What are plant growth stages?
Plant growth stages are sequential developmental phases plants undergo from seed germination to maturity and reproduction.
Why are plant growth stages important in agriculture?
Understanding growth stages helps farmers manage irrigation, fertilizers, pests, and harvest timing effectively.
How many basic growth stages do plants have?
Most plants have five main stages: germination, seedling, vegetative, flowering, and maturity.
What is the germination stage in plants?
Germination is the process where a seed sprouts and begins growth under suitable moisture, temperature, and oxygen.
Which conditions are required for seed germination?
Seed germination requires water, oxygen, suitable temperature, and sometimes light, depending on plant species.
What happens during seed imbibition?
Imbibition is the absorption of water by dry seeds, causing swelling and activation of metabolic processes.
What is the role of enzymes in germination?
Enzymes break stored food into simpler forms, supplying energy for the emerging seedling.
What is radicle emergence?
Radicle emergence is the first visible sign of germination when the embryonic root grows downward.
What is plumule in plant growth?
Plumule is the embryonic shoot that develops into the stem and leaves.
What is the seedling stage?
The seedling stage begins after germination when young plants develop initial roots and leaves.
Why is the seedling stage critical?
Seedlings are vulnerable to pests, drought, and nutrient stress, affecting future plant survival.
What are cotyledons?
Cotyledons are seed leaves that provide stored food to seedlings before true leaves develop.
What is epigeal germination?
Epigeal germination occurs when cotyledons emerge above soil surface, as seen in beans.
What is hypogeal germination?
Hypogeal germination occurs when cotyledons remain below soil surface, common in maize and peas.
What is the vegetative growth stage?
Vegetative stage involves rapid growth of roots, stems, and leaves without flowering.
Why is vegetative growth important?
This stage builds photosynthetic capacity and structural strength needed for flowering and yield formation.
Which nutrients are essential during vegetative growth?
Nitrogen is most important during vegetative growth for leaf expansion and chlorophyll formation.
What happens to roots during vegetative stage?
Roots expand deeper and wider, improving water and nutrient absorption efficiency.
What is leaf area index?
Leaf area index measures total leaf surface area relative to ground area, indicating photosynthetic potential.
What is photosynthesis role in plant growth stages?
Photosynthesis produces carbohydrates that fuel growth, development, flowering, and fruit formation.
What is the reproductive stage?
Reproductive stage begins when plants shift from vegetative growth to flower and seed production.
What triggers flowering in plants?
Flowering is triggered by photoperiod, temperature, plant age, and hormonal changes.
What is photoperiodism?
Photoperiodism is plant response to day length affecting flowering and developmental timing.
What are short-day plants?
Short-day plants flower when day length is shorter than a critical duration.
What are long-day plants?
Long-day plants flower when day length exceeds a critical duration.
What are day-neutral plants?
Day-neutral plants flower regardless of day length, depending mainly on age or temperature.
What is floral initiation?
Floral initiation is the physiological change where vegetative buds transform into flower buds.
What role do hormones play in flowering?
Hormones like gibberellins and florigen regulate flowering and reproductive development.
What is pollination stage?
Pollination occurs when pollen grains transfer from anther to stigma.
Why is pollination important?
Pollination enables fertilization, leading to seed and fruit development.
What is fertilization in plants?
Fertilization is fusion of male and female gametes forming a zygote.
What is fruit set stage?
Fruit set is the successful development of fertilized flowers into fruits.
What factors affect fruit set?
Temperature, moisture, nutrient availability, and pollination efficiency affect fruit set.
What is grain filling stage?
Grain filling is when seeds accumulate starch, proteins, and oils.
Why is grain filling critical?
Proper grain filling determines final yield size, weight, and quality.
What is physiological maturity?
Physiological maturity is when seeds reach maximum dry weight and growth stops.
What is harvest maturity?
Harvest maturity is the stage when crops are suitable for harvesting.
Difference between physiological and harvest maturity?
Physiological maturity marks growth completion, while harvest maturity indicates economic readiness.
What is senescence stage?
Senescence is the aging process where plant parts gradually deteriorate.
Why does leaf senescence occur?
Nutrients are remobilized from leaves to developing seeds during senescence.
What is dormancy in plants?
Dormancy is a temporary halt in growth under unfavorable environmental conditions.
What causes seed dormancy?
Hard seed coats, chemical inhibitors, or immature embryos cause dormancy.
What is vernalization?
Vernalization is cold treatment promoting flowering in certain plants.
What is tillering stage in cereals?
