Effects of NaCl on Flows of N and Mineral Ions and on NO3- Reduction Rate within Whole Plants of Salt-Sensitive Bean and Salt-Tolerant Cotton

Abstract

l h e effects of NaCl on the transport rates of cations, NO3-, and reduced N compounds between roots and shoot and on NOsassimilation rate were examined on plants of two species differing in their sensitivity to salinity, bean (Phaseolus vulgare 1 . cv Cabriella) and cotton (Gossypium hirsutum l. cv Akala). Biomass production after 20 d in response to 50 and 100 mM NaCl decreased by 48 and 59% in bean, but only 6 and 14% in cotton. The comparison of the flow patterns obtained for control and NaCIfed plants showed that salinity induced a general decrease in all the fluxes involved in partitioning of N and the various ions. This decrease was markedly higher in bean than in cotton. Within either species, the different flows (uptake, xylem flux, phloem flux) of a given element were affected by NaCl to the same extent with minor exceptions. No specific effect of salinity on any of the components of N partitioning were discerned. The greater sensitivity of nitrate reductase activity to NaCl in bean leaves compared to cotton leaves seems to be due to a decreased compartmentalization of ions rather than to a difference in salt tolerance of the enzyme itself. Overall, our data show that alteration of mineral nutrition is not solely the reflection of a decreased growth rate, but also is a general process that impairs uptake of all the minerals even at mild NaCl salinity. '

Agrophysiological and biochemical properties associated with adaptation of Medicago sativa populations to water deficit

“…The decrease noted in NRA was positively correlated to the decrease of leaves' nitrate contents and that could be the cause of the NRA reduction. Indeed, Gouia et al (1994) noted that NRA was not sensitive to osmotic effects.…”

Effects of salinity and nitrogen on cotton growth in arid environment

“…There were fewer bolls per plant and a greater chance of shedding under the high soil salinity treatment (SH), which might be attributed to the nutrient imbalance caused by high soil salinity. Gouia et al (1994) reported that high salt stress results in slower growth and even death of seeding cotton, lower dry matter accumulation, less Fig. 2 roots, softer and darker leaves, shorter period of blooming, and even death of seedling cotton.…”

Function of sodium and potassium in growth of sodium-loving Amaranthaceae species

“…Effect of increasing Na/K ratio in solution on mineral uptake, N transport to the shoots and growth of plants Numerous studies have revealed that salinity stress inhibits nitrate (NO 3 ) uptake and transport to the shoot in both glycophytes and halophytes (Gouia et al 1994;Rubinigg et al 2003). An increase in NO 3 supply can ameliorate salinity stress (Liu et al 2004;Ding et al 2010).…”