CHAPTER : 6 Studies on Plant Growth Promoting …shodhganga.inflibnet.ac.in/bitstream/10603/74613/15/15_chapter 6.pdf · The importance of agriculture in the socio-economic fabric

CHAPTER 6: Studies on Plant Growth Promoting Activit of Cyanobacterial Isolates

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CHAPTER : 6

Studies on Plant Growth Promoting

Activity of Cyanobacterial Isolates


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6.1 INTRODUCTION

The importance of agriculture in the socio-economic fabric of India can be

realized from the fact that the livelihood of majority of the country population

depends on agriculture. In India agriculture is facing many constraints, one is,

need of environmental friendly alternative of chemical fertilizers and second is

gradually depletion of nutrient supply in Indian agriculture soil. The use of

Cyanobacteria as PGPR can fulfill these criteria and ensure viability of farming

activity.

While working on the cyanobacteria of Indian paddy fields, Gupta and Lata

(1964) observed that cyanobacteria accelerated seed germination and promoted

seedling growth. In addition, they also observed that both yield and the quality of

the grains was improved because they were richer in proteins. It seems very likely

that the beneficial effect of the algae on the rice crop may not be restricted to their

capacity to fix atmospheric nitrogen alone, especially in fields where nitrogen-

fixing algae may not be present in appreciable quantities. It was assumed that

active substances are gibberellin (GA) type. A gibberellin-like substance has been

isolated from the cyanobacterium Phormidium foveolarum and this is active in

GA-bioassays (Gupta et al 1973). Growth-promoting substances were detected

by the effect of extracts of N. muscorum on seedlings of Panicum miliaceum. The

height of millet plants as well as their dry weight were also increased by all the

extracts (Caire et al., 1976). Others authors have reported that vitamins,

aminoacids and polypeptides benefit plant growth. Information about

cyanobacterial biomass or their substances being incorporated to other plants

different to rice is scarce (Halperin et al., 1981).

With the increasing prices of fertilizers and associated problems of global

warming and environmental pollution, there is a need for identifying organic

options for increasing food quality and yields. Soil fertility is diminishing

gradually due to soil erosions, accumulation of salts and other toxic elements,

water logging and un-balanced nutrient compensation. Organic wastes and bio-

fertilizers are the alternate sources to meet the nutrient requirement of crops and


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to bridge those gaps. Farming regions that emphasized heavy chemical

application led to adverse environmental, agricultural and health consequences.

Many efforts are being exercised to combat the adverse consequences of chemical

farming.

Cyanobacterial biofertilizers have been reported to be very useful in ameliorating

various physico-chemical properties of marginal soils and the EPS produced by

the cyabobacteria seems to play an important role (Nisha et al., 2007). Since

salinity is a major constraint to crop growth and germination is the most

syensitive and decisive stage for successful crop establishment (Soltani et al.,

2006), it would be worthwhile to study whether EPS application is useful in

promoting seed germination in the presence of salts in the medium.

In some filamentous cyanobacteria nitrogen fixing heterocysts are formed.

Heterocysts are terminally differentiated cells whose interior becomes anaerobic,

mainly as a consequence of respiration, allowing the oxygen- sensitive process of

nitrogen fixation to continue. The regulation of dinitrogen fixation has been

extensively studied in the heterocyst system (Böhme, 1998).

The distribution of cyanobacteria in the soil depends on the soil pH, electrical

conductivity, and exchangeable sodium. Amongst these, pH is the most important

factor determining the Cyanobacterial diversity. Under laboratory conditions, the

optimal pH for cyanobacterial growth ranges from 7.5–10, with a lower limit of

6.5–7.0. Although infrequent at pHs below 6.0, cyanobacteria’s ability to grow at

diverse pH and modify their own environment.

A number of studies have demonstrated the growth promotion activity of

cyanobacterial extracts on plant regeneration and plantlet formation.