Tillering is the formation of side shoots from the base of cereal plants.
Why is tillering important?
More tillers usually increase grain-bearing stems and yield potential.
What is stem elongation stage?
Stem elongation involves rapid internode growth raising leaves and reproductive structures.
What is booting stage?
Booting is when developing inflorescence swells inside leaf sheath in cereals.
What is heading stage?
Heading occurs when flower head emerges from the stem.
What is flowering stage in crops?
Flowering stage marks opening of flowers and reproductive organ activity.
What is anthesis?
Anthesis is the period when flowers are fully open and functional.
What is milk stage in grains?
Milk stage occurs when grain content is milky upon pressing.
What is dough stage?
Dough stage is when grain contents become soft or hard dough-like.
What is hard dough stage?
Hard dough stage indicates near maturity with firm grain texture.
What is maturity stage in crops?
Maturity stage indicates completion of growth and readiness for harvest.
How do growth stages vary among crops?
Growth stages vary due to genetic differences, climate, and crop type.
Why do farmers monitor growth stages?
Monitoring helps optimize irrigation, fertilizer application, pest control, and harvest timing.
What is BBCH scale?
BBCH scale is a standardized system describing plant growth stages numerically.
Why is BBCH scale useful?
It provides uniform terminology for crop management and research.
What is Zadoks scale?
Zadoks scale is a decimal code system for cereal growth stages.
Which crops use Zadoks scale?
Wheat, barley, oats, and other cereals commonly use Zadoks scale.
What is phenology in plants?
Phenology studies timing of plant growth stages in relation to climate.
How does temperature affect growth stages?
Temperature influences metabolic rates, flowering time, and growth speed.
What are growing degree days?
Growing degree days measure heat accumulation required for plant development.
Why are growing degree days important?
They help predict growth stages and harvest dates accurately.
How does water stress affect growth stages?
Water stress delays growth, reduces flowering, and lowers yield.
How does nutrient deficiency affect growth stages?
Deficiencies cause stunted growth, delayed flowering, and poor seed formation.
What role does nitrogen play across stages?
Nitrogen supports vegetative growth and protein synthesis throughout development.
What role does phosphorus play?
Phosphorus supports root growth, flowering, and seed development.
What role does potassium play?
Potassium regulates water balance, enzyme activation, and stress tolerance.
How does light intensity affect growth stages?
Light affects photosynthesis, flowering induction, and plant morphology.
What is source-sink relationship?
Source-sink relationship describes movement of photosynthates from leaves to developing organs.
Why is source-sink balance important?
Proper balance ensures efficient grain filling and yield formation.
What is transplant shock stage?
Transplant shock occurs when seedlings experience stress after transplanting.
How to reduce transplant shock?
Proper watering, shading, and root protection reduce transplant shock.
What is acclimatization stage?
Acclimatization is adjustment of seedlings to new environmental conditions.
What is critical growth stage?
Critical stage is when stress severely reduces yield if unmanaged.
Which stage is critical for cereals?
Flowering and grain filling are most critical stages in cereals.
Which stage is critical for legumes?
Flowering and pod formation stages are critical for legumes.
Which stage is critical for oilseeds?
Flowering and seed development stages are critical for oilseed crops.
What is harvest index?
Harvest index is ratio of economic yield to total biomass.
Why is harvest index important?
It indicates efficiency of biomass conversion into yield.
What is crop duration?
Crop duration is total time from sowing to harvest.
How does climate change affect growth stages?
Climate change alters temperature and rainfall, shifting growth stage timing.
What is stress tolerance stage?
Stress tolerance stage indicates plant ability to withstand adverse conditions.
What is lodging stage?
Lodging occurs when stems bend or fall, reducing yield.
Which stage is prone to lodging?
Stem elongation and grain filling stages are most prone to lodging.
What is regrowth stage?
Regrowth is renewed growth after cutting or grazing in fodder crops.
Why is regrowth important in fodder crops?
It ensures multiple harvests and sustained forage availability.
What is bolting stage?
Bolting is rapid stem elongation before flowering, common in vegetables.
Why is bolting undesirable in vegetables?
Bolting reduces edible quality and market value.
What is ripening stage?
Ripening involves color change, softening, and sugar accumulation in fruits.
What hormones regulate ripening?
Ethylene is primary hormone regulating fruit ripening.
What is climacteric fruit?
Climacteric fruits ripen rapidly with increased respiration, like bananas.
What is non-climacteric fruit?
Non-climacteric fruits ripen without respiration surge, like grapes.
What is post-harvest stage?
