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Bulletin of Botanical Research ›› 2022, Vol. 42 ›› Issue (6): 1096-1105.doi: 10.7525/j.issn.1673-5102.2022.06.020

• Physiology and Ecology • Previous Articles     Next Articles

Effects of Shading on Photosynthetic Characteristics and Non-structural Carbohydrate Content of Heptacodium miconioides Seedlings

Chunyan WEI1,2, Yueling LI1,2(), Zexin JIN1,2, Guangyu LUO1,2,3, Chao CHEN1,2,3, Fangquan SHAN4   

  1. 1.Zhejiang Provincial Key Laboratory of Plant Evolutionary and Conservation，Taizhou University，Taizhou 318000
    2.Institute of Ecology，Taizhou University，Taizhou 318000
    3.School of Life Sciences，Shanghai Normal University，Shanghai 200234
    4.Taizhou Green Heart Tourism Development Promotion center，Taizhou 318000
  • Received:2022-03-02 Online:2022-11-20 Published:2022-11-22
  • Contact: Yueling LI E-mail:liyl@tzc.edu.cn
  • About author:WEI Chunyan（1997—），female，master student，mainly engaged in the research of plant physiology and ecology.
  • Supported by:
    Zhejiang Provincial Natural Science Foundation of China(LQ19C030001);National Natural Science Foundation of China(32001113);Zhejiang Provincial Natural Science Foundation of China(LTY22C030002);Outstanding Youth Project of Taizhou University(2019JQ005)

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Abstract:

To investigate the growth and adaptation of Heptacodium miconioides under different light conditions， two-year-old H. miconioides seedlings were used as materials under three light intensities（full light， 60% shade and 90% shade）， and the photosynthetic characteristics and non-structural carbohydrate（NSC） content of H. miconioides were measured. The results showed that： （1）The diurnal changes of net photosynthetic rate（Pn） of H. miconioides seedlings under three light intensities showed “single-peak” curves. The daily mean values of Pn under three light intensities ranked as full light>60% shade>90% shade. The daily mean values of water use efficiency（WUE） under 90% shade treatment was significantly lower than those under full light and 60% shade treatments； （2）Compared with full light， the light compensation point（LCP） and dark respiration rate（Rd） of H. miconioides seedlings under 60% shade decreased significantly， while the light saturation point （LSP）， maximum net photosynthetic rate（Pnmax）， maximum carboxylation rate（Vcmax）， maximum electron transport rate（Jmax）， and triose phosphate utilization rate（TPU） had no significant difference respectively. As shading degree increased， the LSP， Pnmax， LCP， Rd， Vcmax， Jmax and TPU of H. miconioides seedlings under 90% shade were significantly lower than those under full light and 60% shade treatments. （3）The contents of starch， soluble sugar and NSC in leaves of H. miconioides seedlings were highest under 60% shade treatment， and decreased significantly under 90% shade treatment. The NSC content of H. miconioides seedlings was significantly positively correlated with Pn， Vcmax， Jmax and TPU respectively. Therefore， H. miconioides had ability of photopholic and shade-tolerant at the seedling stage， and plants could adjust the photosynthetic characteristics of leaves by reducing LCP and Rd， and maintained a high NSC content under moderate shading conditions， thereby to improve the utilization rate of weak light and carbon assimilation ability， however， excessive shading was not conducive to the growth of H. miconioides seedlings.

Key words: Heptacodium miconioides, shading, photosynthetic characteristics, non-structural carbohydrate

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