Abstract: A solutionculture experiment was conducted to explore the effects of phosphorus application on the seed germination vigor, seedling biomass, photosynthetic pigment content, and electric conductivity of Trifolium repens L. under Cu stress. The results showed that heavy metal Cu²⁺ (0-20 mg·L^-1) inhibited the seed germination and seeding growth of T. repens significantly. After phosphorus application (0.06%), the germination rate suppressed by Cu enhanced markedly, seedling growth was promoted, biomass and photosynthetic pigment content increased, and leaf cell membrane permeability decreased remarkably. Evidently, applying definite amount of phosphorus could alleviate the poisoning of excessive Cu²⁺ to T. repens.

Key words: Species diversity, Biodiversity index, Species richness, Altitude level, Qilian Mountains