SlideShare utilise les cookies pour améliorer les fonctionnalités et les performances, et également pour vous montrer des publicités pertinentes. Si vous continuez à naviguer sur ce site, vous acceptez l’utilisation de cookies. Consultez nos Conditions d’utilisation et notre Politique de confidentialité.
SlideShare utilise les cookies pour améliorer les fonctionnalités et les performances, et également pour vous montrer des publicités pertinentes. Si vous continuez à naviguer sur ce site, vous acceptez l’utilisation de cookies. Consultez notre Politique de confidentialité et nos Conditions d’utilisation pour en savoir plus.
Cytokinin induce cell division especially in carrot root tissue, pea callus etc Cytokinin may also induces cell enlargement in the leaves of Phaseolus vulgaris, pumpkin cotyledons etc.
Pre-sowing treatment of seed with growth regulators has been reported to enhance seed emergence. In tomato, pre sowing seed treatment with 100 ppm IAA, IBA and NAA enhanced the seed germination .
Khan et al in 2013 studied the effect of pt bioregulator on sedd yield……. Having different trtmnt of naa nd ga at 50, 100, 150 ppm along wth control nd found that among diffrnt trtmnt of ga nd naa naa at 100ppm give max germn i.e 94.67 nd ga at 150ppm give smallest seedling length i.e 25.41 compare wth control gave lowest germn nd largst seedling lngth
Induction of flowering which otherwise fails to flower has also been reported with the use of various growth regulators.
Das etal in 2015 study the influenece………… bri mistimorich -1 and lamuyo by using 3 diff growth regulator along with control nd amng diff pgr 4 cpa at 2000 ppm in both var take min days to flwer, produce max no of flwer per plnt and min days to frst fruit hrvst
mila and coworker in 2014 studied the altered sex expression by pgr……. By giving diff treatment of ga3 naa and cepa and found that out of diff trtmnt naa at 50 ppm and cepa at 100ppm give the best result by producing female flower at lowest node i.e 7 nd 6 respectively nd produce max no of female flower per plant. Naa and cepa proved to be best trtmnt for lowering the sex ratio in bitter gourd.
Poor fruit set is a major problem in tomato, brinjal and chillies which is frequently caused by adverse weather conditions during flowering.
Luitel and coworkwer studied the fruit set and yield enhancement in tomato ………by giving diff trtmnt of ga and 2,4-d out diff trtmnt of ga, ga at 10 ppm gave max fruit set, fruit wt nd fruit yield / plnt iily 24 d at 5ppm give max fruit set, fruit wt nd fruit yld per plant. Out of ga nd 24d 2 4 d at 5ppm gave the best reult
Ethephon, an ethylene releasing compound, has been reported to induce ripening in tomato and pepper. (Prajapati, 2015)
Pila and coworker in 2010 studied the effect…………by giving diff trtmnt of ga cacl nd salicylic acid amng diff trtmnt ga at .1%found to b more effective in reducing the weight lossi.e 6-5 as cmpr to control i.e 19, reduce decay of fruits 8.89 as cmpr to control 24.44% nd extend the storage lifeby 18 days
Role of Plant Growth Regulators in Vegetable Crops
Role of Plant Growth
Regulators in Vegetable
Course Title : Master’s Seminar
Course No. : VSC-591
Speaker: Neha Verma
Definition and History of PGR’s
Role of PGR’s in Vegetable Crops
Classification and Functions of PGR’s
A growth regulator is
•An organic compound,
•Can be natural or synthetic,
•It modifies or controls one or more specific
physiological processes within a plant but the
sites of action and production are different.
If the compound is produced within the
plant, it is called as plant hormone.
Both internal plant hormones and lab created
hormones are called plant growth regulators.
Other terms used for Plant growth regulator (PGR) are Phytohormone or Plant hormone or
Bio–regulator or Growth hormone.
Definition of PGR by different Scientists
Olaiya (2013) stated that bio-regulators are
endogenous or synthetically produced
substances that can control one or more
specific biochemical and physiological
functions of many species probably by their
influence on gene and enzyme interactions.
