Salinity is a common stress factor in agricultural areas that causes osmotic stress and reduces plant growth and crop productivity. The document examines the effect of different sodium chloride (NaCl) salt concentrations on germination and morphological attributes of maize. Laboratory experiments showed that higher salt concentrations (150mM - 250mM) significantly decreased germination rates and attributes like root and shoot length, mass, and number of leaves compared to the control. Similar inhibitory effects were observed in pot culture experiments. The study concludes that the maize variety tested is sensitive to NaCl salinity.

1.  Definition
 salinity could be defined as the
presence of minerals at high levels
(cations: Na, K, Mg, Ca and anions: Cl,
NO3, HCO3, SO4) in water and soil.

2. salanity
 . It is well-known that salinity is a
common stress factor in agricultural
areas as a result of extensive irrigation
with saline water and fertilizer
application .
 Salinity is one of the serious
environmental problems that cause
osmotic stress and reduction in plant
growth and crop productivity in irrigated
areas of arid and semiarid regions

3. Extent of salinity problems at
national levels
 In Pakistan, out of 20 million hectares of
agriculture land 6.67 million hectares are salt
affected . The canal irrigation system extends
over about 62,400 km and is mainly confined
to Indus plain.
 Although irrigation covers only about 15% of
the cultivated land in Pakistan, yet irrigated
land has at least twice the productivity of rain-
fed land, and may therefore produce one-third
of the world’s food.
 The reduced productivity of irrigated lands
due to salinity is, therefore,it is a serious issue
.

4. Extent of salinity problems at
global levels
 More than 800 million hectares of land throughout
the world are saltaffected, either by salinity (397
million hactor) or the associated condition of sodicity
(434 million hactor) .
 This is over 6% of the world’s total land area. Most
of this salinity, and all of the sodicity, is natural.
However, a significant proportion of cultivated
agricultural land has become saline because of land
clearing or irrigation.
 Of the 1500 million ha of land farmed by dry land
agriculture, 32 million ha (2%) are affected by
secondary salinity to varying degrees. Of the current(
230 million hactor) of irrigated land, 45 million ha are
salt-affected .

5. Effect of salinity on plant
growth
 Salanity effect the plant growth in three
main ways
1. Osmotic potential
2. Specific ion toxicity
3. Nutritional imbalance

6. Osmotic potential
 Reduction in growth under saline conditions
apparently occurs as a result of a very negative
solute potential in the soil solution, which causes the
overall water potential to also be quite negative, thus
resulting in a decrease in the water uptake by the
plant .
 When the salt concentration of the soil solution
increases, water potential decreases, the turgor
potential of plant cells declines, and cells ultimately
cease to grow.
 Under these water stress conditions, in general,
stomata close resulting in the reduction of
photosynthesis.
 Protein breakdown is enhanced and plants show
poor growth.

7. Specific ion toxicity
 Toxicity occurs as a result of uptake and
accumulation of certain toxic ions from
the irrigation water, within a crop itself.
 . It is different from salinity problem and
may occur even when the salinity is low.
These toxic constituents include mainly
sodium, chloride and sulphate. They can
reduce crop productivity and eventually
cause crop failures.

8. Specific ion toxicity
 . It is different from salinity problem and
may occur even when the salinity is low.
These toxic constituents include mainly
sodium, chloride and sulphate. They can
reduce crop productivity and eventually
cause crop failures.
 Alternatively, they might build up in the
cell walls and dehydrate the cell .

9. Mechanisms of salt stress
Regulation
 Since NaCl is the most soluble salt, plants species
have developed several different mechanisms to
regulate its accumulation.
 Some species avoid the toxic effect of Na+ actively
transporting Na+ through tonoplast and accumulating
it in the vacuole against a high electrochemical
gradient of Na+.
 Another strategy that plants have to tolerate salinity
is the synthesis of organic solutes known as
osmolytes. Compounds such as sugars, proline and
glycine betaine do not interfere with the cell
metabolism at high concentrations but they
participate in retaining water, which allows the plant
to maintain its physiological functions

10. Mechanisms of salt stress
Regulation
 Another strategy that plants have to
tolerate salinity is the synthesis of
organic solutes known as osmolytes.
Compounds such as sugars, proline and
glycine betaine do not interfere with the
cell metabolism at high concentrations
but they participate in retaining water,
which allows the plant to maintain its
physiological functions .

