Botany and Plant Science

Haplostele is prevalent in Rhynia. It consists of a cylindrical core of xylem surrounded by a ring of phloem. It is surrounded by endodermis.

The band of cells located between the endodermis and phloem in plant roots is called pericycle. It regulates the formation of lateral roots by rapidly dividing near the xylem elements of the root.

Both A and B are correct and B is the correct explanation of A. In plants, aphids are found on the underside of a leaf because phloem is present there, from which the aphids obtain their food.

The rate of emergence of leaves from the apical bud is called phyllochron.

Tinospora has assimilatory roots and can perform photosynthesis.

Velamen tissue performs the function of absorbing atmospheric moisture.

Parasitic plants are able to absorb nutrient from the host due to the presence of Hustoria.

Mangrove plants have buttress roots and  prevent the tree from falling over (hence the name buttress) while also gathering more nutrients.

Garlic root contracts and pulls the stem; they do not have hairs.

Prop roots are an example of adventitious roots.

Roots are non-hygroscopic in nature.

Orchids have Clinging roots which help the plant to fix to the supporting host. Clinging roots arise from the node of a stem and pierce the stem and thus, help in fixing the plant to the supporting host.

Root pockets are vestigial root caps, not regenerated and found in aquatic plants because the roots of the plants that hang freely in water have no friction or resistance from the soil particles to overcome.

Prop roots provide Mechanical support to the plant. Prop roots arises from branches and on reaching ground they act as pillars, thus providing mechanical support to the plant

Geminate viruses are twinned isometric particles about 30 x 18 nm. These particles are diagnostic for viruses in the family Geminiviridae which are widespread in many crops especially in tropical regions. The example includes Maize streak virus, genus Mastrevirus.