Plants Nutrition And Reproduction

Question 1

How many inorganic minerals do plants need for nutrition?

Answer 1

Plants require approximately 19 essential inorganic minerals for nutrition.

Question 2

What are some examples of macro nutritions need it for plants?

Answer 2

Carbon, oxygen, hydrogen, nitrogen, phosphorus, potassium, calcium, magnesium, suffer, and silicone.

Question 3

What are some examples of micro nutritions plants need for nutrition

Answer 3

Chlorine boron, iron magnet is sodium, zinc, copper, nickel.

Question 4

Most of the nutrients plants need are provided by?

Answer 4

The soil

Question 5

What is soil

Answer 5

A thin layer of earth’s crust provided from natural actions of weathering water, wind, and organisms

Question 6

What is soil fertility?

Answer 6

Refers to the ability of a soil to supply nutrients to nutrients to plants in adequate amounts and in suitable proportions.

Question 7

What are the abiotic and biotic components of soil

Answer 7

Abiotic components
Inorganic mineral particles. [weathered rocks.]
Organic matter [waste and dead remains ]
Water [water source, dissolved minerals]
Air[ provides needed gases]

Biotic components
Plants, animals, fungi and bacteria.
These organisms interact with the abiotic features and ensure that the minerals are recycled.

Question 8

How do plants reproduce

Answer 8

Plants can reproduce sexually or asexually

Question 9

Features of asexual reproduction

Answer 9

Does not require the fusion of gametes
Offspring is identical to parents
Requires less time and energy
Favorable genotypes preserved if the environment stable

Question 10

Features of sexual reproduction

Answer 10

Requires the fusion of gametes
Offspring is not genetically identical
Longer more complex process
Increase genetic variation
May be difficult to maintain favorable genotypes

Question 11

The structure of a flower

Answer 11

Peduncle/pedicel- stalk of a single flower, contains the xylem and phloem
Receptacle - modified stem that holds the flower
Sepal - protects parts within the floral bud
Petal - important in pollination
Carpel/pistil - female reproductive part
Stamen- male reproductive part

Question 12

What is the reproductive cycle of plant

Answer 12

The reproductive cycle of plants is an alternation of generations( when organisms alternate between haploid and diploid organisms)

Question 13

What is the gametophyte generation of plants

Answer 13

Involves haploid spores that gives rise to gametes when they divide by mitosis
When the gametes fuse the sporophyte generation begins

Question 14

What is the sporophyte generation of plants

Answer 14

When the zygote becomes a diploid sporophyte
Megasporocyte - in ovule
Microsporocyte - in the anther
Sporophyte produces spores by meiosis

Question 15

What are the parts of the female reproductive structure in plants

Answer 15

Stigma - surface where pollen grain lands.
Style - stalk that supports the stigma; pollen tube grows within.
Ovary- contains ovules.
Ovules- contains female gametes.
Flowers can have more than one carpel.

Question 16

What is the structure of the ovule

Answer 16

Integument - the protective covering of nucellus.
Funicle(funiculus) - stalk that carries the nucellus.
Nucellus - mass of cells within the ovule.
Micropyle - the point where pollen tube enters.
Megasporocyte - largest cell within the nucellus.

Question 17

How does the embryo sac develop

Answer 17

When a diploid Megasporocyte in ovule undergoes meiosis, four haploid megaspores are produced but only one survives in each ovule(the other three disintegrates) the Megaspore that survives enlarges and becomes the embryo sac. The haploid nucleus of the surviving megaspore undergoes three mitotic divisions which produces eight haploid nuclei, six haploid cells (antipodal cells, egg cell, synergids) and a cell with two polar nuclei. One of the cells near to the micropyle is the haploid female gamete (egg cell)

Question 18

What makes up the male reproductive structures of a plant

Answer 18

Anther- which produces pollen within pollen sacs
Filament - slender stalk that supports the anther

Question 19

Briefly explain the formation of male gamete of plants

Answer 19

And anther contains 4 pollen sacs that contain diploid microsporoctye and produces pollen. Each diploid mother cell produces 4 pollen grains

Question 20

explain the development of pollen grain

Answer 20

When microsporocyte undergoes meiosis it produces four haploid microspores. each nucleus within each haploid microspore divides by mitosis and forms a binucleate cell that develops into the pollen grain.

Question 21

What is the tube nucleus?

Answer 21

This is what directs the formation and extension of the pollen tube that grows within the style and down the ovule.

Question 22

What is the generative nucleus?

Answer 22

This is used during fertilization when it divides by mitosis and forms two sperm nuclei.

Question 23

Is a pollen grain a gamete

Answer 23

No, the pollen grain is not a gamete, but a carrier of the male gametes .

Question 24

What allows the transfer of pollen

Answer 24

In order for pollen to be transferred, it must be mature when when pollen grain is mature, the anther opens, allowing it to be transferred to the female part of the flower.

Question 25

What is pollination

Answer 25

Pollination is the transfer of pollen grains on the anther to the stigma

Question 26

What are the types of pollination

Answer 26

Self pollination- transfer to stigma on the same flower or the stigma on another flower on the same plant.
Cross pollination- transfer to stigma of flower on a different plant.

Question 27

Strategies that favors cross pollination

Answer 27

Stamen and stigma mature at different rates.
Protandry- the anthers on some plants mature first.
Protogyny - the stigma mature first
Self incompatibility- stigma and self pollen are not compatible.

