Question:

Why is not any one parameter good enough to demonstrate growth through the life of a flowering plant?

Answer:

1. A flowering plant goes through many stages of growth, from a seed to a mature plant.

2. Each stage of growth involves different parameters such as light, temperature, water, soil, and nutrients.

3. Therefore, no single parameter is sufficient to demonstrate the growth of a flowering plant through its life cycle, as the plant needs a combination of all the parameters to grow.

Question:

Would a defoliated plant respond to photoperiodic cycle? Why?

Answer:

1. A defoliated plant is a plant that has lost its leaves, either through natural causes or through human intervention.

2. Photoperiodism is the ability of an organism to respond to seasonal changes in the length of day and night.

3. A defoliated plant may still respond to the photoperiodic cycle, as the photoperiodic cycle is regulated by the amount of light an organism receives, not necessarily the presence of leaves.

4. The response of a defoliated plant to the photoperiodic cycle may be different than that of a plant with leaves, as the presence of leaves can help to regulate the amount of light the plant receives. The plant may also be less efficient in its ability to photosynthesize, as it does not have leaves to absorb sunlight.

5. Therefore, a defoliated plant may still respond to the photoperiodic cycle, but its response may be different than that of a plant with leaves.

Question:

What would be expected to happen if: (a) GA3​ is applied to rice seedlings. (b) Dividing cells stop differentiating. (c) A rotten fruit gets mixed with unripe fruits. (d) You forget to add cytokinin to the culture medium.

Answer:

a) GA3 is applied to rice seedlings: It is expected that the rice seedlings will grow faster and reach maturity sooner than usual.

b) Dividing cells stop differentiating: It is expected that the cells will not be able to develop into their specialized functions, and the organism will not be able to develop properly.

c) A rotten fruit gets mixed with unripe fruits: It is expected that the unripe fruits will become rotten faster than usual due to the presence of the rotten fruit.

d) You forget to add cytokinin to the culture medium: It is expected that the cells in the culture medium will not be able to differentiate properly, and the organism will not be able to develop properly.

Question:

Define growth, differentiation, development, dedifferentiation, redifferentiation, determinate growth, meristem and growth rate.

Answer:

Growth: Growth is the process of increasing in size or number.

Differentiation: Differentiation is the process of cells becoming specialized for a specific function.

Development: Development is the process of growth and change that occurs over time.

Dedifferentiation: Dedifferentiation is the process by which a differentiated cell loses its specialized features and reverts to a less specialized form.

Redifferentiation: Redifferentiation is the process by which a dedifferentiated cell regains its specialized features.

Determinate Growth: Determinate growth is a type of growth in which the size of an organism is predetermined.

Meristem: Meristem is a type of undifferentiated tissue found in plants that can divide and differentiate into other cell types.

Growth Rate: Growth rate is a measure of the rate at which an organism or population increases in size.

Question:

Which one of the plant growth regulators would you use if you are asked to: (a) Induce rooting in a twig (b) Quickly ripen a fruit (c) Delay leaf senescence (d) Induce growth in axillary buds (e) Bolt a rosette plant (f) Induce immediate stomatal closure in leaves.

Answer:

(a) Induce rooting in a twig: Auxin (b) Quickly ripen a fruit: Ethylene (c) Delay leaf senescence: Gibberellin (d) Induce growth in axillary buds: Auxin (e) Bolt a rosette plant: Gibberellin (f) Induce immediate stomatal closure in leaves: Abscisic Acid

Question:

Would a defoliated plant respond to photoperiodic cycle? Why?

Answer:

1. A defoliated plant is a plant that has lost its leaves due to a natural or human-caused event.

2. Photoperiodic cycle is the response of plants to changes in day length, or the length of time between sunrise and sunset.

3. Yes, a defoliated plant would still respond to the photoperiodic cycle. This is because the plant’s internal clock, which is responsible for regulating its circadian rhythms, is still functioning even though the plant has lost its leaves. This internal clock is responsible for the plant’s response to changes in day length.

4. Therefore, a defoliated plant would still respond to the photoperiodic cycle in order to regulate its circadian rhythms and other physiological processes.

Question:

Describe briefly: Arithmetic growth (b) Geometric growth (c) Sigmoid growth curve (d) Absolute and relative growth rates.

