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Acta Prataculturae Sinica ›› 2024, Vol. 33 ›› Issue (5): 41-57.DOI: 10.11686/cyxb2023302

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Effects of drought stress and rehydration on the growth and physiological characteristics of annual herbaceous plants from a desert-oasis ecotone

Lu-jing ZENG1(), Guo-hua WANG1,2()   

  1. 1.College of Geographical Sciences,Shanxi Normal University,Taiyuan 030031,China
    2.Linze Inland River Basin Research Station,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730010,China
  • Received:2023-08-29 Revised:2023-10-17 Online:2024-05-20 Published:2024-02-03
  • Contact: Guo-hua WANG

Abstract:

In desert-oasis ecotones, many annual herbaceous plant populations form permanent plant synusiae, which play important roles as windbreaks and in sand fixation, thereby protecting the stability of the oasis ecosystem. In this study, we selected Chloris virgataSetaria viridisHalogeton arachnoideusAgriophyllum squarrosum, and Bassia dasyphylla as five typical annual herbaceous plants under artificial forests in a typical desert-oasis ecotone in the Hexi Corridor, and conducted pot experiments with simulated drought and rehydration treatments. We measured the changes in root and leaf growth traits (i.e., plant height, root volume, average root diameter, total root surface area, total root length, and root dry weight) and physiological characteristics (i.e., root activity, contents of photosynthetic pigments, malondialdehyde, osmotic adjustment substances, and antioxidant enzyme activity) of seedlings of the five plants to analyze their adaptive strategies to drought stress. The results showed that light drought stress (i.e., soil moisture decreased by 2% compared with the control) had no significant negative effect on the growth of the five annual herbaceous plants, but promoted their growth to some extent. Plant growth was significantly inhibited under moderate (soil moisture decreased by 4%) and severe (soil moisture decreased by 6%) drought stress. The contents of malondialdehyde and osmoregulatory substances and the activity of peroxidase in the roots and leaves increased with increasing severity of drought stress; but the root activity decreased significantly. The activity of superoxide dismutase in the roots of the annual Gramineae C. virgata and S. viridis increased with increasing severity of drought stress; however, its activity in the roots of A. squarrosum and B. dasyphylla (Chenopodiaceae) initially increased and then decreased with increasing severity of drought stress. Upon rehydration treatments, the growth and physiology of all five plant species were compensated to different degrees. Roots recovered better than did leaves, and shallow-rooted plants were better able to recover than deep-rooted ones. The drought tolerance of the five annual herbs differed significantly, and they were ranked from most to least drought tolerant as follows: S. viridis>H. arachnoideus>B. dasyphylla>C. virgata>A. squarrosum.

Key words: annual herbaceous plants, drought stress, rehydration, growth, physiological characteristic