USE OF CHLOROPHYLL FLUORESCENCE TO ASSESS HEAT STRESS IN APPLE FRUIT

Ethanol concentration and chlorophyll fluorescence (CF) were measured as signs of heat stress in apple fruit [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.]. `McIntosh', `Cortland', `Jonagold', and `Northern Spy' apples were placed in trays and exposed to 46 °C for 0, 4, 8, or 12 hours. Following treatments, fruit were stored in air at 0 °C and evaluated after 0, 1, 2, or 3 months. Ethanol and ethylene production, CF, peel and flesh browning, firmness, skin color, soluble solids, and titratable acidity were measured. Increases in ethanol were apparent immediately following 12-hour heat treatments as well as after 3 months. After 3 months, ethanol concentrations were 16-, 52-, 6-, and 60-fold higher in `McIntosh', `Cortland', `Jonagold', and `Northern Spy' apples than in controls, respectively. The concentrations of ethanol accumulated reflected the degree of heat-induced fruit injury. Heat treatments reduced ethylene production relative to control values. After 3 months of storage ethylene production of fruit exposed to 46 °C for 12 h was <0.48 μmol·kg-1·h-1 compared to >4.3 μmol·kg-1·h-1 for controls. Heat treatments also reduced CF which was expressed as Fv/Fm, where Fv is the difference between the maximal and the minimal fluorescence (Fm - Fo), and Fm is the maximal fluorescence. After 3 months storage at 0 °C, Fv/Fm was ≈0.2 in fruit held at 46 °C for 12 hours compared with 0.5-0.6 for control fruit. Exposure to 46 °C for 12 hours caused severe peel and flesh browning in all cultivars. Severity of peel and flesh browning increased with increasing duration of heat treatment and subsequent storage at 0 °C. `Northern Spy' apple fruit were most susceptible to heat stress based on the degree of flesh browning. Heat treatments of 8 and 12 hours reduced firmness of `McIntosh', `Cortland', and `Northern Spy', but not `Jonagold' apples. Hue angle of the green side of fruit was also reduced in `Cortland', Jonagold' and `Northern Spy' apples receiving the 8- and 12-hour treatments. Heat treatments caused a decrease in fruit tiratable acidity, but had no effect on soluble solids content. The increase in ethanol production and decrease in CF correlated with heat-induced injury, and were apparent before browning was visually apparent. Ethanol and CF have the potential to be used to nondestructively predict the severity of injury that develops during storage.

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117 Ethanol Production and Chlorophyll Fluorescence Indicate Freezing and Heat Stress in Apple Fruit During Storage

HortScience ◽

10.21273/hortsci.35.3.409b ◽

2000 ◽

Vol 35 (3) ◽

pp. 409B-409

Author(s):

Jun Song ◽

Lihua Fan ◽

Charles F. Forney ◽

Michael A. Jordan

Keyword(s):

Heat Stress ◽

Chlorophyll Fluorescence ◽

Ethanol Production ◽

Injury Severity ◽

Treatment Time ◽

Apple Fruit ◽

Heat Treatments ◽

Severity Of Injury ◽

Fruit Samples ◽

Flesh Browning

Ethanol production and chlorophyll fluorescence were measured as signals of freezing and heat stress in apple fruit. `Cortland' and `Jonagold' apples were held at –8.5 °C for 0, 6, 12 or 24 h (freezing treatments), or at 46 °C for 0, 4, 8 or 12 h (heat treatments). Following treatments, fruit were stored at 0 °C and evaluated after 0, 1, 2, or 3 months. Following storage, fruit samples were kept for 12 h at 20 °C and then analyzed for ethanol production, chlorophyll fluorescence, and visible injury. Severity of flesh browning increased with increasing treatment time for both freezing and heat treatments. Freezing for 24 h and heating for 12 h caused severe flesh browning in both cultivars. Severity of heat-induced browning increased during storage. Increases in ethanol production were apparent 12 h following treatments and reflected the degree of stress-induced fruit injury. After 2 months of storage, ethanol concentrations peaked and were as much as 400-fold greater than that of controls. These stress treatments also reduced ethylene production and chlorophyll fluorescence. The degree of increase in stress-induced ethanol production and decrease in chlorophyll fluorescence correlated with stress-induced injury and could be used to predict the severity of injury that develops during storage. Other volatile production and their relationship to fruit stress will also be discussed.

