5.11 Exercise Problems

Q1. How is a pinnately compound leaf different from a palmately compound leaf?

Answer: 

\(
\begin{array}{|c|c|}
\hline \text { Pinnate Compound Leaves } & \text { Palmate Compound Leaves } \\
\hline {\text { Definition }} & {\text { Definition }} \\
\hline \begin{array}{l}
\text { It is a venation pattern where several } \\
\text { secondary veins arise from a main vein from } \\
\text { the base to the top. }
\end{array} & \begin{array}{l}
\text { It is a venation pattern where several } \\
\text { main veins project from the base of } \\
\text { the leaf. }
\end{array} \\
\hline {\text { Number of Primary Veins }} & {\text { Number of Primary Veins }} \\
\hline \begin{array}{l}
\text { A single primary vein is present from the } \\
\text { base to the top. }
\end{array} & \begin{array}{l}
\text { Several main veins run from the } \\
\text { base of the leaf to the top. }
\end{array} \\
\hline {\text { Resemblance }} & {\text { Resemblance }} \\
\hline \text { Their outline looks like a feather. } & \text { They resemble a human hand. } \\
\hline {\text { Leaflets }} & {\text { Leaflets }} \\
\hline \begin{array}{l}
\text { Leaflets are borne on an elongated axis } \\
\text { called the rachis. }
\end{array} & \begin{array}{l}
\text { Many leaflets arise from a single } \\
\text { point where the petiole and stem } \\
\text { meet. }
\end{array} \\
\hline {\text { Example }} & {\text { Example }} \\
\hline \text { Cycads and ferns } & \text { Poison ivy and buckeye tree } \\
\hline
\end{array}
\)

Q2. Explain with suitable examples the different types of phyllotaxy.

Answer: Phyllotaxy refers to the pattern or arrangement of leaves on the stem or branch of a plant. It is of three types, alternate, opposite, and whorled phyllotaxy. In alternate phyllotaxy, a single leaf arises from the node of a branch. This type of phyllotaxy is observed in the sunflower, mustard, and peepal. Plants with opposite phyllotaxy have two leaves arising from the node in opposite directions. It is found in guava and jamun plants. Plants with whorled phyllotaxy have three or more leaves arising from the node. It is found in Alstonia.

Q3. Define the following terms:
(a) aestivation
(b) placentation
(c) actinomorphic
(d) zygomorphic
(e) superior ovary
(f) perigynous flower
(g) epipetalous stamen

Answer: (a) Aestivation
The term ‘aestivation’ refers to the mode in which sepals or petals are arranged in a floral bud with respect to other floral members. There are four types of aestivation in plants i.e., valvate, twisted, imbricate, and vexillary.
(b) Placentation
The term ‘placentation’ refers to the arrangement of ovules within the ovary of a flower. It is primarily of five types, namely marginal, basal, parietal, axile, and free central.
(c) Actinomorphic
Actinomorphic flowers can be divided into two radial halves by any radial plane passing through its centre. Examples of these flowers include chilly and mustard.
(d) Zygomorphic
Zygomorphic flowers are those flowers which can be divided into two similar halves by a single vertical plane. Examples of these flowers include pea and beans.
(e) Superior ovary
Superior ovary flowers are those flowers in which the gynoecium is present at the highest position, while other floral parts are arranged below it. A flower with this arrangement is described as hypogynous. Examples include brinjal and mustard.
(f) Perigynous flower
In perigynous flowers, the gynoecium is present in the centre and the rest of the floral parts are arranged at the rim of the thalamus at the same level. Examples include plum and rose.
(g) Epipetalous Stamen
Epipetalous stamens are stamens attached to the petals. They are found in brinjal.

