Sexual Reproduction in Flowering Plants Test - 100

The number of stamens in Allium is 6 and number of stamens in Solanum is 5. For the 5 flowers of Allium and 5 flowers of Solanum the stamen number is of 30 and 25. Therefore the first statement is wrong. 

Pollination in Cycas takes place at 3-celled stage (a prothallial cell, a generative cell and a tube nucleus). In angiosperms it is in 2-3 celled stage.

The availability of favorable conditions (both external and internal) ensures that seeds germinate. Germination can be

1. Epigeal, where a straight radicle comes out and fixes the seed to the soil with the secondary roots coming out of the radicle. The hypocotyl grows to form a loop which comes out of the soil and pulls out the rest of the seed. The seedcoat gets caught to a peg-like projec­tion at the base of the hypocotyl and the cotyledons are brought out in the air. For example, Dolichus lablab
   
2. Hypogeal, where the radicle comes out first, penetrates the soil and forms a root system by giving out secondary branches. The epicotyl grows first which arches out and carries the plumule above ground. The plumule soon forms the aerial shoot. The cotyledons, therefore, remain under soil throughout as is shown in Pisum and Maize. However, at the time, these also tend to show epigynous germination.
   

So, out of 90 seeds in total (thirty each of Dolichus, Pisum and Maize), 30 seeds of Dolichus show epigeal germination with cotyledons above the soil and the rest 60 show hypogeal germination.

when pollen grains from an anther of the flower are transferred to the stigma of the same flower or to the stigma of the different flower of the same plant is called as self-pollination. For example, Pisum sativum (A-II).
Chasmogamy is the condition wherein pollination takes place in open flower. They are normally cross-pollinated. Small, bisexual, colourless flowers which do not secrete nectar and always remain close are called as cleistogamous flowers; their closed condition favors exclusive self-pollination. For example, Commelina (B-I).
Pollination by an agency of insects is known as entomophily or insect pollination. Pollination by the wind is called anemophily. Water hyacinth is an aquatic plant with emergent flowers in which pollination occurs through the wind (C-V).
Protogyny refers to development and maturation of female reproductive parts before that of male parts of the flower to prevent self-pollination. Abutilon is a plant of Malvaceae family and exhibits entomophily (D-IV).
Solanum belongs to family Solanaceae and exhibits cross-pollination (E-III).
Therefore, the correct answer is option A.

Pollen grains can be store in a low temperature for a short time storage or in a sealed containers using dry silica. They can also be stored in -$$80^0C$$ degrees for one year in subfreezing condition.

In the first mitotic division megaspore forms two nuclei. one is function that is chalazal end and other is micropylar. These nuclei are redivided to form eight nucleate stage. This is called as egg apparatus.At the chalazal end 3 out of 4 differentiates as antipodal cells and other two are moved toward nuclei .Hence, at maturity the female gametophyte appears as 7-celled structure and it has 8 nucleates.

A. Correct option- D
B. Explanation for the correct option

Seeds, which store food materials in their cotyledons are called non- endospermic or exalbuminous seeds.

Seeds, which store food materials in their endosperm are called endospermic or albuminous seeds.

A. Cotyledons- It store food material in exalbuminous seed.

B. Hypocotyl- The portion of the axis between the radicle and cotyledonary node is called hypocotyl.

C. It is a persistent nucellus.

D. Endosperm- It store food material in the albuminous seed.

In autogamy, the flowers are bisexual and anther and stigma are close to each other.  The flowers are synchronized in the release of the pollen and the maturation of the stigma to allow successful autogamy. Pollinating agents are not required for the autogamy which is self-fertilization but they are involved in the transfer of the pollen grain by cross pollination. 

Calotropis shows translator or clip mechanism. Pollen grains here are present in the pollinia and these are attached to a rough and sticky disc called corpusculum. When the insect visits the flower, pollinia get entangled in the legs of the insects. When the insect visit another flower, the pollinia are transferred. The lever mechanism of pollination is seen in the salvia. The lever mechanism is also called turn pipe mechanism. The siphon mechanism of pollination is common type present in most of the angiosperms.