Plant Growth And Development Flashcards
Leaves ,flowers and fruits have ______ dimensions .
Limited
Development is the sum of 2 processes :_____and____.
Growth
Differentiation
The first step in the process of plant growth is _______
Seed germination
In the absence of favorable conditions , seeds do not germinate and go into a period of ______ growth .
Suspended
____ is regarded as one of the most FUNDAMENTAL and CONSPICUOUS characteristics of a living being .
Growth
Growth can be defined as an _____, ______ increase in size of an organ or its parts or even of an individual cell .
Irreversible
Permanent
Generally , growth is accompanied by ___ processes that OCCUR AT THE EXPENSE OF ENERGY .
METABOLIC( both catabolic and anabolic)
Expansion of a leaf is growth .T/F
T
_____ growth is UNIQUE .why ?
Plant
Becoz they retain the capacity for UNLIMITED growth throughout their life .
The ability of plants to grow throughout their life without any limit is due to the presence of ________ at certain locations in their body .
Meristems
The cells of meristems have the capacity to _____ and ______ .
Divide
Self-perpetuate
The _____ soon loses the capacity to divide and such cells make up the plant body .
Product ( of division of meristems )
The form of growth wherein new cells are always being added to the plant body by the activity of MERISTEMS is called the __________ FORM OF GROWTH .
OPEN FORM OF GROWTH
The shoot and root apical meristem principally contribute to the ______ of plants along their axis .
Elongation
In __ and ____ , the LATERAL MERISTEMS appear later in the life
Dicots
Gymnos
Growth at CELLULAR LEVEL is principally a consequence of _________ .
Inc in the amt of PROTOPLASM
Since inc in _____ is difficult to measure , one generally measures soe quantity which is more or less proportional to it .
Protoplasm
What are the diff parameters by which we can measure growth
Inc in fresh weight , dry weight , length , area , volume , cell no.
One single ______ an give rise to more than 17500 new cells per hour .
Maize root apical meristem
Cells in a ___ may inc in ice by upto 3,50,000 times .
Watermelon
In a maize plant , growth is expressed as inc in _________.
Cell number
17500 cells are formed per hour
In a watermelon , growth is expressed as inc in ________ .
Size of cell
Size inc upto 3,50,000 times
The growth of POLLEN TUBE is measured in terms of _______.
It’s length
An inc in _____ denotes growth in a dorsiventral leaf .
S.A.
Into how many phases can growth be divided into -
What are they ?
3
Meristematic
Elongation
Maturation
In the meristematic phase of growth in shoot and root apex , the cells are rich in ______ , possess _______.
Protoplasm
Large conspicuous nuclei
The cells of meristematic zone are cell walls that are ______in nature , ___ and ______ with abundant ______.
Primary
Thin
Cellulosic
Plasmodesmata connections
What are the characteristics of the cells in the phase of elongation ?
3
Increased vacuolation
Cell enlargement
New cell wall deposition
The cells of which zone attain their MAXIMAL SIZE in terms of WALL THICKENING and protoplasm is modifications ?
Phase of maturation
Inc in growth per unit time is -
Growth rate
Rate of growth can be expressed _____.
Mathematically
The growth rates show an inc that may be __ or ____.
Arithmetic
Geometrical
In _____ growth , following mitotic cel division , only 1 DAUGHTER CELL continues to divide while the other DIFFERENTIATE and MATURE .
Arithmetic
The simple expression of arithmetic growth can be exemplified by a _____________ at a constant rate .
Root elongation
On plotting the lengths of plant organ against time , a _____ curve is obtained .
Linear
Arithmetic growth
( height of plant vs time )
Give the expression of arithmetic growth -
Lt = Lo +rt
r = growth rate / elongation per unit time
In most systems , the initial growth is ______ and is called _____.
Slow
Lag phase
(In geometrical growth )
After lag phase , the growth ____ thereafter -at an ___ rate and this is called ________phase .
