Home
Class 11
BIOLOGY
The arrangement of ovules within the ova...

The arrangement of ovules within the ovary is known as placentation. What does the term placenta refer to ? Draw various types of placentations in the flower as seen in T.S. and V.S.

Text Solution

Verified by Experts

Placenta is a soft cushion like tissue. Ovules are attached to inner surface of ovary.
The arrangement of ovules within the ovary is known as placentation. The placentation are of different types namely marginal, axile, parietal basal, central and free central etc.
Marginal Placentation :
In this type of placentation the placenta forms a ridge along the ventral suture of the ovary and the ovules are borne on this ridge forming two rows as in pea.
Axile Placentation :
In this type of placentation, when the placenta is axial and the ovules are attached to it in a multilocular ovary, the placentation is said to be axile as in china-rose, tomato and lemon.
Parietal Placentation :
In this type of placentation, the ovules develop on the inner wall of the ovary or on peripheral part. Ovary is one chambered but it becomes two chambered due to the formation of the false septum, eg, mustard.
Free Central Placentation :
In this type of placentation, when the ovules are borne on central axis and septa are absent so ovary is one chambered. e.g. Dianthus and Primose ?
Basal Placentation :
In basal placentation, the placenta develops at the base of ovary and a single ovule is attached to it. eg. sunflower.
Promotional Banner

Topper's Solved these Questions

  • ANATOMY OF FLOWERING PLANTS

    KUMAR PRAKASHAN|Exercise QUESTIONS FROM MODULE (IMPORTANT MCQ FOR NEET)|6 Videos

  • ANATOMY OF FLOWERING PLANTS

    KUMAR PRAKASHAN|Exercise QUESTIONS FROM MODULE (QUESTION PAPER)|10 Videos

  • ANATOMY OF FLOWERING PLANTS

    KUMAR PRAKASHAN|Exercise SECTION-E SOLUTION OF NCERT EXEMPLAR (SHORT ANSWER TYPE QUESTIONS)|14 Videos

  • ANIMAL KINGDOM

    KUMAR PRAKASHAN|Exercise OBJECTIVE SECTION (FILL IN THE BLANKS)|10 Videos

Similar Questions

Explore conceptually related problems

What type of motion is represented by equation Delta s= v Delta t ?

By the term velocity of rain, we mean velocity with which raindrops fall relative to the ground. In absence of wind, raindrops fall vertically and in presence of wind raindrops fall obliqucly. Moreover raindrops acquire a constant terminal velocity due air resistance very quickly as they fall toward the carth. A moving man relative to himself observes an altered velocity of raindrops. Which is known as velocity of rain relative to the man. It is given by the following equation. vec(v)_(rm)=vec(v)_(r)-vec(v)_(m) A standstill man relative to himself observes rain falling with velocity, which is equal to velocity of the raindrops relative to the ground. To protect himself a man should his umbrella against velocity of raindrops relative to himself as shown in the following figure. When you are standstill in rain, you have to hold umbrella vertically to protect yourself. (a) When you walk with velocity 90 cm/s, you have to hold your umbrella at 53^(@) above the horizontal. What is velocity of the raindrops relative to the ground and relative to you ? (b) If you walk with speed 160 cm/s, how should you hold your umbrella ?