Trunks of some of the aged tree species appear to be composed of several fused trunks. Is it a physiological or anatomical abnormality? Explain in detail.
Trunks of some of the aged tree species appear to be composed of several fused trunks. It is an example of anatomical abnormality due to anomalous secondary growth which occurs due to normal activity of an abnormally positioned cambium. Some
stems after secondary growth develop lobed outline and appear as formed by fusion of many stems, e.g., in Serjania, in the beginning a normal ring of vascular bundles is there, but after some time, some of adjacent bundles becoipe joined by cambium and they cut secondary xylem and secondary phloem in normal manner. At later stage, segments of cambium arise outside these fused vascular bundles and produce secondary xylem and secondary phloem.A periderm may be formed around each circle. Thus, a section of old stem shows concentric rings of xylem and phloem and vascular bundles are within.
Arrange the following in the sequence you would find them in a plant starting from the periphery – phellem, phellogen, phelloderm.
Protoxylem is the first formed xylem. If the protoxylem lies next to phloem what kind of arrangement of xylem would you call it?
Trunks of some of the aged tree species appear to be composed of several fused trunks. Is it a physiological or anatomical abnormality? Explain in detail.
Protoxylem is the first formed xylem. If the protoxylem lies next to phloem what kind of arrangement of xylem would you call it?
Plants require waterfortheir survival. But when watered excessively, plants die. Discuss.
Cut a transverse section of young stem of a plant from your school garden and observe it under the microscope. How would you ascertain whether it is a monocot stem or a dicot stem ? Give reasons.
Protoxylem is the first formed xylem. If the protoxylem lies next to phloem what kind of arrangement of xylem would you call it?
Match the following and choose the correct option from below.
A. | Cuticle | (i) | Guard cells |
B. | Bulliform cells | (ii) | Single layer |
C. | Stomata | (iii) | Waxy layer |
D. | Epidermis | (iv) | Empty colourless cell |
Options:
(a) A—(iii), B—(iv), C—(i), D—(ii)
(b) A—(i), B—(ii), C—(iii), D—(iv)
(c) A—(iii), B—(ii), C—(iv), D—(i)
(d) A—(iii), B—(ii), C—(i), D—(iv)
What is present on the surface of the leaves which helps the plant prevent loss of water but is absent in roots?
While eating peach or pear it is usually seen that some stone like structures get entangled in the teeth, what are these stone like structures called?
What are the characteristic differences found in the vascular tissue of gymnosperms and angiosperms?
Assume that a pencil box held in your hand, represents a plant cell. In how many possible planes can it be cut? Indicate these cuts with the help of line drawings.
Match the following and choose the correct option from below.
A. | Meristem | (i) | Photosynthesis, storage |
B. | Parenchyma | (ii) | Mechanical support |
C. | Collenchyma | (iii) | Actively dividing cells |
D. | Sclerenchyma | (iv) | Stomata |
E. | Epidermal tissue | (v) | Sclereids |
Options:
(a) A—(i), B—(iii), C—(v), D—(ii), E—(iv)
(b) A—(iii), B—(i), C—(ii), D—(v), E—(iv)
(c) A—(ii), B—(iv), C—(v), D—(i), E—(iii)
(d) A—(v), B—(iv), C—(iii), D—(ii), E—(i)
A transverse section of the trunk of a tree shows concentric rings which are known as growth rings. How are these rings formed? What is the significance of these rings?
Arrange the following in the sequence you would find them in a plant starting from the periphery – phellem, phellogen, phelloderm.
Explain the process of secondary growth in the stems of woody angiosperms with the help of schematic diagrams. What is its significance?
The transverse section of a plant material shows the following anatomical features – (a) the vascular bundles are conjoint, scattered and surrounded by a sclerenchymatous bundle sheath, (b) phloem parenchyma is absent. What will you identify it as?
Name the three basic tissue systems in the flowering plants. Give the tissue names under each system.
What part of the plant would show the following?
a. Radial vascular bundle
b. Polyarch xylem
c. Well developed pith
While eating peach or pear it is usually seen that some stone like structures get entangled in the teeth, what are these stone like structures called?
Deciduous plants shed their leaves during hot summer or in autumn. This process of shedding of leaves is called abscission. Apart from physiological changes what anatomical mechanism is involved in the abscission of leaves.
Assume that a pencil box held in your hand, represents a plant cell. In how many possible planes can it be cut? Indicate these cuts with the help of line drawings.
What are the characteristic differences found in the vascular tissue of gymnosperms and angiosperms?
The lawn grass (Cynodon dactylon) needs to be mowed frequently to prevent its overgrowth. Which tissue is responsible for its rapid growth?
The lawn grass (Cyandon dactylon) needs to be mowed frequently to prevent its overgrowth. Which tissue is responsible for its rapid growth?
Trunks of some of the aged tree species appear to be composed of several fused trunks. Is it a physiological or anatomical abnormality? Explain in detail.
Product of photosynthesis is transported from the leaves to various parts of the plants and stored in some cell before being utilised. What are the cells/ tissues that store them?
Below is a list of plant fibres. From which part of the plant these are obtained?
(a) Coir
(b) Hemp
(c) Cotton
(d) Jute
Epidermal cells are often modified to perform specialized functions in plants. Name some of them and function they perform.
What is present on the surface of the leaves which helps the plant prevent loss of water but is absent in roots?