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Exploring Morpho-Physiological Variation for Heat Stress Tolerance in Tomato

Plants ◽

10.3390/plants10020347 ◽

2021 ◽

Vol 10 (2) ◽

pp. 347

Author(s):

Samikshya Bhattarai ◽

Joshua Harvey ◽

Desire Djidonou ◽

Daniel Leskovar

Keyword(s):

Heat Stress ◽

Chlorophyll Fluorescence ◽

Open Field ◽

Electrolyte Leakage ◽

Leaf Gas Exchange ◽

Total Yield ◽

Stress Conditions ◽

Heat Injury ◽

Injury Index ◽

Heat Tolerant

Texas tomato production is vulnerable to extreme heat in the spring-summer cropping period, which is exacerbated by the lack of superior genetic materials that can perform well in such environments. There is a dire need for selecting superior varieties that can adapt to warm environments and exhibit high yield stability under heat stress conditions. This research aimed at identifying heat-tolerant varieties under heat-stress conditions in controlled and open-field environments and was carried out in three stages. For the first experiment, 43 varieties were screened based on yield responses in natural open-field environment. From those, 18 varieties were chosen and exposed to control (greenhouse: 26/20 °C) and constant heat-stress (growth-chamber: 34/24 °C) conditions for three months. Measurements were done for chlorophyll fluorescence, chlorophyll content (SPAD), plant height, stem diameter and heat injury index (HII). The last experiment was conducted in an open field with a pool of varieties selected from the first and second experiments. Leaf gas exchange, leaf temperature, chlorophyll fluorescence, SPAD value, electrolyte leakage, heat injury index and yield were assessed. From the combined studies, we concluded that heat-tolerant genotypes selected by using chlorophyll fluorescence and HII in controlled heat-stress conditions also exhibited heat-tolerance in open-field environments. Electrolyte leakage and HII best distinguished tomato varieties in open-field environments as plants with low electrolyte leakage and HII had higher total yield. 'Heat Master,' 'New Girl,' 'HM-1823,' 'Rally,' 'Valley Girl,' 'Celebrity,' and 'Tribeca' were identified as high heat-tolerant varieties. Through trait correlation analysis we provide a better understanding of which traits could be useful for screening and breeding other heat-tolerant tomato varieties.

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Lipid Peroxidation and Chlorophyll Fluorescence of Photosystem II Performance during Drought and Heat Stress is Associated with the Antioxidant Capacities of C3 Sunflower and C4 Maize Varieties

International Journal of Molecular Sciences ◽

10.3390/ijms21144846 ◽

2020 ◽

Vol 21 (14) ◽

pp. 4846

Author(s):

Dilek Killi ◽

Antonio Raschi ◽

Filippo Bussotti

Keyword(s):

Lipid Peroxidation ◽

Antioxidant Activity ◽

Heat Stress ◽

Chlorophyll Fluorescence ◽

Photosystem Ii ◽

Membrane Damage ◽

Drought Tolerant ◽

Maize Varieties ◽

Catalase Peroxidase ◽

Drought And Heat Stress

Agricultural production is predicted to be adversely affected by an increase in drought and heatwaves. Drought and heat damage cellular membranes, such as the thylakoid membranes where photosystem II occurs (PSII). We investigated the chlorophyll fluorescence (ChlF) of PSII, photosynthetic pigments, membrane damage, and the activity of protective antioxidants in drought-tolerant and -sensitive varieties of C3 sunflower and C4 maize grown at 20/25 and 30/35 °C. Drought-tolerant varieties retained PSII electron transport at lower levels of water availability at both temperatures. Drought and heat stress, in combination and isolation, had a more pronounced effect on the ChlF of the C3 species. For phenotyping, the maximum fluorescence was the most effective ChlF measure in characterizing varietal variation in the response of both species to drought and heat. The drought-tolerant sunflower and maize showed lower lipid peroxidation under drought and heat stress. The greater retention of PSII function in the drought-tolerant sunflower and maize at higher temperatures was associated with an increase in the activities of antioxidants (glutathione reductase, superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase), whereas antioxidant activity declined in the drought-sensitive varieties. Antioxidant activity should play a key role in the development of drought- and heat-tolerant crops for future food security.

