Effect of gibberellic acid and potassium silicate on ...

Pure Appl. Biol., 7(1): 8-19, March, 2018 http://dx.doi.org/10.19045/bspab.2018.70002

Published by Bolan Society for Pure and Applied Biology 8

Research Article

Effect of gibberellic acid and potassium

silicate on physiological growth of Okra

(Abelmoschus esculentus L.) under

salinity stress

Qasim Ayub*, Shah Masaud Khan, Ayub Khan, Ijaz Hussain, Zahoor

Ahmad and Muhammad Affan Khan Department of Agricultural Sciences, University Of Haripur, KP-Pakistan *Corresponding author’s email: [email protected] Citation

Qasim Ayub, Shah Masaud Khan, Ayub Khan, Ijaz Hussain, Zahoor Ahmad and Muhammad Affan Khan. Effect of

gibberellic acid and potassium silicate on physiological growth of Okra (Abelmoschus esculentus L.) under salinity

stress. Pure and Applied Biology. Vol. 7, Issue 1, pp8-19. http://dx.doi.org/10.19045/bspab.2018.70002

Received: 23/09/2017 Revised: 22/12/2017 Accepted: 23/12/2017 Online First: 01/01/2018

Abstract The aim of this investigation was to improve salt tolerance abilities in okra (Abelmoschus

esculentus L.) by foliar application of potassium silicate and seed priming with GA3. A pot

experiment was conducted at Awan Nursery Farm, Haripur, to investigate whether seed priming

with GA3 and foliar application of potassium silicate could ameliorate the toxic effects of salinity

on okra growth. Two okra cultivars Sabz Pari and Mehak Pari were exposed to two levels of NaCl

(control and 50mM) according to the saturation percentage of soil. Seeds of okra were primed with

three levels of GA3 (50mg/L, 75mg/L and 100mg/L) before sowing. After 18 days of germination

okra plants were treated with three levels of potassium silicate (2mmol, 3mmol and 4mmol)

exogenously as foliar spray to protect the plants against salt stress. Data for different growth

parameters such as root length, shoot length, plant height, root and shoot fresh weight, root and

shoot dry weight were collected. Okra cultivar Sabz Pari showed maximum resistance towards

salinity as compared to Mehak Pari. Applications of GA3 decreased the harmful effects of salinity

and enhanced the overall growth of okra whereas silicon failed to impart any significant difference

on okra.

Keywords: Gibberellic Acid; Growth; Okra; Potassium silicate; Salinity

Introduction Okra (Abelmoschus esculentus L.) also

known as lady finger in English and bhindi in

Urdu, is a green flowering plant belong to

family Malvacae. It is grown for its edible

seed pods in tropical and sub-tropical

regions. Okra is annual or perennial

depending on the climatic conditions. It

grows up to 2m high, having leaves 10cm to

20cm in length. Diameter of okra flowers are

4 to 8, having white or yellow petals, with a

red or purple spot on each petal base. Fruit of

okra is a capsule shaped pod having length up

to 18 cm, each pod contain numerous white

edible seeds. Okra is cultivated for its fibrous

pods. It has high heat and drought tolerance

among most of the vegetables, and can also

give better yield in heavy soils and in soils

http://dx.doi.org/10.19045/bspab.2018.70002

mailto:[email protected]


Ayub et al.

9

with low moisture content, but it have low

tolerance against chills and frosts. Okra is a

popular vegetable among both the consumers

and farmers because it is rich in vitamins and

minerals [1]. Greenish yellow okra oil is also

obtained from okra seeds, which can be used

as bio fuel [2].

Many abiotic stresses like high and low

temperatures, drought and salinity reduces

the growth and productivity of crops [3] but

among these, salt stress imparts a severe

reduction in plants growth and reproduction

[4]. According to some estimates about

831x106 hector lands is affected by salinity

[5] whereas one-half of total irrigated land

(which is about 2.5 x 108 hector) is severely

affected by salinity [6].

