| Effects of leaf surface melatonin spray on photosynthetic properties of tomato seedlings under NaHCO3 stress |
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| DOI：10.7606/j.issn.1000-7601.2022.02.11 |
| Key Words: tomato seedlings solution culture NaHCO3 stress melatonin photosynthesis OJIP curve |
| Author Name | Affiliation | | JIANG Xiyao | Key Laboratory of Physiology and Germplasm Resources Utilization Corps of Special Fruit and Vegetable Cultivation, School of Agriculture, Shihezi University,Shihezi, Xinjiang 832003, China | | NIU Ning | Key Laboratory of Physiology and Germplasm Resources Utilization Corps of Special Fruit and Vegetable Cultivation, School of Agriculture, Shihezi University,Shihezi, Xinjiang 832003, China | | CUI Hongxin | Key Laboratory of Physiology and Germplasm Resources Utilization Corps of Special Fruit and Vegetable Cultivation, School of Agriculture, Shihezi University,Shihezi, Xinjiang 832003, China | | WEI Shaowei | Key Laboratory of Physiology and Germplasm Resources Utilization Corps of Special Fruit and Vegetable Cultivation, School of Agriculture, Shihezi University,Shihezi, Xinjiang 832003, China | | XIONG Hang | Key Laboratory of Physiology and Germplasm Resources Utilization Corps of Special Fruit and Vegetable Cultivation, School of Agriculture, Shihezi University,Shihezi, Xinjiang 832003, China | | LIU Huiying | Key Laboratory of Physiology and Germplasm Resources Utilization Corps of Special Fruit and Vegetable Cultivation, School of Agriculture, Shihezi University,Shihezi, Xinjiang 832003, China | | DIAO Ming | Key Laboratory of Physiology and Germplasm Resources Utilization Corps of Special Fruit and Vegetable Cultivation, School of Agriculture, Shihezi University,Shihezi, Xinjiang 832003, China |
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| Abstract: |
| The effects of different concentrations of melatonin (MT) on photosynthetic pigments, photosynthetic gas exchange parameters and rapid chlorophyll fluorescence kinetics of leaves of ‘Rigel 87-5’ processed tomato seedlings under NaHCO3 stress (50 mmol·L-1) were studied. The results showed that NaHCO3 stress (MT0 treatment) caused damage to OEC (Oxygen releasing complex) and to PSII receptor side of tomato seedlings, decreased PSII reaction center activity, electron transfer efficiency and photochemical efficiency, and reduced Pn and Gs by 66.21% and 82.36%, respectively. Foliar spraying 100~400 μmol·L-1 MT could change the shape of OJIP curve of tomato seedlings under NaHCO3 stress and reduce the trend of K and J phase. MT0 reduced the maximum fluorescence (Fm) and maximum quantum efficiency (Fv/Fm) of tomato leaves by 27.28% and 18.53%, but 100~400 μmol·L-1 of MT increased Fm and Fv/Fm by 38%~56% and 18.85%~21.22%, respectively. Alkali stress led to the efficiency of electron capture in the reaction center after transfer to QA（Ψo). The photosynthetic performance index (PIABS) decreased by 19.23% and 78.27%， respectively, while MT treatment increased it by 29.51%~47.80% and 2.54~3.43 times, respectively. At the same time, the light energy absorption (ABS/RC), thermal energy dissipation (DIo/RC) and capture energy (TRo/RC) per unit reaction center under NaHCO3 stress decreased by 20.67%~26.79% and 51.44%~57.38%. The light energy absorption per unit light receiving area (ABS/CSo) and the effect of heat dissipation (DIO/CSo) decreased by 0.65%~8.67%, 39.02%~40.32%. The findings indicated that the 100~400 μmol·L-1 MT treatment enhanced the electron transfer rate and light reaction activity under alkali stress, optimized the energy flow distribution per unit reaction center and per unit light receiving area, stabilized and protected the photosynthetic mechanism of tomato leaves under alkali stress, and finally improved its Pn. Of which the 150 mmol·L-1 MT (MT150) had the most significant mitigation effect, which effectively alleviated the damage of alkali stress to tomato seedlings. |
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