3. Results
3.1. Effect of salinity on seedling growth
To analyze growth responses of O. sativa L. cvs. PB
and PK under salinity stress, the seedlings were exposed to
three different levels of NaCl, i.e., low (0–150 mM), medium
(200–250 mM) and high (300 mM), for a period of 42 h. At
low salt levels, the two lines responded similarly, though
cv. PB showed a marginal reduction in its fresh weight. At
medium salt levels, there was a significant difference between
these varieties as salinity-induced depigmentation and
stunting were more severe in cv. PB than cv. PK. Further,
when exposed to 250mM NaCl, cv. PK showed a reduction
in FW of only approximately 6.0%, whereas cv. PB showed
a reduction of approximately 17% (Table 1). However, at
300mM NaCl, both the cultivars showed comparable loss in
FW, indicating similar levels of sensitivity to high salt stress.
On the other hand, while there was hardly any reduction in
dry weight at 300mMNaCl in the case of cv. PK, there was a
slight reduction in cv. PB (approximately 6%). These results
give an overall indication that cv. PK is relatively more tolerant
to NaCl than cv. PB at low to medium levels of stress