Elevated salt concentrations inside plant

tissues reduces the growth and development

by altering physiological processes, such as

change in ions balance, water status, mineral

nutrition, open and closing of stomata, and

rate of photosynthesis [7]. Most plants are

sensitive to salt having relatively low salt

tolerance or show clear reduction in growth

at lower salinity levels [8, 9]. Salt stress

causes osmotic and ionic stress which in turn

affects plant growth at both whole plant and

at cellular level [10]. Higher number of toxic

ions of salts in soil decreases soil water

potential and availability of water to plants

[11]. This shortage of available water under

saline conditions causes dehydration at

cellular level and eventually osmotic stress

occurs. Excess of toxic Sodium and chloride

ions hinders the uptake of useful ions such as

Potassium, Calcium and Manganese [12].

Numerous plant hormones are recognized for

their fruitful effects on those plants which are

exposed to salinity; among these hormones

Gibberellins (GA3) has attained the prime

attentions of scientists [13]. Gibberellic acid

activates the cells of seeds during

germination to generate mRNA molecules,

which contains the code for hydrolytic

enzymes [14]. GA3 enhances the stem

elongations [15], for example when dwarf

bean treated with GA3, turn them into a

climbing bean [16]. Gibberellins (GA3) play

an important part in different stages of plant

growth and development, such as

germination [16-20], stem enlargement and

flower development [21]. GA3 also increases

vegetative growth in plants such as leaf area,

leaf length and width [22].

Silicon is the second most widely found

element in the earth crust, whose

accumulation rate in plants is similar to those

other macro-elements nutrients like calcium,

magnesium and phosphorus [23]. The

beneficial effects of silicon vary in different

growing conditions, these effects are usually

most prominent when plants are exposed to a

verity of abiotic or biotic stresses [24]. It has

been reported by many scientists that silicon

reduces the harmful effects of various abiotic

stresses such as manganese, aluminum and

heavy metal toxicities, soil salinity, drought

stress, chilling and freezing injuries [25].

Moreover, it has been suggested that silicon

enhances the growth of plants and reduces the

toxic effects of salinity by reducing the

specific ion effect of salinity [26]. The effect

of silicon on plant growth depends upon

silicon doses and crop [27]. Among all

minerals silicon is only element whose

excessive amounts do not damage plants due

to its polymerization property and non

dissociation at physiological pH [24].

GA3 and silicon have been used on number of

crops and the main aim of this study in to find

out beneficial outcomes of GA3 and

potassium silicate (silicon) on okra when

grown under salt stress, and to investigate

suitable gibberellic acid and potassium

silicate rate for okra when subjected to

salinity stress.

Materials and methods

Current study was conducted at Awan

Nursery farm Haripur, during summer 2016.

Two okra verities were used namely Sabz

Pari and Mehak Pari. Both verities were


10

selected from local market. Pots of 18 inch

diameter were filled with dam silt. In order to

fulfill plants nutritional requirements

farmyard manure were added in each pot.

Eight seeds were planted in each pot, after 10

days of germination, plants were thinned to

five plants per pot. The experiment was laid

in Complete Randomized Design (CRD).

Each treatment was replicated three times.

Averages were calculated for recorded data

in each replication. These averages were then

subjected to statistical analysis for ANOVA

and LSD [28]. Data were analyzed by using

statistical software Statistix 8.1.

Seed treatment with GA3

The seeds of okra were treated with 50,

75,100 mg/L solution of GA3 before sowing.

Seed were kept in 50ml size beakers for 8

hours, each beaker was properly air tightened

by polyethen sheet.

Silicon levels and application

During this study three silicon level 2mM,

3mM and 4mM were used. Potassium silicate

was mixed in distillated water and was

applied to plants exogenously two days

before the salt application in order to lower

the harmful effect of salt and to prevent plants

from scorches and leaf burning.

Salinity levels

Two salinity levels i.e. control and 50mM

were used for the experiment. Plants were

subjected to salt 20 days after the

germination. In order to prevent plants from

osmotic stress due to salt, final concentration

of salinity i.e. 50mM was completed in two

steps. In first step 25mM salt was applied,

and remaining 25mM of salt was added two

days later.

Parameters

Shoot length (cm)

Measuring rod was used for measurement of

shoot length. One plant form each replication

is taken and the length of shoot is measured

from base to the tip of shoot.

