Restricted root-to-shoot translocation and decreased sink size are responsible for limited nitrogen uptake in three grass species under water deficit |
| |
Affiliation: | 1. Unité de Recherche Pluridisciplinaire Prairies et Plantes Fourragères, INRA, BP6, F-86600 Lusignan, France;2. UMR 7618 BIOEMCO, Université Pierre-et-Marie-Curie–CNRS–INRA, Centre de recherche INRA–INA PG, Bâtiment EGER, 78850 Thiverval-Grignon, France;3. Instituto de Agricultura Sostenible – CSIC, Alameda del Obispo, s/n 14004, Córdoba, Spain;1. Department of Hepatology, First Affiliated Hospital, Guangxi University of Chinese Medicine, PR China;2. Guangxi University of Chinese Medicine, Nanning, Guangxi, PR China;1. School of Traditional Chinese Materia Medica, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016, PR China;2. Key Laboratory of Structure-Based Drug Design and Discovery (Shenyang Pharmaceutical University), Ministry of Education, Shenyang 110016, PR China;3. School of Pharmacy, Shenyang Pharmaceutical University, Shenyang 110016, PR China;4. Mathematics Teaching & Research Section, Shenyang Pharmaceutical University, Shenyang 110016, PR China;1. Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Via Marzolo 5, 35131 Padova, Italy;2. S-IN Soluzioni Informatiche, Via Ferrari 14, 36100 Vicenza, Italy;3. Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy |
| |
Abstract: | Earlier studies showed that water deficit reduces nitrogen (N) uptake and N nutrition index of grasses. So far, the main effect of water deficit on N uptake and N nutrition status was ascribed to the alteration of the transpiration-dependent transport of mineral N in the soil solution. A split-root experiment was performed to determine whether plant and/or solution water potential could alter N uptake and allocation, independently of N fluxes in the soil solution. The split-root experiment allowed to manipulate separately the water and the N status of the root environment and of the plant, by various combinations of addition of polyethylene glycol 6000 (PEG) and mineral N on half or on the entire root system. Tall fescue, Italian ryegrass and cocksfoot, known for their contrasted sensitivities to water deficit, were studied. The addition of PEG largely reduced water and N uptake of the roots on which it was applied (half or entire root system). A significant accumulation of N was observed on the roots to which PEG was added, particularly in cocksfoot and tall fescue, hypothetically contributing to the alteration of N uptake. Cocksfoot displayed a high plasticity in N allocation to leaves related to sheaths, allowing the maintenance of N concentration and therefore its N status despite the reduction in N uptake. By contrast, leaf N concentration and N status of tall fescue and Italian ryegrass was more sensitive to water deficit, similarly to observations of the effect of drought in field studies. Therefore, it is concluded that the effect of soil solution potential on N uptake and plant N allocation may also contribute to the observed effect of drought on N status of grass crops, additionally to the effect of drought on the transfer of mineral N in the soil solution to the root surface. However, the importance of this physiological effect varies among species. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|