Abstract:

The plants in arid zones tend to accumulate more salt because the evaporation is much higher than the rainfall in arid environment, and because the selective uptake of water by plant roots results in the rise of salt concentration in solutions in the rhizosphere. In this study, parameters such as the Na⁺ and K⁺ concentrations, as well as the water status and photosynthesis were measured and analyzed. The results showed that H.ammodendron and T. ramosissima were able to absorb and accumulate more Na⁺ than H. scoparium and E. angustifolia. In accordance, H. scoparium and T. ramosissima also had lower water potentials and osmotic potentials in their tissues, as well as lower transpiration and larger range of water potential for effective photosynthesis than H. scoparium and E. angustifolia. There was a negative correlation between the Na⁺ concentration and the water/osmotic potentials of the plants, a negative correlation between the Na⁺ concentration and the transpirational water loss; but a positive correlation between the Na⁺ concentration and the range of water potential for effective photosynthesis. It is therefore concluded that the salt accumulation could decrease the osmotic potential and water potential of plant tissues, enhance the driving force of water absorption, and reduce the transpiration of the plants, which was beneficial for the plants to retain a relatively higher photosynthesis, implying that salt accumulation in plants could enhance the drought resistance of the plant species in arid zone.

Key words: arid zone, woody plants, salt accumulation, water absorption, drought tolerance