Rapidly inc
Exponential
Log / exponential phase
Lag and log phase are the same thing .T/F
F
Both the progeny cells following mitotic cell division retain the ability to divide and continue to do so , in ________growth
Geometrical
In geometrical growth , the nutrient supply is _______.
Limited
Due to limited nutrient supply , the growth _____ , leading to __phase
Slows
Stationary
If we plot the parameter of growth against time , we get a typical ______ curve . In geometrical growth .
Sigmoid
S-curve
What are the phases of geometrical growth serial wise -
3
Lag
Log/exponential
Stationary
A____ curve is a characteristic of of living organisms growing in a NATURAL environment .
Sigmoid
____ curve is typical for all cells , tissues and organs of a plant .
Sigmoid
Give the expression for exponential growth -
Wt = Wo e(rt) (R= growth rate , e=base of natural logarithm )
In the expression of exponential growth , r is the _____growth rate and is also a measure of the ________.
RELATIVE growth rate
Ability of the plants to produce new plant material
The measure of the ability of the plant to produce new plants (r ) in exponential growth is called -
Efficiency index =r
The final size of the plant depends on the initial size in which type of growth ?
(exponential phase of )Geometrical growth
Wt depend on Wo
(This not happen in arithmetic growth )
Give an example of arithmetic growth -
Root elongation at a constant RATE
Quantitative comparisons between the growth of living systems can be made in how many ways ?
2
1) by measuring absolute growth rate
2) by measuring relative growth rate
Measurements and comparison of TOTAL GROWTH per unit time is called -
Absolute growth rate
The growth of the given system per unit time expressed on a common basis e.g., per unit INITIAL parameters is called -
Relative growth rate
The ______ of cells helps in EXTENSION growth
Turgidity
Plant growth and further development is ultimately linked to te ______of plant .how ?
Water status
Turgidity helps in tension growth of cell
In plants , __provides medium for ENZYMATIC activities needed for growth .
Water
____helps in releasing metabolic energy essential for growth activities .
O2
Nutrients are req by plants for the synthesis of _____ and act as source of ____.
Protoplasm
Energy
Every plant organism has an ____range best suited for its growth .
Optimum temp
Any deviation from optimum temp range could be _____ to its survival .
Detrimental
Environmental signals such as ___ and ____ also affect certain phases /stages of growth .
Light
Gravity
The cells derived from root and shoot apical meristems and CAMBIUM differentiate and mature to perform specific functions . This maturation is called -
Differentiation
During differentiation,cells undergo few to major structural changes both in their _______ and ____.
Cell walls
Protoplasm
During ____ , to form a ______ , the cells would lose their protoplasm .
Differentiation
TRACHEARY element
What changes would a TRACHEARY element undergo during differentiation ?
1) lose their protoplasm
2) develop a very strong , elastic lignocellulosic secondary cell wall (to carry water to long distances even under extreme tension )
The living ____cells that have lost their capacity to divide , can regain the capacity of division under certain conditions . This phenomenon is called -
Differentiated
Dedifferentiation
Give a few examples of dedifferentiation -
Formation of meristems - interfascicular cambium and cork cambium from fully differentiated parenchymatous cells .
By _____ , such meristems are able to divide and produce cells that once again lose their ability to divide but MATURE TO PERFORM SPECIFIC FUNCTIONS . This is called -
Dedifferentiation
Redifferentiation
Growth of plants is open i.e., it can be _____ or _____.
Determinate
Indeterminate
Even ________ in plants is OPEN becoz the cells arising out of the same meristem have diff structures at maturity .
Differentiation
The ____structure at maturity of a cell/tissue is also determined by the ____ of the cell within .
Final
Location
(Ex- cells positioned away from root apical meristem differtiate as root cap cells while those pushed to the periphery mature into epidermis )
Cells positioned away from _____ differentiate as root cap cells while those pushed to periphery mature as ______.
