RBSE Solutions for Class 11 Biology Chapter 21 Flower

Rajasthan Board RBSE Class 11 Biology Chapter 21 Flower

RBSE Class 11 Biology Chapter 21 Multiple Choice Objective Questions

Question 1.
Which of the following have syngenesious condition of stamens?
a. China Rose
b. Sun flower
c. Cucumber
d. Beans

Question 2.
Aestlvation in which edges touch each other but do not overlap
a. Valvate
b. Twisted
c. Imbricate
d. Vexillary

Question 3.
Cruciform corolla are found in
a. Rose flower
b. Mustard flower
c. Dhatura flower
d. China Rose

Answers:
1. b, 2. a, 3. b

RBSE Class 11 Biology Chapter 21 Very Short Answer Questions

Question 1.
Write three part of stamen.
Answer:
Filament, Connective and Anther.

Question 2.
What do you mean by complete flower?
Answer:
When all four whorls calyx, corolla, androecium and gynoecium present in flower than called as complete flower.

Question 3.
What do you mean by perianth?
Answer:
When sepals and petals are same in size and colour and no differention in them then it forms a whorl which called as perianth.

Question 4.
Explain monoadelphous condition in China Rose?
Answer:
When filament of all stamen fuse but anthers are free condition is called monodelphous, e.g. chine rose.

Question 5.
What do you mean by tetradynamous condition?
Answer:
Tetradynamous : when four stamens are long and two are short in height, e.g., Mustard.

Question 6.
What term is used for flowers without stalk?
Answer:
Sessile.

Question 7.
What do you mean by Pistillate flower?
Answer:
Flower having only pistil in it and adroecium is absent is called as pistillate.

Question 8.
What do you mean by petalloid perianth?
Answer:
When tepals are coloured like petals are called petalloid perianth e.g., Onion.

RBSE Class 11 Biology Chapter 21 Short Answer Questions

Question 1.
Explain marginal placentation with labeled diagram.
Answer:
It is the placentation in which gynoecium and ovary is unilocular and placenta developes along the fused margins of the carpel on ventral suture e.g., Pea.

Question 2.
Differentiate twisted and imbricate aestivation with the help of diagram and examples.
Answer:
(i) Twisted or Contorted : If one margin of the appendage overlaps that of the next one and so on as in china rose ladys finger and cotton  it is called twisted.

(ii) Imbricate :
Out of the five petals one is completely external, one completely internal and in each of the remaining three, one margin is internal and the other is external. It is subdivided into four sub parts

1. Simple Imbricate : When one petal is completely overlapped by other and one is completely overlapping to other and rest three arranged in twisted manner.
2. Descending imbricate or Vexillary : In pea and bean flowers, thre are five petals, the anterior petal is innermost and the posterior petal is the outermost and largest (standard) which overlaps the two lateral petals (wings) which in turn overlap the two smallest anterior petals (keel); this type of aestivation is known as vexillary or papilionaceous.
   
3. Ascending Imbricate :
   The posterior petal is innermost, i.e., it s both margins are overlapped e.g. Cassia and Bauhinia.
4. Quincunicial :
   It is modification of imbricate type. Out of the five petals, two are completely internal, two completely external and in the remaining petal one margin is intenal and the other margin is external; eg: Murraya.
   

Question 3.
diagram of ovary having pentacarpellary, pentalocular ovary having one ovule in each locule.
Answer:

Question 4.
What do you mean by androphore? Explain it.
Answer:
Androphore: Elongated intemode of thalamus between Corolla and androecium, e.g., Passion flower.

Question 5.
What is Bract? Write names of its type.
Answer:
Bract : Bract is small leaf or leaf like structure which bear either a single flower or a group of flowers in their axis. Apart from bract when some bract like or scaley structure is also present on pedicel they are known as bracteoles. When bracteoles are in the form of whorl are called as epicalyx as in Malvaceae family (China rose).

Question 6.
Explain cohesion of stamens.
Answer:
When all stamens are free from each other then condition is called polyandrous. Sometimes stamens attach with other stamen then it is known as cohesion of stamens. It is of five type
1. Monoadelphous: When filament of all stamen fuse but anthers are free condition is called monadelphous. E.g. China rose, Althaea, Cotton plant, Lady finger etc.

2. Diadelphous: When filament of all stamen fuse in two groups but anthers are free condition is called diadelphous e.g. Pea.

3. Polydelphous: When filament of all stamen fuse in many groups but anther are free condition is called polyadelphous, e.g., Citrus plant.