Q4. Differentiate between
(a) Racemose and cymose inflorescence
(c) Apocarpous and syncarpous ovary

Answer: 

\(
\begin{array}{|c|c|c|}
\hline \text { S.No. } & \text { Cymose Inflorescence} & \text { Racemose Inflorescence} \\
\hline 1 . & \begin{array}{l}
\text { The main axis terminates in a flower and } \\
\text { has definite growth }
\end{array} & \begin{array}{l}
\text { The main axis continues to grow } \\
\text { indefinitely }
\end{array} \\
\hline 2 . & \begin{array}{l}
\text { Peduncle shows sympodial or multipodial } \\
\text { growth }
\end{array} & \text { Peduncle shows a monopodial growth } \\
\hline 3 . & \begin{array}{l}
\text { The flower is present apically in basipetal } \\
\text { succession }
\end{array} & \begin{array}{l}
\text { The flowers are present laterally in } \\
\text { acropetal succession }
\end{array} \\
\hline 4 . & \text { The arrangement of flowers is centrifugal } & \text { The arrangement of flowers is centripetal } \\
\hline 5 . & \text { The grouping of flowers is more common } & \text { The grouping of flowers is less common } \\
\hline 6 . & \begin{array}{l}
\text { The first formed flower is at the tip of } \\
\text { peduncle }
\end{array} & \begin{array}{l}
\text { The first formed flower is at the base of } \\
\text { the peduncle }
\end{array} \\
\hline 7 . & \text { The number of flowers is definite } & \begin{array}{l}
\text { The formation of flowers is indefinite or } \\
\text { unrestricted }
\end{array} \\
\hline 8 . & \text { Flowers bloom at a long interval } & \text { Flowers bloom at a short interval } \\
\hline 9 . & \text { Newly formed fruits are protected by flowers } & \begin{array}{l}
\text { Newly formed fruits are not protected by } \\
\text { flowers }
\end{array} \\
\hline
\end{array}
\)

 

Apocarpous ovary	Syncarpous ovary
1. The flowers with apocarpus ovary have more than one carpel. These carpels are free.	1. The flowers with syncarpous ovary have more than one carpel. However, these carpels are fused.
2. It is found in lotus and rose flowers.	2. It is found in the flowers of tomato and mustard.

Q5. Draw the labelled diagram of the following:
(i) gram seed (ii) V.S. of maize seed

Answer: 

Q6. Take one flower from each of the families Fabaceae and Solanaceae and write its semi-technical description. Also draw their floral diagram after studying them.

Answer:

(1) Family Fabaceae/Papilionaceae (pea plant)
Fabaceae/Papilionaceae is a sub-family of the Leguminoseae family.
Vegetative features:
Habit: Pinnately compound, alternately arranged with leaf tendrils with the pulvinus present at the leaf base along folacious stipules.
Root: Tap root system with root nodules.
Floral features:
Inflorescence: Racemose, generally axial than terminal
Flower: Zygomorphic and bisexual flowers are found
Calyx: It contains five sepals which are gamosepalous while aestivation is imbricate.
Corolla: It contains five petals (polypetalous) with vexillary aestivation.
Androecium: It consists of ten anthers that are diadelphous with dithecous anthers.
Gynoecium: Monocarpellary superior ovary which is unilocular with marginal placentation.
Fruit: Legume pod with non-endospermic seeds

Economic importance: 
Many plants belonging to the family are sources of pulses (gram, arhar, sem, moong, soyabean; edible oil (soyabean, groundnut); dye (Indigofera); fibres (sunhemp); fodder (Sesbania, Trifolium), ornamentals (lupin, sweet pea); medicine (muliathi).

(2) Flowers of Solanum nigrum
Family Solanaceae
Vegetative features:
Habit: Erect, herbaceous plant
Leaves: Simple, exstipulate leaves with reticulate venation Stem:
Erect stem with numerous branches.
Floral features:
Inflorescence: Solitary and axillary
Flowers: Actinomorphic, bisexual flowers
Calyx: Calyx is composed of five sepals that are united and persistent. Aestivation is valvate.
Corolla: Corolla consists of five united petals with valvate aestivation.
Androecium: It consists of five epipetalous stamens.
Gynoecium: It consists of bicarpellary syncarpous superior ovary with axile placentation.
Fruits: Berry
Seeds: Numerous, endospermous

Economic Importance:

Many plants belonging to this family are source of food (tomato, brinjal,potato), spice (chilli); medicine (belladonna, ashwagandha); fumigatory (tobacco); ornamentals (petunia).

Q7. Describe the various types of placentations found in flowering plants.

Answer: Placentation refers to the arrangement of ovules inside the ovary. It is of five basic types.
(A) Marginal placentation:
The ovary in which the placenta forms a ridge along the ventral suture of the ovary and the ovules develop on two separate rows is known to have marginal placentation. This type of placentation is found in peas.

(B) Parietal placentation
When the ovules develop on the inner walls of the ovary, the ovary is said to have parietal placentation.

