Sterile measurement on the characteristics of chlorophyll fluorescence in plantlets in vitro preserved under low temperature condition

2013 ◽  
Author(s):  
Yanyou Wu ◽  
Deke Xing
Keyword(s):  
Chlorophyll Fluorescence ◽  
Low Temperature

Chilling Injury in Mature Leaves of Rice. II. Varietal Differences in the Response to Interactions Between Low Temperature and Light Measured by Chlorophyll Fluorescence at 77k and the Quantum Yield of Photosynthesis

1989 ◽  
Vol 16 (4) ◽  
pp. 339 ◽  
Author(s):  
LK Huang ◽  
CB Osmond ◽  
I Terashima
Keyword(s):  
Chlorophyll Fluorescence ◽  
Quantum Yield ◽  
Low Temperature ◽  
Chilling Injury ◽  
Bright Light ◽  
Co2 Exchange ◽  
Fluorescence Properties ◽  
Screening Programs ◽  
Detached Leaves

Characteristics of photosynthetic CO2 exchange and 77K chlorophyll fluorescence in attached and detached leaves of rice were used to examine differences between five varieties exposed to a combination of bright light and low temperature. Preliminary studies established that attached leaves of varieties did not differ in the light dependence of photosynthesis at CO2 saturation or fluorescence properties when grown in full sunlight and measured under comparable conditions. All varieties showed a depression in maximum photosynthetic rate, but not in quantum yield or chlorophyll fluorescence when examined in the late afternoon after a period of active photosynthesis in air at 25°C. Attached leaves of all varieties showed depression of the maximum rate of photosynthesis and of quantum yield as well as an increase in Fo and a decrease in Fv/Fm of chlorophyll fluorescence at 77K following horizontal exposure to bright light in air at 25°. Similar results were obtained with detached leaves exposed to bright light while floating on water at 25°C. The rate of photosynthetic CO2 fixation in air as a function of temperature was examined in attached leaves of two representative varieties, Japonica-like cv. Hungarian- 1, and Indica-derived cv. IR-8. The former was capable to rates of photosynthesis at 10°C which were twice those of the latter, although the rates at 25°C were similar in both varieties. When detached leaves of five varieties of rice were floated on water at 10°C while exposed to 700 �mol photons m-2 s-1 of white light, consistent differences in the response of quantum yield, light and CO2 saturated O2 evolion and 77K fluorescence properties were found. Exposure to bright light at low temperature exaggerated the effects of bright light on these parameters, and larger effects were found in the Indica-derived varieties than in Japonica-like cv. Hungarian-1. These treatments at 10°C did not influence the extent of increase in Fo, but led to a greater decline in Fv/Fm of 77K chlorophyll fluorescence compared with treatments at 25°C. Varieties in which there was a larger decline in Fv/Fm showed slower recovery of variable fluorescence in the dark at 25°C, and especially at 10°C. These responses to in vitro treatments seem capable of distinguishing varieties such as cvv. Hungarian-1 and Er Bai Ai, which are believed to be more chilling tolerant by other criteria, from chilling sensitive varieties such as Gui Chao-2 and IR-8. Even though there is potential for application of these methods in screening programs, there is little evidence that the lesions in primary photosynthetic processes indicated by these methods are significant determinants of photosynthesis under field conditions.

scholarly journals Low temperature storage and in vitro germination of cherimoya (Annona cherimola Mill.) pollen

2006 ◽  
Vol 108 (1) ◽  
pp. 91-94 ◽  
Author(s):  
J. Lora ◽  
M.A. Pérez de Oteyza ◽  
P. Fuentetaja ◽  
J.I. Hormaza
Keyword(s):  
Low Temperature ◽  
In Vitro Germination ◽  
Low Temperature Storage ◽  
Annona Cherimola ◽  
Temperature Storage

scholarly journals Arabidopsis ADF5 Acts as a Downstream Target Gene of CBFs in Response to Low-Temperature Stress

