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Scientia Silvae Sinicae ›› 2024, Vol. 60 ›› Issue (8): 120-131.doi: 10.11707/j.1001-7488.LYKX20230322

• Research papers • Previous Articles     Next Articles

Effects of Polyploidization on Leaf Morphology, Photosynthetic Performance and Accumulation of Secondary Metabolites in Cyclocarya paliurus

Shuyang Wang1,Li Tian1,Shuntao Zhou2,Yuee Chu3,Di Mei1,Jiaqiu Yuan4,Yanhao Yu1,Xiangxiang Fu1,*()   

  1. 1. Co-Innovation Center for Sustainable Forestry in Southern China College of Forestry and Grassland, Nanjing Forestry University Nanjing 210037
    2. Nanjing Green Selenium Bio-Pharmaceutical Limited Company Nanjing 211500
    3. Shitai County Forestry Technology Promotion Center in Anhui Province Chizhou 245100
    4. Jiangsu Food & Pharmaceutical Science College Huaian 223005
  • Received:2023-07-20 Online:2024-08-25 Published:2024-09-03
  • Contact: Xiangxiang Fu E-mail:xxfu@njfu.com.cn

Abstract:

Objective: Cyclocarya paliurus is a unique medicinal plant in China, and its diploid and autotetraploid individuals coexist in natural populations. This study aims to compare and analyze the differences in leaf morphology, photosynthetic performance and secondary metabolite accumulation between diploidy and tetraploidy, in order to provide a basis for elite genotype selection for leaf-use plantations. Method: The leaf morphology, anatomical structure, and stomatal parameters in diploid and tetraploid adult plants from Hefeng, Hubei Province and Qingliangfeng, Anhui Province were measured. Their photosynthetic physiological parameters were also determined. The seasonal dynamics and differences of secondary metabolite profiles between two ploidies were compared. Result: 1) The length, width, and area of tetraploid leaves were 10.94 cm, 4.57 cm, and 118.84 cm2, respectively, which were 19.5%, 61.4%, and 94.2% greater than those of diploid leaves. However, there was no significant difference in specific leaf mass. In similar, various tissues in leaf anatomical structure and stomatal morphology in tetraploidy were also significantly larger than that in diploidy. However, the stomatal density in tetraploidy was 158.36 stomata·mm?2, which was 43.8% less than that of diploidy. 2) The carotenoid content in tetraploidy was significantly higher than that in diploidy, and there were no significant differences in chlorophyll a and chlorophyll b between the two ploidies. The parameters obtained from fitted curves of light response showed that maximum net photosynthetic rate (Pnmax), dark respiration rate (Rd), light compensation point (LCP), and light saturation point (LSP) in diploid were 8.367, 0.997, 25.905, and 1 527.96 μmol·m?2s?1, while were 13.797, 1.573, 32.905, and 1 311.36 μmol·m?2s?1 in tetraploidy, respectively. Measurement for instantaneous photosynthesis revealed that net photosynthetic rate, intercellular CO2 concentration, and transpiration rate in tetraploidy were significantly higher than those in diploidy. There were no significant differences in stomatal conductance and vapor pressure deficit. 3) The accumulation peaks of major bioactive substances in leaves of two ploidies all occurred in May and September, respectively. There were no significant differences in the content of triterpenoids and flavonoids in two harvest seasons (May and September) between ploidies. The polyphenol content of tetraploidy (13.64 mg·g?1) was significantly higher than that of diploidy (13.29 mg·g?1) only in May, while the polysaccharide content of tetraploidy remained consistently higher than that of diploidy throughout the entire growing season, reaching 6.80 mg·g?1 and 8.58 mg·g?1 in May and September, respectively. Conclusion: The leaf morphology, anatomical structure and photosynthetic physiological characteristics in tetraploidy are significantly better than those of diploidy, thus promoting its leaf biomass production. The polyphenol content in May and polysaccharide content in whole growth seasons in tetraploidy are significantly higher than those in diploidy, but there is no significant difference in flavonoids and triterpenes contents in the main harvest seasons between two ploides. Comprehensively, the tetraploid is the candidate material for leaf-use plantations in low-altitude areas, and can obtain higher yields of bioactive substances in practice.

Key words: tetraploid, leaf morphology, leaf anatomy, photosynthetic physiology, secondary metabolite

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