Root apical meristem
Epidermis
_____is the term that includes all changes that an organism goes through during its life cycle from GERMINATION of seed to SENESENCE .
Development
Plants follow diff pathways in response to ____ or _____ to form diff kinds of structures
Environment
phases of life
Plants follow diff pathways in response to environmental or phases of life to form diff kinds of structures . This ability is called -
Plasticity
Give examples of plasticity -
Heterophylly in cotton , coriander ,and LARKSPUR
In cotton , coriander and larkspur (plasticity , heterophylly ) , the leaves of ______ plant are diff in ______ from those of mature plants .
Juvenile
Shape
Cotton ,coriander and larkspur show which kind of plasticity ?
Plasticity due to phases of life
Give an example of plasticity due to ENVIRONMENT
Buttercup ( heterophyllous development due to environment )
The phenomenon of ______ is an example of plasticity .
Heterophylly
Diff in SHAPE of leaves produced in ___ and those produced in _____ in ______ represents heterophyllous development due to environment .
Air
Water
Buttercup
_____ , ______ and _____ are very closely related terms in the life of a plant .
Growth
Differentiation
Development
Development which is the sum of ______ and ______ is under the control of _____and _____factors .
Growth
Differentiation
Intrinsic
Extrinsic
The intrinsic factors for the development of plant include-
Intracellular - genetic
Intercellular -chemicals such as plant growth regulators
The PGRs are ____ ,______ molecules of ______chemical composition .
Small
Simple
Diverse
The PGR which is an indole compound is -
Indole-3-acetic acid (IAA)
PGRs that ADENINE DERIVATVES-
N6 - furfurylamino purine
Kinetin
PGRs that are derivatives of CAROTENOIDS -
Absisic acid -ABA
PGR that is a TERPENE -
Gibberellic acid ,GA3
Plant growth regulators are variously described as _____ , _ or ______ in literature .
Plant growth substances
Plant hormones
Phytohormones
The PGRs can be divided into _____ groups based on their ______ in a living plant body .
2
Functions
One group of PGRs can be divided into _______activities, such as -
Growth promoting
Cell division , cell enlargement , PATTERN FORMATION , TROPICAL GROWTH , Flowering , fruiting and seed formation
Which PGRs fall under growth promoting substances -
Auxins
Cytokinins
Gibberellins
The PGRs of which group play an imp role in plant responses to WOUNDS and STRESSES of BIOTIC and ABIOTIC origin .
Growth inhibiting
The growth inhibiting activities that PGRs are involved in are ____and ______ .
Dormancy
Abscission
The gaseous PGR ethylene would fit in which group of PGRs ?
It can fit in either grp
But is largely an INHIBITOR of growth activities
The discovery of PGRs started with the observation of ______ and his son ______ when they observed that the _____of _____ responded to phototropism .
Charles Darwin
Francis Darwin
COLEOPTILES
CANARY GRASS
What did Darwin and his son observe ?
That the coleoptiles of canary grass responded to UNILATERAL ILLUMINATION by growing towards light source (phototropism )
After a series of experiments performed by Darwin and his son , it was concluded that the ____ of coleoptile was the site of _____that caused the bending of ENTIRE coleoptile .
Tip
Transmittable influence
Auxin was isolated by _______ from ____ of ________.
FW Went
Tips of coleoptiles
Oat seedlings
The ______ disease of RICE SEEDLING was caused by a ____pathogen .
Bakanae ( foolish seedling )
Fungal
What was the name of the fungal pathogen that caused disease in rice seedling ?
Gibberella fujikuroi
_____ in the year ______ reported the appearance of symptoms of the disease in RICE SEEDLINGS when they were treated with sterile filtrates of the ______
E . Kurosawa
1926
Fungus
The active substance discovered by E . Kurosawa was -
Gibberellic acid
_____and his co-workers observed that from the ______ of TOBACCO stems the CALLUS proliferated only if , in addition to auxin , the nutrient medium was supplemented with something else .
