# Effects of Growth Stages of Pugionium Gaertn. on Soil Microbial Biomass C:N:P Stoichiometric Ratios and Homeostasis in Northwestern China’s Desert Regions

## TL;DR

This study explores how the growth of desert plants called Pugionium Gaertn. affects soil microbes' nutrient balance, revealing how these plants influence soil health in arid regions.

## Contribution

The study reveals stage-dependent regulation of microbial C:N:P stoichiometry by Pugionium Gaertn. and species-specific responses to phosphorus limitation.

## Key findings

- Pugionium Gaertn. growth increases microbial biomass C, N, and P during vigorous growth stages.
- Phosphorus limitation intensifies during the plant's reproductive stage, affecting microbial stoichiometric ratios.
- Soil nitrogen, phosphorus, and extracellular enzymes regulate microbial stoichiometry through bacterial diversity.

## Abstract

Understanding how desert plants interact with their soil environment is crucial for ecosystem restoration. This study investigated how the growth of Pugionium Gaertn. plants, a genus native to the deserts of northwestern China, affects the balance of carbon (C), nitrogen (N), and phosphorus (P) in surrounding soil microbes. We aimed to identify the key factors driving these nutrient dynamics. Our results show that plant growth significantly increased microbial nutrient levels. However, the ratios of C:N:P in microbes shifted periodically, revealing a strong limitation of phosphorus, especially during the plant’s reproductive stage. We found that soil nitrogen, phosphorus, and the activity of key enzymes control these microbial nutrient ratios by influencing bacterial diversity. Furthermore, different Pugionium Gaertn. triggered distinct responses in fungi and bacteria to phosphorus shortage. These findings provide new insights into plant–microbe interactions in deserts and offer a scientific basis for improving vegetation restoration and soil health in these fragile ecosystems.

Microbial stoichiometry serves as a fundamental indicator of nutrient limitations in microbial communities. However, the dynamic effects of Pugionium Gaertn. growth on soil microbial C:N:P stoichiometric ratios and their primary driving factors in native desert ecosystems remain poorly understood. This study aimed to clarify the stage-dependent regulation of microbial C:N:P stoichiometry by Pugionium Gaertn. in native desert ecosystems. This study examined representative Pugionium Gaertn. (P. cornutum and P. dolabratum) in northwestern China’s desert regions, based on investigations conducted during 2022–2023, conducting systematic analysis of variations in rhizosphere soil microbial biomass C, N, and P levels, C:N:P stoichiometric ratios, fungal and bacterial diversity, soil physicochemical properties, and extracellular enzyme activities (EEAs) across different phenological stages. Results demonstrated that Pugionium Gaertn. growth significantly enhanced microbial biomass C, N, and P accumulation during vigorous growth stages. Simultaneously, stoichiometric ratios (C:N, C:P, N:P) exhibited periodic fluctuations, with P limitation characteristics becoming substantially intensified during the reproductive stage. Total soil nitrogen, total phosphorus, and EEAs significantly regulated microbial C:N:P stoichiometric ratios through their effects on bacterial diversity. In P. dolabratum, distinct response pathways were observed between fungi and bacteria to P limitation, indicating species-specific regulatory mechanisms. These findings provide novel insights into the relationship between Pugionium Gaertn. and soil elemental stoichiometry, as well as its influence on elemental dynamic balance at microbial and community levels. Furthermore, the results support ecological adaptation strategies of Pugionium Gaertn. communities in native habitats, offering scientific evidence for vegetation restoration and soil improvement in desert regions.