Acta Agriculturae Boreali-Sinica ›› 2022, Vol. 37 ›› Issue (2): 84-95. doi: 10.7668/hbnxb.20192694

Special Issue: Cucumber

• Tillage & Cultivation·Physiology & Biochemistry • Previous Articles     Next Articles

Effects of Nitrogen Application on Fluorescence Characteristics of Cucumber in Fruit Growth Stage under High Temperature Stress

SHI Jiaqi, LIU Yuqing, WANG Yanling, YANG Zaiqiang   

  1. School of Applied Meteorology,Nanjing University of Information Science and Technology,Nanjing 210044,China
  • Received:2021-12-16 Published:2022-04-28


To reveal the effect process and mechanism of nitrogen application level on the chlorophyll fluorescence characteristics of cucumber in fruit stage under high-temperature stress,the Jinyou 101 cucumber was used as the tested material,the air temperatures were set at 35 ℃/25 ℃,38 ℃/28 ℃,41 ℃/31 ℃,in the same time the 28 ℃(daily maximum temperature)/18 ℃(daily minimum temperature)was as the control(CK);the nitrogen(N)application level was set at 0(N0),160(N1),240(N2),320 kg/ha(N3);total 16 treatments and three duplicates.The dynamic parameters of chlorophyll fluorescence of cucumber functional leaves were measured systematically after 9-days high-temperature stress in fruit stage,the differences between in various treatments were also discussed.The PSⅡ reaction centre of cucumber leaves were significantly damaged and the maximum fluorescence(Fm),maximum photochemical quantum yield(Fv/Fm),photosynthetic performance index(PIabs),area enclosed by Fm and fluorescence curve(Area)were significantly decreased after high-temperature stress in fruit stage.Under the 35 ℃ high-temperature stress,the values of ΔWO-J and ΔWO-K were negative in treatment N1—N3,and the oxygen evolution complex(OEC)was not inactivated.At the same time,the energy transfer between PSⅡ central thylakoids was unhindered.However,the ΔWO-J of leaves was positive in treatment N1 under 38 ℃ and treatment N2 under 41 ℃,which means the OEC was inactivated.Therefore,the energy transfer between PSⅡ central thylakoids was blocked due to the positive ΔWO-K in treatment N1—N3 under the 38,41 ℃.Under the high-temperature stress,the nitrogen application significantly increased the chlorophyll content,Fm,Fv/Fm,PIabs,PItotal,Area and Sm of cucumber leaves,and enhanced the OEC activity and smooth the energy transfer between the PSⅡ central thylakoids;the ABS/RC,TRo/RC and DIo/RC of cucumber leaves also decreased with the increase of nitrogen application level while the electron transfer energy(ETo/RC)increased.Nitrogen application rate and temperature had significant interactive effects on the fluorescence characteristics and yield of cucumber leaves.Under the 35,38,41 ℃high-temperature stress in fruit stage,when the nitrogen application rates were 236,283,177 kg/ha respectively,the photosynthesis of cucumber leaves was stronger and higher yield could be obtained.Therefore,the reasonable nitrogen application could improve the OEC activity of PSⅡ,promote energy transfer,and slow down the inhibition of electron receptor pool on the side of PSⅠ receptor of cucumber leaves under the high-temperature stress in fruit stage,and also improve the orderly progress of photosynthesis.

Key words: Cucumber, Chlorophyll fluorescence parameters, Pot experiment, Yield, High-temperature stress, Nitrogen application level

Cite this article

SHI Jiaqi, LIU Yuqing, WANG Yanling, YANG Zaiqiang. Effects of Nitrogen Application on Fluorescence Characteristics of Cucumber in Fruit Growth Stage under High Temperature Stress[J]. Acta Agriculturae Boreali-Sinica, 2022, 37(2): 84-95. doi: 10.7668/hbnxb.20192694.

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