CRSCI 3305 MIDTERMS

Growth

irreversible increase in size, mass or volume of plant cells, organs or the whole plant

Development

progression of the plant through different life stages, involving

structural and functional changes (change in form and function)

Growth

quantitative, measurable (height, weight, volume)

Development

qualitative; involves changes in form, structure and function

Growth

results from cell division, cell enlargement, cell differentiation

Development

involves processes like germination, flowering, fruiting and

senescence

Growth

plant height, biomass, leaf area (increase in root length, stem height, leaf size)

Development

changes in morphology, structure, and function, (transformation from vegetative to flowering stage, seed germination or fruit maturation)

Growth

contributes to development, but development encompasses broader changes like differentiation and organ formation

Development

changes in form and function

Germination

It is a developmental process which includes the emergence of embryo, radicle and plumule

Seedling stage

It is a developmental process where the cotyledon appears, develops leaves, stems and roots

Branching

It is a developmental process where formation of lateral buds occur

Leaf formation and maturation

It is a developmental process where leaf shape changes in specialized leaves (tendrils, spines)

Flowering

Also known as reproductive stage. It is a developmental process where floral buds and flowers are formed

Fruiting

It is a developmental process where pollination, fertilization, fruit production takes place

Senescence (Aging)

A developmental process where Yellowing of leaves, slow down metabolism, shedding of leaves occurs

Dormancy

Period of slow or halted growth due to unfavorable environmental conditions

Plant hormone

naturally occurring organic compounds produced within plants that regulates growth and development; produced naturally by plants in small quantities

Plant growth regulator (PGR)

synthetic or natural chemicals that regulates plant growth

and development; can be synthetic (man-made) or natural

Plant growth substances

broader/umbrella term; includes both plant hormone and PGR; can be natural or synthetic

Plant hormone

auxin, cytokinin, abscisic acid, ethylene

Plant growth regulator (PGR)

2-4-D (synthetic auxin), ethephon, paclobutrazol (growth retardant)

Plant Growth Substance

Chemical compound which is biosynthesized within the plant and distributed within the plant kingdom; Shows specific biological activity at extremely low concentrations; Roles in regulating physiological phenomena in vivo (within the living)

PESIGS Rule

( Jacobs, 1959) Assess whether a chemical controls process in an

organism

Presence/Parallel variation

Present; parallel between the amount and the activation of the process; Changes in response in parallel of concentration at different levels for exogenously applied; Can be measured in the exact tissue; Can be found in a wide range of organism

Excision

Removing the source (organ, tissue, organelle) and demonstrate cessation of the process

Substitution

Substitute the pure chemical for the organ or the tissue which had been shown to be the normal source of the chemical in the organism and demonstrate subsequent formation of the structure (PGR application)

Isolation

Isolate and still shows the effect of the chemical is the same in intact plants. E.g. tissue culture of meristem induce formation of shoot and root

Generality

Can induce to different types of plants

Specificity

Only from that compound that response can be seen; Demonstrate that naturally occurring chemical other than the one in question have no such effect on structure; Specific response: others have no effect on

structure

Signal - transduction pathways

Mechanism that allows plants to respond to internal (hormone) and external (environmental stimuli) signals by linking signal reception to a response

Reception

signals detected by receptors, often found on the plasma

membrane of a cell; A chemical or environmental stimuli

(ex. light) stimulates receptor the interaction

Transduction

secondary messenger (usually proteins: cyclic gmp or calcium ions) amplify the signal from reception to enhance a response

Response

second messenger regulates cellular activities by increasing enzyme activity or decreasing mRNA synthesis encoding enzymes

stock solution

a concentrated solution that is diluted to prepare working solutions of desired concentrations. It plays a crucial role in scientific, industrial, and educational applications

Accuracy and consistency

precise and uniform when diluted, reducing errors in measurements

Time efficiency

saves time; eliminates repeated weighing and measuring

Easy dilution

quick dilution using C1V1=C2V2

C1

Concentration of the stock solution

V1

Volume of the stock solution needed

C2

Desired concentration

V2

Final volume required

Stable

concentrated stock are more stable than diluted solutions, minimizing degradation over time

Cost efficiency

reduces chemical wastage

auxein

Greek word that has a meaning of “to grow”

Auxin

first plant hormone discovered in mid 1920s

Darwin and Darwin

first describe the effects of light on movement of canary grass coleoptiles (Phalaris canariensis)

Auxin

Cell elongation, differentiation, flower development; Fruit setting and development

Apical dominance

phenomenon in plants where the main central stem grows more than the side branches due to the influence of the apical bud (terminal bud).

Auxin

Adventitious root formation

Tropism

directional growth response of plants to environmental stimuli. Plants grow either toward (positive tropism) or away from (negative tropism) the stimulus

Phototropism

the directional growth of plant shoot in response to light. Cells on darker side of side of stem elongate faster than those on brighter side, causing shoot to bend toward light.

Indole-3-acetic acid (IAA)

Indole ring (bicyclic structure) is the basic structure of IAA

Auxin transport

Elucidated through the DONOR-RECEIVER AGAR

BLOCK METHOD

Gibberellins

1898 - Konishi first described ‘bakanae’ (foolish seedling)

disease of rice (tall, spindly, with longer leaf sheaths, longer

narrower and thinner leaves, reduced root growth and

tillering, low yield or no yield)

Hori (1910)

He attributed the disease to a fungus belonging

to genus Fusarium (F.heterosporium)

Yabuta (1935)

He isolated non-crystalline solid form G. fujikoroi culture, named

‘gibberellin’. It was first used in scientific literature. They cant produce large amount of fungus in crystalline solid form.

Stodola (1955)

simultaneously purified and isolated in large scale the active compound from G. fujikoroi as GA3

plastid

organelles in cell of plants and algae that contains pigment;

responsible for manufacturing and storing of food

endoplasmic reticulum

produces protein

Cytosol

fluid matrix in the cytoplasm

GA Inhibitor

Ancymidol, Paclobutrazol, AMO 1618, BX-112,

Gibberellin

Promotes cell and stem elongation, effect on whole

plant is more dramatic than that of auxins (application in bush beans will cause them to grow as climbing pole beans or

peas)