Photoperiodism is a plant response to:

The relative lengths of day and night

Florigen is a term for the flowering signal that can move from:

Fruit pulp to the seed coat only

Vernalization is the promotion of flowering by exposure to:

Prolonged low temperature in responsive plants

Continuous darkness in all species

A short-day plant generally flowers when:

The night length exceeds a critical duration, if other conditions are suitable

The day is always longer than the night

It receives no temperature cues

Floral induction is best distinguished from floral initiation as the:

Physiological commitment to flower preceding visible floral meristem development

Visible opening of petals after pollination

Ripening of fruit after fertilization

Which endogenous factor can influence flowering time?

Plant age and genetic regulatory pathways

Only the number of earthworms nearby

A likely agricultural application of understanding flowering physiology is:

Scheduling flowering and crop production

Eliminating the need for water in every crop

Preventing seed formation in all species

A climacteric fruit is characterized by:

A rise in respiration associated with ripening, often with increased ethylene

Ripening only while attached to the plant

An absolute inability to respond to ethylene

Ethylene biosynthesis proceeds through the intermediate:

1-aminocyclopropane-1-carboxylic acid (ACC)

Fruit softening commonly involves:

Modification and degradation of cell-wall components

Formation of more lignified secondary walls in all pulp cells

Complete cessation of enzyme activity

Conversion of all sugars into DNA

The red, orange, or yellow colour of ripening fruit may result from:

Changes in carotenoid or other pigment abundance

Loss of all pigments in every species

Accumulation of lignin exclusively

Controlled-atmosphere storage can delay ripening by adjusting:

Oxygen, carbon dioxide, temperature, and related storage conditions

The fruit's pollination mechanism after harvest

Which change can contribute to the flavour of ripe fruit?

Changes in sugars, organic acids, and volatile compounds

Loss of every organic acid in every species

Formation of meristems in the pulp

Homogamy promotes self-pollination because:

Anthers and stigma mature at about the same time

Male and female flowers are always on separate plants

The stigma is permanently closed

Cleistogamous flowers promote self-pollination because they:

Remain closed and can self-pollinate without opening

Open only at night and require bats

Protandry occurs when:

Anthers mature before the stigma is receptive

The stigma matures before anthers

Protogyny occurs when:

The stigma becomes receptive before anthers release pollen

Anthers mature before the stigma

A plant reproduces only by runners

Herkogamy reduces self-pollination through:

Spatial separation of anthers and stigma

Simultaneous maturity of anthers and stigma

Heterostyly involves:

Different floral morphs with different relative positions of anthers and stigmas

All flowers having identical organ heights

Self-incompatibility is a mechanism that:

Rejects or limits fertilization by genetically self pollen

Ensures all self-pollen tubes grow rapidly

Prevents cross-pollination in every species

Gametophytic self-incompatibility is determined by the:

Genotype of the haploid pollen grain

Genotype of the maternal sporophyte alone in all cases

In sporophytic self-incompatibility, pollen compatibility is determined by:

The diploid genotype of the pollen-producing parent

The pollen grain's haploid genotype alone

The temperature during fruit storage only

The genotype of the embryo after fertilization

Unisexual flowers can promote cross-pollination especially when:

Male and female flowers are spatially or temporally separated

Every flower has both functional anthers and stigma

Which environmental factor can reduce pollination success by limiting pollinator activity?

Heavy rain or unsuitable temperature

Suitable weather during flowering

Pesticide use may reduce pollination by:

Harming pollinators or altering their behaviour

Increasing pollinator diversity in all cases

Making every plant self-compatible

Habitat destruction threatens pollination mainly by:

Reducing nesting sites and floral resources for pollinators

Increasing all pollinator populations

Making plants independent of reproduction

Changing all flowers into cleistogamous flowers

A practical way to support pollination is to:

Conserve habitat and reduce harmful pesticide exposure

Apply broad-spectrum insecticide during peak pollinator activity

A plant's response to drought can involve ABA signalling that causes:

Guard-cell ion and water loss leading to stomatal closure

Guard cells to divide into pollen

Fruit pulp to become a root cap

All stomata to remain fully open

Why can intercalary meristems help grasses recover after grazing?

They permit regrowth from basal or lower regions after distal tissue is removed

They produce secondary wood only

They eliminate the need for photosynthesis

Which tissue is produced by vascular cambium during secondary growth?

Secondary xylem and secondary phloem

Which description of meristematic cells is generally correct?

Dense cytoplasm, relatively prominent nuclei, and limited vacuolation

Large central vacuoles and extensive secondary wall thickening in all cells

No nuclei and no capacity for metabolism

Why does the root cap contain cells that can be shed and replaced?

Its outer cells experience abrasion as the root moves through soil

It prevents the root from sensing gravity

A vegetative apex becomes reproductive when it:

Switches development toward floral meristems and reproductive organs

Stops all cell division permanently

In tissue culture, why is the auxin-to-cytokinin ratio important?

It influences whether roots, shoots, or callus are favoured

It determines the organism's kingdom

It eliminates the need for sterile technique

It always produces flowers immediately

Which statement about non-climacteric fruits is most accurate?

They do not show the typical climacteric respiratory rise, and ethylene responses vary by species

They never undergo any ripening changes

They all ripen only after frost

They have no sugars or organic acids

What is the main biological advantage of dichogamy?

It reduces the chance of self-pollination by separating male and female function in time

It guarantees that pollen is never transferred

It eliminates pollinator dependence in every species

What is the central function of plant hormone signalling pathways?

Convert hormone detection into specific cellular and developmental responses

Store genetic information outside cells

Replace photosynthesis with respiration

Make all plant cells respond identically

Which environmental combination most directly influences many flowering responses?

Fruit aroma and seed colour only

Soil texture without any other factor

Wind speed alone in every species

Which statement best describes the role of ethylene in abscission?

It can promote activation of separation-zone processes, interacting with auxin sensitivity

It always prevents cell-wall enzyme activity

It is the only factor involved in every species

It forms the root apical meristem

Why should synthetic growth regulators be applied at recommended doses?

Responses depend on dose and developmental stage, and off-target effects are possible

Plant hormones are harmless at any concentration

All crops have identical sensitivity

Dose does not affect biological response

Which process most directly links pollination with successful seed formation?

Pollen germination, pollen-tube growth, and fertilization

Fruit softening before flowering

Which option correctly pairs hormone and major response?

ABA — stomatal closure during water stress

Cytokinin — gas-mediated fruit ripening

Ethylene — primary perception of red light

Auxin — seed dormancy in every species

Which mechanism allows a plant to detect seasonal night length?

Photoreceptor and circadian signalling pathways in leaves

Pollen self-incompatibility alone

What is a likely consequence of high ethylene exposure in a sensitive seedling?

Shortened, thicker stem and exaggerated curvature

Permanent absence of root growth in every species

Immediate conversion into a flower

Plant Growth, Development and Reproduction — Quiz 2 of 4

Part 2 of 4 in the 200-question Plant Growth, Development and Reproduction series. This quiz contains questions 51–100 from the original quiz, with original question order, answer keys and explanations preserved where supported. Suggested time: 45 minutes.

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