Thimann (1948) stated that a plant hormone is
an organic compound synthesized in one part of
a plant and translocate to another part where in
very low concentration, it causes a physiological
Phillip (1971) defined growth hormone as
substances which are synthesized in particular
cells and are transferred to other cells where
in extremely small quantities influence the
Moore (1974) stated that it is an organic chemical substance other than nutrients which are active
in low concentration in promoting, inhibiting or otherwise modifying growth and development
may be called growth regulators.
Prajapati et al., (2015) stated that although,
photosynthesis supplies the carbon and
respiration supplies the energy for plant
growth, a group of chemicals produced by
plants known as plant growth regulators
control the growth and development of plant.
Auxin was the first hormone to be discovered in
plant and at one time considered to be only
naturally occuring plant growth hormone.
(Prajapati et al., 2015)
Three types of plant hormones Auxins,
Gibberellins and Cytokinins and these were
discovered in the early decades of the twentieth
century, in 1930’s and in 1960's respectively.
History of Plant Growth Regulators
Characteristics of plant growth regulators
The concentration of hormones required for the plant
response is very low (10-6 to 10-5M) ,comparing with the
requirement of mineral and vitamin for plants.
The biosynthesis of plant hormones within plant is more
diffuse and not always localized.
Plant hormones are not nutrient, but chemicals that in
small amounts promote and influence the growth,
development, and differentiation of cells and tissues.
CLASSIFICATION OF PGR
NATURAL PGR’s SYNTHETIC PGR’s
2,4- D, NAA, IBA, 2,4,5-T,
• Also produced
spontaneously in the
plant body, but their
function is not
e.g. Florigen, Vernalin.
1. ON THE BASIS OF ORIGIN
• Produced by some
tissues in plant.
• Also called
• Produced artificially
and similar to natural
On the basis of nature of functions
Increase the growth of
Inhibit the growth of
Maleic Hydrazide (MH)
Major group of plant growth regulators
Plant Growth Promoters
The word Auxins has been derived from a
Greek word auxein- “to grow/increase”.
It was first isolated from human urine.
These are generally produced by the growing
apex of stem and roots of the plants..
This was the first group of plant hormones
Types of Auxin:
I. Natural Auxin
II. Synthetic Auxin
IBA, NAA, 2,4-D
( Meena, 2015 )
FUNCTIONS OF AUXINS
1. Apical Dominance
•Phenomenon in which the apical
buds dominate over the lateral
buds and does not allow the lateral
buds to grow.
•Pinching of terminal bud stops
flow of Auxins down the stem and
allows side shoots to develop.
2. Root initiation and
•Applied on cuttings to
stimulate root growth and
• Auxins induce parthenocarpy i.e., formation of seedless fruits
without pollination and fertilization.
4. Inhibition of abscission
Formation of an abscission layer at the
base of petiole or pedicel results in
shedding of leaves, flowers or fruits.
Auxins inhibit abscission, as they
prevent the formation of abscission
Foliar spray of NAA, 2,4-D induces
flowering in many crop plants.
• Exogenous application of auxins such as NAA at
high concentration is used to prevent the sprouting
of potato tubers. Hence, increases the storage life
of the produce.
7. Eradication of weeds
• Many synthetic auxins are used as selective weed killers
• e.g 2, 4-D is used to destroy broad leaf weeds. It does
not affect mature monocotyledonous plants much.
Second most important growth hormone.
Gibberellins are named after the fungus Gibberella
fujikuroi , which causes rice plants to grow abnormally
tall . (Kurosawa et al., 1930)
Gibberellin produced in the shoot apex mainly in the
leaf primordial (leaf bud) and root system, hence they
translocates easily in the plant in both directions.
Now 135 different Gibberellins are available.
The most commonly occurring gibberellins is GA3.
( Meena, 2015)
• Gibberellins cause internodes
to stretch in relation to light
intensity. Less is the light
intensity more will be inter
node length and vice versa.
• Stimulate stem growth through
cell elongation and cell
2.Seed germination and
• GA activates germination of
seeds which otherwise require
cold (stratification) or light to
FUNCTIONS OF GIBBERELLINS
GA3 is used to break the seed
dormancy of freshly harvested
seeds in many vegetable crops
such as potato and lettuce.