F.skoog
Internodal segments
F. Skoog and his co-workers used _____segments of ____plant to show that the callus proliferated only if , in addition to _____, the nutrient medium was supplemented with one of the following : ______ , _______ , ______ or ________ .
Internodal Tobacco Auxin Extracts of vascular tissues Yeast extract Coconut milk DNA
________ in the year _____ identified and CRYSTALLISED the CYTOKINESIS promoting active substance that they termed _____.
Miller et al .
1955
Kinetin
What were the natural things in which the cytokinesis promoting active substance was found by F. Skoog ?
Extracts of vascular tissues
Yeast extract
Coconut milk
DNA
During ______ , 3 independent researchers reported the purification and chemical characterisation of 3 diff diff kinds of _____ .
Mid-1960s
Inhibitors
What were the 3 diff inhibitors discovered during the mid-1960s . Were they identical ?
Inhibitor -B
Abscission-II
dormin
They were identical and were named ABSCISIC ACID (ABA)
_______ in the tear _____ conformed the release of a volatile substance from ______ .
H. H. Cousins
1910
Ripened oranges 🍊
H. H. Cousins confirmed the release of a _____substance from _____ that hastened the RIPENING of stored______ .
Volatile
Ripened oranges
Unripened bananas
H. H. Cousins discovered _____
Ethylene
Auxin comes from a Greek word , meaning ____
to Grow
Auxin was first isolated from ______.
Human urine
Auxins are produced by the _____ from where they migrate to ____
Growing apices of the stems and roots
Regions of their action
Auxins like ____and ____have been isolated from PLANTS .
IAA-indole-3-acetic acid
IBA-indole butyric acid
Name 2 synthetic auxins -
NAA- naphthalene acetic acid
2,4-D (2,4-dichlorophenoxyacetic)
Which auxins have been used extensively in agricultural and horticultural practices ?
All these
Maybe natural or synthetic both
OR -maybe just synthetic -NAA and 2,4-D
Give the functions of auxins -
1)Help to initiate rooting in stem cuttings
2)Promote flowering -in pineapples 🍍
3)Prevent fruit 🍇 and leaf 🍂 drop at early stages
4)Promotes absiccion of older mature leaves 🍁 and fruits 🍈
5)Induce parthenocarpy in tomatoes 🍅
6)Used as herbicides (2,4-D)to kill dicot weeds (doesn’t affect monocots )
7)Controls xylem differentiation and helps in cell division
Promotes apical dominance
There are more than ____ gibberellins reported from widely diff organisms such as ____ and _____ .
100
Fungi
Higher plants
_____was the 1st gibberellin to be discovered and remains the MOST INTENSIVELY STUDIED FORM )
GA3 ( gibberllic acid)
All GAs are ______.
Acidic
GAs produce a wide range of ___Responses in plants .
Physiological
Which ability of GAs is used to inc the length of grape 🍇 stalks ?
Their ability to cause an inc in the length of axis
GAs cause fruits like ___ to elongate and improve is _____.
Apple 🍎 🍏
Shape
GAs delay senescence .T/F
T
GAs are used to speed up _____ in BREWING INDUSTRY .
Malting process
____ store carbs as sugars in their stems .
Sugarcane
By spraying sugarcane with GAs , what happens ?
It inc the length of the stem , thus inc the yield by as much as 20 tonnes per acre
Fruits can be left on trees longer to extend their market period by used -
GAs
How much yield is inc by using GAs in sugarcane ?
20 tonnes per acre
Spraying ____ with GAs hastens the maturity period , thus leading to early _________.
Juvenile conifers
Seed production
GAs promote ___ and ___ just prior to flowering .
