Ion Absorption and Allocation of Carbon Resources in Excised Pea Roots Grown in Liquid Medium in Absence or Presence of NaCl

Incorporation of [14C]Glucose into Cell Wall Polysaccharides of Cotton Roots: Effects of NaCl and CaCl2

“…Several factors may have contributed to this discrepancy: first, different species (pea versus cotton) and different plant systems (excised root versus intact seedling) were used; second, release of respiratory '4CO2 from the root tips had been taken into account as part of the total uptake in the earlier report, whereas this was not done in our study; finally, those authors presented their data on a per root tip basis, whereas we expressed the uptake data per unit of fresh weight. It has also been reported that salinity stress did not induce an increase in utilization of exogenous carbon for maintenance respiration in excised pea roots (12,25). We do not know, however, whether the slight stimulation of uptake by 150 mM NaCl in our study is an indication of an increase in utilization of exogenous carbon for maintenance respiration by the stressed seedlings.…”

“…Our data presented in Figure 1 are basically in agreement with most of those published to the effect that NaCl salinity inhibits incorporation of glucose into insoluble (noncellulosic and cellulosic) polysaccharides of the cell wall, so that a relatively larger portion of the absorbed glucose remains in the soluble pool. The exception is the study by Solomon et al (25), in which an increase in the incorporation of glucose into wall substances by salinity was reported on a per cell basis. The effect of supplemental Ca2" under saline condition on cell wall polysaccharide synthesis, however, has not been reported in the studies mentioned above (or in any other study we are aware of).…”

“…Several studies have been reported (12,13,25) regarding the effect of NaCl salinity on the distribution pattern of absorbed ['4C]glucose in various cell fractions. Our data presented in Figure 1 are basically in agreement with most of those published to the effect that NaCl salinity inhibits incorporation of glucose into insoluble (noncellulosic and cellulosic) polysaccharides of the cell wall, so that a relatively larger portion of the absorbed glucose remains in the soluble pool.…”

“…University of California, Davis,California 95616 cating that water and salt stress affect the incorporation of externally supplied glucose into various cell wall fractions in excised root segments or cell suspension culture (12,13,23,25). However, no investigations on intact seedlings have been reported.…”