Smith G S, Judd M J, Miller S A, Buwalda J G
MAFTech, Ruakura Agricultural Centre, Private Bag, Hamilton, New Zealand.
New Phytol. 1990 Jun;115(2):325-333. doi: 10.1111/j.1469-8137.1990.tb00459.x.
The extent to which kiwifruit vines (Actinidia deliciosa var. deliciosa) recovered from transient waterlogging of the root system was determined under controlled conditions. Vines were waterlogged for periods varying from 1 to 7 days. The effects of decreasing concentrations of oxygen in the root zone on growth of the vine were rapid with substantial reductions occurring after being exposed to oxygen concentrations in the surrounding water of less than 0.125 mmol l for as little as 1 day. There was no evidence of recovery of growth once aeration was restored to the roots, except for the appearance of new roots at the base of the stems of vines that had been waterlogged for less than 5 days. The quantity of new roots grown was inversely related to the time of waterlogging. Although new roots were also found on the control vines, the quantities involved were very much less than for the vines stressed for up to 4 days. No new roots were found for vines waterlogged for more than 4 days. The substantial loss of dry weight of roots of vines waterlogged for more than 3 days was due in part to a lack of growth and to a physical loss of root tissue. The loss of tissue resulted from the detachment of the cortex from the central stele through the dissolution of an entire layer of cortical cells which, in the control vines, were filled with starch. A microscopic examination of the cells of the root from waterlogged vines showed the cortical cells to be generally distorted with much of the intercellular material missing. The closure of the stomata within 2-3 h of the roots being waterlogged and the rapid desiccation of the leaves that followed the closure, was consistent with earlier findings with kiwifruit vines. Some recovery of stomata activity occurred for vines that had been waterlogged for less than 4 days once the oxygen supply to the root was restored. For vines that had their roots submerged for only 1 day, stomatal activity was fully restored 3 days after the vines were removed from the water. In contrast, there was no recovery of stomatal activity for vines that had been waterlogged for more than 3 days. A feature of stomatal behaviour that was not related to the effects of oxygen stress was the cyclic pattern which developed. Each cycle repeated itself every 4-6 days and consisted of a period of high stomatal conductance followed by a sharp decline to a much lower level. A highly significant negative relationship was found between the level of photosynthetically active radiation and stomatal behaviour. It was concluded that the speed with which the roots die and the associated damage to the leaves under anoxic conditions greatly limits the ability of kiwifruit vines to resume growth once oxygen supply to the root has been restored.
在可控条件下，测定了奇异果藤蔓（美味猕猴桃美味变种）从根系短暂淹水状态下恢复的程度。藤蔓淹水时间从1天到7天不等。根系区域氧气浓度降低对藤蔓生长的影响迅速，在暴露于周围水中氧气浓度低于0.125 mmol/l仅1天后，生长就大幅下降。根系恢复通气后，除了淹水时间少于5天的藤蔓茎基部出现新根外，没有生长恢复的迹象。新根生长量与淹水时间成反比。虽然对照藤蔓上也发现了新根，但其数量远少于受胁迫达4天的藤蔓。淹水超过4天的藤蔓未发现新根。淹水超过3天的藤蔓根系干重大量损失，部分原因是缺乏生长以及根系组织的物理损失。组织损失是由于皮层通过一整层皮层细胞溶解而从中央中柱分离，在对照藤蔓中，这些皮层细胞充满淀粉。对淹水藤蔓根系细胞的显微镜检查显示，皮层细胞普遍扭曲，许多细胞间物质缺失。根系淹水2 - 3小时内气孔关闭，随后叶片迅速脱水，这与奇异果藤蔓早期的研究结果一致。淹水少于4天的藤蔓，根系恢复供氧后气孔活动有一定恢复。对于根系仅淹水1天的藤蔓，从水中移出3天后气孔活动完全恢复。相比之下，淹水超过3天的藤蔓气孔活动没有恢复。气孔行为的一个与氧气胁迫影响无关的特征是出现的周期性模式。每个周期每4 - 6天重复一次，包括一段高气孔导度期，随后急剧下降到低得多的水平。发现光合有效辐射水平与气孔行为之间存在极显著的负相关。得出的结论是，在缺氧条件下根系死亡的速度以及对叶片的相关损害极大地限制了奇异果藤蔓在根系恢复供氧后恢复生长的能力。
