(a) Mention the terms used to denote bisexual condition and unisexual condition in lower plants.
(b) Compare Marchantia and Chara w.r.t. sexuality.
(c) Mention the factors that regulate the reproductive processes and the associated behavioural expression of
organism.
(d) Explain senescent phase.
Answers
Answer:
(a) In several fungi and plants, terms such as homothallic and monoecious are used to denote the bisexual condition and heterothallic and dioecious are the terms used to describe unisexual condition.
(b) In Marchantia, sexual reproduction involves sperm from the male plant and the ova from the female plant. ... In Chara, which is an algae contains antheridium (male part of the plant) and archegonia (female part of the plant). They are either present on the same plant or on different plant.
(c) Interaction between hormones and environmental factors regulate the reproductive processes and the associated behavioural expressions of organisms.
(d) The senescent phase is the period after reproductive phase, when a cell loses its ability to reproduce. Here, the cell may age and stops dividing, but it does not die. Termed as cell ageing, in this process such cells stay within the body and may cause various illness.