Plant growth and development Class 11 – Introduction-
Plant growth and development Class 11:- What do u mean by development and growth in case of plants? Trees increases in height or girth over a period of time. All the plant organs are build up of a different varieties of tissues,and all cells are descendants of zygote.The sum of two processes including growth and differentiation is called development.
In this chapter we are gonna study the factors affecting the development process,which are both internal and external. So, let us study these in advance.
Plant growth and development Class 11 – Very Short Answer Type Questions
Q.1. Fill in the blanks:
a)Stage of growth that is rapid and maximum is case of _________
b) ________ is present in apical bud in more number causes the apical dominance as displayed in dicotyledonous plants.
c)The sites of photoperiodic perception in the case of vegetative plants are _______
A.1. a) Log phase of an S curve or the Exponential curve.
b) IAA or the Auxin.
c) the leaves.
Q.2. Name the PGS (Plant growth substances) that needs to have practical applications in the following:
a) Improve the yield of sugarcane
b) Increase the lateral shoot growth
c) Basis for sprouting of the potato tuber
d) Hinders the seed germination.
A.2. a) Gibberellin/Gibberellic acid
d) Abscisic acid
Q.3. Name the three physiological processes in the plants that are affected by the light.
A.3. The three processes are –
Q.4. a) Write the two functions of phytohormone – Gibberellins.
b) The seedling disease in the rice is caused by the phytohormone-Gibberellin is due to which feature?
A.4. a) Gibberellin is utilized to accelerate the malting phenomena in the brewing industries. They facilitate the process of bolting in cabbages, beet root and several plants with the rosette habitat.
b) The elongation of Internode.
Q.5. The plant growth regulator that needs to be applied to improve the number of female flowers in a cucumber plant field is?
A.5. The name of the PGR is Ethylene(C2H4).
Q.6. Where the hormones are manufactured in the plants?
A.6. a) Shoot tips and apical buds.
b) Young leaves and root tips.
c) Root tips (meristematic zones).
Q.7.Name the factors affecting Plant Growth?
A.7. The important factors affecting the growth of plants includes-
5.Plant growth regulators, PGR’s
Plant Growth And Development Class 11 Quiz
Q.8.What do u mean by Differentiation?
A.8. Differentiation is defined as process in which a cell changes from one cell type to the another one.
Q.9. Define Cell Maturation?
A.9. Cell maturation is defined as a process of enlarging the cells, which acquires a definite shape to achieve their specific functions.
Q.10.What do you mean by Cell Enlargement?
A.10. It is described as the process in which the size of the cells,the tissues and the organs increases by formation of the protoplasm, absorption of water, development of vacuoles, and the addition of the cell walls to make it more thicker and permanent.
Plant growth and development Class 11 – Short Answer Type Questions
Q.1. Give structural features of the following –
a) Meristematic cells near the root tips of the underground roots.
b) Cells of the elongation zone of the roots underground.
A.1. a) The characteristics are as follows:
- Big and conspicuous nucleus
- Protoplasm rich
- Thin basic cellulosic cell wall
- Number of vacuoles are less
- Mitochondria are more
- Plasmodesmata is plentiful.
b) Cells of elongation zone are –
- Extended in dimensions
- Vacuolation is increased
- New cellulosic cell walls are collected.
Q.2. Give the difference in growth pattern of the plants and the animals? Do every part of the plant grows endlessly? Name the regions of plant that can grow endlessly.
A.2. Yes, the plants and the animals differs in their growth patterns .Plant growth is different as plants have the potential to grow endlessly during their lifetime. They exhibit this property because of presence of the meristems at some parts of the plants. The cells of meristems have an ability of division and grow constantly. The plants are made up of cells which lose their capacity to divide further. The growth form, where the cells are constantly added to body of the plants through actions of meristems is known as the open form of growth process.
