Biology · Science General

Botany and Plant Science

4,989 Questions

Botany and plant science delve into the biological study of plant life, covering structural anatomy, physiological processes, and reproductive mechanisms. Key topics include inflorescence patterns, root modifications, and seed development, which are vital for biology sections in medical entrance exams. This collection of practice questions helps solidify understanding of complex plant functions.

Plant ReproductionPlant AnatomyRoot ModificationsInflorescence PatternsPlant Morphology

Botany and Plant Science Questions

Multiple choice botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

Entry of pollen tube into ovule through chalaza was first discovered by Treub in a xerophyte. The plant is associated with a pair of characters(i) Unisexual flowers (ii) Sessile flowers (iii) Centripetal arrangement of flowers (iv) Bisexual flowers. The correct pair is?

  1. ii and iii

  2. iii and iv

  3. ii and iv

  4. i and ii
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The entry of the pollen tube into the ovule through the chalaza is known as the chalazogamy. This was discovered by Treub. One such example of xerophyte is Casuarina, which is a plant which can withstand prolonged periods of drought. A flower is a bracteate, bracteolate, sessile, incomplete and unisexual.

Thus, the correct option is D.

Multiple choice botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

Movement of pollen tube towards ovule is

  1. Chemotropism

  2. Haptotropism

  3. Thigmotropism

  4. Phototropism
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Chemotropism is the directional growth movement in response to external chemical stimuli. Movement of pollen tube towards ovule is chemotropic movement. Haptotropism is the growth movement of plant part in response to the touch stimuli. Thigmotropism is the growth movement in response to the touch. Phototropism is the growth movement of plant part in response to the light.

Thus, the correct answer is 'Chemotropism'.

Multiple choice botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

Growth of pollen tube is?

  1. Apical

  2. Basal

  3. Intercalary

  4. Diffused
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

After the germination of pollen grains on stigma pollen tube is produced through a germ pore . Pollen tube grows chemotropically through the tissue of stigma and style in response to sugary fluid.

No intercalary meristem is present so pollen tube cannot exhibit intercalary growth , because of chemical stimulus pollen tube grows apically and not basally or diffused. 
So the correct option is ‘apical’                               

Multiple choice botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

In mesogamy, pollen tube enters the ovule through

  1. Middle of integuments after piercing the tissues

  2. Middle of integuments without piercing the tissues

  3. Chalaza

  4. Middle of micropyle
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Mesogamy is the entry of pollen tube in the ovule through the integuments. The pollen tube enters the ovule laterally through integuments by piercing the tissue in the middle and finally enters the embryo sac through micropylar pole, whereas, entry of pollen tube through chalaza is called chalazogamy and through micropyle is called porogamy.
So, the correct answer is A. 
Multiple choice botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

Entry of pollen tube through chalazal end is

  1. Syngamy

  2. Porogamy

  3. Mesogamy

  4. Basigamy
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
•Syngamy is the fusion of male and female gamete which results in the formation of a diploid zygote.
•Porogamy is the entry of pollen tube in the ovule through micropyle.
•Mesogamy is the entry of pollen tube in the ovule through the integuments or nucellus.
•Basigamy is also known as Chalazogamy. It is the entry of pollen tube in the ovule through the chalaza.
So, the correct answer is D.
Multiple choice botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

Pollen tube usually enters the embryo sac

  1. Through one of the synergids.

  2. Directly penetrates the egg.

  3. Between one synergid and central cell.

  4. By knocking of antipodal cells.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Synergids attract the pollen tube by secreting some chemotactic substances and guide the pollen tube entry. Synergids are ephemeral i.e. short-lived structures. In embryo sacs, which have two synergids, one synergid degenerates before the entry of pollen tube. This degenerated synergid provides the way for pollen tube entry in the embryo sac. The pollen tube discharges its content in the degenerated synergid. The other synergid which is the persistent synergid degenerates shortly after the pollen tube has released its contents in the embryo sac.
Hence, pollen tube enters the embryo sac through one of the synergids.
So, the correct answer is A.
Multiple choice botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

Commonly the pollen tube enters the ovule through

  1. Hilum

  2. Chalaza

  3. Funicle

  4. Micropyle
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Pollen tube may enter the ovule via any of the following routes:
1.  Porogamy- when the pollen tube enters the ovule through micropyle. It is common in most of the angiosperms.
2. Mesogamy- when the pollen tube enters through the integuments or through funiculus.
3. Chalazogamy- when the pollen tube enters through the chalazal tissues.
Thus, pollen tube commonly enters the ovule through micropyle.
So, the correct answer is D.
Multiple choice botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

Based on entry of pollen tube into ovule, which one is mesogamy.

  1. Through micropyle

  2. Entry through funiculus, chalaza and embryo sac from egg apparatus end

  3. Through placenta and funiculus

  4. Through integument
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Mesogamy refers to the entry of the pollen tube into the ovule through the integuments, rather than through the micropyle (porogamy) or the chalaza (chalazogamy). This mode of entry is commonly seen in plants like Cucurbita.

Multiple choice botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

Through which cell of the embryo sac, does the pollen tube enter the embryo sac-

  1. Persistant synergid

  2. Egg cell

  3. Central cell

  4. Degenerated synergid
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The pollen tube enters the embryo sac through the micropylar end. It can enter directly through the synergid or can enter from between the egg cell and synergid.

The answer is D- Degenerated synergid. 
So the correct option is D.

Multiple choice botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

When pollen tube enters through microphyte, the process is called _______________.

  1. Porogamy

  2. Chalazogamy

  3. Mesogamy

  4. Apogamy
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Porogamy is the term for pollen tube entry through the micropyle (the small opening in the ovule integuments). Chalazogamy is entry through the chalaza, and mesogamy is through the integument. Apogamy refers to asexual reproduction without fertilization. Note: the question has a typo - it says 'microphyte' but means 'micropyle'.

Multiple choice botany modes of reproduction introduction to flower pre fertilization - plants sexual reproduction in flowering plants the origin of cells and cell division

Length of pollen tube depends on the distance between

  1. Pollen grain and upper surface of stigma

  2. Pollen grain on upper surface of stigma and ovule

  3. Pollen grain in anther and upper surface of stigma

  4. Upper surface of stigma and lower part of style
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Length of pollen tube depends upon distance of pollen on stigma and ovule because after pollination pollen germinates and form pollen tube that reaches upto ovule in ovary and release male gamete to fuse with female gamete.