Cyanobacteria have potential to produce many metabolites which includes the

phytohormones (IAAs, cytokinin and gibberillin-like compounds) and

ironchelators (schizokinen, anachelin and synechobactins) and exhibit profound

effect on the productivity of the ecosystem. (Yadav, et. al., 2011). As plant

growth promoting agents, advantages of cyanobacteria over expensive synthetic

phytohormones include broader spectrum of activity and optimum levels of


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biologically active molecules, which are needed for normal plant development in-

vivo or in-vitro (Sergeeva et. al. 2002, and Prasanna et. al. 2010).

Microbial inoculation is known to play a major role in improving soil fertility and

plant growth/yields; however, most of the published literature on this aspect has

focused on cereals or legumes or important cash crops such as cotton or

fruits/vegetables (Bashan,1998; Balser et al., 2001; Roger et al., 1993;

Prasanna et al., 2013,; Stefan et al., 2013).

Statistical analysis confirm that there is a significant difference in plant height,

root length, number of leaf, fresh and dry weight of root, leaf and stem in treated

plants as compared to control. Venkataraman & Neelakantan (1967) showed

that the production of growth substances and vitamins by the algae may be partly

responsible for the greater plant growth and yield.

The capacity for biosynthesis of growth promoting substances such as auxins,

amino acids, sugars and vitamins (Vitamin B12, Folic acid, Nicotinic acid and

Pantothenic acid) also can enhance plant growth. The other reason that can

suggest for increased plant growth by using cyanobacterial extract is that, the

growth of BGA in soil seems to influence the physical and chemical properties of

soil.

The review of literatures showed that, there are only a few studies on similar

subjects, especially on unicellular Cyanobacterial culture as biofertilizer crops;

however results of heterocystous cyanobacteria as biofertilizer had been

investigated. The results obtained in this work showed that pre-soaking seeds by

Cyanobacterial culture accelerates seed germination and seedling height (Fig. 8.3

& 8.4). Previously, Nanda et al. (1991) showed that, pre-soaking of pumpkin and

cucumber seeds in Westiellopsis prolific extract can accelerate seed germination

and spraying extracts of this cyanobacterium to emerged seedling during their

subsequent cultivation led to significant increase in growth and development of

both crops.


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A. Cyanobacteria and Mung bean (Vigna radiata or Phaseolus aureus)

Mung beans are cheap, reliable and easy to germinate, and offer a useful way to

look at the germination process. Mung beans are legumes (members of the

Fabaceae family), and are most commonly used in the India for growing

nutritious bean sprouts. Mung beans are annuals, growing up to about 1m in

height. The first flowers appear seven to eight weeks after planting and the crop

reaches maturity in 12 to 14 weeks. The mung bean plant comes originally from

India, but is now widespread throughout the tropics. Mung Beans can germinate

within 48-72 hrs.

Agronomic potential of biofilmed preparations of selected cyanobacterial strains

has been investigated. The formulations were prepared using paddy straw

compost:vermiculite (1:1) as carrier and tested as inoculants in mungbean and

soybean. The effects of the formulations were evaluated in terms of

microbiological, nutrient availability, and plant biometric parameters. The

Trichoderma viride–Bradyrhizobium biofilm exhibited 20–45% enhancement in

fresh/dry weight of plants over other microbial treatments, while the T. viride–

Azotobacter biofilm exhibited highest dehydrogenase activity in the soil and

nitrogen fixation. This study highlights the promise of cyanobacterial inoculants

and biofilmed biofertilizers as promising inputs for integrated nutrient

management strategies in agriculture. (Prasanna, R et al. 2014)

Soil and Fertilization

Mung bean performs best in fertile, well-drained sandy loam soil with a pH

between 6.2 and 7.2 and will suffer in poorly-drained, heavy soils. Plants in

alkaline soils will display symptoms of nutrient deficiencies. Nitrogen fertilizer is

unnecessary, though it may encourage early growth and faster establishment.