Bolting
Internode elongation
GAs promote bolting and internode elongation just prior to ______ in. __ , ____ and many _______
Flowering
Beet
Cabbages 🥬
Many plants with ROSETTE HABIT
______ help to initiate rooting in stem cuttings , an application widely used for plant propagation .
Auxins
___ prevent fruit fall at early stages but promote a abscission of older mature leaves and fruits .
Auxin
____promote flowering . Give an example .
Auxins
In pineapples 🍍
In most higher plants ,the growing apical bud inhibits the growth of _______ buds . This is called apical dominance .
Lateral /axillary
Promoted by auxins
Removal of _____usually results in the growth of lateral buds .
Shoot tips / decapitation
The phenomenon of decapitation is widely used in ______ and _____.
Tea ☕️ plantations
Hedge making
______induce parthenocarpy in ____ .
Auxins
Tomatoes 🍅
State all the functions of GAs -
1) Cause apples 🍎 to elongate and improve their shape
2) Used to inc the length of GRAPE 🍇 stalks
3) Delay senescence
4) Speed up malting process in brewing industry
5) Extend the market period of fruits 🍈
6) Inc the length of sugarcane stem to inc the yield by 20 tonnes per acre
7) Early seed production in juvenile conifers
8) Bolting and internode elongation in beet, cabbages ,and many plants with rosette 🏵 habit .
Cytokinins have specific effect on _______and were discovered as____.
Cytokinesis
Kinetin
Cytokinins were discovered from KINETIN -a modified form of _____ from the _________.
Adenine , a purine
Autoclaved herring sperm DNA 🧬
Kinetin occurs naturally in plants .T/F
F
KINETIN DOES NOT OCCUR NATURALLY IN PLANTS
Search for natural substances with cytokinins-like activities led to the isolation of _____ from ____and _____.
ZEATIN
Corn 🌽 kernels
Coconut 🥥 milk 🥛
Since the discovery of ______several naturally occurring cytokinins and some synthetic compounds with cell division promoting activity have been identified .
ZEATIN
Natural cytokinins are synthesised in regions where _______ occurs . For ex _____,_____ and _____
Rapid cell division
Root apices
Developing shoot buds
Young fruits
_____are widely used as herbicides .give examples
Auxins
2,4-D
2,4-D widely used to kill ___ weeds does not affect mature ___plants .
Dicot
Monocot
Auxins are used to prepare ____lawns by gardeners .
Weed free
Auxins control XYLEM _____and helps in ______.
Differentiation
Cell division
___ delay senescence .
GAs
_____helps to produce new leaves and chloroplast in leaves .
Cytokinins
Cytokinins ___shoot growth and ____ shoot formation .
Lateral shoot -growth
Adventitious shoot -formation
Cytokinins help overcome _______.
Apical dominance
_______ promote nutrient MOBILISATION helps in delay of leaf senescence .
Cytokinins
Which PGRs help to delay senesce -
GA
Cytokinins
(Auxins also -sometimes )
State all the functions of cytokinins -
1) produce new leaves , chloroplast in leaves ,lateral shoot growth and adventitious shoot formation .
2) overcome apical dominance
3) promote nutrient mobilisation
4) delay leaf senescence
_____is a simple gaseous PGR .
Ethylene
Ethylene is synthesised in large amounts by tissues undergoing ______ and _______.
Senescence
Ripening fruits
Influences of ethylene on plants include -
3
Horizontal growth of seedlings
Swelling of the axis
Apical hook formation in dicot seedlings
Ethylene promotes _____ and ______ of plant organs especially of leaves and flowers .
Senescence
Abscission
Ethylene is highly effective for _____ .
Fruit ripening
Ethylene enhances _____ during ripening of the fruits .
Respiration rates
Respiratory climatic
The rise in rate of respiration is called ____ (by ethylene ).
Respiratory climatic
Ethylene breaks ___and _____ dormancy .
Seed
Bud
Ethylene initiates GERMINATION in ________ and initiates SPROUTING of ______ .
Peanut seeds
Potato tubers
Ethylene promotes ________ in DEEP WATER RICE PLANTS .
Rapid internode /petiole elongation
Ethylene promotes rapid internode /petiole elongation in _____ plants . What is its significance ?