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Effects of Short-Time Heat Stress on the Parameters of Cation induced Increase of Chlorophyll Fluorescence in Pea Thylakoid Membranes

Journal of Plant Physiology ◽

10.1016/s0176-1617(11)80954-5 ◽

1993 ◽

Vol 142 (2) ◽

pp. 144-150 ◽

Cited By ~ 4

Author(s):

Maya Y. Velitchkova ◽

Alexander G. Ivanov

Keyword(s):

Heat Stress ◽

Chlorophyll Fluorescence ◽

Thylakoid Membranes ◽

Short Time

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Penconazole Induced Heat Tolerance in Scots Pine (Pinus sylvestris) and Evergreen Oak (Quercus ilex)

Arboriculture & Urban Forestry ◽

10.48044/jauf.2010.028 ◽

2010 ◽

Vol 36 (5) ◽

pp. 212-220

Author(s):

Glynn Percival ◽

Kelly Noviss

Keyword(s):

Heat Stress ◽

Chlorophyll Fluorescence ◽

Pinus Sylvestris ◽

Scots Pine ◽

Electrolyte Leakage ◽

Quercus Ilex ◽

Recovery Rates ◽

Photosynthetic System ◽

Heat Damage ◽

Evergreen Oak

The ability of penconazole, a triazole fungicide derivative, to protect against and ameliorate heat stress was studied in evergreen oak (Quercus ilex) and Scots pine (Pinus sylvestris). Under laboratory conditions, heat damage to the leaf photosynthetic system based on the stability of the chlorophyll a/b light-harvesting complex within photosystem II (chlorophyll fluorescence Fo responses) and leaf photochemical efficiency (chlorophyll fluorescence Fv/Fm emissions) of detached leaves was constantly less in penconazole treated trees. In both species, greatest protection of the leaf photosynthetic system to heat induced disorders was achieved by application of penconazole at a concentration of 30 g per liter of water compared to penconazole applied at a concentration of 0.15 or 0.45 g per liter of water. Subjecting containerized trees of both species to 10 minutes at 50°C significantly reduced tree vitality with respect to chlorophyll fluorescence Fo and Fv/ Fm emissions, total foliar chlorophylls, leaf photosynthetic rates (Pn) and significantly increased damage to cellular membrane integrity as manifest by higher leaf electrolyte leakage and visual leaf necrosis between stressed and non-heat stressed well-watered trees. The influence of penconazole applied immediately after heat stress on the pattern of recovery over the following twelve weeks demonstrated penconazole treated trees were the most capable of recovery. With respect to chlorophyll fluorescence Fo and leaf electrolyte leakage values recovery rates of heat damaged trees treated with penconazole ranged from 20%–50% higher than non-triazole treated control trees. In all cases nonpenconazole treated control trees had the least capacity for recovery. Regardless of species, height, leaf area, root, shoot, and total plant dry weight were, in virtually all instances, greater than non-penconazole treated controls. The tactical use of the triazole derivative penconazole as an ameliorant against heat damage and recovery from heat stress in Scots pine and evergreen oak would be of benefit to improve tree recovery rates and growth. From a practical point of view penconazole at 30 g a.i. per liter of water is suggested based on the results of this study.

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Changes in Chlorophyll Fluorescence of Apple Fruit during Maturation, Ripening, and Senescence

HortScience ◽

10.21273/hortsci.32.5.891 ◽

1997 ◽

Vol 32 (5) ◽

pp. 891-896 ◽

Cited By ~ 43

Author(s):

Jun Song ◽

Weimin Deng ◽

Randolph M. Beaudry ◽

Paul R. Armstrong

Keyword(s):