11. Importance of maize
 Maize or corn (Zea mays L.) occupies a key position
as one of the most important cereals both for human
and animal consumption.
 It is not only a food product, maize-derived products
have been used in various aspects in our daily life.
Maize is in the third rank after wheat and rice and
isgrown under diverse environmental conditions
compared to other important grain crops .
 The worldwide production of maize is 785 million
tons. Being highly cross pollinated, maize has
become highly polymorphic through the course of
natural and domesticated evolution and thus
contains enormous variability in which salinity
tolerance may exist .

12. Importance of maize
 The crop is Maize is an annual plant
belonging to the grass family (Poaceae).
 The kernel of maizecontainabout 80-
85% endosperm by weight .
 The major component of the grain is
starch. Starch is the basis for almost all
industrial uses of the maize grain. Corn
has a remarkable diversity of vegetative
types and is grown in a wide range of
environmental conditions.

13. Importance of maize
 In Pakistan, maize is the third most important crop
after wheat and rice. Being an important crop, maize
is grown on about one million hectares with a total
yield of about 2 million tones and an average yield of
1882 kg ha-1.
 In view of its increasing importance, improvement in
agronomic characteristics of maize has got
considerable attention in Pakistan .
 Maize (Zea mays L.) is an important crop in
Pakistan, which is used as food and corn oil for
human consumption, feed for livestock and poultry
and raw material for agro-based industries.

14. Objectives
 The research was conducted to
determine the effect of different levels of
salinity (NaCl) on the germination of
seeds of maize.
 To investigate other morphological
attributes (Root and shoot length, root
and shoot fresh and dry weight, number
of leaves and length and width of
leaves) of maize under different levels of
sodium chloride stress.

15. . MATERIALS AND METHODS
 The research work was conducted to
evaluate the performance of maize
under the different levels of salinity
(NaCl) in Department of Botany,
Government Post Graduate College
Kohat, during the period March – June,
2015. These studies were carried out in
petri plates and pot culture.

16. Seed source, Collection of soil
and Surface sterilization
 The experimental studies were conducted on maize
kernels (Var. AZAM), obtained from Agriculture Research
Station, Sarai Naurang, Khyber Pakhtunkhw.
 Loamy soil was collected from the lawn of Govt. Post
Graduate College Kohat for pots culture experiments.
 Before treating the maize kernels with salt
concentrations in both Petri plates and pots experiments,
they were surface sterilized in 70% ethyle alcohol for five
minutes, then rinsed in distilled water for three times in
order to avoid the chemical effects of ethanol and then put
on a sterilized filter paper.

17. Laboratory experiments
 Morphologically uniform and healthy seeds of maize were
soaked and allowed to germinate in petriplates (110 mm
diameter, 9 mm height) containing nutrients free washed
sand.
 For each treatment, three replications with ten (10) seeds
per replication were used. Five different concentrations
(50 mM, 100 mM, 150 mM, 200 mM and 250 mM) of salt
solution were prepared.
 The seeds in Petri-dishes allocated to the control were
moistened with 30 millilitres of distilled water while that of
the Petri-dishes allocated to the other treatments were
moistened with 30 millilitres of the appropriate
concentrations of the salt solution.
 The Petri dishes were incubated at room temperature in
the dark and were treated with appropriate quantity of
distilled water and salt concentrations every second day.

18. Pot culture experiments
 Pot culture experiments were conducted in a greenhouse
environment in the lawn of Botnay Department,
Government Post Graduate College Kohat. Earthenware
pots were filled with loamy soil.
 Healthy seeds of maize washed with sterilized distilled
water and soaked in water for 4-5 hours.
 The kernels were sown at 2cm depth.
 Each experiment was replicated three times with 5 seeds
per pot. The planted seeds were irrigated with distilled
water different levels of salt solutions (50 mM, 100 mM,
150 mM, 200 mM and 250 mM).
 Pots were irrigated every second day with respective
solutions. After 40 days, maize plants were harvested and
their following morphological attributes were measured
and noted.