Mung bean has the same nutrient requirements as other legumes. A soil test is the

best way to determine phosphorus and potassium requirements. In fields or

gardens where mung beans are planted for the first time, a nitrogen-fixing

Rhizobium bacteria specifically for mung beans should be applied to the seeds or

planting area.


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Irrigation

The deep-rooted mung beans are adapted to warm, dry climates and grow best

with only three to five deep waterings during the growing season. If the soil is

adequately moist at the time of planting, the first watering is not needed until

about 20 days after planting. Irrigation timing and frequency needs vary

depending on humidity, rainfall and winds. A regimen with only a few, deep

waterings limits vegetative growth and encourages seed production. The mung

bean requires adequate water between blooming and pod fill.

Planting and Spacing

Mung bean planting should occur early enough that harvest will occur before the

rainy season and bloom or pod fill will occur before the hottest, driest part of

summer and late enough that all danger of frost has passed and soil temperatures

are above about 60 degrees Fahrenheit. Two plantings annually, one in spring and

another in fall, are often possible in warmer regions. Tilling or cultivating the top

several inches of soil breaks up the ground and controls weeds. Mung bean seeds

germinate best when planted 1 to 2 inches deep in moist soil. One seed every 3

inches in rows 18 to 24 inches apart provides an adequate yield.

Process of germination occurs in different stages. Some steps of seed germination are as follows: • Seed absorbs water and seed coat gets burst. It is the first sign of germination.

There is an activation of enzymes, increase in respiration and plant cells get

duplicated. A chain of chemical changes starts which leads to development of

plant embryo.

• Chemical energy stored in the form of starch is converted to sugar, which is

used during germination process. Soon, embryo gets enlarged and seed coat

burst opens.

• Growing plant emerges out. Tip of root first emerges and helps to anchor the

seed in place. It also allows embryo to absorb minerals and water from soil.

• Some seeds require special treatment of temperature, light or moisture to start

germination.


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B. Cyanobacteria and Wheat

Wheat is an agriculturally important crop and requires high doses of fertilizers.

However, little work has been done on the supplementary input of cyanobacteria

asbiofertilizers to this crop, and available information is scarce. A study of the

application of vermicompost, farmyard manure, and biofertilizers (cyanobacteria

and Azotobacter) in different combinations with chemical fertilizers (N40P30K30)

had promising results for wheat crops (var. HD 2687). The application of

vermicompost in combination with cyanobacteria brings about significant

increases in nitrogenase activity, while Azotobacter + cyanobacteria (+N40P30K30)

treatment gives the highest values of chlorophyll. The addition of vermicompost

and farmyard manure (+N40P30K30) enhances cyanobacterial abundance and

diversity. Nostoc,Anabaena, Calothrix, Oscillatoria, and Phormidium are the

dominant genera in wheat-crop soil (Prasanna et al., 2008b).

Cyanobacteria are known to liberate substantial quantities of extracellular

nitrogenous compounds into the medium. Physiological attributes of a set of

cyanobacterial strains (Calothrix ghosei, Westiellopsis, Hapalosiphon intricatus,

and Nostoc sp.) isolated from the rhizosphere of wheat (var. HD 2687) were

analyzed by Karthikeyan et al. (2009). The concentrated culture filtrates of these

strains enhance wheat-seed germination percentages, and the radicle and

coleoptiles lengths. Thin layer chromatography analyses of the filtrates revealed

the presence of several amino acids such as histidine, and auxin-like compounds.

Co-culturing experiments with selected Cyanobacterial strains recorded

significant enhancements in plant chlorophyll.

6.2 Seed Vigor Index

Seed vigor is the sum total of those properties of seed which determine the level

of activity and performance of the seed or seed lot during germination and

seedling emergence. Although differences in physiological attributes of seed lots

can be demonstrated in the laboratory, it was suggested that the term should be

used to illustrate the performance of seed were shown in the field. The seed lot

showing the higher seed vigor index is considered to be more vigorous Seedling


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vigor index was calculated following modified method of Abdul-Baki &

Anderson.

