scholarly journals Effects of three fungal pathogens on water relations, chlorophyll fluorescence and growth of Quercus suber L

1999 ◽  
Vol 56 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Jordi Luque ◽  
Moshe Cohen ◽  
Robert Savé ◽  
Carmen Biel ◽  
Isabel F. Álvarez
Keyword(s):  
Chlorophyll Fluorescence ◽  
Water Relations ◽  
Fungal Pathogens ◽  
Quercus Suber

Water relations and chlorophyll fluorescence responses of two leguminous trees from the Caatinga to different watering regimes

2009 ◽  
Vol 32 (2) ◽  
pp. 235-244 ◽  
Author(s):  
Bruna D. Souza ◽  
Marcos V. Meiado ◽  
Bruno M. Rodrigues ◽  
Mauro G. Santos
Keyword(s):  
Chlorophyll Fluorescence ◽  
Water Relations ◽  
Leguminous Trees

scholarly journals Drought Response of Young Apple Trees on Three Rootstocks. II. Gas Exchange, Chlorophyll Fluorescence, Water Relations, and Leaf Abscisic Acid

1997 ◽  
Vol 122 (6) ◽  
pp. 841-848 ◽  
Author(s):  
R. Thomas Fernandez ◽  
Ronald L. Perry ◽  
James A. Flore
Keyword(s):  
Abscisic Acid ◽  
Chlorophyll Fluorescence ◽  
Drought Stress ◽  
Gas Exchange ◽  
Water Relations ◽  
Acid Content ◽  
Recovery Period ◽  
Leaf Conductance ◽  
Apple Trees ◽  
Abscisic Acid Content

`Imperial Gala' apple trees (Malus ×domestica Borkh.) on M.9 EMLA, MM.111, and Mark rootstocks were subjected to two drought-stress and recovery periods in a rainshelter. Water relations, gas-exchange parameters per unit leaf area and per tree, chlorophyll fluorescence, and leaf abscisic acid content were determined during each stress and recovery period. Whole-plant calculated gas exchange best indicated plant response to drought stress, with consistent reductions in CO2 assimilation, transpiration, and leaf conductance. Variable and maximal chlorophyll fluorescence and fluorescence quenching were not as sensitive to stress. Other fluorescence parameters showed little difference. The most consistent decreases due to stress for gas exchange per square meter were in transpiration and leaf conductance, with few differences in CO2 assimilation and fewer for mesophyll conductance, internal CO2 concentration, and water-use efficiency. Leaf water potential was consistently lower during drought stress and returned to control values upon irrigation. Leaf abscisic acid content was higher for drought-stressed trees on M.9 EMLA than control trees during the stress periods but inconsistently different for the other rootstock treatments. Trees on M.9 EMLA were least affected by drought stress, MM.111 was intermediate, and Mark was the most sensitive; these results are consistent with the growth data.

Chlorophyll fluorescence imaging as tool for understanding the impact of fungal diseases on plant performance: a phenomics perspective

2009 ◽  
Vol 36 (11) ◽  
pp. 880 ◽  
Author(s):  
Julie D. Scholes ◽  
Stephen A. Rolfe
Keyword(s):  
Chlorophyll Fluorescence ◽  
Fluorescence Imaging ◽  
High Throughput ◽  
Fungal Pathogens ◽  
Photosynthetic Performance ◽  
Plant Performance ◽  
Chlorophyll Fluorescence Imaging ◽  
Infected Leaf ◽  
Experimental Conditions ◽  
The Impact

Chlorophyll fluorescence imaging is a non-invasive, non-destructive means with which to examine the impact of fungal pathogens on the photosynthetic metabolism of host plants. As such, it has great potential for screening purposes in high-throughput phenomics environments. However, there is great diversity in the responses of plants to different plant-fungal pathogens and the choice of suitable experimental conditions and protocols and interpretation of the results requires both preliminary laboratory experiments and an understanding of the biology of the specific plant-pathogen interaction. In this review, we examine the interaction between biotrophic, hemi-biotrophic and necrotrophic fungal pathogens and their hosts to illustrate the extent to which chlorophyll fluorescence imaging can be used to detect the presence of disease before the appearance of visible symptoms, distinguish between compatible and incompatible fungal interactions, identify heterogeneity in photosynthetic performance within the infected leaf and provide insights into the underlying mechanisms. The limitations and challenges of using chlorophyll fluorescence imaging in high throughput screens is discussed.

