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GLYCINE BETAINE IN DURUM WHEAT SEEDLINGS SUBMITTED TO SALT STRESS BY A ROOT SPLIT SYSTEM
No full textCombined effect of nitrate and salt concentrations on growth and nitrogen metabolism on durum wheat seedlings kept in hydroponics
No full textNitrate reductase in durum wheat seedlings as affected by nitrate nutrition and salinity
No full textThe combined effects of nitrate (0, 0.1, 1, 10 mM) and salt (0, 100 mM
NaCl) on nitrogen metabolism in durum wheat seedlings were investigated
by analysis of nitrate reductase (NR) expression and activity, and
metabolite content. High salinity (100 mM NaCl) reduced shoot growth
more than root growth. The effect was independent of nitrate
concentration. NR mRNA was present at a low level in both leaves and
roots of plants grown in a nitrogen-free medium. NaCl increased NR mRNA
at low nitrate, suggesting that chloride can mimic nitrate as a signal
molecule to induce transcription in both roots and leaves. However, the
level of NR protein remained low in salt-stressed plants, indicating an
inhibitory effect of salt on translation of NR mRNA or an increase in
protein degradation. The lower activity of nitrate reductase in leaves
of high-nitrate treated plants under salinity suggested a restriction of
NO3- transport to the shoot under salinity. Salt treatment promoted
photorespiration, inhibiting carbohydrate accumulation in plants grown
on low nitrate media. Under salinity free amino acids, in particular
proline and asparagine, and glycine betaine could function as osmolytes
to balance water potential within the cell, especially when nitrogen
availability exceeded the need for growth.The combined effects of nitrate (0, 0.1, 1, 10 mM) and salt (0, 100 mM NaCl) on nitrogen metabolism in durum wheat seedlings were investigated by analysis of nitrate reductase (NR) expression and activity, and metabolite content. High salinity (100 mM NaCl) reduced shoot growth more than root growth. The effect was independent of nitrate concentration. NR mRNA was present at a low level in both leaves and roots of plants grown in a nitrogen-free medium. NaCl increased NR mRNA at low nitrate, suggesting that chloride can mimic nitrate as a signal molecule to induce transcription in both roots and leaves. However, the level of NR protein remained low in salt-stressed plants, indicating an inhibitory effect of salt on translation of NR mRNA or an increase in protein degradation. The lower activity of nitrate reductase in leaves of high-nitrate treated plants under salinity suggested a restriction of NO3- transport to the shoot under salinity. Salt treatment promoted photorespiration, inhibiting carbohydrate accumulation in plants grown on low nitrate media. Under salinity free amino acids, in particular proline and asparagine, and glycine betaine could function as osmolytes to balance water potential within the cell, especially when nitrogen availability exceeded the need for growth
Nitrate reductase and glutamate synthase in the metabolism of compatible compounds in durum wheat under salt stress
No full text
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