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Acta Prataculturae Sinica ›› 2016, Vol. 25 ›› Issue (7): 131-139.DOI: 10.11686/cyxb2015436

• Orignal Article • Previous Articles     Next Articles

Effects of Chromium stress on physiological and ecophysiological characteristics of male and female plants of Humulus scandens

WANG Bi-Xia1, XIAO Juan1, FENG Xu2, GAN Li-Fen3, TANG Ya1   

  1. 1.College of Environmental Science and Engineering, China West Normal University, Key Laboratory of Environmental Science and Biodiversity Conservation, Nanchong 637009, China;
    2.College of Life Science, China West Normal University, Ministry of Education Key Laboratory of Southwest China Wildlife Resources Conservation, Nanchong 637009, China;
    3.College of Postgraduates, China West Normal University, Nanchong 637009, China
  • Received:2015-09-14 Revised:2015-11-23 Online:2016-07-20 Published:2016-07-20

Abstract:

This paper studied the differences of sex-specific and photophysiological characteristics of male and female plants of Humulus scandens exposed to chromium (0, 50, 200 and 300 mg Cr3+/kg soil). The results showed: 1) the net photosynthetic rate (Pn), chlorophyll fluorescence parameters, root fresh weight and stem length were greater in the females than males for the plants grown under 0 mg/kg (control), but the chlorophyll and malondialdehyde (MDA) concentrations were lower for females than for the males. 2) Compared with control plants, Pn was significantly increased in the 50 mg/kg Cr3+ treatment for both male and female plants, but chlorophyll fluorescence parameters were significantly decreased by Cr3+ in male plants and the value of other photophysiological indexes and plant growth were slightly increased by Cr3+, while Cr3+ had no effect on the value of photophysiological indexes and growth of female plants. The value of Pn and the MDA concentration were similar to those of control plants in 200 mg/kg Cr3+ treatment, but the root fresh weight and chlorophyll fluorescence parameters were significantly lower than for control plants. However, the 300 mg/kg Cr3+ treatment significantly inhibited both of the male and female plants, and in this treatment Pn was significantly decreased (especially in male plants; females demonstrated enhanced ability to repair damage) compared to control plants, and all of the above-mentioned indexes and parameters were also significantly lower than control plants. 3) Overall, Pn of male and female plants first increased and then decreased with Cr3+ exposure time, while stem length, root fresh weight and chlorophyll fluorescence parameters were directly decreased, and MDA content and the apparent electron transport rate (ETR) were promoted. However, the chlorophyll content of males decreased with increasing Cr3+ concentration, but there was no significant decrease in chlorophyll content and photosystem II reaction centers for the female plants. In summary, Pn was increased by low Cr3+ concentration and inhibited by higher Cr3+ both in male and female plants. The plants demonstrated self-protective physiological response mechanisms. This was especially true for the female plants, which have a more flexible response strategy with higher tolerance capacity.