Growth and Physiological Responses of Conifer Seedlings to Salt Stress and Nutrient Deficiency

• Author / Creator

  Olivier, Samantha

• Oil sands extraction and refining can cause many negative environmental impacts and because these activities usually take place in the forest region, the Government of Alberta requires that, after mine sites are closed, the companies perform reclamation. The properties of reclaimed oil sands soils may include a poor nutrient regime and high concentration of dissolved Na and Cl, affecting soil quality and plant development. The present research examined the relationship between salt uptake, tissue concentration, and plant injury in black spruce (Picea mariana), white spruce (Picea glauca), and jack pine (Pinus banksiana) subjected to different treatment concentrations of NaCl (30, 60, and 90 mM), and how other environmental factors, including deficiency of N, P, and K, affect plant growth and development in white spruce and jack pine. The studies were conducted through a series of controlled-environment experiments in sand culture and hydroponic system. Compared with control seedlings, stem diameter and heights of black spruce, white spruce, and jack pine were significantly reduced by all NaCl treatments. White spruce and jack pine also exhibited reduced biomass. Needle chlorophyll concentrations decreased under NaCl treatments in all species. Visible symptoms of salt injury were observed in young and old needles of seedlings treated with NaCl and significant necrosis was present in most of the plants under 90 mM NaCl treatment. The greatest effect was observed in white spruce, with an average of 58% of the needles injured. However, jack pine showed a slightly higher accumulation of Na and Cl in the needles than white spruce. The critical Na concentration differed between species. In black spruce, a concentration of 2.67 mg g-1 of Na in needles of seedlings treated with 30 mM NaCl caused up to 10% of necrosis while 17.72 mg g-1 of Na in needles of seedlings treated with 90 mM NaCl had 34% needle necrosis. In white spruce, with 11.62 mg g-1 of Na in needles of seedling treated with 30 mM NaCl caused 10% necrosis. Similarly, jack pine with10.91 mg g-1 of Na in needles of seedling treated with 30 mM NaCl, had 18% needle necrosis, suggesting that level of salt injury can be correlated, and therefore, predicted from shoot Na concentrations. The effects of combined NaCl and nutrient concentrations treatments varied between the species studied, but, in general, the effects of NaCl on stem diameters, heights, total dry weights, chlorophyll concentrations, net photosynthesis, and transpiration rates were aggravated by P deficiency, with greater impacts on jack pine compared with white spruce. Therefore, P fertilization should be considered as an important factor in revegetation areas.

• Subjects / Keywords

  • Plant physiology
  • Conifers
  • Salinity

• Graduation date

  Spring 2018

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3M03ZC5H

• 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.