5. Induction of maleness in
6. Bolting in long day
4. Seed dormancy
They were first isolated from
They are synthesized in root
apex, endosperm of seeds, young
fruits, where cell division takes
Functions of Cytokinin
Induce flowering in short day plants.
Dormancy of certain light sensitive seeds such as
lettuce can also be broken by kinetin treatment.
Delays leaf senescence.
Inhibit apical dominance and help in growth of
lateral buds. Therefore, it is also known as anti-
Ethylene is a colourless gaseous hormone.
Found in ripened fruits, flowers and leaves
and nodes of stem.
Synthesis of ethylene is inhibited by carbon
dioxide and requires oxygen.
Functions of Ethylene
Induces ripening of fruits.
Promotes abscission and
senescence of leaf, flowers etc.
Induction of Femaleness:
cucumber, squash, melon.
It stimulates the formation
of adventitious roots.
It is also known as dormins, which acts as anti-
It is synthesized in leaves of wide variety of
Responsible for closing stomata during drought
conditions, hence acts as plant stress hormone.
Functions of Abscisic Acid
Induces senescence of leaves, abscission of
leaves, flowers and fruits.
It induces dormancy of buds and seeds as
opposed to Gibberellins, which breaks dormancy.
It inhibits seed germination and development.
ABA also plays important role in controlling
stomata opening and closing.
Other Plant Growth Regulators
•Brassinosteroids have been recognized as a
sixth class of plant hormones.
•Brassinolide was the first identified
brassinosteroid and was isolated from
extracts of rapeseed (Brassica napus) pollen
•It stimulate cell elongation and division,
resistance to stresses.
•They inhibit root growth and
Morphactins are the group of substances which act on
morphogenesis and modulate the expression of plants.
Role of morphactins
Seed germination- inhibition.
Growth of seedlings- inhibit.
Stem elongation- dwarfing effect.
Commercial uses of bio- regulators in
COMMERCIAL USE OF PLANT
GROWTH REGULATORS IN
In tomato, pre sowing seed
treatment with 100 ppm IAA,
IBA and NAA enhanced the
(Olaiya et al.,2009)
In muskmelon, soaking of
seeds in ethephon at 480
mg/litre of water for 24 hours
improves germination in
muskmelon at low temperature.
Pre-sowing treatment of seed with GA3 and
KNO3 @ 50 ppm enhanced the germination of
endive and chicory, respectively.
IAA, NAA @
seed germination in
Seed dormancy is main problem in Potato and Lettuce.
Chemicals which have been reported to break the rest
period are GA3, Ethylene chlorhydrin and Thiourea.
Lettuce is another vegetable in which treatment with
GA3 or cytokinin has been reported to break seed
dormancy induced by high temperature.
Soak the tubers in 1% aqueous solution of
Thiourea for 1 hour or solution containing 5-10
ppm GA3 for 10- 20 minutes can be used to
break the dormancy of potato.
(Byran , 1989)
Breaking the dormancy in potato comprise the
vapour heat treatment with ethylene chlorhydrin
(1 litre per 20 q) followed by dipping in
thiourea (1% sol.) for 1h & finally in GA (1
mg/l) for 2 seconds.
NAA 50ppm has been reported to
induce early flowering in paprika.
( Kannan et al., 2009)
Plants sprayed with 300ppm GA3 were
earliest to flower and recorded highest
number of fruits and yield per plant in
tomato. ( Sharma et al.,1992)
Application of GA@50 mg/l to young
leaves of non- flowering varieties of
potato, when floral buds had
just formed, resulted in flower
induction in all varieties.
Gibberellic acid has been reported to
induce early flowering in lettuce.
VARIETIES TREATMENTS DAYS TO 1ST
NO. OF FLOWERS
DAYS TO 1ST
Control 57.33 29.67 122.33
GA3 at 100 ppm 53.67 30.33 113.67
4-CPA at 2000
49.67 32.67 101.67
Litosen at 1000
50.33 31.33 109.67
Control 52.67 31.67 119.33
GA3 at 100 ppm 51.67 32.67 109.33
4-CPA at 2000
48.67 33.33 103.67
Litosen at 1000
50.00 32.67 107.00
CD at 5% 2.623 1.838 0.896 9.976
( Das et al., 2015 )
The treatment with growth
regulators has been found to change
sex expression in cucurbits, okra
GA3 (10-25 ppm), IAA (100 ppm)
and NAA (100 ppm) when sprayed
at 2-4 leaf stage in cucurbits, then
they have been found to increase
the number of female flowers.