Deep water rice plants
It helps leaves /upper parts of the shoot to remain above water
____ promotes root growth and root hair formation , thus helping the plants to INC their ABSORPTION SURFACE .
Ethylene
Ethylene is used to initiate ______ and for ________ fruit-set in _____.
Flowering
Synchronising
Pineapples
____ induces flowering in MANGO .
Ethylene
Which is the most widely used PGR in AGRICULTURE . Why ?
Ethylene
Becoz it regulates so many physiological processes .
The most widely used compound as a source of ethylene is -
Ethephon
_____ in an ________ solution is READILY ABSORBED AND TRANSPORTED WITHIN THE PLANT AND RELEASES ETHYLENE SLOWLY .
Ethephon
Aqueous
Ethephon accelerates fruit ripening in ____and ______ .
Tomatoes 🍅
Apples 🍏
Ethephon accelerates ___ in flowers and fruits .( thinning of cotton , cherry and walnut )
Abscission
Thinning of ___,____and_____ is caused by ethephon ( ethylene)
Cotton
Cherry
Walnut
Ethephon promotes _____ flowers in CUCUMBER 🥒,thereby increasing the yield .
Female
ABSCISIC acid was discovered for its role in regulating _____and ____ .
Abscission
Dormancy
Like other PGRs , ABA also has other wide ranging effects on plant growth and development .T/F
T
ABA acts as a general ______ inhibitor and an inhibitor of plant ______.
Plant growth
Metabolism
ABA inhibits seed _______ .
Germination
ABA stimulates the ___ of stomata and increases the ___of plants to various kinds of _______.
Closure
Tolerance
Stresses
ABA is also called ________ .
Stress hormone
ABA plays an imp role in seed ___ ,____ and ______.
Development ,
Maturation
Dormancy
By inducing dormancy , ABA helps seeds to withstand _______ and other factors unfavourable for ______.
Desiccation
Growth
ABA acts as an antagonist to _____.
GAs
The roles of diff PGRs could be_____ or ___. They could be ____ or ____.
Complimentary
Antagonistic
Individual
Synergistic
Give some examples of the events in plants where more than 1 PGR interact to affect that event -
1) dormancy in seed /buds
2) abscission
3) senescence
4) apical dominance
The role of PGR is only one kind of ______ control .
Intrinsic
Along with ____ control and __ factors , PGRs play an imp role in plant growth and development
Genomic
Extrinsic
Many of the extrinsic factors such as ___ and _____ , control plant growth and development via PGRs .
Temp
Light
Some plants require a _____ exposure to light to induce flowering .
Periodic
Plants that require periodic exposure to light to induce flowering are able to __________________.
Measure the duration of exposure to light
Long day plants require expire to light for a period ____ a well defined _____.
Exceeding (above)
Critical
Short day plants must be exposed for a period ___ the critical period .
Less than(Below)
The cortical duration is same for all plants .T/F
F
It is diff for all
When there is no such correlation btw exposure to light duration and induction of flowering , such plants are called -
Day-neutral plants
Not only the duration of light period , but also of the ______ is of ______.
Dark
Equal imp
It can be said that flowering in certain plants not only depends on a _____ of light and dark explores but also their ________ .
Combinations
Relative durations
The response of plants to periods of day /nigh is termed -
Photoperiodism
While shoot apices modify themselves into flowering=g apices proir to flowering , they (shoot apices ) themselves can perceive photoperiods .T/F
F
The site of perception of light /dark duration are the ______.
Leaves
It has been hypothesised that there is a ___ substance responsible for flowering .
Hormonal
The HORMONAL substance migrates from __ to ____ for induction of flowering only when the plants are exposed to the necessary _______.
Leaves
Shoot apices
Inductive photoperiod
There are plants for which flowering is either ____ or ____ dependent on exposure to ____ temp .
Quantitatively
Qualitatively
Low
What is vernalisation ?