(C) Axile placentation
In axile placentation, the placenta is axial and ovules are attached to it. Examples include China rose, lemon, and tomato.

(D) Basal placentation
The ovary in which the placenta develops from its base and a single ovule is found attached to the base is said to have basal placentation. It is found in marigold and sunflower.

(E) Free central placentation
In free central placentation, the ovules develop on the central axis while the septa are absent. This type of placentation is found in Dianthus and primrose.

Q8. What is a flower? Describe the parts of a typical angiosperm flower.

Answer: A flower can be defined as the reproductive unit of any flowering plant (angiosperms). Flowers carry out sexual reproduction in angiosperms. A typical flower is a modified stem with a condensed axis. A flower has four different parts i.e., the calyx, corolla, androecium, and gynoecium. Androecium and gynoecium represent the male and female reproductive organs of a flower (respectively). Bisexual flowers are those which contain both androecium and gynoecium, while unisexual flowers contain either gynoecium or androecium. The corolla and the calyx are generally distinct, but may sometimes be fused (called perianth). A flower that contains all four floral parts is called a complete flower.
Parts of flowers
(A) The calyx forms the outermost whorl of a flower, which contains sepals. They are green, leaf-like structures that cover and protect the flowers during the bud stage. When the sepals of a flower are free, they are called polysepalous, while fused sepals of a flower are called gamosepalous.
(B) The corolla of a flower is a layer that lies inside the calyx. It contains beautifully coloured petals, which help in attracting insects for pollination. When the petals are free, they are called polypetalous, while fused petals are called gamopetalous.
(C) The androecium or the stamen is the male reproductive part of a flower. It consists of two parts, the filament and the bilobed anther. The bilobed anther is the site for meiosis and the generation of pollen grains.
(D) Gynoecium represents the female reproductive part of a flower. It consists of an ovary. The ovary is connected by a long tube (called style) to the stigma. The ovary bears numerous ovules attached to the placenta.

Q9. Define the term inflorescence. Explain the basis for the different types inflorescence in flowering plants.

Answer: Inflorescence is the manner in which the flowers are arranged on the flowering axis. During the flowering season, the vegetative apex of the stem gets converted into a floral meristem. Based on whether the floral axis continues to grow or end in a flower, inflorescence is classified into racemose and cymose. In racemose inflorescence, the floral axis continues to grow and produces flowers laterally. On the other hand, in cymose inflorescence, the main axis terminates into a flower. Hence, it is limited in growth.

Q10. Describe the arrangement of floral members in relation to their insertion on thalamus.

Answer: Based on the position of the calyx, corolla, and androecium (with respect to the ovary on the thalamus), the flowers are described as hypognous, perigynous, and epigynous.
In hypogynous flowers, the ovary occupies the highest position on the thalamus while other floral parts are situated below it. In such flowers, the ovary is superior
e.g., China rose, mustard, etc.
In perigynous flowers, the ovary is situated at the centre and other floral parts are arranged on the rim of the thalamus. The ovary here is said to be half inferior e.g., plum,
rose, peach
In epigynous flowers, the thalamus grows around the ovary fusing with its wall. The other floral parts are present above the ovary. Hence, the ovary is said to be inferior
e.g., flowers of guava and cucumber.

Exemplar Section

VERY SHORT ANSWER TYPE QUESTIONS

Q1. Roots obtain oxygen from air in the soil for respiration. In the absence or deficiency of \(O _2\), root growth is restricted or completely stopped. How do the plants growing in marshlands or swamps obtain their \(O _2\) required for root respiration?

Answer: In some plants such as Rhizophora and Sonneratia (mangrove plant) growing in swampy areas near river mouths (saline marshy soil or halophytes), many roots come out of the ground and grow vertically upwards (negatively geotropic: against gravitational force). Such roots, called pneumatophores or breathing roots or respiratory roots, help to get oxygen for respiration.

Q2. Write floral formula for a flower which, is bisexual; actinomorphic; pentamerous sepal, petal, stamens free with ovary, syncarpous, superior, trilocular with axile placentation.

Answer:

Q3. In Opuntia the stem is modified into a flattened green structure to perform the function of leaves (i.e., photosynthesis). Cite two other examples of modifications of plant parts for the purpose of photosynthesis.

