USE OF POLAROGRAPHY IN ASSAY OF OXYGEN DIFFUSING FROM ROOTS IN ANAEROBIC MEDIA
USE OF POLAROGRAPHY IN ASSAY OF OXYGEN DIFFUSING FROM ROOTS IN ANAEROBIC MEDIA
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DOI：
10.1111/j.1399-3054.1967.tb07195.x
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发表时间：
1967-01-01
影响因子：
6.4
通讯作者：
ARMSTRONG, W
中科院分区：
文献类型：
--
作者：
ARMSTRONG, W
本文详细介绍了一种可以测量植物根部氧气向外扩散速率的“极谱”技术。研究发现，10种沼泽植物[Eriophorum an-gustifolum，E.zzinata，Juncus effusus，Menyanths trifoliata，Molinia Blue utea，Narthecium ossiFragum，Schoenus nigricans，Spartina town sendii，Tricophorum caespososum，稻草cv.]的根中都有氧气弥散。到目前为止进行了测试，其中8个物种的氧扩散速率(ODR)表明存在种间差异。由硅橡胶管子制成的模型根给出了与活根周围获得的相同的“极谱图”。伴随着根的成熟而发生的硫化被认为是A、氧扩散与根的顶端区域的联系，以及B、氧扩散速率的降低与冬季休眠有关。这种根部氧扩散的局部化可能在还原土壤中具有生存价值。实验表明，如果气孔长期关闭，通风组织可以在植物中起到氧气贮存库的作用。根据模型系统内部气体浓度计算的预期ODR读数与使用硅橡胶管材模型实验获得的ODR非常相似。根据报道的门扬特、赖斯、斯巴迪纳和舍恩斯的内部气体浓度进行的进一步计算，也显示出实际值和预期值之间的密切相似。结论是，至少在这些物种中，根的某些区域对氧气从根胞间到周围介质的传递的阻力可以忽略不计。结果表明，根基对氧气相对不渗透，这表明其他工作者报道的根基区域的氧气吸收可能是通过根基侧枝进行的。从根中扩散氧气的一个重要功能可能是为根分生组织提供外部氧气来源。
A "polarographic" technique by which the rate of outward diffusion of oxygen from plant roots may be measured, is described in detail. Oxygen has been found to diffuse from the roots of all of the ten species of bog-plants [Eriophorum an-gustifolium, E. vaginatum, Juncus effusus, Menyanthes trifoliata, Molinia coerutea, Narthecium ossifragum, Schoenus nigricans, Spartina townsendii, Trichophorum caespitosum, rice cv. "Engkayang" ] so far tested, and the oxygen diffusion rates (ODR) of eight of these species show the existence of interspecific differences. Model roots made from silicone rubber tubing give "polarographs" identical with those obtained around the living roots. Suberization accompanying root maturation is thought to account for a. the association of oxygen diffusion with the apical regions of roots, and b. the lowered diffusion rates associated with winter dormancy. This localization of root oxygen diffusion may be of survival value in reduced soils. Experiments suggest that aerenchyma can function as an oxygen reservoir in the plant if the stomata were closed for long periods. Calculations of expected ODR based on the internal gas concentrations of a model system give readings very similar to the ODR obtained experimentally using the silicone rubber tubing models. Further calculations, based on reported internal gas concentrations for Menyanthes, rice, Spartina, and Schoenus, also show a close similarity between real and expected values. It is concluded that in these species at least, there is negligible resistance in certain regions of the root to the passage of oxygen from the root intercellular spaces to the surrounding medium. Results have shown that root bases are relatively impermeable to oxygen, and it is suggested that oxygen intake into roots in the basal regions reported by other workers, probably occurs through basally-borne laterals. One important function of diffusing oxygen from the root is probably the supply of an external source of oxygen to the root meristem.