Whereas, GA3 (1500-2000 ppm),
silver nitrate (300-400 ppm) and
silver thiosulphate (300-400 ppm)
sprayed at 2-4 leaf stage induces
male flower production in
Application of silver thiosulphate followed by
silver nitrate @ 400 ppm was found better for
induction of staminate flowers, in gynoecious lines
(Hatwal et al., 2015 )
Application of ethephon at two true leaf stage to
both Cucurbita maxima and C. pepo caused
suppression of male flowers and increase in
numbers of female flowers. Thus gave rise to an
increase in the ratio of female to male flowers
per plant. ( Hume et al., 1983 )
(Source : Mia et al.,2014)
NODE NO. OF
FEMALEMale Female Male Female Male Female
Control 38 53 10.50 12.20 310 27.42 11.31
GA3@ 50 ppm 35 49 9.55 11.80 383 29.42 13.02
NAA@ 50 ppm 37 41 8.45 7.00 250 35.14 7.48
NAA@100 ppm 36 46 10.75 8.90 285 33.43 8.11
40 42 8.50 6.50 210 38.33 5.48
33 43 6.25 9.70 342 31.43 10.88
CD at 5% 0.95 0.75 0.35 0.85 12.45 1.65 0.55
( Mila etal., 2014 )
Plant growth regulators helps to
stimulate the fruit development
2,4-D at 50 ppm when applied
at anthesis showed better
performance over other in
parthenocarpic fruit development
( Choudhury et al., 2007)
Seed treatment with 2,4-D @
2-5ppm gives early fruit set and
leads to parthenocarpy in
tomato. ( Meena, 2015)
Staminate flowers were induced in parthenocarpic line of
cucumber through use of plant growth regulator GA3@ 1500
ppm and silver nitrate @ 200-300ppm by four sprays at 4 days
interval. (Singh and Ram, 2004)
In brinjal, application of 2,4-D at 2.5ppm in lanolin paste to cut
end of styles or as foliar sprays to freshly opened flower cluster
has been reported to induced parthenocarpy.
Stimulation of fruit Set
In tomato, 75 ppm conc. of 4-
CPA resulted not only the
highest increase in fruit set
(32.19%) but also increased
the yield by 64.99%.
(Baliyan et al., 2013)
Fruit set in bottle gourd can
be increased by spraying the
plant twice at 2 and 4 true-leaf
stage with MH @ 400ppm and
TIBA @ 50ppm. (Meena, 2015)
Hybrid seed production
Bioregulators have also been used
for maintenance of gynoecious lines
Growth regulator like GA3 (1,500-
2000ppm) and chemical like silver
nitrate (200-300ppm) induces the
male flowers on gynoecious
Exogenous application of silver
thiosulphate (300-400ppm) induces
the male flower in gynoecious
( Meena, 2015 )
Some PGR’s posseses gametocidal
action to produce male sterility which can
be used for F1 hybrid seed production.
MH at 100 to 500 ppm appeared most
effective in inducing a high level of male
sterility in eggplant, okra, peppers and
tomato, without detrimental influence on
female fertility. (Saimbhi et al., 1978)
A high concentration of gibberellic acid
(2%) was found to act as a gametocide
for the common onion (Allium cepa L.),
when sprayed in the beginning of the
bolting process. (Meer et al., 1973)
Fig : Male sterility in cauliflower as induced by GA.
Left : Male fertile flowers Right : Male sterile flowers
(Source : Meer and Dam, 1979)
Application of ethephon at 1000 mg/l at turning stage of
earliest fruits induced early ripening of fruits thus
increasing the early fruit yield by 30-35%.