Answer:

a) Arithmetic growth: Arithmetic growth is a type of growth in which a quantity increases at a constant rate over time. This type of growth is typically seen in linear equations, where the rate of change is constant.

b) Geometric growth: Geometric growth is a type of growth in which a quantity increases exponentially over time. This type of growth is typically seen in exponential equations, where the rate of change increases exponentially.

c) Sigmoid growth curve: A sigmoid growth curve is a type of growth curve that follows an S-shaped pattern. This type of growth is typically seen in biological systems, where the rate of growth starts off slow, accelerates, and then slows again.

d) Absolute and relative growth rates: Absolute growth rate is the rate at which a quantity increases over time, without taking into account any other factors. Relative growth rate is the rate at which a quantity increases relative to other factors, such as population size or economic growth.

Question:

List five main groups of natural plant growth regulators. Write a note on discovery, physiological functions and agriculture/horticultural applications of any one of them.

Answer:

1. Auxins: Auxins are one of the most important groups of natural plant growth regulators. They were first discovered by Charles Darwin and his son Francis in the late 19th century. Auxins are involved in various physiological processes, such as cell elongation, cell division, and differentiation. In horticulture and agriculture, auxins are used to promote root growth, encourage fruit setting, and induce flowering.

2. Gibberellins: Gibberellins are a group of plant growth regulators first discovered in Japan in the early 20th century. They are involved in various physiological processes, such as stem elongation, germination, flowering, and fruit ripening. In agriculture and horticulture, gibberellins are used to promote seed germination, induce flowering, and increase fruit size.

3. Cytokinins: Cytokinins are a group of plant growth regulators first discovered in the 1950s. They are involved in various physiological processes, such as cell division, differentiation, and senescence. In horticulture and agriculture, cytokinins are used to promote root growth, induce flowering, and delay leaf senescence.

4. Abscisic Acid: Abscisic acid is a plant growth regulator first discovered in the 1960s. It is involved in various physiological processes, such as seed dormancy, leaf senescence, and stress responses. In horticulture and agriculture, abscisic acid is used to promote seed dormancy, induce leaf senescence, and reduce stress.

5. Ethylene: Ethylene is a plant growth regulator first discovered in the late 19th century. It is involved in various physiological processes, such as fruit ripening, leaf senescence, and root growth. In horticulture and agriculture, ethylene is used to promote fruit ripening, induce leaf senescence, and stimulate root growth.

Question:

Why is Abscisic acid called as stress hormone?

Answer:

Step 1: Abscisic acid (ABA) is a plant hormone that helps plants respond to environmental stress.

Step 2: ABA is responsible for regulating a range of processes in plants, including seed dormancy, stomatal closure, and the inhibition of growth in response to stress.

Step 3: ABA is produced in response to environmental stress, such as drought, cold, and high salinity, and helps plants survive in these conditions.

Step 4: Therefore, it is called a ‘stress hormone’ because it helps plants cope with stressful conditions.

Question:

Both growth and differentiation in higher plants are open. Comment.

Answer:

Growth and differentiation in higher plants are two vital processes that are essential for the development and functioning of the plant. Growth refers to the increase in size and mass of the plant, while differentiation is the process of a cell becoming specialized for a particular function.

Both growth and differentiation in higher plants are open processes, meaning that they can be affected by external factors such as light, temperature, and water availability. For example, plants exposed to more light tend to grow faster and differentiate more quickly than those that are not. Additionally, plants that are exposed to different temperatures may experience different rates of growth and differentiation.

Thus, the external environment can have a significant influence on the growth and differentiation of higher plants. This is why it is important to provide plants with the right conditions in order to ensure their optimal development and functioning.

Question:

Both a short day plant and a long day plant can produce flower simultaneously in a given place. Explain.

Answer:

Answer:

1. Short day plants require long nights and short days in order to produce flowers.
2. Long day plants require long days and short nights in order to produce flowers.
3. Depending on the location, it is possible for both a short day plant and a long day plant to produce flowers simultaneously.
4. This is because the length of the days and nights in the given place may be long enough to meet the requirements of both the short day plant and the long day plant.
5. For example, if the given place has 12 hours of daylight and 12 hours of darkness, then the short day plant and the long day plant can both produce flowers simultaneously.