Post-harvest stage involves handling, storage, and processing after harvest.
Why is post-harvest management important?
It reduces losses and maintains quality.
What is crop maturity index?
Maturity index indicates readiness for harvest based on physical indicators.
How does variety affect growth stages?
Different varieties mature at different rates and growth patterns.
What is early maturing variety?
Early maturing varieties complete growth quickly, suitable for short seasons.
What is late maturing variety?
Late maturing varieties require longer growth duration but often yield higher.
What is stress escape mechanism?
Stress escape allows plants to complete lifecycle before stress onset.
What is stress avoidance mechanism?
Stress avoidance reduces exposure to unfavorable conditions.
What is stress tolerance mechanism?
Stress tolerance enables plants to survive and grow under stress.
What is crop phenophase?
Phenophase refers to specific observable growth stage.
Why study phenophases?
They help predict crop responses to environmental changes.
What is canopy development stage?
Canopy development involves leaf expansion covering soil surface.
Why is canopy cover important?
It reduces evaporation, weeds, and increases photosynthesis.
What is root-shoot ratio?
Root-shoot ratio measures balance between root and shoot growth.
Why is root-shoot ratio important?
It indicates plant adaptation to water and nutrient availability.
What is maturity duration classification?
Crops are classified as short, medium, or long duration based on maturity.
What is crop growth curve?
Crop growth curve shows biomass accumulation over time.
What is lag phase in growth curve?
Lag phase shows slow initial growth after germination.
What is exponential growth phase?
Exponential phase shows rapid growth during vegetative stage.
What is stationary phase in plants?
Stationary phase indicates slowed growth near maturity.
What is decline phase?
Decline phase corresponds to senescence and death.
Why is understanding growth stages essential for exams?
It helps answer agriculture, biology, and competitive examination questions accurately.
What is seed viability?
Seed viability refers to the ability of a seed to germinate and develop into a healthy plant.
How does seed age affect germination?
Older seeds generally show reduced germination percentage due to loss of stored food and enzyme activity.
What is seed vigor?
Seed vigor indicates seed’s ability to germinate rapidly and produce strong seedlings under varied conditions.
Why is seed vigor important?
High seed vigor ensures uniform crop establishment and better yield potential.
What is pre-germination treatment?
Pre-germination treatments enhance germination by breaking dormancy or improving water absorption.
What is seed scarification?
Scarification weakens hard seed coats mechanically or chemically to promote germination.
What is seed stratification?
Stratification exposes seeds to cold or moist conditions to break physiological dormancy.
What is emergence stage?
Emergence stage occurs when seedling shoots appear above soil surface.
What factors affect seedling emergence?
Soil moisture, temperature, depth of sowing, and seed quality affect emergence.
What is early vegetative stage?
Early vegetative stage involves rapid leaf initiation and establishment of photosynthetic system.
What is late vegetative stage?
Late vegetative stage includes maximum leaf area development before reproductive transition.
What is leaf initiation rate?
Leaf initiation rate refers to speed of new leaf formation during vegetative growth.
Why is leaf initiation important?
More leaves increase photosynthesis, supporting higher biomass accumulation.
What is canopy closure?
Canopy closure occurs when plant leaves fully cover soil surface.
Why is canopy closure beneficial?
It reduces weed growth, soil evaporation, and improves light interception.
What is nutrient uptake peak stage?
Nutrient uptake peaks during vigorous vegetative and early reproductive stages.
What is nitrogen remobilization?
Nitrogen remobilization transfers nitrogen from older leaves to developing seeds.
What is reproductive transition stage?
Reproductive transition marks shift from vegetative growth to flowering initiation.
What is floral differentiation?
Floral differentiation involves development of distinct flower organs from meristematic tissues.
What is inflorescence development?
Inflorescence development is formation and growth of flower clusters.
What is spikelet initiation?
Spikelet initiation is formation of basic floral units in cereals.
Why is spikelet initiation important?
It determines potential number of grains per plant.
What is pollen viability?
Pollen viability refers to pollen’s ability to fertilize ovules successfully.
How does temperature affect pollen viability?
High temperatures reduce pollen viability, lowering fertilization and yield.
What is stigma receptivity?
Stigma receptivity is the period when stigma can receive and support pollen germination.
What is fertilization success rate?
It is percentage of flowers successfully forming seeds after pollination.
What is embryo development stage?
Embryo development involves growth of fertilized egg into mature embryo.
What is endosperm development?
Endosperm development provides stored nutrients for embryo and seedling growth.
