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

施氮对高温胁迫下黄瓜果期荧光特性的影响

石嘉琦, 刘宇庆, 王艳玲, 杨再强   

  1. 南京信息工程大学 应用气象学院,江苏 南京 210044
  • 作者简介:
    作者简介:石嘉琦(1995—),女,河北沧州人,在读硕士,主要从事设施农业减灾机制研究。
  • 基金资助:
    国家自然科学基金项目(42077087)

Abstract:

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

摘要:

为了揭示果期高温胁迫下氮素施用水平对黄瓜叶绿素荧光特性的影响过程与机制,以津优101号黄瓜为试验材料,以28 ℃/18 ℃为对照,设置了35 ℃/25 ℃、38 ℃/28 ℃、41 ℃/31 ℃ 3个高温处理,施氮量设置0(N0),160(N1),240(N2),320(N3)kg/hm2 4个水平,共16个处理,每个处理3次重复。果期高温胁迫9 d后测定了黄瓜功能叶片的荧光诱导动力学参数,并探讨了各处理间变化差异的原因。结果表明,果期高温胁迫后黄瓜叶片光系统Ⅱ(PSⅡ)反应中心显著受损,叶片的最大荧光(Fm)、最大光化学量子产量(Fv/Fm)、光合性能指数(PIabs)、Fm与荧光曲线围成的面积(Area)均显著降低。35 ℃胁迫下各施氮处理黄瓜叶片的ΔWO-J和ΔWO-K均为负值,放氧复合体(OEC)未失活且PSⅡ中心类囊体之间的能量传递顺畅; 而38 ℃胁迫下N2处理和41 ℃胁迫下N1处理黄瓜叶片的ΔWO-J均为正值,OEC失活,且N1~N3处理的叶片ΔWO-K均为正值,PS Ⅱ中心类囊体之间的能量传递受阻。高温胁迫下施氮可显著增加黄瓜叶片的叶绿素含量及Fm、Fv/Fm、PIabs、PItotal、Area、Sm,增强OEC活性且促进PS Ⅱ中心类囊体之间的能量传递; 高温胁迫下黄瓜叶片PS Ⅱ单位活性反应中心的吸收光能(ABS/RC)、捕获光能(TRo/RC)、热耗散光能(DIo/RC)均表现为随着施氮水平的提高呈下降趋势,而电子传递的能量(ETo/RC)则呈上升趋势。施氮量和温度对黄瓜叶片荧光特性和产量存在显著的交互效应,在果期35,38,41 ℃高温环境中,施氮量分别为236,283,177 kg/hm2时黄瓜叶片光合作用较旺盛,且能获得较高产量。因此,果期高温胁迫下合理施氮可以提高黄瓜叶片PS Ⅱ的OEC活性,促进能量传递,减缓PS Ⅰ受体侧末端电子受体库的抑制,促进叶片光合作用的有序进行。

关键词: 黄瓜, 叶绿素荧光参数, 盆栽试验, 产量, 高温胁迫, 施氮水平