Root length (cm)

The length of root was measured in

centimeter with the help of measuring rod.

One plant from each replication was uprooted

and the length of root was measured from

base to the tip of longest root.

Plant height (cm)

Total plant height was calculated by adding

the root length and shoot length of each plant.

Shoot fresh weight (gm)

The weight of shoots was measured by using

digital balance. The roots were detached from

the stem and the stem is cut into two or three

small pieces so that the weight of long stems

can easily be calculated.

Root fresh weight (gm)

The fresh weight of roots was measured by

using digital balance. The roots were washed

properly to remove any dust ore mud on

them. Then these washed roots were dried on

tissue paper to remove any extra water on

them.

Shoot dry weight (gm) The shoots were kept in oven for 24 hours at

a temperature of 60̊ C. After 24 hours the

dried shoots were weighted by using a digital

balance.

Root dry weight (gm)

To find the dry weight of shoots, shoots were

oven dried and were kept in oven for 24 hours

at 60̊ C. After 24 hours the shoots are

weighted for dry weight by using a digital

balance.

Results and discussions

Shoot Length (cm)

Statistically significant differences were

observed in salt, treatment and variety for

shoot length, whereas the interactions

salt*variety and treat*variety were

statistically significant (Table 1).

Maximum shoot length (38.92 cm) was

observed in control while minimum shoot

growth (37.21cm) was observed at 50mM

salinity (Table 2). The maximum shoot

length in non-saline soils may be due to fact

that these plants have osmotically adjusted


Ayub et al.

11

themselves in a way which helps in cell

elongation hence [29].

The okra cultivar Sabz Pari showed the

maximum shoot length (41.76cm) when

grown in non-saline conditions. Similarly the

minimum shoot length (36.09cm) was

observed in Mehak Pari when grown in

50mM salinity (Table 3); same results were

found by [30]. The decreased growth of shoot

because of salinity is due to low water

potential inside plants tissues which cause a

decrease in cell turgidity; this low cell turgor

reduced cell elongation and cell division [31].

At higher salinity closing of stomatal walls

occurred which limits carbon dioxide

absorption by the plant, as CO2 is main

energy source for plants and their growth

development depend upon amount of

absorbed CO2, thus a reduced stem growth

obtained [32].

The maximum shoot length (44.66cm) was

noted in Sabz Pari when treated with 4mMol

potassium silicate, whereas as minimum

shoot length (34.33cm) was observed in

Mehak Pari when treated with 3mM silicon

(Table 3). These results indicate that silicon

have imparted a significant increase in shoot

length of okra. Silicon is considered as

essential element for plants because silicon

deficient plants show many growth

abnormalities [33]. Plant root absorb silicon

in the form of Silicic acid [(Si (OH)4] [34].

This difference in shoot length among okra

cultivars may be due to availability of silicon

to plant, which mainly depend on soil pH,

presence of aluminum and iron oxide [35]

and plant species [24].

Table 1. Analysis of variance table of shoot length (SL), root length (RL), plant height (PH),

shoot fresh weight (SFW), root fresh weight (RFW), shoot dry weight (SDW), root dry weight

(RDW)

Source DF S L(cm) R L (cm) P H (cm) SFW (g) RFW (g) SDW (g) RDW (g)

Salt 2 61.714** 1.190NS 45.76** 0.093NS 0.17554** 0.0805NS 0.04030**

Treat 1 11.567* 1.361NS 16.07* 0.191* 0.01301** 0.1862* 0.00609**

Variety 6 260.762** 663.048** 1755.43** 154.714** 2.80869** 62.0576** 0.91354**

Salt*Treat 1 2.853NS 2.718* 6.07NS 0.082NS 0.00482* 0.0830NS 0.00112NS

Salt*Variety 6 96.429** 0.429NS 109.71** 0.347* 0.45762** 0.3219* 0.20800**

Treat*Variety 1 53.067** 3.687* 50.68** 0.146* 0.02657** 0.1529* 0.01016**

Salt*Treat*Variety 6 1.290NS 3.567* 1.96NS 0.081NS 0.02084** 0.0877NS 0.00714*

Error 6 4.993 1.161 4.18 0.052 0.00156 0.0518 0.00185

Total 54

Root length (cm)

Analysis of variance showed that interactions

salt*treatment, treatment*variety and

salt*treatment*variety were statistically

significant for P<0.005 (Table 1).

