Nitrogen and phosphorus stoichiometric homoeostasis characteristics of four dominant plants in a desert steppe

Exploring the characteristics of plant stoichiometric homoeostasis is important to further understand the growth adaptation strategies of grassland plants. This study selected four dominant plants (Lespedeza potaninii, Sophora alopecuroides, Stipa breviflora, and Artemisia scoparia) in the desert steppe of Etuokeqianqi in Inner Mongolia as the research objects. The results indicated that: The contents of N and N ꞉ P in leaves of A. scoparia were significantly different from those of the other three dominant plants. The content of P in leaves of A. Artemisia was also significantly different from those of the other three dominant plants (P < 0.05). The N homeostasis index (H_N) of L. potaninii was the highest among the four dominant plants, belonging to homeostasis. The P homeostasis index (H_P) of A. scoparia was the highest among the four dominant plants, implying homeostasis. The N ꞉ P homeostasis index (H_{N ꞉ P}) of L. potaninii was also the highest among the four dominant plants, belonging to weak homeostasis. The results of RDA analysis showed that the explanation rates of soil total carbon and total nitrogen contents to the stoichiometric homoeostasis were 56.9% and 9.9%, respectively, reaching significant levels (P < 0.05); the effects of the other soil physical and chemical factors were relatively weak. In conclusion, the endogenous stability of N and N ꞉ P of perennial plants were higher in the desert steppe with low nitrogen content, and perennial plants adopted conservative nutrient strategies. The shrub L. potaninii showed higher endogenous stability of N and better adaptation. The P internal stability of annual plants was higher but the N ꞉ P internal stability was lower, and adopted the luxury allocation strategy. The main factors of stoichiometric homoeostasis were soil total carbon and total nitrogen contents.