Plant Growth And Development Flashcards
Growth is measured by a variety of parameters some of which are: ^ parameters
Increase in
fresh weight
dry weight
length
area
volume
cell number
One single maize root apical mersitem can give rise to more than……..new cells per hour
17,500
Cells in a watermelon may increase in size by upto……… times
3,50,000
Meristematic cells
Rich in protoplasm
Possess large conspicuous nuclei
Cell walls are primary in nature, thin and cellulosic with abundant plasmodesmatal connections
Increased vacuolation, cell enlargement and new cell wall deposition are the characteristics of the cells in this phase
Phase of cell elongation
The cells of this zone, attain their maximal size in terms of wall thickening and protoplasmic modifications
Maturation zone
In…………. type of growth, following mitotic cell division, only one daughter cell continues to divide while the other differentiates and matures.
arithmetic growth
Statement 1: In most systems the initial growth is slow (lag phase), and it increases rapidly thereafter – at an exponential rate (log or exponential phase). Here, both the progeny cells following mitotic cell division retain the ability to divide and continue to do so.
Statement 2: However, with limited nutrient supply, the growth slows down leading to a stationary phase.
Both are true for geometric type of growth
The r in exponential growth formula is the relative growth rate and is also the measure of the ability of the plant to produce new plant material, referred to as……………
efficiency index.
The plant cells grow in size by cell enlargement which in turn requires……..
water
Turgidity of cells helps in…….. growth
extension growth
Assertion: The plant growth and further development is intimately linked to the water status of the plant
Reason: The plant cells grow in size by cell enlargement which in turn requires water and turgidity of cells helps in extension growth
Both are correct and correct explanation
Nutrients (macro and micro essential elements) are required by plants for (2) things as per NCERT
The synthesis of protoplasm
Act as source of energy
Environmental signals such as……… & …………. also affect certain phases/stages of growth.
light and gravity
…………… is a term that includes all changes that an organism goes through during its life cycle from germination of the seed to senescence
Development
Plants follow different pathways in response to environment or phases of life to form different kinds of structures. This ability is called……….
Plasticity
Heterophylly due to development stages is seen in
Cotton
Coriander
Larkspur
Environmental heterophylly is seen in
Buttercup
Plant growth regulators could be
% categories as per NCERT
Indole compounds (indole-3-acetic acid, IAA)
Adenine derivatives (N6-furfurylamino purine, kinetin),
Carotenoid derivatives (abscisic acid, ABA)
Terpenes (gibberellic acid, GA3)
Gases (ethylene, C2H4)
A group of PGRs are involved in growth promoting activities, such as
7 ways in NCERT lines
Cell division
Cell enlargement
Pattern formation
Tropic growth
Flowering
Fruiting
Seed formation
The gaseous PGR………. could fit either of the groups, but it is largely an inhibitor of growth activities.
ethylene
Charles Darwin and his son Francis Darwin when they observed that the coleoptiles of canary grass responded to unilateral illumination by growing towards the light source. This phenomenon can be called……
phototropism
Auxin was isolated by……..from tips of coleoptiles of oat seedlings.
F.W. Went
The ‘bakanae’ (foolish seedling) disease of rice seedlings, was caused by a fungal pathogen………..
Gibberella fujikuroi
F. Skoog and his co-workers observed that from the internodal segments of tobacco stems the callus (a mass of undifferentiated cells) proliferated only if, in addition to auxins the nutrients medium was supplemented with one of the following: extracts of(4) things
Vascular tissues
Yeast extract
Coconut milk
DNA
………… later identified and crystallised the cytokinesis promoting active substance that they termed kinetin
Miller et al. (1955)
During mid-1960s, three independent researches reported the purification and chemical characterisation of three different kinds of inhibitors:
Inhibitor-B
Abscission II
Dormin
H.H. Cousins (1910) confirmed the release of a volatile substance from ripened oranges that hastened the ripening of stored unripened bananas.
Later this volatile substance was identified as………. a gaseous PGR.
ethylene
