Rearrange the following zones as seen in the root in vertical section and choose the correct option.
A. Root hair zone
B. Zone of meristems
C. Rootcapzone
D. Zone of maturation
E. Zone of elongation
(a) C, B, E, A, D (b) A,B,C,D,E
(c) D, E, A, C, B (d) E, D, C, B, A
(a): A typical root possesses five parts
or regions:
(i) Root cap covers the root meristem. The cells of the root cap secrete mucilage which lubricates the passage of root through the soil. Cells of root cap possess starch grains which are believed to take part in graviperception. Function cap is the protection of root meristem from soil particles.
(ii) Growing point or meristematic zone produces new cells for the root cap and basal region of the root. Therefore, it is essential for the growth of the root.
(iii) Cells of zone of elongation are newly formed cells which lose the power of division. They elongate rapidly which increases length of the root. The external cells possess the power of absorption of water and mineral salts from the soil.
(iv) Root hair zone also represents the zone of differentiation or maturation. Most of the water absorption occurs in this region. Some of the outer cells of this zone give rise tq lateral tubular outgrowths called root hairs. The root hairs increase the exposed surface of the root for absorption.
(v) Region or zone of mature cells forms the bulk of the root without undergoing any – further change. The outermost layer of this region cannot help the root in water absorption because they have thick walled or impermeable cells. Its only function is to anchor the plant firmly in the soil. Lateral roots also arise from the interior of this region.
Mango and coconut are ‘drupe’ type of fruits. In mango fleshy mesocarp is edible. What is the edible part of coconut? What does milk of tender coconut represent?
Roots obtain oxygen from air in the soil for respiration. In the absence or deficiency of 02, root growth is restricted or com pletely stopped. How do the plants growing in marshlands or swamps obtain their 02 required for root respiration?
Write floral formula for a flower which, is bisexual; actinoiflorphic; sepals five, twisted aestivation, petals five; valvate aestivation; stamens six; ovary tricarpellary, syncarpous, superior, trilocular with axile placentation.
In swampy areas like the Sunderbans in West Bengal, plants bear special kind of roots called __________ .
Tendrils are found in the following plants. Identify whether they are stem tendrils or leaf tendrils,
a.Cucumber
b. Peas
c. Pumpkins
. Grapevine
e. Watermelons
Seeds of some plants germinate immediately after shedding from the plants while in other plants they require a period of rest before germination. The later phenomena is called as dormancy. Give the reasons for seed dormancy and some methods to break it.
Match the followings and choose the correct option.
|
Group A |
Group B | ||
|
A. |
Aleurone layer | (i) |
Without fertilization |
|
B. |
Parthenocarpic fruit | (ii) |
Nutrition |
|
C. |
Ovule | (iii) |
Double fertilization |
| D. |
Endosperm |
(iv) |
Seed |
Options:
Mango and coconut are ‘drupe’ type of fruits. In mango fleshy mesocarp is edible. What is the edible part of coconut? What does milk of tender coconut represent?
The essential functions of roots are anchorage and absorption of water and minerals in the terrestrial plant. What functions are associated with the roots of aquatic plants. How are roots of aquatic plants and terrestrial plants different?
Reticulate venation is found in dicot leaves while in monocot leaves venation is of parallel type. Biology being a ‘Science of exceptions’, find out any exception to this generalisation.
Rhizome of ginger is like the roots of other plants that grows underground. Despite this fact ginger is a stem and not a root. Justify.
Write the floral formula of an actinomorphic, bisexual, hypogynous flower with five united sepals, five free petals, five free stamens and two united carples with superior ovary and axile placentation.
You have heard about several insectivorous plants that feed on insects. Nepenthes or the pitcher plant is one such example, which usually grows in shallow water or in marsh lands. What part of the plant is modified into a ‘pitcher’? How does this modification help the plant for food even though it can photosynthesise like any other green plant?
Tendrils of grapevines are homologous to the tendril of pumpkins but are analogous to that of pea. Justify the above statement.
Roots obtain oxygen from air in the soil for respiration. In the absence or deficiency of 02, root growth is restricted or completely stopped. How do the plants growing in marshlands or swamps obtain their 02 required for root respiration?
The essential functions of roots are anchorage and absorption of water and minerals in the terrestrial plant. What functions are associated with the roots of aquatic plants? How are roots of aquatic plants and terrestrial plants different?
Stolon, offset and rhizome are different forms of stem modifications. How can these modified forms of stem be distinguished from each other?
In Opuntia the stem is modified into a flattened green structure to perform the function of leaves (i.e., photosynthesis). Cite some other examples of modifications of plant parts for the purpose of photosynthesis.
Reticulate and parallel venation are characteristic of ________ and ______ respectively.
Given below are a few floral formulae of some well known plants. Draw floral diagrams from these formulae.
Mango and coconut are ˜drupe' type of fruits. In mango fleshy mesocarp is edible. What is the edible part of coconut? What does milk of tender coconut represent?
The arrangements of ovules within the ovary is known as placentation. What does the term placenta refer to? Name and draw various types of placentations in the flower as seen in T.S. or V.S.
How do you distinguish between hypogeal germination and epigeal germination? What is the role of cotyledon (s) and the endosperm in the germination of seeds?
Write floral formula for a flower which, is bisexual; actinomorphic; sepals five, twisted aestivation, petals five; valvate aestivation; stamens six; ovary tricarpellary, syncarpous, superior, trilocular with axile placentation.
Give two examples of roots that develop from different parts of the angiospermic plant other than the radicle.
Reticulate venation is found in dicot leaves while in monocot leaves venation is of parallel type. Biology being a 'Science of exceptions', find out any exception to this generalization.
Justify the following statements on the basis of external features:
(i) Underground parts of a plant are not always roots.
(ii) Flower is a modified shoot.
In Opuntia the stem is modified into a flattened green structure to perform the function of leaves (/’.e., photosynthesis). Cite some other examples of modifications of plant parts for the purpose of photosynthesis.
Stolon, offset and rhizome are different forms of stem modifications. How can these modified forms of stem be distinguished from each other?
A typical angiosperm flower consists of four floral parts. Give the names of the floral parts and their arrangements sequentially.
You have heard about several insectivorous plants that feed on insects. Nepenthes or the pitcher plant is one such example, which usually grows in shallow water or in marsh lands. What part of the plant is modified into a 'pitcher'? How does this modification help the plant for food even though it can photosynthesize like any other green plant?
Rearrange the following zones as seen in the root in vertical section and choose the correct option.
A. Root hair zone
B. Zone of meristems
C. Rootcapzone
D. Zone of maturation
E. Zone of elongation
(a) C, B, E, A, D (b) A,B,C,D,E
(c) D, E, A, C, B (d) E, D, C, B, A
