Reproduction In Plants

Plants that bear both male and female flowers on the same plant are called monoecious plants. Maize is an example of a monoecious plant.
Geitonogamy refers to the transfer of pollen between flowers on the same plant.
Xenogamy refers to the transfer of pollen between flowers of different plants. Maize exhibits both types of pollination.

In angiosperms, the embryo sac is located within the nucellus, which is a part of the ovule. The nucellus contains the female gametophyte, the embryo sac, where fertilization takes place.

The dotted line indicates the carrying capacity ( ) of the environment. It represents the maximum population size that the environment can sustain with available resources.

Stationary age pyramid.

Garden Pea: F progeny exhibits complete dominance, showing the dominant flower color. Antirrhinum: F progeny exhibits incomplete dominance, resulting in an intermediate flower color (e.g., pink when red and white are crossed).

‘K’ represents the carrying capacity of the environment, which is the maximum population size that the environment can sustain with the available resources.

Step 1: P is the fertilized egg or zygote.
Step 2: Q is the suspensor that pushes the embryo into endosperm.
Step 3: R represents cotyledons in the heart-shaped embryo.
Step 4: S indicates the radicle in the mature embryo.

Step 1: P is the fertilized egg or zygote.
Step 2: Q is the suspensor that pushes the embryo into endosperm.
Step 3: R represents cotyledons in the heart-shaped embryo.
Step 4: S indicates the radicle in the mature embryo.

Let's analyze each statement for a typical monocotyledonous embryo:
(A) Scutellum is present towards the centre of the embryonal axis. This statement is incorrect. The scutellum is the cotyledon in monocots and it is lateral to the embryonal axis.
(B) Embryonal axis of the lower end has radicle and root cap covered by coleoptile. This statement is incorrect. In monocots, the radicle and root cap are covered by the coleorhiza, not coleoptile. Coleoptile covers the shoot apex and leaf primordia.
(C) The portion of embryonal axis above the level of attachment of scutellum is epicotyl. This statement is correct. The epicotyl is the part of the embryonal axis above the cotyledon(s). In monocots, it's above the scutellum.
(D) Shoot apex and few leaf primordia of embryo are enclosed in a hollow foliar structure. This statement is correct. The shoot apex and leaf primordia in a monocot embryo are enclosed within a protective sheath called the coleoptile. Therefore, statements (iii) and (iv) are true for a typical monocotyledonous embryo.

Step 1: Introduction to outbreeding devices.
Outbreeding devices in plants help to promote cross-pollination, which is the transfer of pollen from one plant to another. Cross-pollination enhances genetic diversity, leading to stronger and more adaptable offspring.
Step 2: Three outbreeding devices.
1. Dioecious plants: In dioecious plants, male and female reproductive organs are present on separate plants. This ensures that pollen is transferred between different plants, facilitating cross-pollination. 2. Heterostyly: Plants with heterostyly have different types of flowers with different styles (the part of the flower that receives pollen). This encourages cross-pollination by preventing self-pollination. 3. Temporal separation: Some plants release pollen at different times of the day or during different seasons, reducing the chance of self-pollination and encouraging cross-pollination by attracting different pollinators.
Step 3: Conclusion.
These outbreeding devices ensure that pollen is transferred between genetically diverse plants, promoting stronger, more resilient generations.

(i) Tassels of Corn Cob:
The tassels of the corn cob are the male reproductive structures of the plant. They produce pollen, which is carried by the wind to fertilize the female flowers (ears) of the corn plant.
(ii) Scutellum:
The scutellum is a single, large cotyledon present in the seeds of monocots (like corn). It plays an important role in the process of seed germination by absorbing nutrients from the endosperm and transferring them to the growing embryo.

Step 1: No Need for Replanting Every Year.
Apomictic seeds are favored by farmers because they do not require replanting every year, unlike hybrid seeds which require new seeds to be purchased each season.
Step 2: Genetic Stability.
Apomictic seeds are genetically stable and produce offspring that are genetically identical to the parent plant. This results in uniformity and predictability, whereas hybrid seeds may exhibit variability in the next generation.