Selina Concise Class 10 Biology Solution Chapter No. 7- ‘Chemical Coordination on Plants’ For ICSE Board Students.
A) MULTIPLE CHOICE TYPE
1) A plant hormone related with inhibition of senescence is :
Answer:- d) GA
Explanation: GA hormone that inhibit the plant growth.
2) Apical dominance phenomenon is caused by:
Answer:– a) Auxins
Explanation: Auxin is transported from apical buds. So apical dominance caused by auxin.
3) Which of the following hormones regulated stomatal closure:
Answer: d)Cytokinin
Explanation: Stomatal closure is regulated by cytokinin hormones.
4) Auxins are abundantly produced in:
Answer:- Meristematic region of the shoot.
Explanation: Auxin produced in shoot tip, it helps in cell elongation.
5) A higher concentration of ethylene is found
Answer:-b) Ripe banana
Explanation: Ethylene is gaseous which help to fruits ripen fast.
6) Common gibberellin is:
Answer:-c) GA3
Explanation: GA3 gibberllin is widely studied as plant growth regulator.
7) Stems are:
Answer:-c) Negatively geotropic and positively phototropic.
Explanation: Stem grow upward so it is negatively geotropic and grow toward the light so its positively phototropic.
8) In tropic movement, plant parts move
Answer:- either towards Or away from the stimulus.
Explanation: Generally, tropic movement is the plant movement that determine by stimulus direction.
B) SHORT ANSWER TYPE
1) Match the item in column A with those of column B
Column A Column B
a)Auxin i)apical dominance
b) Gibberellin ii)cell-division
c) Cytokinin iii)fruit ripening
d)Ethylene iv)internodal elongation
Answer:-
Column A Answer
a) Auxin → I) Apical dominance
b) Gibberellin → V) Internodal elongation
c) Cytokinin →II) Cell-division
d) Ethylene →III) Fruit repining
2) Differentiate between:
a) Thigmotropism and geotropism
Answer:-
Thigmotropisum | Geotropism |
It shows the growth of plant towards the touch stimulus. | It shows the growth of plants towards the earth |
It is mostly Shownby twinning of plants or tendrils. | It is shown by the roots of the plants. |
b) Positive and negative tropism
Answer:-
Positive tropism | Negative Tropism |
It is the growth of plant towards the stimulus | It is the growth of plant away from stimulus |
These contains shoots which grows in response to the light | These contains Shoot growing away from water and earth. |
Also roots which grows towards the water and earth | Roots which grows away from the light. |
c) Phototropism and chemotropism
Answer:-
Phototropism | Chemotropism |
These is the movement of plant in response to the light. | These is the movement of growth of plant in response to the chemicals. |
Positive tropism occurs In the response of light by the stem | Here positive tropism occurs in the response to the stimulus.
Occurs in the pollen tube growing at the ovary of flower. |
3) Solution:
Answer:- plants and animals both are the living organism. But, they are different in their one characterThat is movements. Movements in plants like turning, bending, elongation. And movements in animals like running, soaring, jumping. Animals having special protein to promote the movements. And when changes the external and internal factors in plants,then plant’s movements possible. And this change is nothing bit the stimulus. Due to stimulus movements can possible, it’s known as the response. In this way, plants movements are different from animals.
4) Solution:
Phototropism, thigmotropism, hydrotropism and geotropism.
Answer:
Movements– — →Stimulus
Phototropism — →Light
Thigmotropism— →Touch stimulus
Hydrotropism— →Water
Geotropism—→Gravity of earth.
5) Solution:
a) A hormone that stimulates growth by cell division.
Answer:- Cytokinin is a hormone that stimulates growth by cell division.
b) A growth-retarding hormone in plants .
Answer:- Abscisic acid is a growth -regarding hormone in plant.
c) main auxin found in most plants.
Answer:- In most of the plant,the main auxin is Indole-3-acetic acid [IAA] found.
C.DESCRIPTIVE TYPE
1) Solution:
a) phytohormones
Answer:- Phyto hormones also are called as growth regulator. It’s nothing but chemical substance that occur in plant that help in their development, growth, process of reproduction and even in death also. And this called phytohormone
b) Tropism
Answer:- “the growth of plant in response to external stimulus, is named as tropism.”
c) Clinostat
Answer:-
Clinostat is an apparatus which may be uses determine plant’s gravity effect
d) Apical dominance
Answer:-
It is phenomenon during which suppressed the expansion of lateral buds via apical bud, is named as apical dominance.
e) Parthenocarpy
Answer:- It is fruits producing process with none fertilization, is named as parthenocarpy.
f) Abscission
Answer:- Abscission is that the process, during which plants parts separate by normal separation like falling and shedding of plant parts.
g) Heliotropism
Answer:- Heliotropism is a type of tropism, which growth of plant direction towards sunlight.
2.) Solution:
Answer:-
There are five growth hormones-Auxin, Gibberellin, abscisic acid, Cytokinine Ethylene. And their functions as follows-
a) Auxin- Auxin help in growth of stem, roots, fruits. And also control the cell elongation of plants. And they delay the leaf senescence.
b) Gibberllin- Gibberllin promotes fruits development, stem elongation. And also in growth of internodes. It also helps to flowers germination.
c) Cytokinin- Cytokinin causes to seed in growth of cotyledon. It’s help to chloroplast to chlorophyll synthesis. And also help in cell division.
d) Abscisic acid(ABA) – ABA inhibit the seed germination. It is the general plant inhibitors. It also accelerate to abscission of fruits, leaves , flowers.
e) Ethylene- Ethylene help in to grow up the potato tuber. And in fruits ripening. Germination of peanut seed can occur by Ethylene hormone.
