scholarly journals (454) Detecting Plant Stress by Chlorophyll Fluorescence

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1036C-1036
Author(s):  
Hussein Al-Amier ◽  
Robert Lussier ◽  
Ming Coler ◽  
Margaret Stoltzman ◽  
Lyle Craker

The stress level in a plant may be directly associated with the intensity of the Kautsky effect (the sudden increase in fluorescence emission by chlorophyll following a dark adaptation). The decrease in photosynthetic efficiency, linked with the rate of photochemistry of plants under stress, provides a definitive signature (graphical pattern) that can be quantified and monitored, even for plants that have no visible stress symptoms. Using a prototype GrowScanner®, signature differences in plants under nitrogen and water stress, as compared with plants not under stress, could be detected and measured. Returning stressed plants to a nonstressed condition returned the stress signatures to that of control plants not under stress. Development of the technology may provide a relatively quick, presymptomatic methodology for detecting plant stress without sacrificing plant tissue.

2002 ◽  
Vol 29 (1) ◽  
pp. 35 ◽  
Author(s):  
Eduardo A. Tambussi ◽  
Jaume Casadesus ◽  
Sergi Munné-Bosch ◽  
José Luis Araus

We analysed the photoprotective response in water-stressed plants of durum wheat (Triticum turgidum L. var. durum cv. Mexa). The plants were grown in a greenhouse for 4 weeks and then exposed to water stress by withholding water for 8 d. Development of water stress was monitored as the decrease in relative water content (RWC) and net CO2 assimilation of the last fully developed leaf. The photoprotective response was evaluated in the same leaves by analysing modulated chlorophyll fluorescence, leaf spectroradiometrical changes, and pigment content. Measurements were performed 3, 6 (moderate stress) and 8 (severe stress) d after water-stress treatment began. The non-photochemical quenching of chlorophyll fluorescence (qN), as well as the contents of zeaxanthin and antheraxanthin increased significantly after 6 d of treatment. However, a further rise in these xanthophylls on day 8 was not associated with any increase in qN. In addition, the β-carotene content rose significantly on day 8, suggesting an increase in antioxidant defences. The photochemical index (PI), derived from spectroradiometrical measurements, showed a strong progressive drop on days 6 and 8, which was paralleled by an increase in the de-epoxidation state of the xanthophyll cycle (DPS), in particular by the zeaxanthin content. At midday, PI was strongly (negatively) correlated with DPS and qN. These results suggest that the PI may be a reliable indicator of photoprotection in the study of plant stress, and in breeding programs.


2019 ◽  
Author(s):  
Mutakusi B Ragimana ◽  
Alastair J Potts

Aim. The re-establishment of Portulacaria afra in the landscape-scale Subtropical Thicket Restoration Programme has exclusively used vertically-orientated truncheons (i.e. large cuttings with the main stem planted 10-20 cm into the ground). Despite the planting of millions of truncheons, the rates of survival, growth and restoration are low. This may be driven by browsing pressure and/or drought conditions during the truncheon establishment phase. Here we conduct a common garden experiment to explore the establishment of horizontal versus vertically orientated truncheons. Horizontal truncheons have their main stem buried in the soil and only a few side branches exposed above ground — these truncheons may experience reduced water stress. Here we compared the levels of water stress during the establishment phase of truncheons with different orientation. Location. Eastern Cape, South Africa. Methods. Our experiment involved three planting treatments for truncheons: vertical orientation, horizontal orientation, and horizontal orientation with exposed side branches clipped. Truncheons were grown for two months and plants were well-watered. On two occasions during the experiment, photosynthetic efficiency was measured on all plants to ascertain levels of plant stress. After the experiment, the root, stem and leaf dry mass were recorded for each replicate, as well as leaf moisture. Results. The root mass proportion (of the total plant) was not significantly different among treatments. Despite this, leaf-level photosynthetic efficiency was recorded as significantly lower in vertical truncheons versus horizontal truncheons. Main conclusions. Smaller horizontally-orientated truncheons do not grow roots at a faster rate (relative to their total size) than the larger vertically-orientated truncheons that have more leaf material to support. Nonetheless, under well-watered conditions, the larger truncheons experienced stress evidenced by lowered leaf photosynthetic efficiency values. Thus, we suggest that horizontal buried truncheons may have a higher likelihood of survival under seasonal drought-stress conditions. It remains to be tested whether horizontally-orientated truncheons (with less above-ground biomass) experience lower rates of herbivory than the standard vertical cuttings.