Vigor Index = Seedling length (mm) x Germination %

Importance of Seed Vigor Testing

Vigor testing does not only measure the percentage of viable seed in a sample, it

also reflects the ability of those seeds to produce normal seedlings under less than

optimum or adverse growing conditions similar to those which may occur in the

field. Seeds may be classified as viable in a germination test which provides

optimum temperature, moisture and light conditions to the growing seedlings;

however, they may not be capable of continuing growth and completing their life

cycle under a wide range of field conditions. Generally, seeds start to lose vigor

before they lose their ability to germinate; therefore vigor testing is an important

practice in seed production programs.

Testing for vigor becomes more important for carryover seeds, especially if seeds

were stored under unknown conditions or under unfavorable storage conditions.

Seed vigor testing is also used as indicator of the storage potential of a seed lot

and in ranking various seed lots with different qualities.

The biological basis of the seed vigor concept

It has been established that the conditions of seed development, maturation,

storage and aging influence seed vigor. Seeds developed under moisture stress,

nutrient deficiency, extreme temperatures, etc. often result in light, shriveled seed

or collectively called poor-vigor seed. Preharvest environment of high humidity

and warm temperatures can also cause loss in seed viability and vigor. Seed

mechanical damage, whether induced by harvesting or conditioning equipment, as

well as improper storage conditions are among the factors that adversely affect

seed vigor. In addition, genetic factors such as hard-seededness, resistance to

diseases, and seed chemical composition influence the expression of seed vigor.


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Methods of measuring seed vigor

The general strategy of determining seed vigor is to measure some aspects of seed

deterioration or weaknesses, which is inversely proportional to seed

vigor.

Cold test, accelerated aging test, electric conductivity test, seedling vigor

classification, and seedling growth rate are among the tests that are used to

measure seed vigor. In addition, the tetrazolium (TZ test) can be used as a vigor

test by classifying the pattern of stained seeds into high, medium and low quality.

The AOSA Seed Vigor Testing Handbook is a good source of information on

seed vigor testing. Below is a brief description for some of the most common seed

vigor tests that are used for various crops including corn, soybean, field beans,

peas, grasses, vegetable seeds, and other crops.

a) Electric Conductivity Test

This test measures the integrity of cell membranes, which is correlated with seed

vigor. It is well established that this test is useful for garden beans and peas. It has

been also reported that the conductivity test results are significantly correlated

with field emergence for corn, and soybean. As seeds lose vigor, nutrients exude

from their membranes, and so low quality seeds leak electrolytes such as amino

acids, organic acids while high quality seeds contains their nutrients within well

structured membranes. Therefore, seeds with higher conductivity measurement

are indication of low quality seeds as vice versa.


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6.2 MATERIAL & METHODS

6.2.1 Seed Selection

Seeds were selected based on seed vigour index. The electrical conductivity test is

used to measure veed vigour index. Two cultivas were selected for the

conductivity test.

6.2.2 Germination Test.

Seeds of Vigna radiata and Triticum aestivum were surface sterilized with 5%

sodium hypochlorite for 8 min, then rinsed with distilled water several times to

remove any trace of sodium hypochlorite. The seeds were classified into two

groups. Then seeds were incubated with cyanobacterial isolates under shaking

condition for 2 hours. Water treated seeds were used as control.

Control and bacterized seeds (10 seeds per pot) were sown in sterilized pot

containing autoclaved soil (approximately 100 g). All pots were labeled properly.

The pots were kept at 25 ± 2°C, 60% relative humidity, under 8 hours/16 hours

dark/light photoperiod. Pots were observed and watered regularly during this

period. After 10 days, plants were harvested and their growth parameters were

analyzed.

At the end of the experiment total fresh weight, length of shoots and roots per

plant were determined.

