① Causing plant physiological drought. Excessive soluble salts in saline soil will increase the osmotic pressure of soil solution, which will cause physiological drought of plants, make the roots and seeds of plants unable to absorb enough water from the soil during germination, and even lead to water leakage of root cells, which will make plants wilt and even die.
② Damage to plant tissues. The salt content in soil is too high, especially in dry season. The accumulated salt in the surface soil often causes damage to hypocotyls, and sodium carbonate and potassium carbonate have the greatest damage ability. At high PH value, it will also lead to the direct damage of hydroxyl ions to plants. Some plants have accumulated too much salt, damaged protoplasm, and seriously hindered the synthesis of protein, resulting in the accumulation of nitrogen-containing intermediate metabolites and cytotoxicity.
③ Affect the normal nutrition of plants. Due to the competition of sodium ions, the absorption of potassium, phosphorus and other nutrients by plants is reduced, and the transfer of phosphorus is also inhibited, thus affecting the nutritional status of plants.
(4) affect the stomatal closure of plants. Under the action of high concentration of salt, the formation of starch in stomatal guard cells is hindered, so that cells cannot be closed, so plants are prone to drought and wither. The vast saline-alkali environment can not meet the growth demand of garden plants, and its geographical distribution has been developed, so the landscaping construction can not meet the needs of contemporary urban economic and ecological economic development.