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Chinese Journal of Applied Ecology ›› 2016, Vol. 27 ›› Issue (4): 1177-1188.doi: 10.13287/j.1001-9332.201604.035

• Original Articles • Previous Articles     Next Articles

Characteristics of photosynthesis and light energy partitioning in Amorphophallus xiei grown along a light-intensity gradient.

FU Zhong1,2,3, XIE Shi-qing1,2, XU Wen-guo4, YAN Suo4, CHEN Jun-wen1,2,3*   

  1. 1Yunnan Research Center on Good Agricultural Practice for Dominant Chinese Medicinal Materials, Yunnan Agricultural University, Kunming 650201, China;
    2Institute of Konjac, Yunnan Agricultural University, Kunming 650201, China;
    3College of Agronomy and Biotechnology, Yunnan Agricultural University, Kunming 650201, China;
    4Dehong Extension Center of Agricultural Technology, Mangshi 678400, Yunnan, China
  • Received:2015-10-27 Revised:2016-01-26 Online:2016-04-22 Published:2016-04-22
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (no. 31160392).2015-10-27 Received, 2016-01-26 Accepted.*

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Abstract: The objective of the present study was to examine the adaptation strategy of Amorphophallus xiei, a shade-demanding species, grown under different levels of light intensity. The responses of leaf to photosynthetic active radiation, CO2 and simulated sunflecks were analyzed in A. xiei grown under 100% (high light), 32.6% (moderate light) and 5.98% (low light) of full sun. Meanwhile, chlorophyll a fluorescence parameter and light energy partitioning were also recorded and calculated in the above-mentioned responsive process. The results showed that in most cases, the maximum photosynthetic rate (Pmax), dark respiration rate, apparent quantum yield and carboxylation efficiency in A. xiei significantly decreased with increasing the light level, however, the light compensation point, CO2 compensation point significantly increased. The photosynthetic induction was quicker in individuals grown under moderate light (P<0.05), and the initial stomatal conductance (gs-i) during dark adaptation increased significantly with increasing the light level. There was a ne-gative correlation between gs-i and the time required to reach 30%, 50% and 90% of Pmax during the process of photosynthetic induction. Moreover, the values of actual photochemical efficiency of PSⅡ (ΔF/Fm′) in the light, phototochemical quenching of chlorophyll fluorescence (qP) and photosynthetic electron transport rate (ETR) were higher and non-photochemical quenching (NPQ) recorded in photosynthetic induction was also higher in individuals grown under high light, nevertheless, the maximum photochemical efficiency of PSⅡ in the light (Fv′/Fm′) was higher in individuals grown under low light. The proportion of light energy allocated to non-photochemical quenching (ФNPQ) was lower in individuals grown under high light, and, correspondingly, it was higher in ones grown under low light. The results obtained here suggested that, when exposed to high light stress, moderate- and low-light-grown A. xiei would activate the mechanism of energy dissipation to protect itself from injury. Correspondingly, high-light-grown individuals would employ the strategy of increasing heat dissipation and forming quenching complex to cope with high light stress, which, however, might be one of reasons for the sensitivity of A. xiei to high light environment.