麻豆淫院

A new study in the Journal of Plant Ecology has found that temperate forest tree species, regardless of their root symbiosis with either ectomycorrhizal (ECM) or arbuscular mycorrhizal (AM) fungi, consistently prefer absorbing nitrate (NO鈧冣伝) over ammonium (NH鈧勨伜). The findings challenge longstanding assumptions about nitrogen uptake strategies among different tree functional groups and offer new insights into how plant鈥揻ungus interactions shape nutrient cycling in forest ecosystems.

Led by Dr. Fang Yunting from the Institute of Applied Ecology of the Chinese Academy of Sciences, researchers conducted an extensive field experiment in northeastern China using a novel approach known as the paired-鹿鈦礜 labeling technique. This method involves injecting isotopically labeled ammonium nitrate (NH鈧凬O鈧�) into the rhizosphere鈥攖he soil zone surrounding plant roots鈥攁nd tracing the rate and proportion of 鹿鈦礜 uptake by the plants. The approach enables precise measurement of a plant's nitrogen source preference under natural conditions.

The experiment, conducted at the Qingyuan Forest Ecosystem National Observation and Research Station, included seedlings from 10 temperate tree species鈥攕ix broadleaved and four coniferous. These were grouped based on their root mycorrhizal associations: AM-associated broadleaved trees, ECM-associated broadleaved trees, and ECM-associated conifers.

Results showed that all 10 species took up more nitrate (NO鈧冣伝) than ammonium (NH鈧勨伜), with nitrate accounting for between 49% and 83% (average 69%) of total nitrogen absorbed. Among the groups, AM-associated broadleaved species demonstrated the strongest nitrate preference (average 79%), followed by ECM-associated broadleaved species (70%) and ECM-associated conifers (60%).

The researchers employed a random forest model鈥攁n advanced machine learning algorithm used for variable selection鈥攖o identify the primary drivers of this variation. They found that mycorrhizal type, plant functional group, and the ratio of fine root mass to above-ground biomass (fine root-to-shoot ratio) were the most influential factors determining nitrate uptake patterns.

Nitrogen, a fundamental nutrient for plant development, exists in forest soils primarily as ammonium and nitrate. The form that plants preferentially absorb influences species competition, forest productivity, and carbon storage capacity. The study's results suggest that AM-associated trees may be better adapted to nitrate-rich soils, a factor that could be critical when designing reforestation or afforestation programs under changing environmental conditions.

The study underscores the complex interplay between root symbioses and nutrient acquisition, highlighting the potential for further application of the paired-鹿鈦礜 labeling method in ecological studies. By deepening our understanding of species-specific nutrient preferences, it provides valuable evidence for forest management and biodiversity conservation under changing environmental conditions.