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Acta Prataculturae Sinica ›› 2023, Vol. 32 ›› Issue (1): 99-111.DOI: 10.11686/cyxb2022027

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Effects of salt stress on the growth, physiology, and biochemistry of five Bromus inermis varieties

Rui-qiang LI(), Yu-xiang WANG, Yu-lan SUN, Lei ZHANG, Ai-ping CHEN()   

  1. College of Grassland Science,Xinjiang Agricultural University,Ministry of Education Key Laboratory for Western Arid Region Grassland Resources and Ecology,Xinjiang Key Laboratory of Grassland Resources and Ecology,Urumqi 830052,China
  • Received:2022-01-12 Revised:2022-02-24 Online:2023-01-20 Published:2022-11-07
  • Contact: Ai-ping CHEN

Abstract:

The aim of this study was to compare the salt tolerance of different Bromus inermis varieties. Seedlings of five B. inermis varieties (L1-5) were used as the experimental materials. According to the composition of soil salts in Xinjiang, two treatments were established; neutral salt (M salt) (NaCl∶Na2SO4∶Na2CO3=1∶4∶0) and alkaline salt (A salt) (NaCl∶Na2SO4∶Na2CO3=1∶1∶8). When seedlings reached the three-leaf stage, each pot was irrigated with 2 L salt treatment solution with an electrical conductivity (EC) of 20 ms·cm-1 at a one-time treatment. The control (CK) was irrigated with the same amount of tap water. After 30 days of treatment, the growth index, chlorophyll fluorescence characteristic parameters, malondialdehyde (MDA) content and osmoregulation substance content were measured. Then, correlation analysis, principal component analysis, and a membership function analysis were used to analyze and evaluate 13 indicators. The results showed that, other than maximum quantum efficiency (Fv/Fm) and potential quantum efficiency (Fv/Fo), the other 11 indexes were strongly affected by salt stress, and the values of the indexes differed significantly among the five Bromus varieties (P<0.05). The plant height, stem diameter, tiller number, aboveground biomass, root-crown ratio, MDA content, and proline content of the five B. inermis varieties showed different adaptive changes under different types of salt stress. The plant height of L2 and L4 was significantly higher in the A salt treatment than in the M salt treatment; the A salt treatment significantly increased the aboveground biomass of L3, while the M salt treatment had no significant effect compared with CK. The MDA content of L1, L2, and L5 increased more under the A salt treatment than under the M salt treatment, and the MDA content of L2 was higher than that in the other lines under the A salt treatment. Salt stress seriously inhibited root development and the accumulation of soluble sugars in all B. inermis varieties. The underground biomass and soluble sugar contents in the five B. inermis varieties were decreased to varying degrees in the salt treatments compared with CK. A principal component analysis showed that osmotic adjustment substance content and growth indexes could be used as comprehensive indexes of the salt tolerance of B. inermis. According to the salt tolerance evaluation D value, L4 has strong salt tolerance and L5 has weak salt tolerance.

Key words: Bromus inermis, saline alkali stress, correlation analysis, principal component analysis, membership function analysis