JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2017, Vol. 41 ›› Issue (04): 71-79.doi: 10.3969/j.issn.1000-2006.201608009

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Effects of cerium nitrate on growth and photosynthetic characteristics of Pseudostellaria heterophylla

MA Yingli, GU Hui, ZHANG Yufeng, DAI Li, LI Jing, JIANG Fanglei, XIA Dajuan, XIE Yinfeng*   

  1. Co-Innovation Center for the Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
  • Online:2017-08-18 Published:2017-08-18

Abstract: 【Objective】In order to improve the yield of the traditional Chinese medicinal plant Pseudostellaria heterophylla and to establish a theoretical and practical basis for its high-yield cultivation, the present study investigated the stimulatory effects of cerium nitrate on photosynthesis and root tuber yield of the plant. 【Method】The effects of cerium nitrate on the growth indices and photosynthetic parameters of P. heterophylla were analyzed. 【Result】The relative growth yield of seedling height and ground diameter, root tuber length, diameter, fresh weight, dry weight, yield per unit area, and chlorophyll and carotenoid contents initially increased and then decreased in response to increasing cerium nitrate concentrations. In particular, the changes induced by the optimal cerium nitrate concentration(400 mg/L)were statistically significant. In response to cerium nitrate treatment, the fresh and dry root tuber yields per unit area increased significantly by 42.59% and 41.83%, respectively, over that of the control treatment, and appropriate cerium nitrate concentrations also alleviated midday photosynthetic depression,improved the mean net photosynthetic rate(Pn), stomatal conductance(Gs), and transpiration rate(Tr)values associated with diurnal variation in photosynthetic parameters, and reduced intercellular CO2 concentration(Ci). During the experiment, the chlorophyll fluorescence parameters the maximal efficiency of PSⅡ photochemistry(Fv/Fm), the effective efficiency of PSⅡ photochemistry(Fv'/Fm'), the actual efficiency of PSⅡ photochemistry(ΦPSⅡ), and photochemical quenching(CPQC)initially increased and then decreased with increasing cerium nitrate concentrations, whereas non-photochemical quenching(CNPQ)exhibited a contrasting trend. Pn exhibited a significant positive correlation with seedling height, ground diameter, chlorophyll and carotenoid contents, Gs, ΦPSⅡ and Fv'/Fm', but a negative correlation with Ci and CNPQ. And grey correlation analysis indicated that the photosynthetic pigments, ΦPSⅡ, Fv'/Fm' and CPQC were the primary factors impacting photosynthesis. 【Conclusion】The present study demonstrates that appropriate concentrations of cerium nitrate improve the growth, root tuber yield and photosynthetic characteristics of P. heterophylla,and that the regulatory effect of cerium nitrate on photosynthesis is related to the promotion of light energy absorption and conversion, improvement in photochemical efficiency, and alleviation of photoinhibition. Regarding stomatal factors, the improvement of the non-stomatal limitation factor is the primary factor mitigating midday photosynthetic depression.

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