Botany and Plant Science

In some plants, when the mature pollen falls on the receptive stigma of the same flower, it fails to bring about self-pollination. It is called self-incompatibility. Under such conditions, cross-pollination is the only option.

The genus Salvia belongs to family Labiatae (Mint family) in which the gamopetalous corolla is two-lipped (Bilabiate). The lower lip provides platform for the visiting insect and the upper lip is just like a hood which protects the floral organs. The flowers are protandrous. Each flower has two epipetalous stamens located in anterio-lateral position.It is an entomophilus flower.

Fourth whorl (female organ of the flower) consists of carpel or megasporophylls. The pistil consists of Fourth whorl (female organ of the flower) consists of carpel or megasporophylls. The pistil consists of ovary, style and stigma.The ovary contains one or more round or oval ovules (rudimentary seeds). Each ovule encloses embryo sac.

Xylem tissue is composed of several types of cells, including tracheids (long, tapered cells) and vessels (shorter, wider cells arranged in columns). Both tracheids and vessels are conducting elements that transport water and minerals, so option C is correct.

Lignin is a complex organic polymer that makes cell walls both hard (rigid) and strong (resistant to compression and deformation). It provides structural support and waterproofing to plant cell walls, especially in xylem tissue. The option 'both (1) and (2)' correctly captures both of these properties.

Xylem vessels consist of vessel elements that are dead at maturity, forming long continuous tubes for water transport. These cells lose their protoplasm and end walls to create efficient pipelines.

Mature xylem vessels are dead cells with no living contents. They lack cytoplasm, nuclei, and all other organelles, forming empty tubes for water conduction.

Pits are thin areas in cell walls present in both xylem and phloem cells. They allow lateral transport of water and substances between adjacent cells.

Xylem vessel walls contain both cellulose for structural strength and lignin for waterproofing and rigidity. This combination creates strong, impermeable tubes for water transport under tension.

The endodermis is the single cell layer surrounding vascular tissues in roots, acting as a selective barrier. It regulates mineral uptake into the vascular cylinder via the Casparian strip.

The root cortex is the tissue region between the epidermis (outer layer) and endodermis (inner layer). It stores food and helps transport water and minerals to the vascular cylinder.

Phloem tissue is composed of sieve tubes (sieve tube elements plus companion cells) that transport organic nutrients like sugars. Sieve tubes are the characteristic conducting cells of phloem, arranged end-to-end with perforated sieve plates. Cell tubes is not a standard biological term, sieve cells are found in less advanced plants, and stomata pores are part of leaves, not vascular tissue.

The cells of meristematic tissues are dividing cells. So, they are present in the growing regions of plants.

Fertilization is the process where pollen grains enter ovules, enabling seed development. Offal refers to animal waste, ore is mineral-bearing rock, and anther produces pollen.

Inflorescence is a cluster or group of flowers arranged on a stem or branch. Pedicel is a single flower stalk, rachis is the main stem, and metatopy refers to abnormal flower position.