Question 28

Briefly explain the process of fertilization in angiosperms

Answer 28

After pollination the pollen grain germinate forming a pollen tube which grows through this stigma into the style and the two nuclei of the pollen grain enters the pollen tube. The growth of the pollen tube is controlled by the tube nucleus and the generative nucleus divides by mitosis forming two haploid sperm nuclei. The pollen tube enters into the ovule by way of the micropyle and the two male gamete are released into the embryo sac and the tube nucleus disintegrates.

Question 29

What double fertilization

Answer 29

When gametes fuse a diploid zygote is formed which develops into the embryo.
When the two haploid polar nuclei fuse with a haploid male gamete nucleus it forms into a triploid endosperm nucleus. The endosperm nucleus directs the growth of the endosperm which is a nutritive tissue that surrounds the embryonic plants within a seed.

Question 30

What are the contents in plants before and after fertilizer

Answer 30

Before- ovary and it’s contents
After - fruit
Before - ovule
After - seed
Before - integuments
After- testa (seed coat)
Before- funicle
After - hilum ( seed scar)

Question 31

Briefly explain the formation of embryo and seed

Answer 31

When the micropyle closes the triploid endosperm nucleus leads to the formation of a triploid endosperm and the diploid zygote through the process of mitosis develops into the plant embryo and suspensor cells.The developing embryo takes nutrients from the endosperm and the suspensor cells helps anchor and aids in the uptake of nutrients from the endosperm(short lived) . The development of the endosperm ceases and goes dormant.
The radicle is the embryonic root
The plumule is the embryonic shoot.

Question 32

What are the embryonic stages of dicot plants

Answer 32

Globular stage - globular shaped embryo and cells become specialized.
Heart stage - cotyledons form furthest away from the suspensor cells.
Torpedo stage - hypocotyl, radicle and plumule forms and the cotyledon continues to grow.
Mature embryo stage
Dormancy - once mature seed becomes dormant and dehydrates funcile may break leaving behind the seed scar(hilum) .

Question 33

Mature seeds

Answer 33

Seed devolves from ovule which contains embryonic plants and food stored in either the cotyledons or endosperm.
Endospermous seed - food is stored in endosperm outside the plant embryo.
E.g monocots, maize and wheats

Non - endospermous seed - food is stored in the cotyledon of the plant embryo.
E.g dicots, broad beans
Seeds are enclosed in fruits
Mature ovule separates from ovary, breaks at funicle.
Integuments grow and mature into the testa ( seed coat)

Question 34

Fruit development

Answer 34

As seed develops ovaries increases in size and the tissue changes into fruit. The fruit provides protection as dispersal of seeds. Stigma and style often wither away, but some remnants may remain. Other structures may of may not be incorporated into the fruit. (Sepals, petals etc)

Question 35

Fruit layers

Answer 35

Pericarp - entire fruit wall
Endocarp - innermost later
Mesocarp - middle layer
Exocarp (epicarp) - outer skin or peel
Fruit can be fleshy or dry

Question 36

Types of fruit

Answer 36

True fruit - contents derived from the ovary.
Accessory fruit - contents may have sepals,petals
Simple vs aggregate
Dehiscent vs indehiscent
Seed dispersal - plant, fruit, wind, water and animals

Question 37

What is germination

Answer 37

The process of seed sprouting.
Seeds are dormant until favorable conditions arises.
Influenced by genes, hormones and environmental factors.

Question 38

Requirements for germination

Answer 38

Water (imbibition)
Oxygen (cellular respiration)
Proper temperature
Some seeds require sunlight most do not

Question 39

Explain the process of imbibition in germination

Answer 39

It’s the movement of water into seed which causes it to swell and rupture. When it ruptures the seed is exposed to oxygen which allows aerobic respiration to take place. The radicle(embryonic root) is activated first. Germination ends when root breaks through seed coat.

Question 40

What is Tropism

Answer 40

Directional growth response in plants
There are three types
Phototropism - in response to direction of light
Gravitropism - in response to the influence of gravity
Thigmotropism - in response to contact with a solid object

Question 41

What are plant hormones

Answer 41

They are organic compounds that give chemicals signals that coordinate and regulate plant growth and development

Question 42

What are some common plant hormones

Answer 42

Auxins
Gibberellins
Cytokinins
Ethylene
Abscisic acid

Question 43

What does the hormone auxin do

Answer 43

Stimulate cell elongations
Stimulate growth of flower plants
Promotes fruit development
Promotes apical dominance
Produced in apical meristems, young leaves and and seeds

Question 44

What does the hormone gibberellin do

Answer 44

Promotes fruit development
Stimulates stem elongation by stimulating cell division and elongation
Breaks dormancy to stimulate germination
Stimulates flowering
Produced in apical meristem, young leaves and embryo in seeds

Question 45

What does the hormone cytokinins do

Answer 45

Inhibition of apical dominance
Promotes embryo development,germination and flower development.
Stimulates cell division
Produced in roots

Question 46

What does the hormone ethylene do

Answer 46

Stimulates fruit ripening
Regulates response to mechanical stimuli
Inhibits elongation
Stimulates flower and leaf senescence and abscission
Produced in ripening fruit, stem nodes and damaged or senescing tissue

Question 47

What does the hormone abscisic acid do

Answer 47

Induces seed to synthesize storage proteins
Has some effect on induction and maintenance of dormancy
Stimulates the closure of stomata
Produced in leaves, stem and roots