Response of the main qualities of tropical perennial herbaceous spice plant (Pandanus amarylllifolius Roxb.) to regional precipitation changes

Pandanus amarylllifolius Roxb. a tropical aromatic crop with both economic value and ecological adaptability, exhibits quality attributes significantly influenced by precipitation patterns. Under the context of global climate change, fluctuations in tropical rainfall have emerged as critical factors constraining the stability of its phytochemical profile, underscoring the importance of related research. This study employed five precipitation gradient experiments to quantify soil microenvironment parameters and the core volatile constituents of Pandanus amarylllifolius. Utilizing two-factor variance analysis and other statistical methods, the mechanisms by which precipitation modulates leaf quality were elucidated. Results indicated that precipitation markedly affects soil temperature(ST), soil moisture(SM), soil organic matter（SOM), and volatile compound profiles. The highest overall quality index was observed under the P+6 treatment, with soil temperature(ST） and soil organic matter（SOM) positively correlated with quality, while soil moisture(SM) showed a negative correlation. Additionally, interactions between precipitation and annual variation significantly influenced most volatile compounds. This research clarifies the response of tropical aromatic herb quality to precipitation variability, providing theoretical and practical guidance for adapting cultivation practices to mitigate the impacts of precipitation fluctuations.