What is meant by 'unisexual flowers' and 'bisexual flowers' ? Give two examples of each.

Which among the following statements are true for unisexual flowers?

(i) They possess both stamen and pistil

(ii) They possess either stamen or pistil

(iii) They exhibit cross pollination

(iv) Unisexual flowers possessing only stamens cannot produce fruits

Which of the following statements are true for flowers ?

(i) flowers are always bisexual

(ii) they contain sexual reproductive organs

(iii) they are produced in all groups of plants

(iv) after fertilisation they give rise to fruits

Which of the following is the correct sequence of events of sexual reproduction in a flower ?

The length of pollen tube depends on the distance between :

In a flower, the parts that produce male and female gametes are respectively:

The flask-shaped organ A at the centre of a flower is surrounded by a number of little stalks B having swollen tops which lie just inside the ring of petals.

(a) Name A. What are the various parts of A?

(b) Which part of A contains gametes?

(c) Name B. What is the swollen top of B known as ?

(d) What does the swollen top of B contain ?

(e) Out of A and B, which one is (i) male part, and (ii) female part of the flower?

The part of a seed which grows and develops into root on germination is:

When an insect sits on the flower of a plant then some particles A present in the top of little stalks in the flower attach to its body hair. When this insect now sits on the flower of another similar plant, then particles A attached to the hair of insect are put on the top of a flask-shaped organ at the centre of flower. The particle A grows a long tube B from the top of flask-shaped organ through which C moves down and reaches the bottom part of flask-shaped organ. Here C fuses with the nucleus of D contained in structure E. The fusion of C and D forms a new cell F which grows and develops into a seed of the plant.

(a) What are particles A ? What is the process of transferring A from one flower to another flower of similar plant by the insect known as ?

(b) What is the name of tube B?

(c) What is C which moves down through the tube B?

(d) Name D and E.

(e) What is F ?

In the figure given alongside, the parts marked A, B and C are sequentially:

In what ways is fertilisation in a plant :

(a) similar to fertilisation in a human?

(b) different from fertilisation in a human?