Maximum root length (15.81cm) was shown

by Sabz Pari while the Mehak Pari showed

the minimum root length (10.89cm) (Table

2). This difference in root length of both

tested cultivars of okra may be attributed to

genetic makeup of each cultivar and the

climatic conditions in which both cultivars

were grown [36].

The maximum root length (14.00cm) was

observed in plants which were grown in

control and non-saline soil, whereas the

minimum root length (12.00cm) observed in

plants grown under 50mM salinity and

treated by 2mMol solution of potassium

silicate (Table 3). These results suggest that

neither GA3 nor Si have imparted prominent

reduction to lower the toxic effect of salinity

but salinity reduces the root length of okra. A

decrease in root length with the increments in

salinity in present assessment confirmed the

results of previous studies [37- 30]. Roots of

plants are directly grown in growth media


12

containing toxic salt ions, which prevent the

long time root growth [40].

The maximum root length (16.50cm) was

observed in Sabz Pari when treated with

100mg/L of GA3, while minimum root length

(9.16cm) was observed in Mehak Pari when

treated with 100mg/L of GA3 (Table 3).

These outcomes are similar with those of [41]

who noted same increment on root length of

barley when treated with GA3. This increase

in root length of okra plants may be due to

proven fact that GA3 increases cell division

and elongation [42].

Table 2. Mean of salt, treatment and variety for shoot length (SL), root length (RL) plant

height (PH) and shoot fresh weight (SFW)

Salt SL (cm) RL (cm) PH (cm) SFW (g)

S1 38.929 A 13.119 A 51.810 A 4.7452 A

S2 37.214 B 12.881 A 50.333 A 4.6786 A

Treatment

T1 36.917 B 13.417 A 50.333 B 4.9667 A

T2 37.417 B 12.667 A 50.083 B 4.7917 AB

T3 37.833 B 12.917 A 50.750 B 4.6833 B

T4 37.833 B 12.833 A 50.667 B 4.6333 B

T5 38.000 B 12.667 A 50.667 B 4.6417 B

T6 38.500 AB 13.000 A 51.500 B 4.6333 B

T7 40.000 A 13.500 A 53.500 A 4.6333 B

Variety

V1 39.833 A 15.810 A 55.643 A 6.0690 A

V2 36.310 B 10.190 B 46.500 B 3.3548 B

Plant height (cm)

Results concerning interaction of salt*variety

and treatment*variety, were statistically

highly significant (P<0.001), whereas the

interaction salt*treatment and

salt*treatment*variety were non-significant

(P>0.005) (),

Sabz Pari showed the maximum plant height

(57.52cm) when grown under control,

similarly the minimum plant height

(46.09cm) was noted in Mehak Pari when

grown in 50mM salinity (Table 2). These

results are in accord with [29, 36] who also

reported that increasing salt level cause a

significant decrease in height of okra plants.

The prominent symptoms of soil salinity on

okra plants were stunted growth [43]. Those

okra plants which were grown under non

saline soils may have osmotically adjusted

themselves according to growing conditions

due to which plants have managed to attain

desirable cell enlargement hence showed

maximum plant height [30]. The decreased

plant height under saline soil can be

attributed to toxic effect of sodium and

chloride ions and lower water potential in

root zone [44].

The maximum plant height was noted in Sabz

Pari (66.32cm) when treated with 4mM

silicon solution, while the minimum plant

height was observed in Mehak Pari

(44.66cm) when treated with 3mM solution

of potassium silicate (Table 2). These results

are in accord with [45] who noted that at

increasing levels of silicon, the height of

wheat plants also increased.

Shoot fresh weight (g)

The interactions Salt*Variety and

Treat*Variety were significant for P<0.005

whereas the interactions salt*treatment and

salt*treatment*Variety were non-significant

(Table 1).


Ayub et al.

