| 树木体内水分长距离运输的负压传递机制 |
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| 引用本文： | 尚念科. 树木体内水分长距离运输的负压传递机制[J]. 山东林业科技, 2011, 41(3): 90-92 |
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| 作者姓名： | 尚念科 |
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| 作者单位： | 山东省莱芜市林业局,山东莱芜,271100 |
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| 摘 要： | 蒸腾能使木质部产生不超过-0.1MPa的有限负压,这个负压在木质部内自上而下依次向下传递。水分在导管或管胞内所受的吸附力、毛管力、真空力等综合作用力要大于或等于所受的重力,这个综合作用力可以将水分托住而不受重力作用而下移,使水分在负压作用下以分段移动的方式从根部上升到植物顶端。空穴和栓塞是两个不同的概念,其形成过程、恢复机制都有其本质的不同。空穴的发生与负压和水分的分段移动有密切的关系。
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| 关 键 词： | 水分长距离运输 负压传递 分段移动 空穴 栓塞 |
Negative Pressure Transport Mechanism of Long-distance Water Transport in Trees |
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| Shang Nianke. Negative Pressure Transport Mechanism of Long-distance Water Transport in Trees[J]. Journal of Shandong Forestry Science and Technology, 2011, 41(3): 90-92 |
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| Authors: | Shang Nianke |
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| Affiliation: | Shang Nianke(Laiwu Forestry Bureau in Shandong Province,Laiwu,Shandong 271100) |
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| Abstract: | Transpiration can prompt the xylem to produce no more than-0.1MPa limited negative pressure,which delivering in a top-down sequence in the xylem.The combined effects of adsorptive force,capillary force,and vacuum force that water accepts within the vessels or tracheids are greater than or equal to the gravity suffered,so that water could be supported by this combined force to transport from bottom to top in the plant section by section,instead of reversing as a result of the gravity.Cavitation and Embolism ... |
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| Keywords: | Long-distance Water Transport Negative Pressure Transport Sub-segment Movement Cavitation Embolism |
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