PG&D

Question 1

What is definity in indefinite growth?

Answer 1

Trees continue to increase in girth& height over a period of time however the leaves flowers fruits of the tree not only have limited dimensions but also fall periodically or some time repeatedly

Question 2

Define Development

Answer 2

Development is the sum of two processes growth and differentiation

Question 3

What is the nature of plant development? What is the first process of plant growth?

Answer 3

The development of a mature plant from a zygote(fertilized egg) follow a precise and highly ordered succession of events
The first step in process of plant growth is seed germination

Question 4

Elaborate on seed germination and favourable Factors

Answer 4

Seed germination when favourable conditions are met under unfavourable conditions the seed goes under suspended phase or rest when favourable conditions return it resumes it’s metabolic activities and growth takes place

Question 5

Nature of Factors affecting plant development

Answer 5

Nature of Factors affecting plant development are both intrinsic(internal) and extrinsic(external) to the plant

Question 6

Name the future shoot , the future root , root in bean and shoot in bean

Answer 6

Plumule
Radicle
Hypocotyl
Epicotyl

Question 7

Define growth

Answer 7

Growth can be defined as an irreversible permanent increase in size of an organ or a part or even an individual cell
Growth is accompanied by metabolic activities (both anabolic and catabolic) which occur at the expense of energy

Question 8

What is the cause of indeterminate growth in plants

Answer 8

Plants carry out indeterminate growth due to the presence of meristem in different parts of their body
The cells of such meristem have the capacity to divide and self perpetuate

Question 9

What is open form of growth

Answer 9

The form of growth where new cells are being always being added to the plant body by the activity of meristem is called the open form of growth

Question 10

Primary growth of plants elaborate

Answer 10

The root apical meristem and the shoot apical meristem are responsible for the primary growth of the plant they also contribute in the elongation of the plant along their axis

Question 11

Elaborate on Secondary growth

Answer 11

In dicotyledonous plants and gymnosperms the lateral meristem the vascular cambium and cork cambium appear later in life this is known as Secondary growth of the plant

Question 12

Growth depends on what factor in cellular level

Answer 12

In cellular level growth is principally the consequence of increase in the amount of protoplasm

Question 13

Parameters to measure growth

Answer 13

Growth is measured by a verity of parameters such as dry weight fresh weight length volume area and cell number

Question 14

Give an example of increase in cellular no
An example of increase in volume

Answer 14

Maize apical meristem can give rise to more than 17500 new cells per hour
Cells in a watermelon may increase in size upto 350000 times

Question 15

Length and area example of growth

Answer 15

A pollen tube is measured in terms of its length
an increase in surface area denotes growth in a dorsiventral leaf

Question 16

What are the phases of growth

Answer 16

There are 3 phases of growth namely meristimatic elongation and maturation

Question 17

How can you detect the zones of elongation

Answer 17

The zones of elongation can be detected by the parallel line method

Question 18

Constituents of meristematic growth

Answer 18

Constantly dividing cells both at the root apex and the shoot apex represent the meristimatic phase of growth

Question 19

What are the features of meristimatic cells

Answer 19

The cells are rich in protoplasm posses large conspicuous nuclei their cell walls are primary thin and cellulosic with abundant plasmodesmata connections

Question 20

Elongation phase cell features

Answer 20

Increased vacuolation cell enlargement and new cell wall deposition are the characteristics of cells in this phase

Question 21

Maturation zone cell features

Answer 21

The cells of this zone attain their maximal size in terms of wall thickening and protoplasmic modifications

Question 22

Define growth rate
What are the types of growth rate increase

Answer 22

The increased growth per unit time is known as growth rate
Two types of growth rate increase arithmetic (constant increase) and geometric increase (exponential increase)

Question 23

Give an example of arithmetic growth

Answer 23

Simplest expression or arithmetic growth is exemplified by a root contacting at a constant rate

Question 24

What is the arithmetic growth formula

Answer 24

Lt = Lo + rt

Where
Lt= length at time t
Lo= length at time 0
r= growth rate/ elongation per unit time

Question 25

What are the Phases of geometric growth

Answer 25

In most systems the initial growth rate is slow (lag phase) It increases rapidly thereafter at exponential rate (log or exponential phase) With limited nutrient supply the growth slows down leading to (stationary phase)

Question 26

What is a sigmoid curve

Answer 26

A sigmoid curve is a characteristic of a living organisms growing in a natural environment It is typical for all cells tissues and organs of a plant

Question 27

What kind of curve can you expect in a tree showing seasonal activities

Answer 27

A sigmoid curve can be observed Lag phase in the spring time Log phase during the summer Stationary phase during winters

Question 28

What is the geometric growth formula

Answer 28

W1 = Wo e^rt Where W1=final size (weight height number etc) Wo= initial size at the beginning of the period r= relative growth rate t= time of growth e= base of natural logarithms

Question 29

What is efficiency index

Answer 29

The ,ensure ofnthe ability of the plant to produce new plant material is referred to as efficiency index

Question 30

Where can an ideal sigmoid curve be found

Answer 30

An idealized sigmoid growth curve typical of cellsnin culture and many higher plants and plant organisms