Answer: Some plants of arid regions modify their stems into flattened (Opuntia), or fleshy cylindrical (Euphorbia) structures. These modified stems of indefinite growth are called phylloclades. They contain chlorophyll and carry out photosynthesis.

Q4. In swampy areas like the Sunderbans in West Bengal, plants bear special kind of roots called _____________.

Answer: Pneumatophores

Q5. In aquatic plants like Pistia and Eichhornia, leaves and roots are found near _____________.

Answer: Node

Q6. Reticulate and parallel venation are characteristic of _____________ and _____________ respectively.

Answer: Dicotyledons and monocotyledons

Q7. In epigynous flower, ovary is situated below the _____________.

Answer: Calyx, corolla and androecium.

Q8. Add the missing floral organs of the given floral formula of Fabaceae.

Answer:

Q9. Name the body part modified for food storage in the following
a. Carrot __________________________
b. Colocasia __________________________
c. Sweet potato __________________________
d. Asparagus __________________________
e. Radish __________________________
f. Potato __________________________
g. Dahlia __________________________
h. Turmeric __________________________
i. Gladiolus __________________________
j. Ginger __________________________
k. Portulaca __________________________

Answer:

(a) Carrot — Tap root
(b) Colocasia — Stem
(c) Sweet potato — Root
(d) Asparagus — Root
(e) Radish — Root
(f) Potato — Stem
(g) Dahlia — Adventitious root
(h) Turmeric — Stem
(i) Gladiolus — Stem
(j) Ginger — Stem
(k) Portulaca — Adventitious root

SHORT ANSWER TYPE QUESTIONS

Q1. Give two examples of roots that develop from different parts of the angiospermic plant other than the radicle.

Answer: The root that arise from parts of plant other than radicle are called adventitious roots. Pneumatophores – for respiration Stilt roots – for support Prop roots – for support

Q2. The essential functions of roots are anchorage and absorption of water and minerals in the terrestrial plant. What functions are associated with the roots of aquatic plants. How are roots of aquatic plants and terrestrial plants different?

Answer: The roots of aquatic plants help in balancing and anchorage. In terrestrial plants, functions of roots are anchorage and absorption of water and minerals.

Q3. Draw diagrams of a typical monocot and dicot leaves to show their venation pattern.

Answer: 

Q4. A typical angiosperm flower consists of four floral parts. Give the names of the floral parts and their arrangements sequentially.

Answer: A typical flower has four different kinds of whorls arranged successively on the swollen end of the stalk or pedicel, called thalamus or receptacle. These are calyx, corolla, androecium and gynoecium. The calyx is the outermost whorl of the flower and the members are called sepals. Corolla is the second outermost whorl composed of petals. Androecium is the second innermost whorl composed of stamens. Gynoecium is the innermost whorl which is female reproductive part of the flower and is made up of one or more carpels.

Q5. Given below are floral formulae of some plants. Draw floral diagrams from these formulae.

Answer: 

Q6. Reticulate venation is found in dicot leaves while in monocot leaves venation is of parallel type. Mention one exception to this generalization.

Answer: Smilax and Dioscorea are monocots having reticulate venation. Calophyllum and Eryngium are dicots having parallel venation.

Q7. You have heard about several insectivorous plants that feed on insects. Nepenthes or the pitcher plant is one such example, which usually grows in shallow water or in marsh lands. What part of the plant is modified into a ‘pitcher’? How does this modification help the plant for food even though it can photosynthesize like any other green plant?

Answer:  In Nepenthes, picher is modified lamina. Insectivorous plants capable of growing in nitrogen or nitrate deficient soil. Pitcher help in providing the nitrogen to the plant. Leaves also photosynthesize their food.

Q8. Mango and coconut are ‘drupe’ type of fruits. In mango fleshy mesocarp is edible. What is the edible part of coconut? What does milk of tender coconut represent?

Answer: Edible part of coconut is endosperm or seed. Milk of tender coconut represent free nuclear liquid endosperm.

Q9. How can you differentiate between free central and axile placentation?

Answer: When the ovules are borne on central axis and septa are absent, as in Dianthus and Primrose the placentation is called free central. When the placenta is axial and the ovules are attached to it in a multilocular ovary, the placentation is said to be axile, as in China rose, tomato and lemon.

