JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2021, Vol. 45 ›› Issue (1): 93-100.doi: 10.12302/j.issn.1000-2006.202003080

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Comparison of photosynthetic characteristics of two new Triadica sebifera varieties

XU Zhongqiu1(), SUI Dezong2,*(), XIE Yinfeng1,*(), WANG Junyi1   

  1. 1. Co-Innovation Center for the Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
    2. Jiangsu Academy of Forestry, Nanjing 210014, China
  • Received:2020-03-26 Accepted:2020-08-03 Online:2021-01-30 Published:2021-02-01
  • Contact: SUI Dezong,XIE Yinfeng E-mail:1923743340@qq.com;535122107@qq.com;xxyy@njfu.edu.cn

Abstract:

【Objective】The photosynthetic characteristics of two new Triadica sebifera varieties ‘Haibin Feihong’ (‘Feihong’) and ‘Haibin Zijing’ (‘Zijing’) in summer were studied and compared. This provided a theoretical basis for the cultivation and application of new T. sebifera varieties. 【Method】The photosynthetic pigment content, diurnal variation of photosynthesis, light response curve and CO2 response curve of 2-year-old grafted seedlings were measured under pot culture conditions, and a grey correlation analysis was conducted. 【Result】① The contents of chlorophyll a (Chl a), chlorophyll b (Chl b), carotenoid (Car) and chlorophyll a/b (Chl a/b) of ‘Zijing’ were all higher than that of ‘Feihong’, and the differences in Chl a, Chl b and Car content were significant. ② The diurnal variation curves of the photosynthesis of the two cultivars in August were a typical single peak type, and there was no ‘noon break’ phenomenon. The daily mean and peak values of the net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr) of ‘Zijing’ were significantly higher than those of ‘Feihong’, while the intercellular CO2 concentration (Ci) was the opposite. The grey correlation analysis showed that the main environmental factors affecting the two varieties of Pn were atmospheric temperature (Ta) and light intensity (PAR). Compared with ‘Feihong’, Pn was more related to Ta, but less to atmospheric CO2 concentration (Ca) in ‘Zijing’. ③ The maximum net photosynthetic rate (Pn,max), light saturation point (LSP), dark respiration rate (Rd) and light compensation point LCP) of ‘Zijing’ were all higher than those of the ‘Feihong’, and the apparent quantum efficiency (AQY) was lower than that of the ‘Feihong’, in which Pn,max, LSP and Rd were significantly different. ④ The maximum photosynthetic capacity (An,max), CO2 saturation point (CSP), carboxylation efficiency (CE) and light absorption rate (Rp) of the ‘Zijing’ were higher than those of ‘Feihong’, the CO2 compensation point (CCP) was smaller than that of the ‘Feihong’, and there were significant differences between An,max and CSP. 【Conclusion】The two new varieties of S. sebiferum showed strong adaptability to summer growth in terms of photosynthetic characteristics. Compared with ‘Feihong’, ‘Zijing’ had the best photosynthetic performance and better adaptability to high temperature and strong light. Its stronger photosynthetic capacity is related to its relatively small non-stomatal limitation. The higher carboxylation efficiency and RUBP regeneration ability may be the main reason for the improvement of non-stomatal limitation by ‘Zijing’. Photorespiration may be a mechanism to avoid light suppression and light destruction under high temperature and strong light.

Key words: new varieties of Triadica sebifera, diurnal variation of photosynthesis, light response curve, CO2 response curve

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