6.2.3 sterile soil

The soil was sterilized twice by autoclaving, through intermittent sterilization for

2 h at 121.4 °C and 15 lbs pressure, on two consecutive days (to destroy spores

and avoid or minimize contamination). The physico-chemical properties of soil

should be done. Plastic pots of 6 inch size were employed in the study.

6.2.4 Plant Inoculation Experiments

Seeds of Vigna radiata and Triticum aestivum were surface sterilized with 5%

sodium hypochlorite for 8 min, then rinsed with distilled water several times to

remove any trace of sodium hypochlorite. The seeds were classified into two


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groups. Then seeds were incubated with cyanobacterial isolates under shaking

condition for 2 hours. Water treated seeds were used as control.

Control and bacterized seeds (8 seeds per pot) were sown in sterilized pot

containing autoclaved soil (approximately 100 g). All pots were labeled properly.

The pots were kept at 25 ± 2°C, 60% relative humidity, under 8 hours/16 hours

dark/light photoperiod. Pots were observed and watered regularly during this

period. After 10 days, plants were harvested and their growth parameters were

analyzed.At the end of the experiment total fresh weight, length of shoots and

roots per plant were determined.

6.2.5 Growth Analysis

A. Growth Analysis: Above ground parts

Plant height:

Measurements of plant height were taken at the crop maturity stage in

three replicates of five plants each. Plant height was measured from the soil line

to shoot tip. Plant height was measured by placing the plant on a centimeter scale.

Plant population was uniform at the time of maturity of crop.

Dry matter production

At maturity fifteen plants (five plants from each replicate) were randomly

selected and the data on component part dry weights (leaf, root and shoot) were

recorded. Leaf, stem and root were dried at 60 ºC for 72 hours. Pods were

separated and the total numbers of branches were recorded. Dry weights of seed

components were recorded after drying at 35–40 ºC for 10 days.

Growth Analysis: Below ground parts

Root length:

The measurements of root length were done in plants at 10 days. Roots

were taken out carefully, washed, and measured against a cm scale.

Root fresh and dry weight

Plant roots with nodules at each sampling were washed and dried on filter

paper and weighed for the fresh weight. For dry weight roots were dried at 60oC

for 72 hours and weighed.


79

6.3 RESULT AND DISCUSSION

Seed cultivar Mung-2 and wheat-1 is better quality of seeds as they have

comparatively less conductivity value.

Type of seed Electrical conductivity mean Mung-1 0.5167 Mung-2 0.3467

Wheat-1 0.16 Wheat-2 0.23

Table 6.1 Result of electrical conductivity test

Cyanobacteria play a key role in improving growth of many plants when applied

as biofertilizers. This evidence was clearly appeared in growth criteria of wheat

and mung seeds as represented in Table 6.2 to 6.7. The growth profile of wheat

and mung plants, in terms of plant height and biomass (fresh and dry weight)

were enhanced by administration of cyanobacterial extracts (Fig 6.1 to Fig 6.7).

Figure 6.1 Comparison of growth between Cyanobacterization PBJ1 of the Mung Seed with control

Visual observation of wheat plants and comparison with control treatments

illustrated the significant improvement brought about by cyanobacterial

inoculation with the seed, with distinctly greener leaves and better plant

development (Fig. 6.1). Plant biometrical parameters, especially fresh and dry

weight were significantly higher in cyanobacterial PBG1 treated seeds.