Chlorophyll Fluorescence ◽

Apple Fruit ◽

Initial Value ◽

High Quality ◽

Fluorescence Parameters ◽

Holding Period ◽

Golden Delicious ◽

Hue Angle ◽

Rate Of Decline ◽

Accuracy Speed

Trends in chlorophyll fluorescence for `Starking Delicious', `Golden Delicious' and `Law Rome' apple (Malus ×domestica Borkh.) fruit were examined during the harvest season, during refrigerated-air (RA) storage at 0 °C, following RA and controlled-atmosphere (CA) storage, and during a poststorage holding period at 22 °C. Fluorescence parameters of minimal fluorescence (Fo), maximal fluorescence (Fm), and quantum yield [(Fm-Fo)/Fm, otherwise denoted as Fv/Fm] were measured. During `Starking Delicious' fruit maturation and ripening, Fv/Fm declined with time, with the rate of decline increasing after the ethylene climacteric. During RA storage, all fluorescence parameters remained constant for approximately 2 weeks, then steadily declined with time for `Starking Delicious' fruit. Superficial scald was detected after Fv/Fm had declined from an initial value of 0.78 to ≈0.7. Fv/Fm was consistently higher for CA-stored fruits than for RA-stored fruits. We were able to resegregate combined populations of “high-quality” (CA) and “low-quality” (RA) `Law Rome' fruit with 75% accuracy using a threshold Fv/Fm value of 0.685, with only 5% RA-stored fruit incorrectly identified as being of high quality. During a poststorage holding period, Fo, Fm, and Fv/Fm correlated well with firmness for `Starking Delicious', but not for `Golden Delicious' fruit, which were already soft. Fo and Fm were linearly correlated with hue angle for 'Golden Delicious' fruit, decreasing as yellowness increased. The accuracy, speed of assessment, and light-based nature of fluorescence suggests that it may have some practical use as a criterion to assist in sorting apple or other chlorophyll-containing fruit or vegetables on commercial packing lines.

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Chlorophyll fluorescence photography to detect mutants, chilling injury and heat stress

Carlsberg Research Communications ◽

10.1007/bf02906179 ◽

1980 ◽

Vol 45 (4) ◽

pp. 269-282 ◽

Cited By ~ 4

Author(s):

Gregory C. Gibbons ◽

Robert M. Smillie

Keyword(s):

Heat Stress ◽

Chlorophyll Fluorescence ◽

Chilling Injury

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The sun-exposed peel of apple fruit has a higher photosynthetic capacity than the shaded peel

Functional Plant Biology ◽

10.1071/fp07111 ◽

2007 ◽

Vol 34 (11) ◽

pp. 1038 ◽

Cited By ~ 16

Author(s):

Li-Song Chen ◽

Lailiang Cheng

Keyword(s):

Chlorophyll Fluorescence ◽

Electron Transport ◽

Oxygen Evolution ◽

Photosynthetic Capacity ◽

Light Exposure ◽

Calvin Cycle ◽

Apple Fruit ◽

Thermal Dissipation ◽

The Sun ◽

Significant Difference

To determine whether the sun-exposed peel of apple fruit has a higher photosynthetic capacity than the shaded peel, fruit peel samples were taken in both early July and early September from the exterior part of the canopy of mature ‘Liberty’/M.9 trees for measuring oxygen evolution, key enzymes and metabolites involved in photosynthesis, and chlorophyll fluorescence. Compared with the shaded peel, the sun-exposed peel had higher light-saturated oxygen evolution rate and higher light saturation point, but lower apparent and true quantum yields. The activity of ribulose-1,5-bisphosphate carboxylase/oxygenase, glyceraldehyde-3-phosphate dehydrogenase, phosphoribulokinase, stromal fructose-1,6-bisphosphatase, ADP-glucose pyrophosphorylase and sucrose-phosphate synthase (SPS) were higher in the sun-exposed peel than in the shaded peel on both sampling dates except that no significant difference was found in SPS activity between the two peel types in September. No significant difference was detected in the concentration of key metabolites (G6P, F6P, G1P, and PGA) between the sun-exposed peel and the shaded peel, suggesting that the response of the key enzymes to light exposure is well coordinated. Chlorophyll fluorescence quenching analysis showed that the sun-exposed peel had higher PSII quantum efficiency than the shaded peel at each given PFD, which resulted mainly from the higher photochemical quenching coefficient (qP). The sun-exposed peel had higher thermal dissipation capacity, as indicated by larger NPQ and Fo quenching, than the shaded peel at high PFD. In conclusion, the sun-exposed peel of apple fruit has higher activities of the Calvin cycle enzymes and higher rate of electron transport, leading to higher photosynthetic O2 evolution capacity. It appears that the acclimation of the Calvin cycle activities, thermal dissipation, and electron transport in apple peel are well coordinated in response to light exposure.

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