Recovery of kiwifruit vines from transient waterlogging of the root system

Abstract

SUMMARYThe 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 1"^ 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 vmes 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 stomatal 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.

Intercellular location of glycoprotein in soybean nodules: effect of altered rhizosphere oxygen concentration

“…Vigna unguiculata, Atkins et al, 1984), suggesting that they may be common in legume nodules. It is further possible that they are a device used in other plant tissues, for example, kiwi fruit {Actinidia deliciosa) roots, where Smith et al (1990) showed that an electron-dense intercelluar material normally present in unstressed roots was lost when they were waterlogged.…”

Plant water stress: Associations between ethylene and abscisic acid response

“…One of the major anatomical effects of hypoxia occurs at the root level. Some studies have reported hypertrophic lenticel formation (Jones and Sharitz, 1990;Shimamura et al, 2010), adventitious root development, and parenchymal tissue changes (Aloni and Rosenshtein, 1982;McNamara and Mitchell, 1989;Smith et al, 1990). Several types of tropical and subtropical fruit trees show anatomical or morphological adaptations to flooding stress, such as the development of hypertrophied stem lenticels, adventitious rooting or the formation of porous aerenchyma tissue (Schaffer et al, 2006).…”

Effects of transient soil waterlogging and its importance for rootstock selection

“…The dynamics of root growth and the ability of trees to recover from transient inundations are significant in evaluating short-term effects of waterlogging (Smith et al, 1990). Species reduce their growth under anoxic conditions, but in contrast to sensitive species, tolerant species can resume growth rapidly once aeration has been restored.…”