Tag: pre fertilization - plants
Questions Related to pre fertilization - plants
When a dicot plant is infected by Agrobacterium tumefaciens, the T-DNA in Ti-plasmid induces the plant to produce?
-
Growth hormones like auxins and cytokinins
-
Growth inhibitors like absciscic acid
-
Fatty acids
-
Leghaemoglobin
Agrobacterium tumefaciens is the causal agent of crown gall disease (the formation of tumours). It is a rod-shaped, Gram-negative soil bacterium. The plasmid of this bacterium is called Ti-plasmid, it shows T-DNA. This plasmid used to produce growth hormones like auxins and cytokinins.
So, the correct option is ‘Growth hormones like auxins and cytokinins’.
Length of pollen tube depends on the distance between
-
Pollen grain and upper surface of stigma
-
Pollen grain on upper surface of stigma and ovule
-
Pollen grain in anther and upper surface of stigma
-
Upper surface of stigma and lower part of style
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.
Mesogamy is
-
Fusion of similar male and female gametes
-
Fusion of morphologically different but physiologically similar gametes
-
Entry of pollen tube through the integument
-
None of the above
There are various ways by which the pollen tube can reach embryo sac for pollination.
What is the function of the filiform apparatus at the entrance into ovule?
-
Guides pollen tube from synergid to egg
-
Helps in the entry of pollen tube into a synergid
-
Prevents entry of more than one pollen tube into a synergid
-
Brings about opening of the pollen tube
What is the function of filiform apparatus in an angiospermic embryo sac?
-
Guides pollen tube from synergid to egg
-
Helps in the entry of more than one pollen tube into a synergid
-
Prevents entry of more than one pollen tube into a synergid
-
Brings about opening of the pollen tube.
The function of filiform apparatus in an angiospermic embryo sac is to guide the entry of pollen tube from synergid to egg. The synergid cells present within the female gametophyte play a vital role in the reproduction process in angiosperm. The cell wall of synergid develops an extremely thick structure called the filiform apparatus at the micropylar end of the ovule.
The most common type of entry of pollentube into the ovule is
-
Mesogamy
-
Chalazogamyy
-
Basigamy
-
Porogamy
Porogamy is the most common type in which the pollen tube enters the ovule through the micropyle. An example includes lily, etc.
So the correct option is D.
Siphonogamy occurs in
-
Gymnosperms
-
Monocots
-
Dicots
-
All of the above
Growth of the pollen tube is
-
Apical
-
Intercalary
-
Basal
-
Intermittent
In sexual reproduction of plants, the sperm is transferred to the egg through a long, polarized tube of a pollen cell called as the pollen tube. The growth of the pollen tube is apical. It grows at its tip at very rapid rate. The rapid growth is due to a highly polarized fusion of apical vesicles. These transport cell wall components to the growing tip via cytoplasmic streaming and are incorporated into a zone of elongation in the apical region of the pollen tube. Hence, the pollen tube extends its length by apical growth in a relatively small region.
Choose the correct answers from the alternatives given.
Entrance of a pollen tube into an ovule through the micropyle is called
-
porogamy
-
mesogamy
-
chalazogamy
-
apogamy
After reaching ovary, the pollen tube enters the ovule. When the pollen tube enters the ovule through micropyle, it is called porogamy. It is the most common type. e.g., Lily.
Entry of pollen tube in the ovule through integument is called
-
Chalazogamy
-
Basigamy
-
Mesogamy
-
Porogamy