semillon' and 30/25 °C for the other three V. vinifera cultivars. The A, gs, E, chlorophyll content, and chlorophyll fluorescence values at 40/35 °C were lower in `Cynthiana' than `Pinot Noir'. In general, reduction of A coincided with decline in gs in `Cynthiana', whereas no strong relationship between A and gs was observed in V. vinifera cultivars. Variable chlorophyll fluorescence (Fv) and the quantum efficiency of photosystem II (Fv/Fm) of intact leaves for all the cultivars decreased at 40/35 °C, with severe decline in `Cynthiana' and `Cabernet Sauvignon,' moderate decline in `Semillon' and `Chardonnay', and slight decline in `Pinot Noir'. A distinct effect of high temperature on Fv and Fv/Fm of `Cynthiana' was exerted after 2 weeks of exposure. Prolonged-exposure to 40/35 °C led to 78% decrease in Fv/Fm in `Cynthiana', compared with 8% decrease in `Pinot Noir'. In general, Fv and Fv/Fm of extracted thylakoids declined as temperature increased, with more decline in `Cynthiana' than in `Pinot Noir'. Based on A rates and Fv/Fm ratios, results showed that `Cynthiana' has lower optimal temperature for photosynthesis (20/15 °C) than `Pinot Noir' (30/25 °C). Chlorophyll fluorescence responses of intact leaves and extracted thylakoids to high temperatures indicate that `Pinot Noir' possess higher photosynthetic activity than `Cynthiana'. Results of this work could be used in selection programs for the development of heat resistant cultivars in the warmest regions.

scholarly journals Gas exchange and chlorophyll fluorescence parameters in four maize genotypes influenced by first phase of salt stress

2019 ◽  
Vol 30 ◽  
pp. 26-32
Author(s):  
MN Uddin ◽  
MIU Hoque ◽  
S Monira ◽  
MAA Bari
Keyword(s):  
Salt Stress ◽  
Chlorophyll Fluorescence ◽  
Stomatal Conductance ◽  
Chlorophyll Content ◽  
Net Photosynthesis ◽  
Pure Line ◽  
Photosynthesis Rate ◽  
Chlorophyll Fluorescence Parameters ◽  
Maize Genotypes ◽  
Fluorescence Characteristics

Responses in photosynthesis, transpiration, stomatal conductance, chlorophyll fluorescence characteristics and chlorophyll content of four maize (Zea mays L.) genotypes were examined under first phase of salt stress. In the experiment four maize genotypes viz. indigenous yellow pure line, indigenous yellow, hybrid, and indigenous white were tested in two levels of salinity (control: without NaCl application; salinity: 12 dS m-1 by applying NaCl). The experiment was laid out following completely randomized design (CRD) with four replications in the net house of Department of Crop Botany, Bangladesh Agricultural University, Mymensingh. Plants were harvested on day 21 after 7 d application of full salt stress (12 dS m-1). The reductions of shoot fresh masses under salinity were 70, 57, 55 and 61% in indigenous yellow pure line, indigenous yellow, hybrid, and indigenous white, respectively. Some core physiological parameters viz. net photosynthesis rate (Pn), transpiration rate (E), stomatal conductance (gs), and the chlorophyll content decreased in all the maize genotypes except indigenous white under first phase of salt stress. In contrast, the ratio of variable fluorescence to maximal fluorescence (Fv/Fm) of photosystem II significantly decreased only in indigenous yellow pure line under salinity stress. Thus the first phase of salt stress seemed to be deleterious on its response to shoot fresh mass production in all the tested four maize genotypes with the concomitant decrease in rate of photosynthesis, rate of transpiration, stomatal conductance and chlorophyll content in all genotypes except indigenous white. Progressive Agriculture, Vol. 30, Suppl. 1: 26-32, 2019

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