Botany and Plant Science

Bracteoles are correctly defined as small, thin bract-like structures present on the pedicel (flower stalk). An involucre is a whorl of bracts (not bracteoles) typically found at the base of an inflorescence. Sepals are usually green, not brightly colored - that's the role of petals. Epicalyx is indeed arranged on the thalamus, but the question asks which statement is correct, and only (b) is fully accurate.

Guard cells are the specialized kidney-shaped cells that surround each stoma and control its opening and closing through changes in turgor pressure. Hydathodes are involved in guttation (water secretion), bulliform cells aid in leaf rolling in grasses, and epidermal cells are the general pavement cells forming the outer layer. The distinctive kidney shape is unique to guard cells in dicot leaves.

A runner is a weak stem that grows horizontally on the soil surface, producing new plants at nodes (e.g., grass, strawberry). Stolons are similar but grow above ground. Twiners climb by coiling around supports. Suckers grow from the base.

The tap root system is called the normal root system because it develops from the radicle (the normal embryonic root) and is the most common type in dicots. Adventitious roots arise from non-root tissues, prop roots provide support, and fibrous roots are a modification of tap roots.

In palmately compound leaves, all leaflets radiate from a single point at the tip of the petiole (like fingers from a palm). Pinnately compound leaves have leaflets arranged along a central rachis, while the terms reticulate and parallel refer to venation patterns, not leaf arrangement.

Adventitious roots develop from any plant part other than the radicle (embryonic root), such as stems, leaves, or branches. Roots from radicle or primary root are normal roots, not adventitious. The underground part of a plant could be roots themselves or underground stems.

A bisexual (hermaphrodite) flower contains both male (androecium - stamens) and female (gynoecium - pistils/carpels) reproductive parts. Monoecious plants have separate male and female flowers on the same individual, dioecious plants have them on separate individuals, and polygamous refers to plants with multiple sexual conditions.

Tepals are the individual segments of the perianth when sepals and petals are undifferentiated (similar in appearance and color), as in lilies and tulips. Petals are the inner whorl, sepals are the outer whorl, and pistil is the female reproductive organ - none describe perianth segments.

In a typical angiosperm, 4 pollen sacs are present in the anther.

The microsporogenesis takes place at anther.

Myosotis yields the smallest pollen grain.

Sporogenous cells divide to form microspore mother cells.

Pollen grains begin to germinate, while still in the anther lobe.

Pollen grain is the male gametophyte of angiosperms.

The larger cell of pollen grain is called vegetative cell.