13

Table 3. Mean of interactions salt x treatment, salt x variety and treatment x variety for

shoot length (SL) root length (RL) plant height (PH) and shoot fresh weight (SFW)

Salt x Treatment SL (cm) RL (cm) PH (cm) SFW (g)

S1xT1 38.167 BCDE 14.000 A 52.16 ABCD 5.1833 A

S1xT2 38.167 BCDE 12.333 BCD 50.50BCDEF 4.8167 B

S1xT3 38.667ABCD 12.833ABCD 51.500 BCDE 4.7000 B

S1xT4 38.00ABCDE 12.167 CD 50.167 DEF 4.6167 B

S1xT5 39.500 ABC 13.333 ABC 51.500 BCDE 4.6333 B

S1xT6 39.667 AB 13.00ABCD 52.667 ABC 4.6500 B

S1xT7 40.333 A 13.833 A 54.167 A 4.6167 B

S2xT1 35.667 E 12.83ABCD 48.500 F 4.7500 B

S2xT2 36.667 DE 13.00ABCD 49.667 EF 4.7667 B

S2xT3 37.000 CDE 13.00ABCD 50.000 DEF 4.6667 B

S2xT4 37.667 BCDE 13.500 AB 51.167 BCDE 4.6500 B

S2xT5 36.500 DE 12.000 D 49.833 DEF 4.6500 B

S2xT6 37.333 BCDE 13.00ABCD 50.333 CDEF 4.6167 B

S2xT7 39.667 AB 13.16ABCD 52.833 AB 4.6500 B

Salt x Variety

S1xV1 41.762 A 15.762 A 57.524 A 6.0381 A

S1xV2 36.524 BC 10.000 B 46.905 C 3.4524 B

S2xV1 37.905 B 15.857 A 53.762 B 6.1000 A

S2xV2 36.095 C 10.381 B 46.095 C 3.2571 C

Treatment x Variety

T1XV1 36.333 EFG 15.667 A 52.000 E 6.1167 AB

T2xV1 37.167 DEF 15.500 A 52.667 E 6.2500 A

T3xV1 38.333 CDE 15.833 A 54.167 DE 6.1000 AB

T4xV1 39.000 CD 16.500 A 55.500 CD 6.1000 AB

T5xV1 40.667 BC 16.000 A 56.667 BC 6.0167 AB

T6xV1 42.667 AB 15.500 A 58.167 AB 5.9333 B

T7xV1 44.667 A 15.667 A 60.333 A 5.9667 B

T1xV2 37.500 DEF 11.167 BC 48.667 F 3.8167 C

T2xV2 37.667 DEF 9.833 DE 47.500 FG 3.3333 D

T3xV2 37.333 DEF 10.000 CDE 47.333 FG 3.2667 D

T4xV2 36.667 DEFG 9.167 E 45.833 GH 3.1667 D

T5xV2 35.333 FG 9.333 DE 44.833 H 3.2667 D

T6xV2 34.333 G 10.500 BCD 46.667 FGH 3.3333 D

T7xV2 35.333 FG 11.333 B 45.222 GH 3.3000 D

T1=Control T2=GA3 50mg/L, T3= GA3 75mg/L, and T4= GA3 100 mg/L, T5= Si 2mMol, T6=Si 3mMol,

T7=Si 4 mMol, S1= control, S2=50mM, V1=SABZ PARI V2=MEHAK PARI

Maximum shoot fresh weight was notes in

Sabz Pari (6.03 gm) when grown under

control, whereas the minimum shoot fresh

weight (3.25 gm) was seen in Mehak Pari

when subjected to 50mM salinity (Table 2).

These results are in accordance with [46] who

reported that saline medium have adversely

affected the shoot fresh weight of okra. Plants

grown under saline stress failed to set off the

dehydration avoidance mechanism which

made the root membranes resistant for toxic

ions of Na+ and Cl- and failed to keep

stomatal conductance up to desirable rate

[47], thus plants could not bear the high salt

stress and experienced the drop in growth of

fresh weight [30]. Soil salinity causes soil


14

water stress, which hinders the development

of the growing tissues as a result decrease in

shoot fresh weight occurs [7].

