Characterization and Detection of Leaf Photosynthetic Response to Citrus Huanglongbing from Cool to Hot Seasons in Two Orchards

2020 ◽  
Vol 63 (2) ◽  
pp. 501-512
Author(s):  
Haiyong Weng ◽  
Yibing Zeng ◽  
Haiyan Cen ◽  
Mubin He ◽  
Youqing Meng ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Random Forest ◽  
Quantum Yield ◽  
Fluorescence Imaging ◽  
Chlorophyll Fluorescence Imaging ◽  
Photosynthetic Response ◽  
Citrus Huanglongbing ◽  
Asymptomatic Stage ◽  
Citrus Leaves ◽  
Quantum Yield Of Psii

HighlightsAn abnormal accumulation of sucrose and glucose was found in HLB-infected leaves, and it presented a similar pattern in different orchards from cool to hot seasons.A decreasing value of the actual quantum yield of PSII (FPSII) in HLB-infected leaves was mainly related to an increase of non-regulated energy quenching (FNO) due to the irreversible damage of PSII.Chlorophyll fluorescence imaging combined with a random forest was able to identify HLB at the asymptomatic stage.Abstract Citrus Huanglongbing (HLB) poses a serious threat to citrus production. This research aimed to explore chlorophyll fluorescence imaging for characterizing the photosynthetic response to HLB-infected citrus leaves in different orchards and seasons. Chlorophyll fluorescence images of citrus leaves were acquired with an in-house chlorophyll fluorescence imaging system. It was found that sucrose and glucose accumulated earlier than starch in HLB-infected leaves, and a similar carbohydrate metabolic pattern was observed in HLB-infected leaves grown in different orchards from cool to hot seasons. The pathogen damaged the thylakoid structure of chloroplasts with a higher value of Fo. It decreased photosynthetic activity of the host by reducing the number of active photosynthetic centers and the maximum quantum yield of PSII (Fv/Fm) with lower values of Fv/Fo and Fv/Fm. Additionally, the pathogen modified the allocation of excitation energy in citrus leaves by reducing the actual quantum yield of PSII (FPSII) due to an increase of non-regulated energy quenching (FNO), which indicated irreversible PSII damage before symptom development. Moreover, photosynthetic signatures combined with the random forest method were able to identify HLB in the asymptomatic stage with an overall accuracy of 91.8%. These results demonstrated the potential of chlorophyll fluorescence imaging for evaluating the photosynthetic response to HLB as well as disease diagnosis. Keywords: Carbohydrate metabolism, Chlorophyll fluorescence imaging, Citrus Huanglongbing, Photosynthetic efficiency, Random forest model.

Distinction and characterisation of rice genotypes tolerant to combined stresses of salinity and partial submergence, proved by a high-resolution chlorophyll fluorescence imaging system

2019 ◽  
Vol 46 (3) ◽  
pp. 248 ◽  
Author(s):  
Bhubaneswar Pradhan ◽  
Koushik Chakraborty ◽  
Nibedita Prusty ◽  
Deepa ◽  
Arup Kumar Mukherjee ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Quantum Yield ◽  
Fluorescence Imaging ◽  
Imaging System ◽  
Oryza Sativa L ◽  
Photochemical Efficiency ◽  
Combined Effect ◽  
Chlorophyll Fluorescence Imaging ◽  
Photochemical Quenching ◽  
Submergence Stress

Chlorophyll a fluorescence (ChlF) parameters measured with fluorescence imaging techniques were used to investigate the combined effect of salt and partial submergence stress to understand photosynthetic performance in rice (Oryza sativa L.). ChlF parameters such as maximal fluorescence (Fm), variable fluorescence (Fv=Fm –F0), the maximal photochemical efficiency of PSII (Fv/Fm) and the quantum yield of nonregulated energy dissipation of PSII (Y(NO)) were able to distinguish genotypes precisely based on their sensitivity to stress. Upon analysis, we found the images of F0 were indistinguishable among the genotypes, irrespective of their tolerance to salt and partial submergence stress. On the contrary, the images of Fm and Fv/Fm showed marked differences between the tolerant and susceptible genotypes in terms of tissue greenness and the appearance of dark spots as stress symptoms. The images of effective PSII quantum yield, the coefficient of nonphotochemical quenching (qN) and the coefficient of photochemical quenching (qP) captured under different PAR were able to distinguish the tolerant and susceptible genotypes, and were also quite effective for differentiating the tolerant and moderately tolerant ones. Similarly, the values of electron transport rate, qN, qP and Y(NO) were also able to distinguish the genotypes based on their sensitivity to stress. Overall, this investigation indicates the suitability of chlorophyll fluorescence imaging technique for precise phenotyping of rice based on their sensitivity to the combined effect of salt and partial submergence.

scholarly journals Chlorophyll Fluorescence Imaging Analysis for Elucidating the Mechanism of Photosystem II Acclimation to Cadmium Exposure in the Hyperaccumulating Plant Noccaea caerulescens

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2580 ◽  
Author(s):  
Gülriz Bayçu ◽  
Julietta Moustaka ◽  
Nurbir Gevrek ◽  
Michael Moustakas
Keyword(s):  
Chlorophyll Fluorescence ◽  
Quantum Yield ◽  
Photosystem Ii ◽  
Fluorescence Imaging ◽  
Heat Dissipation ◽  
Chlorophyll Fluorescence Imaging ◽  
Imaging Analysis ◽  
Noccaea Caerulescens ◽  
Psii Photochemistry ◽  
Cd Exposure

We provide new data on the mechanism of Noccaea caerulescens acclimation to Cd exposure by elucidating the process of photosystem II (PSII) acclimation by chlorophyll fluorescence imaging analysis. Seeds from the metallophyte N. caerulescens were grown in hydroponic culture for 12 weeks before exposure to 40 and 120 μM Cd for 3 and 4 days. At the beginning of exposure to 40 μM Cd, we observed a spatial leaf heterogeneity of decreased PSII photochemistry, that later recovered completely. This acclimation was achieved possibly through the reduced plastoquinone (PQ) pool signaling. Exposure to 120 μM Cd under the growth light did not affect PSII photochemistry, while under high light due to a photoprotective mechanism (regulated heat dissipation for protection) that down-regulated PSII quantum yield, the quantum yield of non-regulated energy loss in PSII (ΦNO) decreased even more than control values. Thus, N. caerulescens plants exposed to 120 μM Cd for 4 days exhibited lower reactive oxygen species (ROS) production as singlet oxygen (1O2). The response of N. caerulescens to Cd exposure fits the ‘Threshold for Tolerance Model’, with a lag time of 4 d and a threshold concentration of 40 μM Cd required for the induction of the acclimation mechanism.

Detecting crop population growth using chlorophyll fluorescence imaging

2017 ◽  
Vol 56 (35) ◽  
pp. 9762 ◽  
Author(s):  
Heng Wang ◽  
Xiangjie Qian ◽  
Lan Zhang ◽  
Sailong Xu ◽  
Haifeng Li ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Population Growth ◽  
Fluorescence Imaging ◽  
Chlorophyll Fluorescence Imaging
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