Partial root-zone irrigation （PRI） has been proved to be an optimal water-saving irrigation technology, however, few studies were done on water transportation and distribution under PRI. The present study was perfor...Partial root-zone irrigation （PRI） has been proved to be an optimal water-saving irrigation technology, however, few studies were done on water transportation and distribution under PRI. The present study was performed to investigate the water transportation and distribution among the wet and dry root-zones and the shoot using deuterium water （D2O） in 1/4 root-zone PRI experiment. It also aimed to determine and analyze the D2O relative abundance within different types of roots and shoots. The results indicated that water could be transported from roots in wet root-zone to roots in dry root-zone and shoots within 2 h after irrigation. Water transportation in roots of wet-zone was carried out by absorbing root, 1-2 mm root, 2-5 mm root, and〉5 mm root progressively, while through a reverse process in three dry root-zones. In shoots, water was transported to trunk, central trunk, annual branches, shoot and leaf progressively. Thus in the young apple trees subjected to PRI, water was distributed ifrst in the roots, including the roots in the wet and dry root-zones, to satisfy the water need of roots itself, and then transported to the shoot within hours of irrigation.展开更多
Macroscopic spatiotemporal patterns arising in grey matter may explain the clinical manifestations of several functional neurological syndromes (migraine aura, epilepsies). Detailed descriptions of these patterns in c...Macroscopic spatiotemporal patterns arising in grey matter may explain the clinical manifestations of several functional neurological syndromes (migraine aura, epilepsies). Detailed descriptions of these patterns in central grey matter and their physicochemical or pharmacological manipulations can be useful in many scientific fields ranging from drug design to functional brain imaging. These evanescent dynamic structures are electrochemical in nature and show macroscopic tissue polarization due to coupled and macroscopic flow of ions and water across, along and between neuronal and glial membranes. So far the importance of the water flow in the CNS functional syndromes has been examined by manipulations of water channels aquaporines (AQP). In this paper we show the result of substituting H2O for D2O in retinal spreading depression experiments. This inverts the present logic by changing the flow in the water channels in intact tissue and observing the evolution of electrochemical patterns and recording the optical profiles of excitation waves in isolated chick retinas. D2O flow through AQPs is ~20% slower than that of H2O. The slower flux disturbs the tight coupling between ion and water flows across membranes and slowdown the Na-KATPase rate of change with metabolic consequences for the tissue. The whole tissue excitability shifts in a non-stationary manner toward a non-excitable state.展开更多
基金supported by the Beijing Natural Science Foundation,China (6102006)the New-Star of Science and Technology of Beijing Metropolis,China (2011051)
文摘Partial root-zone irrigation （PRI） has been proved to be an optimal water-saving irrigation technology, however, few studies were done on water transportation and distribution under PRI. The present study was performed to investigate the water transportation and distribution among the wet and dry root-zones and the shoot using deuterium water （D2O） in 1/4 root-zone PRI experiment. It also aimed to determine and analyze the D2O relative abundance within different types of roots and shoots. The results indicated that water could be transported from roots in wet root-zone to roots in dry root-zone and shoots within 2 h after irrigation. Water transportation in roots of wet-zone was carried out by absorbing root, 1-2 mm root, 2-5 mm root, and〉5 mm root progressively, while through a reverse process in three dry root-zones. In shoots, water was transported to trunk, central trunk, annual branches, shoot and leaf progressively. Thus in the young apple trees subjected to PRI, water was distributed ifrst in the roots, including the roots in the wet and dry root-zones, to satisfy the water need of roots itself, and then transported to the shoot within hours of irrigation.
文摘Macroscopic spatiotemporal patterns arising in grey matter may explain the clinical manifestations of several functional neurological syndromes (migraine aura, epilepsies). Detailed descriptions of these patterns in central grey matter and their physicochemical or pharmacological manipulations can be useful in many scientific fields ranging from drug design to functional brain imaging. These evanescent dynamic structures are electrochemical in nature and show macroscopic tissue polarization due to coupled and macroscopic flow of ions and water across, along and between neuronal and glial membranes. So far the importance of the water flow in the CNS functional syndromes has been examined by manipulations of water channels aquaporines (AQP). In this paper we show the result of substituting H2O for D2O in retinal spreading depression experiments. This inverts the present logic by changing the flow in the water channels in intact tissue and observing the evolution of electrochemical patterns and recording the optical profiles of excitation waves in isolated chick retinas. D2O flow through AQPs is ~20% slower than that of H2O. The slower flux disturbs the tight coupling between ion and water flows across membranes and slowdown the Na-KATPase rate of change with metabolic consequences for the tissue. The whole tissue excitability shifts in a non-stationary manner toward a non-excitable state.