19.  Libortry experiment data

20. Germination response to salt
stress

0
1
2
3
4
5
6
7
8
9
10
Control 50 mM 100 mM 150 mM 200 mM 250 mM
Germination%
Salt treatment
48h 72h 96h
*
*
*

21. Effect of salt solutions on
root length of maize
0
5
10
15
20
25
Control 50 mM 100 mM 150 mM 200 mM 250 mM
Rootlength(Cm)
Salt treatment
**
*
*
*

22. Effect of salt solutions on
shoot length of maize
0
2
4
6
8
10
12
14
16
18
20
Control 50 mM 100 mM 150 mM 200 mM 250 mM
Shootlength(Cm)
Salt treatment
*
*
*
*

23. Effect of salanity on seedling
mass (fresh and dry) of maize
0
2
4
6
8
10
12
14
16
Control 50 mM 100 mM 150 mM 200 mM 250 mM
Rootfreshweight(g)
Salt treatment
*
*
*
*

24. Effect of salanity on seedling
mass (fresh and dry) of maize
0
0.5
1
1.5
2
2.5
3
Control 50 mM 100 mM 150 mM 200 mM 250 mM
Rootdryweight(g)
Salt treatment
*
*
*
*

25. Effect of salanity on shoot fresh
weight of maize
0
1
2
3
4
5
6
7
Control 50 mM 100 mM 150 mM 200 mM 250 mM
Shootfreshweight(g)
Salt treatment
*
*
*
*
*

26. Effect of salanity on shoot dry
weight of maize
0
0.1
0.2
0.3
0.4
0.5
0.6
Control 50 mM 100 mM 150 mM 200 mM 250 mM
Shootdryweight(g)
Salt treatment
*
*
*
*
*

27. Effect of salt stress on number
of leaves of maize
0
1
2
3
4
5
6
7
8
9
10
Control 50 mM 100 mM 150 mM 200 mM 250 mM
No.ofleaves
Salt treatment
*
**
**

28. Effect of salt stress on length of
leaves of maize
0
5
10
15
20
25
30
35
40
Control 50 mM 100 mM 150 mM 200 mM 250 mM
Leaflenght(Cm)
Salt treatment
*

29. Effect of salt stress on width
of leaves of maize
0
0.5
1
1.5
2
2.5
3
3.5
Control 50 mM 100 mM 150 mM 200 mM 250 mM
LeafWidth(Cm)
Salt treatment

31. Comparison of 50mM and
control

32. Comparison of 100mM and
control

33. Comparison of 150mM and
control

34. Comparison of 200mM and
control

35. Comparison of 250mM and
control

36. Pot culture
experiment

37. Effect of salanity on shoot
length of maize
0
10
20
30
40
50
60
70
Control 50 mM 100 mM 150 mM 200 mM 250 mM
Shootlength(Cm)
Salt treatment
*
*
*

38. Effect of salt stress on
number of leaves of maize
0
1
2
3
4
5
6
7
8
9
10
Control 50 mM 100 mM 150 mM 200 mM 250 mM
No.ofleaves
Salt treatment
*
**
**

39. Effect of salt stress on length
of leaves of maize
0
5
10
15
20
25
30
35
40
Control 50 mM 100 mM 150 mM 200 mM 250 mM
Leaflenght(Cm)
Salt treatment
*

40. Effect of salt stress on width
of leaves of maize
0
0.5
1
1.5
2
2.5
3
3.5
Control 50 mM 100 mM 150 mM 200 mM 250 mM
LeafWidth(Cm)
Salt treatment

41. conclusion

42. CONCLUSION
 On the basis of present study it can be concluded that Zea
mays L. (Var. AZAM)is sensitiveto NaCl salinity.
 The study indicates that the saline growth medium had an
adverse effect on germination and other growth attributes of
maize.
 The growth inhibitory effect of NaCl were more pronounced in
concentrated solutions (150 mM, 200mM and 250 mM of NaCl
as compared to the 0mM, 50mM and 100 mM of NaCl.
 Application of NaCl significantly decreased the morphological
attributes of maize such as seed germination, root and shoot
length of seedlings, fresh and dry weights of roots and shoots,
number of leaves and leaf length and width of maize, especially
at higher concentrations, in both laboratory and pot culture
experiments.