Sabz Pari showed highest shoot fresh weight

(6.25 gm) when treated with 50mg/L GA3

solution whereas the minimum shoot fresh

weight (3.16 gm) was noted in Mehak Pari

when treated with 100mg/L of GA3 (Table 2).

[48] have also reported an increase in shoot

fresh weight of okra plants when treated with

GA3. GA3 is usually related with cell

division, physiological growth of plants,

these hormones manages seed germination,

leaf expansion, stem enlargement and

flowering [49, 50].

Root fresh weight (g)

The maximum value of root fresh weight

(1.14 gm) was noted in those okra plants

which were treated with 50 mg/L GA3

solution and grown under control, while

minimum root fresh weight (0.91 gm) was

noted in plants grown under 50 mM salinity

and treated with 4 mM silicon (Table 4).

These results are in agreement with those of

[48] who noted similar increase in root fresh

weight of okra when treated with GA3. The

results of current study confirmed the

beneficial effect of GA3 treatment on Okra

plants, plants showed maximum root fresh

weight which were treated with GA3 as

compared to those plants which were treated

only with salt.

The maximum root fresh weight (1.21gm)

was show by Sabz Pari under control, while

minimum root fresh weight (0.70gm) was

noted in Mehak Pari when grown in 50 mM

salt level (Table 4). Salinity negatively

affected the root dry weight of both cultivars.

Similar reduction in root fresh weights of

Cabbage, Sugar beet, Paniculate amaranth

and Pak-choi due to salinity was also noted

by [51- 53]. Roots have less salt tolerance

than the shoots, because roots were grown

directly in saline soil having high

concentrations of Na+ ion in root zone, which

imparts osmotic effects and reduces growth

and development of roots [54-56].

Maximum root fresh weight (1.21gm) was

noted in Sabz Pari when treated with 75mg/L

GA3 and minimum root fresh weight (0.74

gm) was observed in Mehak Pari when

treated with 4mM silicon (Table 4). [48]

observed similar increase in the root fresh

weight of okra and [56] in soya beans when

treated with GA3

Shoot dry weight (g)

Sabz Pari showed maximum shoot dry

weight (3.10g) under control, whereas Mehak

Pari showed minimum shoot dry weight

(1.25g) when grown under 50mM salinity

(Table 4). These findings were in agreement

with [29, 46, 58] who noted that salinity

imparted significant reduction in shoot dry

weight of okra. It was evident that at 50mM

salinity, decrease in dry shoot weight of

plants was more as compared to that of

control. Plants which were treated with

higher salinity level (50mM) cannot avoid

dehydration, have high sodium and chloride

ion toxicity inside roots, and experienced low

stomatal conductance, all these factors

contributed towards reduction in dry weight

of shoots [30, 47].

The maximum shoot dry weight (3.25g) was

noted in Sabz Pari when treated with 50mg/L

GA3, whereas the minimum shoot dry weight

(1.16g) was noted in Mehak Pari when

treated with 100mg/L GA3 (Table 4). [48]

also confirmed these results who reported

that GA3 enhances the shoot dry weight of

okra; while working on tomato plants an

increase in shoot dry weight was noted when

treated with GA3 [59, 60].

Root dry weight (g)

Sabz Pari showed maximum root dry weight

(0.91g) under control, whereas Mehak Pari

showed minimum root dry weight (0.60g)

when grown under 50mM salinity (Table 4).

These findings were similar to [30, 61].

Reason for this reduced root dry weight under

salinity stress could be, insufficient


Ayub et al.

15

photosynthesis, fewer stomatal conductance,

and therefore inadequate carbon dioxide

uptake [62, 63] which in turn produced less

dry root mass. Salinity also decreases cell

division and cell expansion [64]. The

reduction in root dry weight may be because

of reduced root length which is commonly

seen in plants grown under salt stress [55,

56].

