Unveiling the role of foliar fungi in mediating leaf photosynthesis under global change

Global nitrogen (N) deposition and changes in precipitation patterns profoundly influence leaf photosynthesis and carbon sequestration in terrestrial ecosystems. Foliar fungi, a critical microbial community on leaf surfaces, could simultaneously impact several leaf functions. However, the regulated effects of foliar fungi on leaf photosynthesis in response to nitrogen and water additions remain unclear.  Here, using a long-term field and a complementary pot fungicide experiment in an alpine meadow, we quantified the effects of nitrogen and water addition on leaf photosynthesis and foliar fungal communities in two dominant species.
, Site description
The experiment was conducted at Haiyan County (36.92° N, 100.94° E, 3090 m a.s.l), located on the northeastern Qinghai-Tibetan Plateau. This region has a mean annual temperature of 0.94°C and mean annual precipitation of 404.66 mm, with approximately 80% of precipitation occurring during the growing season (June to August). The vegetation at this site is dominated by Carex alatauensis and Leymus secalinus. The soil at the study site is classified as Mat-Gryic Cambisol with a clay-loam texture. Additionally, the soil pH is approximately 8.09, soil total carbon concentration is 21.28 g kg-1, and soil total nitrogen concentration is 3.33 g kg-1.
Experimental design
Our study conducted both a long-term field experiment and a complementary pot experiment. The field experiment was separated from the adjacent pot experiment by 5 m buffer zone.
Field experiment
The nitrogen (N) and precipitation addition experiment has been established since 2017. Nitrogen was applied as urea a..., # Unveiling the role of foliar fungi in mediating leaf photosynthesis under global change

Dataset DOI: [10.5061/dryad.w0vt4b95p](https://doi.org/10.5061/dryad.w0vt4b95p)

### Description of the data and file structure

**Overview**

1. This study includes four data files (CSV format) and one analysis file (R). All data and code referenced in the main text have been uploaded.
2. Some data mentioned in the Supplementary Information (SI) relate to other, currently unpublished manuscripts. If needed, please contact: [[e-mail]](mailto:[e-mail])**.**Notes added for clarity:

The four CSV files and the single R script are **sufficient to reproduce all analyses and figures reported in the main text**.

Additional SI-related datasets are **not required** to reproduce the main results described in the article.

### Files and variables

#### Files at a glance

* `data/` — four CSV files (file names listed below)
* `Photo_upload.csv` — [Experimental Plot Leaf Photosynthetic M...,