Q10. Tendrils are found in the following plants. Identify whether they are stem
tendrils or leaf tendrils.
a. Cucumber
b. Peas
c. Pumpkins
d. Grapevine
e. Watermelons

Answer: a. Cucumber—stem tendrils
b. Peas Leaf Tendrils
c. Pumpkins—stem tendrils
d. Grapevine – stem tendrils
e. Watermelons—stem tendrils

Q11. Why is maize grain usually called as a fruit and not a seed?

Answer: Maize is an example of caryopsis fruit which is a simple, one seeded dry, indehiscent fruit in which pericarp and testa are fused. Pericarp is also called fruit wall which is present in maize grain, hence maize grain is actually a fruit and not a seed.

Q12. Tendrils of grapevines are homologous to the tendril of pumpkins but are analogous to that of pea. Justify the above statement.

Answer: Tendrils of grapevines are homologous to the tendril of pumpkins because both are the modification of stem (i.e., stem tendrils). Homologous structure have same origin.
Analogous structure have different origin but similar function. Tendrils of grapevines are analogous to that of pea because tendrils of grapevines are modification of stem while tendrils of pea are modification of leaves. Both have different origin but performing same function, i.e., support.

Q13. Rhizome of ginger is like the roots of other plants that grows underground. Despite this fact ginger is a stem and not a root. Justify.

Answer: Rhizome is a underground stem growing parallel to soil surface. Ginger is a stem which can be differentiated from root as it has nodes and intemodes.

Q14. Differentiate between
a. Bract and Bracteole
b. Pulvinus and petiole
c. Pedicel and peduncle
d. Spike and spadix
e. Stamen and staminoid
f. Pollen and pollenium

Answer: a. Reduced leaf found at the base of the pedicel is called bract while leaf like structure present between bract and flower is called bracteole.
b. In some leguminous plants the leafbase may become swollen is called pulvinus. The petiole (mesopodium) connect the leafbase with lamina and help hold the blade to light.
c. Pedicie is the stalk of flower while peduncle is the stalk of inflorescence.
d. In spike sessile flowers are attached on elongated peduncle. E.g.: Achyranthes. Spadix is a special type of spike having a fleshy peduncle and a large brightly coloured bract called spathe. E.g.: Palm, Colocasia.
e. Androecium is composed of stamens. Each stamen represents the male reproductive organ. A sterile stamen is called staminode.
f. Male gametophyte of angiosperms is called pollen or microspore. A group of pollens forms the pollinium (present in Calotropis).

LONG ANSWER TYPE QUESTIONS

Q1. Distinguish between families Fabaceae, Solanaceae, Liliaceae on the basis of gynoecium characteristics (with figures). Also write economic importance of any one of the above family.

Answer: 

Economic importance of fabacae:
i. Source of pulses (gram, arhar)
ii. Edible oil (soyabean, groundnut)
iii. Dye (Indigofera)
iv. Fibres (sunhemp)
v. Fodder (Sesbania, Trifolium)
vi. Ornamental {Lupin)
vii. Medicine (mulaithi)

Q2. Describe various stem modifications associated with food storage, climbing and protection.

Answer: The stem may not always be typically like what they are expected to be. They are modified to perform different functions. Underground stems of potato, ginger, turmeric, zaminkand, Colocasia are modified to store food in them. They also act as organs of perennation to tide over conditions unfavourable for growth. Stem tendrils which develop from axillary buds, are slender and spirally coiled and help plants to climb such as in gourds (cucumber, pumpkins, watermelon) and grapevines. Axillary buds of stems may also get modified into woody, straight and pointed thorns. Thoms are found in many plants such as Citrus, Bougainvillea. They protect plants from browsing animals. Some plants of arid regions modify their stems into flattened {Opuntia), or fleshy cylindrical {Euphorbia) structures. They contain chlorophyll and carry out photosynthesis.

Q3. Stolon, offset and rhizome are different forms of stem modifications. How can these modified forms of stem be distinguished from each other?

Answer: Underground stems called stolon of some plants spread to new niches and when older parts die new plants are formed.
Offest: A lateral branch with short intemodes and each node bearing a rosette of leaves and a tuft of roots is found in aquatic plants like Pistia and Eichhornia.
Rhizome is underground stem growing parallel to soil surface. In ginger, turmeric, Gloriosa and lotus stem is called rhizome which is differentiated from roots in having scale leaves and axillary buds and helps in vegetative propagation.