Q.3. Describe the following
a) Process of Differentiation
b) Process of Dedifferentiation
c) Process of Redifferentiation
a) Differentiation is permanent in the structure, size, functions, and the composition of the cells, tissues or the organs. For example, the meristematic tissues give rise to the new cells that mature and get differentiated into a special tissue or a plant organ. For instance the formation of the treachery element results in the loss of the cell’s protoplasm. Water is carried at a stretch under extreme tension, they develop an elastic, strong, lignocellulosic secondary cell wall.
b) De-differentiation – Under certain conditions, the cells that have dropped the capability to divide can regain the capacity, this process is referred to as de-differentiation. For example – the development of meristems – the cork cambium from completely transformed parenchyma cells.
c) Re-differentiation – During the de-differentiation process, before mentioned tissues or the meristems after the division generate the cells that loses the ability to divide once more but mature to take up certain functions. They get re-differentiated. Example the secondary cortex.
Q.4.It is difficult to designate any of the effect to a single hormone during the experimentation.Explain the following.
A.4. Several hormones have an antagonistic and tr synergistic impact with each other. Hence it becomes difficult.
Q.5. Where are plant hormones formed? How hormones are transferred to the specific site of the activity?
A.5. Plant hormones are produced by the several tissues like the root tips,the shoot tips, the leaves, the meristematic tissues, and the apical buds, etc. The presence of vascular tissues like the phloem and the xylem help in translocation of the hormones to the sites of the activity.
Q.6. What do u mean by plant growth regulators i.e. PGR’s?
A.6. Plant growth regulators also referred to as phytohormones or plant hormones. They are a group of organic compounds, which functions by controlling and modifying physiological processes. Fir eg. growth, development, and the movement of plants.
Q.7. Which PGR manipulates and stimulates maturation of the sugarcane crop?
A.7.Ethylene, which is also known as the ripening hormone in the plants helps in the maturation of the sugarcane crops by increasing storage of the level of sucrose in plants.
Q.7. Write important functions of Auxins in the growth of the plant?
A.7. Auxins- These are one of the most important plant hormones. These plant hormones are generally produced at tips of the stems and the roots. In all the vascular plants, it plays a vital role in the :
- Division of the cell.
- Propagation of plant.
- Promotes flowering process in the plants.
- Initiation of the roots and the stem cuttings.
- Prevents the premature dropping of the fruits and the leaves.
Plant Growth And Development Class 11 Study materials
Plant growth and development Class 11 – Long Answer Type Questions-
Q.1. Winter season varieties, when planted in the spring season, do not make flowers or the mature grains within the span of a flowering season. Discuss your answers in groups.
A.1. In some the plants, flowering is either qualitatively or quantitatively reliant on the subjection to the lower temperatures, the process is referred to as vernalization. This limits advanced reproductive development rate in the maturing season thereby allowing them to have enough time to gain maturity. Vernalisation is the process that promotes flowering by a span of low temperatures. Some of the plants like wheat, barley have two types of the varieties – the spring and the winter varieties. The spring variety is planted in spring and the flowers, produces grains towards termination of growing season. While the winter varieties, when planted in the spring fail to flower or generate mature grains within the flowering season, this is why they are planted in autumn. Over the winter season, they germinate and turn out as the small seedlings, restarting the development in the spring and are gathered in the mid-summer.
Q.2. Several variations of the wheat crops are cultivated in the autumn season and harvested in next midsummer.
a) Give reasons for your answer.
b) What is flowering in lower the temperatures Called?
c) Name plant growth hormone,PGR that can substitute for cold treatment.
a) If a plant is planted in spring season, winter varieties do not produce flower or generates the mature grains in a span of flowering season, hence they are grown in the autumn season. Over the winter season, they sprout and come out as the tiny seedlings, resuming the growth of the plant in the spring season and are collected in the mid-summer.
b) Vernalisation is the flowering in the lower temperature.
c) Gibberellin can subtitle for cold treatment.
Q.3. Name the hormone that:
a) Is in the nature, as gaseous form.
b) Is in the charge of the phototropism.
c)that influences femaleness in the cucumber flowers.
d) It is utilized to kill the weed plants (dicots).
e) In the long-day plants, it induces flowering.
A.3. a) Ethylene(C2H4)
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