Abstract:
Background Acid rain pollution can indirectly affect plants through direct leaching to plants or by causing soil acidification. Nitrogen (N) and phosphorus (P) are important components for the growth and development of organisms, and acid rain leaching to plant seedlings can affect the N and P content of plants, and different concentrations of acid rain treatment affect different plant species differently. The study area is located in the Jinyun Mountains of Chongqing, which is one of the most affected areas by acid rain in China. The aim of the study is to investigate the relationship between plant nutrients and their stoichiometry and their responses to acid rain by investigating the effects of acid rain on the N and P contents and ecological stoichiometry of plant seedlings.
Methods Taking two-year Cunninghamia lanceolata, Pinus massoniana, Cinnamomum camphora and Phyllostachys edulis seedlings as the research objects, in May 2021 in Jinyun Mountain, Chongqing, the pH value was set to 7.0 (control), 4.5, 3.5 and 2.5, a total of 4 gradients, record as CK, pH4.5, pH3.5 and pH2.5 respectively, an in situ simulated acid rain spraying trial was carried out for a period of 4 months. The N, P content and stoichiometric ratio of different measured plant seedlings were analyzed, and the nitrogen-phosphorus ratio was calculated.
Results Under different concentrations of acid rain, the N and P contents of leaves of C. lanceolata, P. massoniana, C. camphora and P. edulis were higher than those of roots and stems. The sensitivity coefficient of N content in roots and leaves of seedlings to acid rain treatment was higher than that of stems. At pH3.5 and pH4.5 of C. lanceolata and P. massoniana were N-limited, P. edulis was N-limited at pH3.5, and C. camphora was P-limited at pH3.5 and pH4.5. Organ N: P measured characteristics had different effects, affecting the balance of N and P content in plant seedlings. There was a positive correlation between N and P contents in C. lanceolata, P. massoniana, C. camphora and P. edulis roots, and N and P contents showed a certain proportion of composition and coordination.
Conclusions Different plants respond differently to acid rain treatment, and the nutrient content of plants and their distribution among various organs are related to the morphological and structural characteristics of the plants themselves and the characteristics of external environmental changes.
下载: