RESUMO
Ammonium promotes rice P uptake and reutilization better than nitrate, under P starvation conditions; however, the underlying mechanism remains unclear. In this study, ammonium treatment significantly increased putrescine and ethylene content in rice roots under P deficient conditions, by increasing the protein content of ornithine decarboxylase and 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase compared with nitrate treatment. Ammonium treatment increased rice root cell wall P release by increasing pectin content and pectin methyl esterase (PME) activity, increased rice shoot cell membrane P release by decreasing phosphorus-containing lipid components, and maintained internal P homeostasis by increasing OsPT2/6/8 expression compared with nitrate treatment. Ammonium also improved external P uptake by regulating root morphology and increased rice grain yield by increasing the panicle number compared with nitrate treatment. The application of putrescine and ethylene synthesis precursor ACC further improved the above process. Our results demonstrate for the first time that ammonium increases rice P acquisition, reutilization, and homeostasis, and rice grain yield, in a putrescine- and ethylene-dependent manner, better than nitrate, under P starvation conditions.
Assuntos
Compostos de Amônio , Oryza , Compostos de Amônio/metabolismo , Compostos de Amônio/farmacologia , Membrana Celular/metabolismo , Parede Celular/metabolismo , Esterases/metabolismo , Etilenos/metabolismo , Lipídeos , Nitratos/metabolismo , Ornitina Descarboxilase/metabolismo , Oryza/metabolismo , Oxirredutases/metabolismo , Pectinas/metabolismo , Fósforo/metabolismo , Raízes de Plantas/metabolismo , Putrescina/metabolismoRESUMO
OBJECTIVE: To explore clinical effect of treatment of fractures of the talar neck with hollow compression screw via inner malleolus tomy approach. METHODS: Twelve patients with fractures of the talar neck included 7 males and 5 females with a mean age of 38 years (reaging from 20 to 56 years). According to the Hawkins classification, 8 cases were type II and 4 cases were type II. Twelve patients were treated with hollow compression screw via inner malleolustomy approach. RESULTS: All the patients were followed up for 1 year to 6 years and 8 months (average 4 years and 5 months), all the fractures were bony union. The mean Hawkins score was excellent in 5 cases, good in 5 cases, fair in 1 case and poor in 1 case. CONCLUSION: It is a good method to treat the fractures of the talar neck with hollow compression screw via inner malleolus tomy approach.