Tropical forest face significant challenges due to global climate change, particularly shifting precipitation patterns that including delayed rainy seasons and extreme rainfall events. These changes will impact soil water and nutrient cycling and alter plant strategies for water and nutrient absorption and utilization. The highly weathered soils common in tropical regions result in phosphorus (P) deficiency, and changes in precipitation patterns may exacerbate this issue. Thus, it is crucial to understand the mechanisms of plant response to water and nutrient availability under such dual pressures.

We conducted a study at the Xiaoliang Tropical Coastal Ecosystem Research Station using the "Precipitation Pattern Change" experimental platform in a tropical secondary forest. We focused on four dominant tree species, i.e., Carallia brachiata, Symplocos poilanei, Schefflera heptaphylla and Tetradium glabrifolium. The primary objectives were to detect water absorption sources, dynamics of soil and leaf P fractions under altered precipitation patterns. Results showed that under the delayed wet season treatment (DW), trees significantly increased their use of groundwater. Conversely, within the wetter wet season treatment (WW), trees primarily absorbed water from soil layers at the depth of 40-60 cm. Additionally, soil P fraction responded more sensitive to altered precipitation patterns than total soil P content. DW treatment reduced plant-available P in the soil, while WW treatment elevated soil pH and NH₄⁺-N content. These changes indirectly influenced leaf P fractions and the efficiency of nitrogen and phosphorus in photosynthesis, ultimately affecting plant photosynthetic rates. Furthermore, different dominant tree species exhibited specific adaptive strategies to changes in water availability.

These study have been published in Agricultural and Forest Meteorology and Plant and Soil, titled "Responses of plant water uptake sources to altered precipitation patterns in a tropical secondary forest" and "Dynamics of soil and foliar phosphorus fractions in a secondary tropical forest under altered seasonal precipitation patterns", respectively. Xiaofang He is the first author and Professor Jun Wang is the corresponding author of these two papers. These studies were supported by the National Natural Science Foundation of China and other Foundations. The papers can be accessed at https://doi.org/10.1016/j.agrformet.2024.110138 and https://doi.org/10.1007/s11104-024-06774-9.

First author information: Xiaofang He: Post-doctoral, Research Center for Ecology and Environmental Sciences, South China Botanical Garden, Chinese Academy of Science, Research field: Plant physiology and ecology, E-mail: hexiaofang@scbg.ac.cn.