What is pod development stage?
Pod development occurs after fertilization in legumes, enclosing developing seeds.
What is capsule formation?
Capsule formation is development of dry fruit containing seeds.
What is boll development stage?
Boll development is formation and growth of cotton fruit.
Why is boll retention important?
Higher boll retention leads to increased cotton yield.
What is sink strength?
Sink strength refers to ability of developing organs to attract photosynthates.
What increases sink strength?
High metabolic activity and hormone levels increase sink strength.
What is assimilate partitioning?
Assimilate partitioning distributes photosynthates among plant organs.
Why is assimilate partitioning important?
Proper partitioning ensures balanced growth and higher economic yield.
What is stress-sensitive growth stage?
Stress-sensitive stage is when plants are most affected by environmental stress.
Which stage is most drought-sensitive?
Flowering and early grain filling stages are most drought-sensitive.
What is frost-sensitive stage?
Flowering and seedling stages are most sensitive to frost damage.
What is heat stress stage?
Heat stress affects pollination and grain filling stages most severely.
What is recovery stage?
Recovery stage is period when plants resume growth after stress removal.
What is compensatory growth?
Compensatory growth is accelerated growth following stress recovery.
What is tiller mortality stage?
Tiller mortality occurs when excess tillers die due to competition.
Why does tiller mortality occur?
Limited nutrients and light cause weaker tillers to die.
What is reproductive efficiency?
Reproductive efficiency is proportion of flowers converting into seeds.
What is harvest loss stage?
Harvest loss stage involves losses during harvesting operations.
What is physiological drying?
Physiological drying occurs naturally after maturity when grain moisture decreases.
What is shattering stage?
Shattering occurs when mature seeds fall off before harvest.
Which crops are prone to shattering?
Rice, mustard, and pulses are commonly prone to shattering.
What is lodging resistance stage?
Lodging resistance develops during stem strengthening stages.
What is stem lignification?
Lignification strengthens stems by depositing lignin in cell walls.
What is growth retardation stage?
Growth retardation is slowed growth due to stress or nutrient deficiency.
What is vegetative regrowth?
Vegetative regrowth is new shoot growth after cutting or grazing.
What is ratoon crop growth stage?
Ratoon stage is regrowth from stubble after harvest.
Which crops show ratooning?
Sugarcane, rice, and some fodder crops show ratooning ability.
What is perennial growth cycle?
Perennial growth cycle repeats growth and dormancy over multiple years.
What is annual growth cycle?
Annual plants complete entire lifecycle within one growing season.
What is biennial growth cycle?
Biennial plants complete lifecycle over two seasons.
What is bud break stage?
Bud break is resumption of growth from dormant buds.
What is shoot elongation stage?
Shoot elongation involves rapid extension of stem internodes.
What is flowering synchrony?
Flowering synchrony refers to uniform flowering across plants.
Why is flowering synchrony important?
It improves pollination efficiency and uniform maturity.
What is uniform maturity stage?
Uniform maturity occurs when most plants reach harvest stage together.
What is maturity mismatch?
Maturity mismatch occurs when plants mature unevenly within field.
Why is maturity mismatch undesirable?
It complicates harvesting and reduces overall yield quality.
What is physiological stress marker stage?
Physiological markers indicate stress impact on plant growth stages.
What is chlorophyll degradation stage?
Chlorophyll degradation occurs during senescence causing yellowing of leaves.
What is remobilization efficiency?
Remobilization efficiency measures nutrient transfer from vegetative parts to grains.
What is post-flowering stress?
Post-flowering stress affects grain filling and final yield.
What is grain abortion stage?
Grain abortion occurs when developing grains fail to mature.
What causes grain abortion?
Water stress, heat stress, and nutrient deficiency cause grain abortion.
What is crop maturity uniformity index?
It measures evenness of crop maturity across field.
What is physiological harvest window?
Harvest window is optimal time range for harvesting crop.
Why is harvest window important?
Harvesting within window maximizes yield and quality.
What is over-maturity stage?
Over-maturity occurs when crops remain unharvested after optimum maturity.
What problems occur during over-maturity?
Shattering, lodging, and quality loss increase during over-maturity.
What is crop senescence pattern?
Senescence pattern describes sequence of aging in plant organs.
What is terminal drought stage?
Terminal drought occurs near maturity severely affecting yield.
What is physiological resilience stage?
Physiological resilience reflects plant’s capacity to withstand stress during growth stages.
Why is understanding growth stages essential for crop management?
It enables precise input application, stress management, and yield optimization.