Azimuthal variations in xylem structure and water relations in cork oak (Quercus suber)

IAWA Journal ◽  
2011 ◽  
Vol 32 (1) ◽  
pp. 25-40 ◽  
Author(s):  
Nadia Barij ◽  
Jan Čermák ◽  
Alexia Stokes
Keyword(s):  
Moisture Content ◽  
Water Relations ◽  
Sap Flow ◽  
Quercus Suber ◽  
Cork Oak ◽  
Wood Moisture Content ◽  
Wood Moisture ◽  
Vessel Size ◽  
Xylem Structure ◽  
Crown Size

Azimuthal variations in xylem conductivity and transpiration can occur in trees and may be due to heterogeneity in environmental factors. In cork oak (Quercus suber L.), it can be hypothesized that such modifications may be more pronounced because the insulating layer of bark is harvested every 9–10 years, thus cambial cells will be exposed to fluctuations in the microenvironment. To investigate whether xylem structure and water relations differed around the stems of mature cork oak, sap flow per section and xylem structure were measured on the northern (N) and southern (S) sides of nine trees during three months in Portugal, using the Trunk Sector Heat Balance method. Crown size was measured on both sides of each tree and increment wood cores were extracted from the sites where sap flow was measured in five trees. Wood moisture content, earlywood (EW) vessel size and density were measured and theoretical hydraulic conductivity for individual vessels (Lth) was calculated along the N and S stem radial profiles. No significant differences in crown size between the two sides of the tree were found, but sap flow was higher on the S side of the tree in May only. No differences in wood moisture content were observed along the length of each wood core throughout the heartwood. Significant differences in vessel size occurred, with a greater diameter and surface area on the N side of the tree, and consequently Lth was significantly greater. These conduit diameters on the S facing side of the tree may be smaller in response to a combination of signals and trade-offs due to the heterogeneous air and soil environment around the tree.

Water relations of crok-oak (Quercus suber L.) under natural conditions

Vegetatio ◽  
1992 ◽  
Vol 99-100 (1) ◽  
pp. 199-208 ◽  
Author(s):  
G. Oliveira ◽  
O. A. Correia ◽  
M. A. Martins-Lou��o ◽  
F. M. Catarino
Keyword(s):  
Water Relations ◽  
Quercus Suber ◽  
Natural Conditions

scholarly journals Potential of chlorophyll fluorescence and VIS/NIR spectroscopy measurement use for the detection of nitrogen content and disease infection of apple leaves

2011 ◽  
Vol 59 (6) ◽  
pp. 317-328 ◽  
Author(s):  
Václava Spáčilová ◽  
Ivana Šafránková
Keyword(s):  
Chlorophyll Fluorescence ◽  
Nitrogen Content ◽  
Fungal Pathogens ◽  
Venturia Inaequalis ◽  
Vegetation Indices ◽  
Photochemical Efficiency ◽  
Correlation Coefficients ◽  
Nir Spectroscopy ◽  
Effective Quantum Yield ◽  
Significant Difference

A possibility of using spectral methods for determining a nutritional status and detecting pathogens in apple-tree cvs. ’Jonagold’ and ’Idared’ was verified in an orchard and pot experiments in 2007–2010. Treatments differed in the fertilizer or fungicide dose. Leaf samples were collected from the experimental variants to determine nitrogen content and to measure spectral reflectance (spectrophotometer Avantes USB 2000) and chlorophyll fluorescence imaging (FluorCam). Results of the measurements were correlated to leaf analyses for nitrogen content in dry matter. At the same time, a health status (the occurrence of fungal pathogens Venturia inaequalis and Podosphaera leucotricha) was assessed and changes of photochemical efficiency of PSII of infected leaves were evaluated. The parameters providing the best description of differences in the photosynthetic activity of leaves depending on treatments (parameter Fv/Fm and parameter GENTY, known as ΦPSII – effective quantum yield of PSII) were selected. The values of correlation coefficients of Fv/Fm and ΦPSII depending on fertilization treatments were as follows: Fv/Fm: r = −0.4735, p<0.000089, α = 0.05; ΦPSII: r = 0.755; p < 0.00038, α = 0.05. Data obtained from measuring with a spectrophotometer was used for the calculation to normalized difference vegetation indices NDVI; a significant relationship was found for the index GNDVI (r = 0.4691, p < 0,0002, α = 0.05). The significant difference between healthy leaves and leaves infected by the pathogens V. inaequalis and P. leucotricha was confirmed using the spectrophotometer, and the largest differences in reflectances were found in wavelengths around 400 nm. The values of indices GNDVI, RNDVI and NDVI 450 obtained from measuring reflectance of leaves with symptoms of V. inaequalis and P. leucotricha infections were significantly lower compared to the indices of healthy leaves. The values of indices NDVI were as follows: GNDVI 0.930; RNDVI 0.912; NDVI 450 0.917 for healthy leaves and GNDVI 0.519/0.623; RNDVI 0.428/0.540; NDVI 450 0.432/0.499 for leaves infected by pathogens V. inaequalis/P. leucotricha, respectively. There was found significant difference between infected and healthy leaves for all indices (α = 0.05). Also, the ΦPSII exhibited significant responses to the presence of V. inaequalis and P. leucotricha (ΦPSII: healthy leaves 0.182; V. inaequalis/P. leucotricha presence 0.232/0.222; α = 0.05).

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