Photochemical responses of cucumber (Cucumis sativus L.) plants to heat stress


  • Ali DOĞRU Sakarya University Faculty of Arts and Science Department of Biology Esentepe 54187 Sakarya (TR)



chlorophyll a fluorescence; cucumber; Cucumis sativus; heat stress; JIP test


In this study, photochemical responses of cucumber (Cucumis sativus L.) cultivar, ‘Beith Alpha F1’, under moderate and severe heat stress (45 °C and 55 °C, 4 hours) was studied. Chlorophyll a fluorescence measurement and the results of the JIP test indicated that severe heat stress was more drastically affected the photosynthetic activity as compared to moderate heat stress in the cotyledons of cucumber plants. Severe heat stress, for example, led to the increased level of Fo and decreased level of Fm, Fv/Fo, and Fv/Fm, suggesting remarkable photoinhibition on electron transport reactions in cucumber plants. Also, severe heat stress caused the increased level of accumulation of inactive reaction centers, resulting in a decreased amount of trapped light energy and electron transport on PSII. The enhanced values of DIo/RC and fDo in the cotyledons of cucumber plants indicated that the trapped energy cannot be used for photochemical reactions and lost as heat. Consequently, the reduction of the plastoquinone pool was partly inhibited due to the decreased yield of photochemistry. As a result, it may be concluded that severe heat stress inhibited PSII activity in several points and decreased photosynthetic yield in the cotyledons of cucumber plants.


Metrics Loading ...


Abdelrahman M, El-Sayed M, Jogaiah S, Burritt DJ, Tran LSP (2017). The “stay green” trait and phytohormone signaling networks in plants under heat stress. Plant Cell Reports 36:1009-1025.

Allakhverdiev SI, Kreslavski VD, Kimov VV, Los DA, Carpentier R, Mohanty P (2008). Heat stress: an overview of molecular responses in photosynthesis. Photosynthesis Research 98:541.

Biswal B, Joshi PN, Raval MK, Biswal U (2011). Photosynthesis, a global sensor of environmental stress in green plants: stress signaling and adaptation. Current Science 101:47-56.

Chen ST, He NY, Chen JH, Guo FQ (2017). Identification of core subunits of photosystem II as action sites of HSP21, which is activated by the GUN5-mediated retrograde pathway in Arabidopsis. Plant Journal 89:1106-1118.

Doğru A (2019). Evaluation of lead tolerance in some barley genotypes by means of chlorophyll a fluorescence. Bartın University International Journal of Natural and Applied Science 2:228-238.

Doğru A, Çakırlar H (2020a). Effects of leaf age on chlorophyll fluorescence and antioxidant enzymes activity in winter rapeseed leaves under cold acclimation conditions. Brazilian Journal of Botany 43:11-20.

Doğru A, Çakırlar H (2020b). Is leaf age a predictor for cold tolerance in winter oilseed rape plants? Functional Plant Biology 47(3):250-262.

Force L, Critchley C, van Rensen JJS (2003). New fluorescence parameters for monitoring photosynthesis in plants. 1. The effect of illumination on the fluorescence parameters of the JIP test. Photosynthesis Research 78:17-33.

Georgieva K, Lichtenthaler HL (1999). Photosynthetic activity and acclimation ability of pea plants to low and high-temperature treatment as studied by means of chlorophyll fluorescence. Journal of Plant Physiology 155:416-423.

Govindjee (2004). Chlorophyll a fluorescence: a bit of basics and history. Springer, Dordrecht.

Kalaji MH, Govindjee, Bosa K, Koscielniak J, Golaszewska KZ (2011). Effects of salt stress on photosystem II efficiency and CO2 assimilation of two Syrian barley landraces. Environmental and Experimental Botany, 73:64-72.

Maxwell K. Johnson NG (2000). Chlorophyll fluorescence-a practical guide. Journal of Experimental Botany 51:659-668.

Meravi N, Prajapati SK (2018). Temporal variation in chlorophyll fluorescence of different tree species. Biological Rhythm Research 49:1-7.

Schöffl F, Prandl R, Reindl A (1999). Molecular responses to heat stress. In: Shinozaki K, Yamaguchi-Shinozaki K (Eds). Molecular Responses to Cold, Drought, Heat and Salt Stress in Higher Plants, R.G. Landes Co., Austin, Texas, pp 81-99.

Sehgal A, Sita K, Nayyar H (2016). Heat stress in plants: Sensing and defense mechanism. Journal of Plant Science Research 32:195-210.

Strasser RJ, Srivastava A, Tsimilli-Michael M (2000). The fluorescence transient as a tool to characterize and screen photosynthetic samples. In: Yunus M, Pathre U, Mohanty P (Eds). Probing Photosynthesis: Mechanisms, Regulation and Adaptation. Taylor & Francis, London, pp 445-483.

Wahid A, Gelani S, Ashraf M, Foola MR (2007). Heat tolerance in plants: an overview. Environmental and Experimental Botany 61:199-223.

Wang QL, Chen JH, He NY, Guo FQ (2018). Metabolic reprogramming in chloroplasts under heat stress in plants. International Journal of Molecular Science 19:849-870.

Yusuf MA, Kumar D, Rajwanshi R, Strasser RJ, Tsimilli-Michael M, Govindjee, Sarin VB (2010). Overexpression of -tocopherol methyltransferase gene in transgenic Brassica juncea plants alleviates abiotic stress: physiological and chlorophyll fluorescence measurements. Biochimica et Biophysica Acta 1797:1428-1438.

Zhang SR, Sharkey TD (2009). Photosynthetic electron transport and proton flux under moderate heat stress. Photosynthesis Research 100:29-43.

Zhao B, Wang J, Gong H, Wen X, Ren H, Lu C (2008). Effects of heat stress on PSII photochemistry in cyanobacterium Spirulina platensis. Plant Science, 175:556-564.




How to Cite

DOĞRU, A. (2020). Photochemical responses of cucumber (Cucumis sativus L.) plants to heat stress. Notulae Scientia Biologicae, 12(4), 829–835.



Research articles
DOI: 10.15835/nsb12410815