Table 4. Mean of interaction salt x treatment x variety for root fresh weight (RFW), shoot

dry weight (SDW) and root dry weight (RDW)

SALT x TREATMENT x VARIETY RFW(g) SDW (g) RDW (g)

S1xT1xV1 1.0700 F 3.1667 AB 0.7700 FGH

S1xT2xV1 1.1533 CDE 3.3000 A 0.8533 CDE

S1xT3xV1 1.2167 ABC 3.1000 ABC 0.9167 ABC

S1xT4xV1 1.1867 ABCD 3.0667 ABC 0.8867 ABCD

S1xT5xV1 1.1533 CDE 3.0000 ABC 0.8533 CDE

S1xT6xV1 1.1733 BCDE 2.8667 BC 0.8733 BCDE

S1xT7xV1 1.1800 BCD 2.7667 C 0.8800 ABCDE

S1xT1xV2 1.1133 EF 2.2000 D 0.8133 EFG

S1xT2xV2 1.1367 DE 1.2667 E 0.8367 DEF

S1xT3xV2 0.8533 HI 1.3000 E 0.7533 GHI

S1xT4xV2 0.8133 IJ 1.1667 E 0.6800 JKL

S1xT5xV2 0.9267 G 1.2667 E 0.7233 HIJ

S1xT6xV2 0.9033 GH 1.4667 E 0.7700 FGH

S1xT7xV2 0.8600 HI 1.4333 E 0.6933 IJK

S2xT1xV1 1.2233 AB 3.0667 ABC 0.9200 ABC

S2xT2xV1 1.2133 ABC 3.2000 AB 0.9133 ABC

S2xT3xV1 1.2133 ABC 3.1000 ABC 0.9133 ABC

S2xT4xV1 1.1900 ABCD 3.1333 ABC 0.8900 ABCD

S2xT5xV1 1.2267 AB 3.0333 ABC 0.9267 AB

S2xT6xV1 1.2467 A 3.0000 ABC 0.9467 A

S2xT7xV1 1.2233 AB 3.1667 AB 0.9133 ABC

S2xT1xV2 0.7200 KLM 1.4333 E 0.6200 LMN

S2xT2xV2 0.7633 JK 1.3333 E 0.6633 JKLM

S2xT3xV2 0.7467 KL 1.1667 E 0.6467 KLMN

S2xT4xV2 0.7367 KL 1.2667 E 0.6367 KLMN

S2xT5xV2 0.6867 LM 1.2333 E 0.5867 NO

S2xT6xV2 0.6600 MN 1.1333 E 0.5933 MN

S2xT7xV2 0.6200 N 1.2333 E 0.5200 O

T1=Control T2=GA3 50mg/L, T3= GA3 75mg/L, and T4= GA3 100 mg/L, T5= Si 2mMol, T6=Si 3mMol,

T7=Si 4mMol, S1= control, S2=50mM, V1=SABZ PARI V2=MEHAK PARI

It was observed that Sabz Pari showed

maximum root dry weight (0.91g) when

treated with 50mg/L GA3, whereas the

minimum root dry weight (0.60g) was

showed by Mehak Pari treated with 4mM

silicon (Table 4). The increase in root dry

weight could be attributed to the fact that GA3

enhance cell growth, and cell division [65],

due to this increased number of cells okra

plants treated with GA3 showed maximum

root dry weight. The promoting effects of

GA3 increased the multiplication of ribose

and polyribosome, which caused an

increment towards biomass of aerial plant

parts, improved activity of enzymes, may

also result in biomass gathering in plants as

they grow. GA3 increase membrane

permeability which in turn facilitated


16

assimilation and consumption of mineral

nutrients [66]. This would have contributed

towards enhancing the capacity of the treated

plants for increased biomass production.

Conclusions and recommendations

It is obvious that salt stress have imparted

destructive effects on the growth and

development of okra. However, the response

to salinity differs greatly among both okra

cultivars; Sabz Pari showed maximum

tolerance against salt stress as compared to

Mehak Pari. The use of exogenous GA3 and

Potassium Silicate under salt stress condition

has been found to be very much effective to

alleviate salt induced damages and increased

the root length, shoot length, plant height,

root and shoot fresh weight, root and shoot

dry weight of tested okra cultivars.

Authors’ contributions Conceived and designed the experiments:

SM Khan, Performed the experiments: Q

Ayub, Analyzed the data: A Khan & MA

Khan, Contributed reagents/ materials/

analysis tools: I Hussain & Z Ahmad, Wrote

the paper: Q Ayub.

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