Flowering dependent on exposure to low temp
___ prevents precocious reproductive development late in the growing season and enables the plant to have sufficient time t reach maturity .
Vernalisation
Extrinsic factors control plant development via PGRs of which events ?
Vernalisation Flowering Dormancy Seed germination Plant movements
\vernalisation refers specially to the promotion of ______ by a period of _____.
Flowering
Low temp
Food plants that have 2 kinds of varieties . Names -
Wheat
Barley
Rye
Wheat barley and rye have which 2 varieties ?
Winter variety
Spring variety
Spring varieties are normally PLANTED in _______ and come to flower and produce grain before the ______.
Spring
(Before) End of the growing season
_____ varieties if planted in spring would fail to flower or produce mature grain within a span of a flowering season .
Winter
Winter varieties are planted in _____.
Autumn
Winter varieties planted in winter ,GERMINATE and over ______ come out as small seedlings , resume growth in _____ and are HARVESTED IN _____.
Winter
Spring
Around mid-summer
Winter varieties are harvested in ___ .
Around mid-summer
Winter varieties resume growth in spring .T/F
T
When do winter varieties germinate ?
Over winter
Another example of vernalisation is seen in______.
Biennial plants
Biennials are ________ plants that normally flower and ____ in the ____ season .
Monocarpic
Die
Second
Give a few examples of biennials -
Sugar beet
Cabbage 🥬
Carrots 🥕
Subjecting the growing of a biennial plant to a _____ treatment stimulates a subsequent _______ response .
Cold
Photoperiodic flowering
_____ are monocarpic plants that flower and die in the ______.
Biennials
2nd season
There are certain seeds that fail to _____ even when external conditions are available .why ?
Germinate
Becoz dormancy doesn’t depend on external conditions
Seeds that fail to germinate even when EXTERNAL conditions are called ________ which is controlled not by ______ but are under _______control or conditions ______ the seed itself .
Dormant
External environment
Endogenous
Within
State some reasons which cause seed dormancy -
1) impermeable and hard seed coat
2) presence of chemical inhibitors such as ABA , phenolic acids , para ascorbic acid
3) immature embryos
Name some chemical inhibitors which causes seed dormancy -
ABSCISIC acids (ABA )
Phenolic acids
Para-ascorbic acid
Dormancy can be overcome through _____ means and various other ____ measures .
Natural
Man-made
Seed coat barrier in some seeds can be broken by ______ using ____, ____or _____.
Mechanical abrasions
Knives
Sandpaper
Vigorous shaking
In nature , the seed coat can be broken by ABRASIONS caused by _____ and _____.
Microbial action
Passage through digestive tract of animals
Effect of inhibitory substances (causing seed dormancy ) can be removed by subjecting the seeds to _______ or by application of certain _______.
Chilling conditions
Chemicals (GA or nitrates )
Changing the environmental conditions such as ____ and ___ are othermethos to overcome seed dormancy .
Light
Temp
The effect of inhibitory substances ( causing seed dormancy ) can be removed by the application of which chemicals ?
Gibberellic acid
Nitrates
State the functions of ethylene -
1) Promotes senescence and abscission of plant organs(leaves and flowers )
2) fruit ripening
3) enhances respiration rates during fruit ripening
4) breaks seed and bud dormancy
5) initiates germination in peanut seeds
6) initiates sprouting of potato tubers
7) promotes rapid internode/petiole elongation in deep water rice plants
8) promotes root growth and root hair formation(inc SA )
9) initiates flowering and synchronising fruit set in pineapples
10) induces flowering in mango
11) hastens fruit ripening in tomatoes and apples
12) accelerates abscission in flowers and fruits (thinning of cotton,cherry ,walnut)
13) promotes female flowers in cucumber , inc the yield .
What all fruits does ethylene affect ?
Pineapple Apple Mango Tomatoes Cucumber Rice plants Cotton, cherry ,walnut
