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Class 11 Biology textbook Solutions for Class 11, Biology Chapter 8 Plant Tissues and Anatomy maharashtra state board are provided here with simple step-by-step detailed explanations. These solutions for Plant Tissues and Anatomy are very popular among Class 11 students for biology chapter 8 Plant Tissues and Anatomy Solutions come handy for quickly completing your homework and preparing for compititive exams like NEET, CET abd verious medical entrance examination also. All questions and answers are taken from the class 11 Biology textbook, Bjology Textbook Solutions of Class 11 Biology Chapter 8 are provided here for you for without any charge its free for you. All Biology textbook Solutions for class 11. Solutions for class 11 Biology subject, These biology textbook solutions are prepared by experts in the field and are 100% accurate for you.
1. Choose the correct option
A. Location or position of meristematic
regions is divided into ………………. types
d. none of the above
B. Cambium is also called …………….
a. apical meristem
b. intercalary meristem
c. lateral meristem
d. none of the above
C. Collenchyma is a type of ……………..
c. living and dead
d. none of the above
D. ………………… is a complex permanent
E. Mesophyll tissue is present in…………….
2. Answer the following questions
A. A fresh section was taken by a student but he was very disappointed because there were only few green and most colourless cells. Teacher provided a pink colour solution. The section was immersed in this solution and when observed it was much clearer. What is the magic?
Answer : The transverse section of a typical dicotyledonous root shows following anatomical features. The outermost single layer of cells without cuticle is Epiblema. Some of its cells are prolonged into unicellular root hair. Next to it is the Cortexwhich consists of several layers of typical parenchymatous cells. After the death of epiblema, outer layer of cortex become cutinized and is called Exodermis. The cortical cells store food and water. The innermost layer of cortex is called Endodermis.
B. While observing a section many scattered vascular bundles could be seen. Teacher said but in spite of this large number the stem cannot grow in girth. Why?
Answer : Monocot stem has scattered vascular bundles. They lack cambium, thus cannot show secondary or lateral growth(no growth in girth).
C. A section of the stem had vascular bundles, where one tissue was wrapped around the other. How will you
technically describe it?
Answer : A section of the stem had vascular bundles, where one tissue was wrapped around the other. The structure is known as the monocot stem. Explanation: In certain instances of monocot stem, the structure has its vascular bundles in a scattered format.
D. There were two cut logs of wood lying
in the campus. One had growth rings and other didn’t. Teacher said it is due to differences in their pattern of growth
which is dependent on season. How?
Answer : it is said that the age of trees can be calculated through those rings. if it has 1 ring it is one year old. given that one log has grown rings it is probably years old and been through different season of years. where as the other log doesn’t possesse any ring so it wasn’t old enough or less than a year old.
E. While on the trip to Kashmir, Pintoo observed that cut portions of large trees
shows distinct rings, which he never found in Maharashtra. Why is so?
Answer : The distinct rings observed by Pintu while a trip to Kashmir In The Cut portions of large trees are called growth rings. This growth rings are absent in the trees of Maharashtra because the formation of growth rings are highly influenced by climatic conditions.
F. A student was observing a slide with no label under microscope. The section had some vascular bundles scattered in the ground tissue. It is section of a monocot stem! He exclaimed. No! it is section of fern rachis, said the teacher. Teacher told to observe vascular bundle again. Student agreed, Why?
Answer : In fern rachis xylem consists only tracheids whereas in monocot stem xylem consists vessel like protoxylem and metaxylem as well as monocot shows presence of lysigenous cavity just below the protoxylem thus
2. phloem consists of only sieve cells and whereas monocot stem phloem consists of sieve tubes and campionion cells thus students must be observed these different in the given and agreed to teacher and also to remember given section of fern rachis and not of monocot stem.
G. Student found a wooden stopper in lab. He was told by an old lab attendant that it is there for many years. He kept
thinking how it did not rot?
Answer : this is because they are atored under chemicals which not acllw to rot the substance.
H. Student while observing a slide of leaf
section observed many stomata on the
upper surface. He thought he has placed
slide upside down. Teacher confirmed it
is rightly placed. Explain.
Answer : Stomata is present on the upper surface of leaf
Explanation: This is because of easy exchange of gases between surrounding and stomatal pores
3. Write short notes on the following points
A. Structure of stomata
Answer : When a leaf is examined under the microscope, we observe many tiny pores, which are collectively called stomata.
The length and breadth of stomata is about 10-40µ and 3-10µ respectively. Mature leaves contain between 50 and 500 stomata per mm2. Stomata are made up of two guard cells, special semi-lunar or kidney-shaped living epidermal cells in the epidermis. Guard cells are attached to surrounding epidermal cells known as subsidiary cells or accessory cells. The guard cells are joined together at each end but they are free to separate to form a pore between them. The inner wall of the guard cell is thicker than the outer wall (Figure 11.14). The stoma opens to the interior into a cavity called sub-stomatal cavity which remains connected with the intercellular spaces.
B. Secondary growth
The vertical growth of the roots and stems in length with the help of apical meristem is called as primary growth. Dicotyledonous plants and gymnosperms exhibit increase in girth of root and stem. In dicot stem, secondary growth begins with the formation of a continuous cambium ring.
- The cambium present between the primary xylem and primary phloem of a vascular bundle is called intraf asicular cambium.
- The cells of medullary rays adjoining these intrafascicular cambium strips become meristematic (regain the capacity to divide) and form the interf ascicular cambium.
- Thus a complete and continous ring of vascular cambium is formed.
- The cambium ring cuts off new cells, towards both the sides, inner and outer.
- The cells that are cut-off towards pith (inner side) mature into secondary xylem and cells that are cut-off towards periphery mature into secondary phloem. Generally, amount of secondary xylem is more than the secondary phloem.
C. Peculiarity of a sclerenchyma cell wall
Answer : It is simple permanent tissue
made up of compactly arranged thick walled dead cells. The cells are living at the time of production but at maturity they become dead. As cells are devoid of cytoplasm their thickened walls are due to uniform deposition of lignin. Cells remain interconnected through several
pits. It is of two types viz. fibres and sclerids. Fibres are thread-like, elongated and narrow structures with tapering and interlocking end walls. These are mostly in bundles, pits are narrow, unbranched and oblique. They provide mechanical strength. Sclerids are usually broad, with blunt end walls. These occur singly or in loose groups and their pits are deep branched and straight. These are developed due to secondary thickening of parenchyma
cells and provide stiffness only
A. Vascular bundle of monocot and dicot
- Monocot stems have scattered vascular bundles. Dicot stems have their vascular bundles in a ring arrangement.
- Dicot stems have bundles in a ring surrounding parenchyma cells in a pith region. Between the bundles and the epidermis are smaller (as compared to the pith) parenchyma cells making up the cortex region.
B. Xylem and Phloem functioning
- Xylem transports only minerals and waters from the roots. Phloem transports food materials that are prepared by the green parts of the plants to other parts of the plant.
- Xylem is the dead tissues at maturity, but no cell contents. Phloem is the living tissue, but not with the nucleus.
C. Internal or anatomical difference between monocots and dicots.
- Monocot Embryo with single cotyledonwhile dicot Embryo with two cotyledons.
- Monocot Pollen with single furrow or poredicot Pollen with three furrows or pores.
- Monocot Flower parts in multiples of three dicot Flower parts in multiples of four or five.
- Monocot Major leaf veins parallel dicot Major leaf veins reticulated.
5. Draw neat labelled diagrams
A. T. S. of Dicot leaf.
B. T. S. of Monocot root.
C. T. S. of dicot stem.