Mung Control Mung Experimental

CHAPTER 6: Studies on

Parameter after 10 days

Germination %

Shoot Length in cm

Root Length in cm

No of leaves

Plant fresh weight in (mg)

Weight of fresh

Weight of dry root (

Weight of fresh

Weight of dry

Table 6.2 Effect of Cyanobacterium PBJ1 on Growth Parameters of Mung

Figure 6.2 Comparative study of effect of

0

20

40

60

80

100

120

140

160

Effect of Cyanobacterium PBJ1 on

Growth Parameters of Mung

Studies on Plant Growth Promoting Activit of Cyanobacterial Isolates

80

Parameter after 10 days Control Experimental

Germination % 70 ± 2.6

Length in cm 10.1± 0.13

Root Length in cm 9.1± 0.12

7.33± 1.52

Plant fresh weight in (mg) 101 ± 0.29

fresh root (mg) 63.6 ± 0.5

Weight of dry root (mg) 8.1 ± 0.20

Weight of fresh shoot (mg) 41.7 ± 0.29

Weight of dry Shoot (mg) 3.6 ± 0.3

Effect of Cyanobacterium PBJ1 on Growth Parameters of Mung at 10 Days after sowing

Comparative study of effect of Cyanobacterium PBJ1 inoculation vis a vis controls in the Mung


Growth Parameters of Mung

Control

Experimental

Plant Growth Promoting Activit of Cyanobacterial Isolates

Experimental

94 ± 1.6

17.4± 0.11

13.7± 0.11

12.00±1.73

150 ± 0.12

93.6± 0.11

11 ± 0.21

63.6 ± 0.32

4.5 ± 0.5

Effect of Cyanobacterium PBJ1 on Growth Parameters of Mung

Cyanobacterium PBJ1 inoculation


Control

Experimental


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Data presented in the table 6.2, 6.3, 6.5 and 6.6 indicates the effect of

Cyanobacterial treatment on growth of mung and wheat seedlings in terms of root

and shoot length. The treatments with PBG1 culture showed significant

stimulatory effect on the length of roots and shoots.

Treatment of mung seeds with cyanobacteria PBJ1 significantly effect all growth

parameters.There was 20 % increase in germination % upon cyanobacterization

of seed with isolate PBJ1.

Days Control

(Shoot length in cm)

Experimental (Shoot length in cm)

2 1.7± 0.12 3.7± 0.10

4 3.6± 0.14 8.7± 0.14

6 5.3± 0.11 10.9± 0.10

8 6.9± 0.15 13.7± 0.13

10 10.1± 0.13 17.4± 0.11

Table 6.3 Effect of Cyanobacterium PBJ1 on Shoot length of Mung

Fig 6.3 Effect of Cyanobacterium PBJ1 on Shoot length of Mung

0

5

10

15

20

25

30

1 2 3 4 5

Cm

Effect of Cyanobacterium PBJ1 on Shoot

length of Mung

Experiment

al (Shoot

length in

cm)

Control

(Shoot

length in

cm)

2 4 6 8 10

No. of Days


Days (Root length in cm)

2

4

6

8

10

Table 6.4 Effect of Cyanobacterium PBJ

Fig 6.4 Effect of Cyanobacterium PBJ1 on

Figure 6.5 Comparison

0

5

10

15

20

25

1

Cm

Effect of Cyanobacterium PBJ1 on Root

Wheat Control

2


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Control

(Root length in cm)

Experimental

(Root length in cm)

2.0± 0.11 3.2± 0.12

3.2± 0.13 4.7± 0.14

5.6 ± 0.14 6.4± 0.10

6.3± 0.15 9.7± 0.12

9.1± 0.12 13.7± 0.11

Effect of Cyanobacterium PBJ1 on Root length of Mung

Effect of Cyanobacterium PBJ1 on Root length of Mung

ison of growth between Cyanobacterization PBJ1 of the wheat Seed with control

2 3 4 5


length of Mung

Experiment

al (Root

length in

cm)

Control

(Root length

in cm)

Wheat Control Wheat Experimental

2 4 6 8 10

No. of Days


on Root length of Mung

length of Mung

between Cyanobacterization PBJ1 of the


Experiment

al (Root

length in

cm)

Control

(Root length

in cm)

Wheat Experimental


Parameter after 10 days

Germination %

Shoot Length in cm

Root Length in cm

No of leaves

Plant fresh weight in (mg)