2019 ◽  
Author(s):  
Mutakusi B Ragimana ◽  
Alastair J Potts

Aim. The re-establishment of Portulacaria afra in the landscape-scale Subtropical Thicket Restoration Programme has exclusively used vertically-orientated truncheons (i.e. large cuttings with the main stem planted 10-20 cm into the ground). Despite the planting of millions of truncheons, the rates of survival, growth and restoration are low. This may be driven by browsing pressure and/or drought conditions during the truncheon establishment phase. Here we conduct a common garden experiment to explore the establishment of horizontal versus vertically orientated truncheons. Horizontal truncheons have their main stem buried in the soil and only a few side branches exposed above ground — these truncheons may experience reduced water stress. Here we compared the levels of water stress during the establishment phase of truncheons with different orientation. Location. Eastern Cape, South Africa. Methods. Our experiment involved three planting treatments for truncheons: vertical orientation, horizontal orientation, and horizontal orientation with exposed side branches clipped. Truncheons were grown for two months and plants were well-watered. On two occasions during the experiment, photosynthetic efficiency was measured on all plants to ascertain levels of plant stress. After the experiment, the root, stem and leaf dry mass were recorded for each replicate, as well as leaf moisture. Results. The root mass proportion (of the total plant) was not significantly different among treatments. Despite this, leaf-level photosynthetic efficiency was recorded as significantly lower in vertical truncheons versus horizontal truncheons. Main conclusions. Smaller horizontally-orientated truncheons do not grow roots at a faster rate (relative to their total size) than the larger vertically-orientated truncheons that have more leaf material to support. Nonetheless, under well-watered conditions, the larger truncheons experienced stress evidenced by lowered leaf photosynthetic efficiency values. Thus, we suggest that horizontal buried truncheons may have a higher likelihood of survival under seasonal drought-stress conditions. It remains to be tested whether horizontally-orientated truncheons (with less above-ground biomass) experience lower rates of herbivory than the standard vertical cuttings.


2019 ◽  
Author(s):  
Arun K. Shanker ◽  
Robert Coe ◽  
Xavier Sirault

AbstractAn experiment was conducted in controlled conditions in three varieties of wheat under water stress, heat and heat +water stress treatments with the objective of studying Chlorophyll a fluorescence, chlorophyll fluorescence induction kinetics and the function of Photosystem II by plant phenotyping as affected by stress. We hypothesised that during stress, specific adaptive strategies are employed by plants, such as structural and functional changes in PS II by which they acquire new homeostasis which may be protective adaptations. Water stress stress treatment was imposed on Water stress and Heat +Water stress treatments at 43 DAS. Heat treatment was imposed on 48 DAS. Maximum quantum yield of primary photochemistry was measured with PAM 2500 and OJIP was measured with FluorPen FP 100 after the onset of stress at four observation times on two days viz., pre-dawn and afternoon during stress. In addition continuous monitoring of photosynthetic efficiency was done with Monitoring PAM. Heat +Water stress stress was more detrimental as compared to Heat or Water stress alone in terms of maximum quantum yield of photochemistry. This could have been due to higher decrease in connectivity between PSII and its antennae resulting in lower photosynthetic efficiency resulting in the impairment and disruption of the electron transport. K step was observed in heat stress and heat +Water stress stress which may be because of damage to Oxygen Evolving Complex indicating that low thermostability of the complex. The stress treatments had a reduction in the plastoquinone pool size as indicated by the reduced area above the OJIP curve. Our study indicated that the instrument PAM 2500 sensed both stresses separately and combined earlier than the other instruments, so in terms of sensitivity PAM 2500 was more effective than FluorPen FP 100 and MultispeQ. Rapid screening of stress was more effectively with FluorPen FP 100 and MultispeQ than by PAM 2500.


2021 ◽  
Vol 66 (1) ◽  
pp. 80-86
Author(s):  
Thin Pham Thi Thanh ◽  
Bang Cao Phi ◽  
Hai Nguyen Thi Thanh ◽  
Khuynh Bui The ◽  
Mai Nguyen Phuong ◽  
...  

Indian Lettuce (Lactuca indica L.) is a valuable medicinal herb but there are still no many researches about this plant. In this work, the physiological responses of Indian lettuce plants under water deficit conditions (5, 8, and 11 days of water stress) were investigated. The Indian lettuce wilted after 5 days of water stress (66.66%), the wilting rate increased after 8 (93.33%) and 11 days (100%) of water stress. The longer duration of water deficit stress caused the slower recovery of plants after rewatering. The water deficit stress caused a decrease in chlorophyll fluorescence, non-associated water content as well as flower formation of Indian lettuce. But the water deficit stress increases the associated water content and the flowering time of this plant.


2010 ◽  
Vol 64 (1) ◽  
pp. 99-108
Author(s):  
Anna Giulini ◽  
Nicoletta La Rocca ◽  
Diego Durantini ◽  
Antonino Malgioglio ◽  
Francesca Dalla Vecchia ◽  
...  
Keyword(s):  

Author(s):  
S. M. Irteza ◽  
J. E. Nichol

Solar Induced Chlorophyll Fluorescence (SIF), can be used as an indicator of stress in vegetation. Several scientific approaches have been made and there is considerable evidence that steady state Chlorophyll fluorescence is an accurate indicator of plant stress hence a reliable tool to monitor vegetation health status. Retrieval of Chlorophyll fluorescence provides an insight into photochemical and carbon sequestration processes within vegetation. Detection of Chlorophyll fluorescence has been well understood in the laboratory and field measurement. Fluorescence retrieval methods were applied in and around the atmospheric absorption bands 02B (Red wavelength) approximately 690 nm and 02A (Far red wavelengths) 740 nm. Hyperion satellite images were acquired for the years 2012 to 2015 in different seasons. Atmospheric corrections were applied using the 6S Model. The Fraunhofer Line Discrimanator (FLD) method was applied for retrieval of SIF from the Hyperion images by measuring the signal around the absorption bands in both vegetated and non vegetated land cover types. Absorption values were extracted in all the selected bands and the fluorescence signal was detected. The relationships between NDVI and Fluorescence derived from the satellite images are investigated to understand vegetation response within the absorption bands.


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