2021 ◽  
Vol 9 ◽  
Author(s):  
Pan Zhang ◽  
Dong Qian ◽  
Changxin Luo ◽  
Yingzhi Niu ◽  
Tian Li ◽  
...  
Keyword(s):  
Low Temperature ◽  
Actin Cytoskeleton ◽  
Temperature Stress ◽  
Regulatory Element ◽  
Low Temperature Stress ◽  
Knockout Mutant ◽  
Triple Mutant ◽  
Freezing Resistance

Low temperature is a major adverse environment that affects normal plant growth. Previous reports showed that the actin cytoskeleton plays an important role in the plant response to low-temperature stress, but the regulatory mechanism of the actin cytoskeleton in this process is not clear. C-repeat binding factors (CBFs) are the key molecular switches for plants to adapt to cold stress. However, whether CBFs are involved in the regulation of the actin cytoskeleton has not been reported. We found that Arabidopsis actin depolymerizing factor 5 (ADF5), an ADF that evolved F-actin bundling function, was up-regulated at low temperatures. We also demonstrated that CBFs bound to the ADF5 promoter directly in vivo and in vitro. The cold-induced expression of ADF5 was significantly inhibited in the cbfs triple mutant. The freezing resistance of the adf5 knockout mutant was weaker than that of wild type (WT) with or without cold acclimation. After low-temperature treatment, the actin cytoskeleton of WT was relatively stable, but the actin cytoskeletons of adf5, cbfs, and adf5 cbfs were disturbed to varying degrees. Compared to WT, the endocytosis rate of the amphiphilic styryl dye FM4-64 in adf5, cbfs, and adf5 cbfs at low temperature was significantly reduced. In conclusion, CBFs directly combine with the CRT/DRE DNA regulatory element of the ADF5 promoter after low-temperature stress to transcriptionally activate the expression of ADF5; ADF5 further regulates the actin cytoskeleton dynamics to participate in the regulation of plant adaptation to a low-temperature environment.

scholarly journals Impact of Exposure to Low Temperature Degrees in Field Conditions on Leaf Pigments and Chlorophyll Fluorescence in Leaves of Mango Trees

2020 ◽  
Vol 10 ◽  
pp. 30-45
Author(s):  
Ali A.S. Sayed ◽  
Farouk M. Gadallah ◽  
Mohamed A. Seif El-Yazal ◽  
Gamal A. Abdel-Samad
Keyword(s):  
Chlorophyll Fluorescence ◽  
Low Temperature ◽  
Chlorophyll Concentration ◽  
Ambient Air ◽  
Sampling Time ◽  
Chlorophyll B ◽  
Physiological And Biochemical ◽  
Sampling Times ◽  
Fayoum Governorate

This experiment was conducted to found the connection between low temperature stress in vivo conditions (ambient-air temperature) and the changes in some physiological and biochemical events (leaf pigments and chlorophyll fluorescence) of mango trees in response to exposure to natural low temperature (cold). To verify this objective, 12 popular commonly mango cultivars (25 years old) which grown in private orchard in Fayoum Governorate, Egypt were selected for this study which carried out during the period from November to March of years; 2012 and 2013. The selected cultivars were: Alphonso, Baladi, Bullock's Heart, Helmand, Hindi Besennara, Mabrouka, Mestekawy, Nabeeh, Oweisi, Spates, Taimour and Zebda. Based on the obtained results, it can be stated that, chlorophyll (a) concentration in the leaves was significantly differed among the cultivars throughout the whole sampling times, in this respect, Helmand one gave the highest one while, and the highest one by sampling times was November one. The concentration of chlorophyll (b) was significant as effected by the effect of cultivars and sampling time recorded the highest value by the cultivar of Spates and December sample, respectively. Total chlorophyll concentration in the leaves reached its peak by the cultivar of Nabeeh and sampling time of December as compared to others. The both of Ewais cultivar and the sample of March showed the highest values of carotenoids concentration in the leaves. The levels of anthocyanin in leaves were significantly differed as affected by the cultivars and sampling times, indicating that the cultivar of Helmand and November sample recorded the highest values of anthocyanin in leaves. The greatest reductions in Fv/Fmratio were recorded at month of November and indicated that the reductions were in the order of Alphonso˃ Mabrouka˃Taimour˃ others. The effect of sampling time, cultivars and their interaction on Fv/Fm were significant, but small between some values of Fv/Fm.

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