Weight of fresh

Weight of dry root (

Weight of fresh

Weight of dry

Table 6.5 Effect of Cyanobacterium PBJ1 on Growth

Figure 6.6 Comparative

0

20

40

60

80

100

120

140

160

Effect of Cyanobacterium PBJ1 on Growth


83

Parameter after 10 days Control Experimental

Germination % 60 ± 2.6

Shoot Length in cm 11± 0.14 14.26 ± 0.11

Root Length in cm 6.2 ± 0.13

2.0 ± 1.52

Plant fresh weight in (mg) 90 ± 0.26 153.6 ± 0.10

fresh root (mg) 32.36± 0.14

Weight of dry root (mg) 6.94 ± 0.23

Weight of fresh shoot (mg) 56.9± 0.13

Weight of dry shoot (mg) 5.5 ± 0.12

Effect of Cyanobacterium PBJ1 on Growth Parameters of Wheatat 10 Days after sowing

Comparative study of Effect of Cyanobacterium PBJ1 inoculation

vis a vis controls in the wheat


Parameters of Wheat


Experimental

90 ± 1.6

14.26 ± 0.11

7.8± 0.12

4.00±1.73

153.6 ± 0.10

78.3 ± 0.12

12.2± 0.13

81.3± 0.21

9.4 ± 0.12

Parameters of Wheat

Effect of Cyanobacterium PBJ1 inoculation


Control

Experimental


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Cyanobacterization of wheat seeds with isolate PBJ1 singnificantly enhanced the

growth parameters in the seedlings. There is 30 % increase in germination % in

cyanobacterized seed as compared to controls.

Days Control (Shoot length in cm)

Experimental (Shoot length in cm)

2 3± 0.12 4.5± 0.12

4 4.7± 0.18 5.1± 0.14

6 5.4± 0.11 7.5± 0.10

8 6.8± 0.15 10.5± 0.13

10 11± 0.14 14.26 ± 0.11

Table 6.6 Effect of Cyanobacterium PBJ2 on Shoot length of Wheat

Table 6.7 Effect of Cyanobacterium PBJ2 on Shoot length of Wheat

Days Control

(Root length in cm)

Sample

(Root length in cm)

2 1.5 ± 0.10 2.5± 0.14

4 2.5± 0.12 4.0± 0.11

6 3.6± 0.11 4.5 ± 0.12

8 4.2 ± 0.09 5.8 ± 0.10

10 6.2 ± 0.13 7.8± 0.12

Table 6.7 Effect of Cyanobacterium PBJ2 on Root length of Wheat

0

5

10

15

20

25

30

1 2 3 4 5

Cm

Effect of Cyanobacterium PBJ2 on Shoot length

of Wheat

Experimental

(Shoot length

in cm)

Control

(Shoot length

in cm)

2 4 6 8 10

No. of Days


85

Other growth parameters such as shoot length, root length, number of leaves, dry

and fresh weight of the seedlings were also positively effected by bacterization of

seed.

Table 6.8 Effect of Cyanobacterium PBJ2 on Root length of Wheat

Cyanobacteria produce bioactive compounds including plant growth regulators

that influence the physiological and biochemical profile of inoculated plants. The

objective of the present investigation was to study the effect of cyanobacterial

species PBJ1 on growth of mung and wheat parameters.Seeds presoaked in the

culture extract of cyanobacterial species PBJ1 shawed enhanced the germination

percentage, vegetative growth as well as chlorophyll content. These effects were

statistically proved significant. In all the treatments, the germination of wheat and

mung seeds were growing faster compared to the control.

0

2

4

6

8

10

12

14

16

1 2 3 4 5

Cm

s

Effect of Cyanobacterium PBJ2 on Root length

of Wheat

Sample (Root

length in cm)

Control (Root

length in cm)

2 4 6 8 10

No. of Days


86

6.4 REFERENCES

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11. Karthikeyan, N., Prasanna, R., Lata., and Kaushik, B.D., (2007).

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