4. Syngenesious (Synantherous): When filaments are free but anthers are fused condition is called as syngenesious e.g., Sunflower, Tridax.

5. Synandrous: When stamens are fused by both their filaments as well as anthers, e.g., Cucurbita.

Question 7.
Define floral diagram. How we represent mother axis in a floral diagram?
Answer:
Floral diagram:

• Diagrammatic respresenation of theoretical transverse section and ground plan of a floral bud in relation to the mother axis which lies at the posterior side is called floral diagram
• It is highly illustrative and describes most of the features of the floral and its part like:
• Symmetry
• Regular or irregular
• Sexuality
• Number of the floral parts of each t) (sepals, petals etc)
• Shows cohesion and adhesion of floral parts.
• Aestivation, relation between different floral organs.
• Numbers of anthers, monothecous or bithecous condition of anther
• Number of carpels, number of locules and placentation of ovule in ovary.
  
• Show mother axis by a dot. Mother Axis is the axis stem upon which the flowers are borne. When the flowers are borne laterally upon it, the side of the flower towards the mother axis (or precisely towards the apex of mother axis) is known as the posterior side while the side away from it (the side of the flower towards the bract
  when it is present) is called as the anterior side.
  
• In a floral diagram the outer most whorl is of bracyeole then bract, calyx, wrolla, Androecium and invermost is gynoecium. To show cohession and adhesion of cohesive and adhesive members are comiected by a thin line. Mother axis is shown by a black spot (dot). Complete floral diagram is drawn on the basis of mother axis.

Question 8.
Differentiate regular flower with irregular type of flower.
Answer:
When all whorls have same numbers and members of each whorl are similar in shape and are placed at equidistance are called regular flower, e.g., Musturd. When all the floral whorls are unequal called irregular flower, e.g., Pisum.

Question 9.
Explain bracteate flower and ebracteate flower with suitable examples.
Answer:
Various Technical Terms related to flowers:

1. Bract: A small leaf like, green structure present at the base of flower is called bract.
2. Bracteole: When a small leaf like structure is present anywhere on pedicel apart from bract is called Bracteole.
3. Bracteate (Br): When flower bom in axis of bract is called breacteate.
4. Ebracteate (EBr): When flower is directly present on peduncle and bract is absent.
5. Ebracteolate(EBiT): When breacteoles are absent in the axis of flower.
6. Pedicellate: Flower with stalk.
7. Sessile: Flowere without stalk.
8. Subsessile: Flower with very small stalk.
9. Complete : Flower with all four whorls namely calyx, corolla, androecium and gynoecium are present is called complete flower, e.g., China rose.
10. Incomplete: A flower in which if any of four whorls is absent is called incomplete flower.,e.g.. Caster flower and flower of Cucurbitaceae family.
11. Actinomorphic: When a flower can be cut into two equal halves along any planes passing through central axis, e.g.,  Brassic China rose, Potato, Ipomoea.
12. Zygomorphic: When a flower can be cut into two equal halves only along one planes passing through central axis.
    
13. Medianly zygomorphic: When a flower can be put into two equal halves only from median longitudinal plane (anterior to posterior plane), e.g. Pea and Basil.
14. Laterally zygomorphic: When a flower can be cut into two equal halves only from lateral plane, e.g. Fumaria.
15. Asymmetrical: When a flower cannot be cut into two equal halves from any plane, e.g., Canna.
16. Unisexual: When any one of Androecium or Gynoecium is present in flower, eg, Coster.
17. Male or staminate: A flower only with androecium where gynoecium is absent, e.g., Tassel of Zeamays.
18. Female or pistillate: A flower only with gynoecium where androecium is absent, e.g., Cob of Zeamays.
19. Bisexual or hermaphrodite: When both androecium and gynoecium are present in a flower, e.g., China rose.
20. Neuter: When both androecium and gynoecium are absent or non-functional, e.g., Ray florets of Sun flower.
21. Regular: When all whorls have the same number of members and the members of each whorl are similar in shape and are placed at equidistance, e.g, Mustard.
22. Irregular: When all the floral whorls are unequal, e.g., Pisum, Iberis.
23. Cyclic: When all whorls of flower are arranged on thalamus in cyclic pattern.
24. Semicyclic: When in a flower some members are cyclic and some members are non – cyclic. e.g.. Rose.
25. Acyclic: When all whorls of flower are not arranged on thalamus in cyclic pattern, e.g., Ranunculus.
26. Dimerous: When the floral members are in two or in the multiple of two; e.g., Qpium.
27. Trimerous: When the floral members are in three or in the multiple of three; e.g., Monocotelydon flowers.
28. Tetramerous: When the floral members are in four or in the multiple of four; e.g., Mustard.
29. Pentamerous: When the floral members are in five or in the multiple of five; e.g., China rose.