Q4. The mode of arrangements of sepals or petals in a floral bud is known as aestivation. Draw the various types of aestivation possible for a typical pentamerous flower.

Answer: The mode of arrangement of sepals or petals in floral bud with respect to the other members of the same whorl is known as aestivation. The main types of aestivation are valvate, twisted, imbricate and vexillary. When sepals or petals in a whorl just touch one another at the margin, without overlapping, as in Calotropis, it is said to be valvate. If one margin of the appendage overlaps that of the next one and so on as in china rose, lady’s finger and cotton, it is called twisted. If the margins of sepals or petals overlap one another but not in any particular direction as in Cassia and gulmohur, the aestivation is called imbricate. 
In pea, bean and Crotolaria flowers, there are five petals, the largest (standard) overlaps the two lateral petals (wings) which in turn overlap the two smallest anterior petals (keel); this type of aestivation is known as vexillary or papilionaceous (or descending imbricate).

Q5. The arrangements of ovules within the ovary is known as placentation. What does the term placenta refer to? Name and draw various types of placentations in the flower as seen in T.S. or V.S.

Answer: The ovules are female reproductive structures and borne in the ovary of the flower. The number, structure, their position in the ovary varies in different plants. They also differ in mode of attachment with the ovary wall. At the point of attachment there is a cellular ridge or cushion of cells called placenta. The mode of attachment of ovule to the placenta is known as placentation which is of the following types: (a) Parietal (b) Marginal (c) Axile (d) Free central (e) Basal.

Q6. Sunflower is not a flower. Explain.

Answer: Sunflower is actually an inflorescence (capitulum), it is not a flower.
Capitulum (Head): Here the peduncle is flattened which is called receptacle. Inflorescence is surrounded by whorl of bracts collectively called involucre. On receptacle two kinds of florets are present: .
1. Ray florets: Zygomorphic, unisexual female, corolla ligulate or strap shaped.
ii. Disc florets: Actinomorphc, bisexual, corolla tubular, present in centre. Ray florets present towards periphery and disc florets present in the centre, e.g.: Compositae (Asteraceae) family—Sunflower (Helianthus), Tagetus (Marigold) and Dahlia.

Q7. How do you distinguish between hypogeal germination and epigeal germination? What is the role of cotyledon (s) and the endosperm in the germination of seeds?

Answer: 1. Hypogeal Germination: When the epicotyl grows first, only the plumule is pushed out of the soil. While cotyledons and all other parts remain under the soil, the germination is called hypogeal. E.g.: Most of the monocots (Maize, Rice and Coconut) and some of the dicots (Pea, Gram, Broad bean = Vicia faba, Mango).
2. Epigeal Germination: When hypocotyl grows first, it pushes the cotyledons and other parts of the seed out of the soil. This germination is called epigeal. E.g.: Helianthus (sunflower), mustard, cucurbits, castor, Onion, Tamarindus, French bean, Alisma.

Q8. Seeds of some plants germinate immediately after shedding from the plants while in other plants they require a period of rest before
germination. The later phenomena is called as dormancy. Give the reasons for seed dormancy and some methods to break it.

Answer: There are certain seeds which fall to germinate even when external conditions are favourable. Such seeds are understood to be undergoing a period of dormancy which is controlled not by external environment but are under endogenous control or conditions within the seeds itself.

Reasons for seed dormancy:

Impermeable and hard seed coat; presence of chemical inhibitors such as abscisic acid (ABA), phenolic acid; para-ascrobic acid; and immature embryos are some of the reasons which causes seed dormancy.

Methods of breaking seed dormancy:

Seed dormancy allows the plants to overcome unfavourable climatic conditions. This dormancy however can be overcome through natural means and various other man-made measures. For example, the seed coat barrier in some seeds cane be broken by mechanical abrasions are caused by microbial action, and passage through digestive tract of animals. Weakening of hard seed coat with sharp edge or knives is called scarification. Prechilling treatment to break seed dormancy is called stratification. Effect of inhibitory substances can be removed by subjecting the seeds to chilling conditions or by application of certain chemical like gibberellic acid and nitrates. Seed domancy is also breaked by auxin and cytokinin. Changing the environment conditions, such as light and temperature and other methods to overcome seed dormancy.