Post-harvest dip treatment with ethephon at 500-2000
mg/l has also been reported to induce ripening in mature
green tomatoes. (Gould, 1992)
Spraying with 60 ppm GA3 10 days before transplanting increased the yield per
ha of variety Roma. ( Naeem et al., 2001)
Spray with 6ppm 2,4-D gave highest yield of tomato. ( Patel et al., 2014)
Foliar sprays of 2,4-D @4 ppm gave the highest yield of brinjal.
( Patel et al., 2012)
Seed treatment with 10ppm GA3 or IAA gave the highest yield in brinjal.
(Sharma et al., 1992)
Foliar sprays of 2 ppm 2,4-D, 40 ppm NAA and 10 ppm GA3 gave 28.75%,
13.61% and 2.30% higher fruit yield over control, respectively.
(Choudhaury et al., 2006)
Spraying plants with 10 ppm NAA gave significantly highest fruit yield (277.8
g/plant). ( Sultana et al., 2006)
Cycocel (CCC) 250-500 Foliar spray Cucurbits,
Flowering, sex expression,
Acetic acid (PCPA)
50 Foliar spray Tomato Fruit set and Yield
Ethephon (CEPA) 100-500 Foliar spray Cucurbits,
Flowering, fruiting, sex
expression and yield
2000 Post- harvest Tomato,
10 Foliar spray Water melon,
Sex expression, fruiting ,
10-15 Foliar spray Okra,
Seed germination, fruit set
List of plant growth regulators and their important uses in vegetable
Growth and yield
Flower drop, fruit set and yield
Seed germination, growth and
-ic acid (NOA)
Tomato, Okra Germination, growth and yield
Silver nitrate 500 Foliar
Cucumber Induction of male flower in
400 - Musk melon Induction of male flower in
Cucurbits Flowering, sex expression and
Tricontanol 2 Foliar
Chillies and Peas Fruit set and yield
Source :Chadha and Kalloo,1993
Growth substances should be sprayed preferably in the
Avoid to spray in windy hours.
Spray should be uniform and wet both the surface of
Add surfactant or adhesive material like Teepol, Tween-
20 are Gum with growth substances @ 0.5 – 1.0 ml/l
Use growth substances at an appropriate stage of plant
growth is of great importance.
Chemical should be completely dissolved before
Precaution in Growth Regulator Application
Use always fresh solution of chemicals.
Use PGR’s strictly at recommended concentration.
Solution should always be prepared in distilled water
Fine spray can be ensured by hand automizer. It is most
economical and effective method of spray.
Wash the machine/pump after each spray.
Repeat the spray within eight hours, if chemical is wash
out due to rain.
The difference in sensitivity of each plant species or
even cultivars to a given chemical treatment prevent easy
predication of the biological effects.
The cost of developing new plants growth regulator is
very high, due to which they are very much costly.
Screening for plant growth regulatory activities entails
high costs and is very much difficult.
Constraints in the use of growth regulators
Some synthetic plant growth regulators cause human
health hazards e.g. dominozide.
Lack of basic knowledge of toxicity and mechanism of
Inadequate market potential.
Lack of support from agricultural researchers in public
and private sectors.
Difficulty in identification of proper stage of crop at
which the growth regulators should be applied.
Most of the biological processes associated are polygenic, so gene
transfer may be difficult and hence the use of PGR’s may be
beneficial for short imperatives.
PGR’s provide an immediate impact on crop improvement
programmes and are less time consuming.
Applications of PGR’s must lead to quantifiable advantages for
Industries involved in development of PGR’s should be well
informed about the latest scientific development in production of
PGR’s must be specific in their action and
toxicologically and environmentally safe.
Plant growth regulators should be recognized as
more than academic curiosities. They are not only
interesting but profitable to use to grower,
distributor and manufacturer.
More research is needed to develop simple,
economical and technical viable production
systems of PGR’s.
Plant growth regulators has an immense potential
in vegetable production to increase the yield,
quality, synchronization in flowering, earliness,
cold and high temperature fruit setting, sex
modification, increase post-harvest life and
resistance to biotic and abiotic stresses of
vegetables to better meet the requirements of food
supply in general. But more research is needed to
develop simple, economical and technical viable
production system of bio-regulator. Bioregulators
must be toxicologically and environmentally safe.