Engelaar W M H G, VAN Bruggen M W, VAN DEN Hoek W P M, Huyser M A H, Blom C W P M
Department of Ecology, University of Nijmegen, Toernooiveld, 6526 ED Nijmegen, The Netherlands.
New Phytol. 1993 Nov;125(3):565-574. doi: 10.1111/j.1469-8137.1993.tb03904.x.
The effects of hypoxia in ballotini and quartz sand with respectively large and small soil pore diameters on root porosity was studied for Rumex palustris Sra., Rumex acetosa L. and Plantago major L. ssp. major. Under hypoxic conditions R. palustris produced large root pores when large soil pores were present. Absence of such large soil pores resulted in the collapse of the root structure and a reduced root growth. Increases in intercellular spaces in P. major roots seemed to result in a higher root porosity upon hypoxia, a small soil pore diameter or a combination of both but this was not significant. Only a limited number of roots with large root pores was produced. The morphological structure of P. major roots without large root pores remained intact also in soils with a small soil pore diameter. R. acetosa only slightly increased its root porosity upon hypoxia and its morphological structure also remained intact when soil pore diameter was small. Radial oxygen loss (ROL) was found in R. palustris roots when grown in waterlogged, uncompacted soils. P. major had some roots with ROL in all treatments except in waterlogged, compacted soil. R. acetosa did not produce any roots showing ROL. Under field conditions aerenchyma is of no use in water saturated, compacted soils. This explains why a species like R. palustris only grows on hypoxic soil when it is not compacted, in contrast to P. major which will grow on moist, compacted soils. R. acetosa cannot be found on either very moist or heavily compacted soil, since it does not produce a healthy root system under these conditions.
研究了分别具有大、小土壤孔隙直径的陶土球和石英砂中的缺氧对酸模、醋栗和大车前草根系孔隙率的影响。在缺氧条件下，当存在大土壤孔隙时，酸模会产生大的根孔隙。缺乏这种大土壤孔隙会导致根系结构崩溃和根系生长减少。大车前草根系细胞间隙的增加似乎导致在缺氧、小土壤孔隙直径或两者结合的情况下根系孔隙率更高，但这并不显著。只产生了有限数量的具有大根孔隙的根。在小土壤孔隙直径的土壤中，没有大根孔隙的大车前草根系形态结构也保持完整。醋栗在缺氧时根系孔隙率仅略有增加，当土壤孔隙直径小时，其形态结构也保持完整。在淹水、未压实的土壤中生长时，酸模根中发现了径向氧损失（ROL）。除了淹水、压实的土壤外，大车前草在所有处理中都有一些根具有ROL。醋栗没有产生任何显示ROL的根。在田间条件下，通气组织在水饱和、压实的土壤中没有用处。这就解释了为什么像酸模这样的物种只在未压实的缺氧土壤上生长，而大车前草则会在潮湿、压实的土壤上生长。在非常潮湿或严重压实的土壤中都找不到醋栗，因为在这些条件下它不能产生健康的根系。