3) What are tropic movement? Briefly explain various types of tropic movements in plants.
Answer:- Tropic movement is the plant movement in presence with external stimulus such astemperatures,light,water. There are five types of tropical movement as follows:-
Phototropism:- It is form of tropism, in which plant growth towards the light, is called as phototropism. Example of phototropism-Sunflower. Itoccurs in plants and also in fungi. There are two tropism occurred in phototropism like as positive phototropism and Negative phototropism. Positive phototropism is the direction of growth towards sunlight. Ex-Stem. Stem grow upward direction of light.Negative phototropism is the direction of growth away from light. Ex-root. Root grow away from light. In phototropism Auxin is hormone which responsible for growth control.
Geotropism:- Geotropism is also called as Gravitropism. Movement towards or away from earth’s gravity. There are root of plant grow down so it’s the Positive geotropism. Stem of plant which grow away from gravity, so it is Negative geotropism. In geotropism, auxin is regulate the growth hormone.
Hydrotropism:-The tendency of plants to grow towards or away from water, is called as hydrotropism. Plant root grow towards water, is the positive hydrotropism. Stem grow away from water, is called Negative hydrotropism. Example of hydrotropism-tomato roots, carrots.
Thigmotropism:- Bending of a plant in response with touch stimulus, is called as Thigmotropism. Example-tendrils of sweet pea plant . This tropism occur due to action of plant hormone auxin.
Chemotropism:- This tropism will occurred due to chemical stimulus by growing of plants,This phenomenon is called as chemotropism. This presence in bacteria, plants, fungi. Example of
Positive chemotropism is the flowers formed during fertilization i.e.pollen tubes grow toward stimulus. Example of Negative Chemotropism is the plant root as they grow away from harmful acids or away from stimulus.
4) Solution:
Answer:- In other word, Geotropism is called Gravitropism. Geotropism is nothing but the response of plans to gravity. Root need to grow downwardsoil, as they called Positive geotropism. And Shoot need to grow upward it can grow in height. Plants are very Sensing gravity. In laboratory, when we done the experiment on response of plants to gravity , by taking a pit that filled with moist soil place seeds into it, and observed after sometime, they grown up from seed into pot.
5) Solution:
Answer:- Positive tropism:- The direction of the plant to growing up towards the stimulus, is called as the positive stimulus.Example of positive stimulus:- Shoot growth towards light, root growth towards gravity and roots growth towards water.
Negative tropism:-The direction of the plant to growing up is away from the stimulus, is called as the Negative stimulus.Example of negative stimulus:- Growth of shoot away from water, growth of shoot away from gravity, growth of root is away from light.
6) Solution:
Answer:-
Experiment –
Aim:- To demonstrate the roots are more Positively hydrotropic than geotropic.
Apparatus:- Bean seeds(generated), moist sawdust, wire guaze, wire.
Procedure:-
1) First, take a piece of wire guaze.
2) Hang the wire guaze with the help of wires.
3) Keep the 1inch moist sawdust on the net of wire.
4) Implanted the some germinated bean seeds in sawdust.
Observation:- At seeds geminated, grow the radicles on downward by wire netting. After sometime, they growing upward towards the moist sawdust which is the source of water. Thus, they grow but in against the gravity. And always, shoots growing direction is upward.
Conclusion:- The direction of grow of root towards water and water is powerful and effective stimulus for root than gravity. But in case of shoot, their growing direction is always upward.
Results:- This experiment show that the roots are more hydrotropic than geotropic.
D.STRUCTURED /APPLICATION/SKILL TYPE
1) Solution:
a) Name the scientific phenomenon that is being overcome by pruning.
Answer:- Apical dominance is a scientism phenomenon that is being overcome by pruning.
b) What plant hormone is responsible for the scientific phenomenon mentioned in (a).
Answer:- The Scientific phenomenon mentioned in (a) is Auxin plant hormone.
c) Name one plant hormone which inhibits the said phenomenon.
Answer:– Cytokinins is plant hormone which inhibits the said phenomenon.
2) Solution:
a) Solution:
Answer:- For above change, ethylene hormone is responsible.
b) Solution:
Answer:- Ethylene hormone having characteristics are as -Fruits ripping, Sprouts of potato tubes.
3) Solution:
a)
Answer:- Chemotropism phenomenon shown in diagram.Chemotropism is defined as , plants grow due to chemical stimulus these phenomenon is known as chemotropism.
- b)
Answer:-
1) Pollen grain,
2) Pollen tube ,
3) Ovule,
4) Ovary.
c)
Answer:- Peptones and Sugars are the two effective stimulus that help in the growth of parts(2).
d)
Answer:- There are two groups of the plants as-Gymnosperm and Angiosperm where part 2 grows towards gametophyte with the help of the stimulants mentioned in C.
4) Solution:
a)
Answer:- In the figure (A) the structures shown as X is Stem Tendrils and in the figure (B) the structure as Y is leaf tendrils.
b)
Answer:- Structure X and Y are of the Stem tendrils and Leaf tendrils respectively. Stem tendrils and leaf tendrils are providing Support the plant for climbing up. This is main function of their.
c)
Answer:-Thigmotropismphenomenon is stated over here.
Thigmotropismis defined as, “ It is the growth of plants movement in the direction ofdirect contact of stimulus.”
d)
Answer:- The structure X -Stem tendrils which arise from the stem, as well as the structure Y-leaf tendrils which arises from the leaf.
e)
Answer:- Sweet pea, vines are examples of the plants which show