In order to investigate the influence mechanism of pH level on the growth and development of rice and nutrient uptake under different nitrogen forms, rice cultivar Guanghui 751 was grown with five pH treatments (pH 3.5, 4.5, 5.5, 6.5, and 7.5) to study the effects on the biomass accumulation, root morphology, and nutrient uptake of rice under ammonium-nitrogen and nitrate-nitrogen conditions hydroponically. The results showed that under ammonium-nitrogen conditions, the highest rice biomass accumulation was found at pH 6.5 treatment; compared with the pH 3.5 treatment, the shoot and whole-plant biomass accumulation increased by 146.6% and 142.5%, respectively. Plant height and maximum root length increased significantly; total root length, root surface area, and root volume increased by 612.6%, 317.8%, and 147.1%, respectively. The uptake of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), copper (Cu), zinc (Zn), iron (Fe), and manganese (Mn) increased by 159.5%, 114.3%, 181.9%, 241.4%, 124.4%, 74.9%, 173.4%, 366.2%, and 3058.0%, respectively. Under nitrate-nitrogen conditions, the highest rice biomass accumulation was found at pH=4.5 treatment; compared with the pH=3.5 treatment, the shoot, root, and whole-plant biomass accumulation increased by 36.7%, 49.6%, and 38.6%, respectively. Plant height and maximum root length increased significantly; total root length, root surface area, and root volume increased by 129.9%, 83.0%, and 47.5%, respectively. The uptake of N, P, K, Ca, Mg, Cu, Zn, Fe, and Mn increased by 40.0%, 27.7%, 51.0%, 78.5%, 71.2%, 53.9%, 292.1%, 1449.5%, and 695.1%, respectively. In conclusion, the optimum pH values for rice under ammonium-nitrogen and nitrate-nitrogen conditions were 6.5 and 4.5, respectively. Under their respective optimum pH conditions, ammonium-nitrogen and nitrate-nitrogen primarily increased rice biomass accumulation by promoting root growth and development and increasing nutrient uptake.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |