The question asks about the method of vegetative propagation in Bryophyllum. Vegetative propagation is a form of asexual reproduction in plants where new plants grow from vegetative parts like leaves, stems, or roots, without the involvement of seeds or spores. We need to identify the specific vegetative part responsible for propagation in Bryophyllum.
B) Adventitious buds developing on the margins of its leaves — Bryophyllum is famous for its ability to produce new plantlets from the notches present on the margins of its leaves. These plantlets are adventitious buds that develop roots and shoots while still attached to the parent leaf. Once mature, they detach and grow into new independent plants.
The question asks to identify an artificial method of vegetative propagation commonly used in horticulture for fruit trees like mango and rose. We need to evaluate each option to determine if it's an artificial vegetative propagation method and if it's used for the mentioned plants.
D) Grafting is an artificial method of vegetative propagation where parts of two plants are joined to grow as one. It is extensively used in horticulture for propagating fruit trees such as mango, apple, and citrus, as well as ornamental plants like roses, to combine desirable traits like disease resistance from the rootstock and high-quality fruit/flowers from the scion.
The question asks to identify the process of 'layering' in plant propagation. We need to understand the definition of layering and distinguish it from other methods of plant propagation described in the options.
B) Bending a stem of the parent plant so part of it touches the soil and develops roots while still attached to the parent plant. This is the precise definition and mechanism of layering. The stem remains connected to the parent plant, receiving nutrients and water, until it has successfully rooted, increasing the chances of survival for the new plant.
The question describes a process of producing genetically identical plantlets from a small piece of plant tissue under sterile laboratory conditions. This process is a well-known technique in plant biotechnology. We need to identify the correct term for this specific method from the given options.
Correct Option: B) Micropropagation
Micropropagation is the practice of rapidly multiplying stock plant material to produce a large number of progeny plants, using modern plant tissue culture methods. It is widely used for commercial production of plants as it allows for the production of genetically identical copies (clones) of a desired plant in a short amount of time and space, under sterile conditions.
The question asks to identify the characteristic feature of sexual reproduction. We need to evaluate each option against the definition and common understanding of sexual reproduction in biology.
Correct Option: C) The fusion of a male gamete and a female gamete, usually involving two parents
This option correctly defines sexual reproduction. The key events are the formation of specialized reproductive cells (gametes) and their subsequent fusion (fertilization) to form a zygote. This process typically involves two parents, leading to genetic variation in the offspring.
The question asks to identify the primary biological advantage of sexual reproduction over asexual reproduction. We need to evaluate each option based on the fundamental principles of reproduction and evolution.
Correct Option: D) Introduces genetic variation in the offspring, which is important for the survival and evolution of a species.