G. Villora et al., PLANT NITROGEN CHARACTERISTICS OF A SEMI-SALT-TOLERANT ZUCCHINI VARIETY TO SODIUM-CHLORIDE TREATMENTS, Journal of plant nutrition, 21(11), 1998, pp. 2343-2355
Plants of a Zucchini (Cucurbita pepo L. var. Moschata) cultivar consid
ered to be semi-salt-tolerant were grown in artificial soil in l-m con
tainers under greenhouse conditions with differing supplies of sodium
chloride (NaCl) [0 (T-0), 30 (T-1), 60 (T-2) or 120 (T-3)g m(-2) plot(
-1)] during the entire growth cycle. These plants were used to determi
ne the concentrations of nitrogen (N) forms and fractions, together wi
th antagonistic anions in both leaves and fruits. The ammonium (NH4) c
oncentration increased and nitrate (NO3) concentration decreased in bo
th leaves and fruits, and chloride (Cl) concentration increased while
sulphate (SO4) concentration decreased in both leaves and fruits with
NaCl treatments. Organic-N concentration in leaves increased according
to the soil salinity treatments, while in the fruit there was a sligh
t increase at low salinity, although values returned to those of the c
ontrol when soil salinity increased. In leaves there was an increase i
n proline concentrations when salinity was low. As soil salinity incre
ased further, this level then fell slightly. In the fruit skin, howeve
r, proline concentration decreased as soil salinity increased. Soluble
protein and amino-acid concentrations in the skin of the fruit increa
sed when there was a moderate increase in soil salinity from T-0 to T-
1. However, as soil salinity increased further, these concentrations d
ecreased and returned to levels near the control. The results of fruit
yield showed a positive effect of the NaCl treatments with an enhance
ment of commercial and also total fruit yield and a decrease in substa
ndard fruit yield.