Question 10.
Explain position of stamens on the basis of cohesion of stamens in China rose and pea flower with labeled diagram.
Answer:
1. Monoadelphous : When filament of all stamen fuse but anthers are free condition is called monadelphous. E.g. China rose, Althaea, Cotton plant. Lady finger etc.

2. Diadelphous : When filament of all stamen fuse in two groups but anthers are free condition is called diadelphous, e.g. Pea.

RBSE Class 11 Biology Chapter 21 Essay Type Questions

Question 1.
Explain hyogynous, epigynous and perigynous flowers with labeled diagram.
Answer:
Based on the position of calvx. corolla and androccium in respect of the ovary on thalamus, the flower are described as hpogynous. perignous and cpigvnous.
1. Hypogynous : In the hypogynous flover the gnoecium occupies the highest position while the other parts are situated below it. The ovary in such flower is said to be superior. e.g., Mustard, China rose and Brinjal.

2. Perigynous :
if gvnoecium is situated in the centre and other parts of the flower are located on the rim of the thallamus
almost at the same level, it is called perigynous. The osar here is said to be half interior, e.g.. Plum Rose Peach.

3. Epigynous :
In epigynous flowers, the margin of thalamus grows upward enclosing the ovary completely and getting fused with it. the other parts of flower arise above the ovary. The ovary is said to be inferior as in flowers of guava and cucumber. and the ray forets of sunflower. Thalamus provides place for insertion of floral leaves and protects ovar in inferior condition of ovar.

Question 2.
What do you mean by aestivation? Explain its types with labeled diagram and examples.
Answer:
1. Aestivation: the arrangement of petals (and also of sepals) in bud condition with respect to the members of the same whorl is known as aestivation.

2.  Valvate : When sepals or petals in a whorl just touch one another at the margin, without overlapping, as in Calotropis, Mustard and Acacia (Babool) are said to be Valvate.

3. Twisted or Contorted : If one margin of the appendage overlaps that of the next one and so on as in china rose, lady’s finger and cotton, it is called twisted.

4. Imbricate : Out of the five petals one is completely external, one completely internal and in each of the remaining three, one margin is internal and the other is external. It is subdivided into four sub-parts:

1. Simple Imbricate : When one petal is completely overlapped by other and one is completely overlapping to other and rest three arranged in twisted manner.
2. Descending imbricate or Vexillary : In pea and bean flowers, thre are five petals, the anterior petal is innermost and the posterior petal is the outennost and largest (standard) which overlaps the two lateral petals (wings) which in turn overlap the two smallest anterior petals (keel); this type of aestivation is known as vexillary or papilionaceous.
   
3. Ascending Imbricate : The posterior petal is innermost, i.e., it’s both margins are overlapped; eg Cassia and Bauhinia.
4. Quincunicial : It is modification of imbricate type. Out of die five petals, two are completely internal, two completely external and in the remaining petal one margin is intenal and the other margin is external; eg : Murraya.
   

Question 3.
What do you mean by placentation? Explain its types with labeled diagram and examples.
Answer:
Placentation: The arrangement of ovules within the ovary is known as placentation.

(i) Marginal:
Simplest type of placentation. Gynoecium is monocarpellary and the ovary is unilocular. The placenta develops along the fused margins of the carpel or on ventral suture, e.g., Pea, Bean, Gram etc.

(ii) Axile:
It occurs in syncarpous pistils Ovary is partitioned into two or more chambers. Ovules are attached on a centrally placed axis, e.g. Asphodelus, Tomato, China Rose, Onion etc.

(iii) Parietal:
Ovary is unilocular with two or more carpels. Ovules are borned on inner wall of the ovary, e.g., Mustard family (Cruciferae) In mustard plant a false septum or replum develops and divides the unilocular ovary’ in to two locules or chambers.

(iv) Free central:
It is polycarpellary and syncarpous with unilocular ovary in which ovules are attached on axis. It does not have any partitioned or walls, e.g., Primula, Dicinthus.

(v) Basal:
It is monocarpellary or syncarpous with unilocular condition in which single ovule attached at the base of ovary, e.g., Sunflower, Marigold.

(vi)Superficial:
It is similar to axile placentation. Ovules are borne on inner surface of partition walls of a multilocular ovary, e.g. Nymphaea.

RBSE Solutions for Class 11 Biology