Physiological responses of glycophytic and halophytic grasses Poa pratensis, Poa juncifolia, and Puccinellia nuttalliana to salt stress

• Author / Creator

  Vaziriyeganeh, Maryamsadat

• Responses of two halophytic grasses Puccinellia nuttalliana and Poa juncifolia to treatments with NaCl were compared with the glycophytic grass Poa pratensis to better understand salt tolerance mechanisms in these plants. The experiments were carried out under controlled-environment conditions with hydroponically-grown seedlings. The plants were subjected to 50, 150, and 300 mM NaCl treatments for up to 10 days and compared with their respective untreated controls (0 mM NaCl). At the lower NaCl concentrations, shoot and root dry weights were drastically reduced in Poa pratensis, but increased in Puccinellia nuttalliana and Poa juncifolia. The examined NaCl treatment concentrations had either no effect (Puccinellia nuttalliana) or little effect (Poa juncifolia) on the net photosynthesis and transpiration rates in the halophytic plants, but severely decreased the gas exchange parameters in Poa pratensis. Similarly, to growth and gas exchange, shoot water content in Puccinellia nuttalliana was not affected even by the highest, 300 mM NaCl concentration, while Poa pratensis showed decreased shoot water content in all examined NaCl treatments and Poa juncifolia in 150 and 300 mM NaCl. Cell hydraulic conductivity in Poa pratensis also showed high sensitivity to NaCl and drastically decreased in all examined treatments. Cell hydraulic conductivity in Poa juncifolia was less affected by NaCl compared with Poa pratensis and it increased in response to NaCl treatments in Puccinellia nuttalliana. Both Puccinellia nuttalliana and Poa juncifolia accumulated less Na in their shoot tissues compared with Poa pratensis and maintained relatively higher K concentrations in roots. Puccinellia nuttalliana also accumulated more P and Mg in the shoot and root tissues compared with the two other examined grass species. The results demonstrate the importance of restricting root to shoot Na transport and maintenance of aquaporin-mediated water transport in salt tolerance of the two studied halophytes.

• Subjects / Keywords

  • Water relations
  • Gas exchange
  • Glycophytes
  • Growth
  • Halophytes
  • Salt stress

• Graduation date

  Fall 2017

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3PN8XV6X

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.