Plant Anatomy Plant Tissues MCQs for NEET — Botany Questions with Answers

In plants, phloem is responsible for the transport of nutrients, mainly sugars, throughout the plant. Sieve tubes are the main conductive cells in the phloem, and they lack a nucleus at maturity. This helps in the efficient flow of nutrients. Companion cells are closely associated with sieve tubes and help in their functioning, but they do have a nucleus.

Trichomes are epidermal hairs on the sterm and help in prevention of water loss due to transpiration.

Answer 2.  Collenchyma cells are much thickened at the corners due to a deposition of cellulose, hemicelluloses and pectin.

Read page 85 XI NCERT

Statement I is incorrect. Read page 88 of class XI NCERT 

(c) Heartwood also called duramen is the central dead wood of trees. It comprises of dead, lignified cells containing organic compounds, eg. tannins or other substances. These substances make it darker in colour and aromatic. Heartwood is strong durable and resistant to decay. It does not conduct water and minerals because of the presence of dead elements. Thinking Process The conduction of water and
minerals is carried out by sapwood, because it contains living cells.

(c) Stomata are tiny pore complexes. Each stomata is surrounded by two specialised green epidermal cells called guard cells.The opening of the stoma is facilitated by the orientation of the microfibril in the cell walls of the guard cells.Cellulose microfibrils are oriented radially rather than longitudinally making it easier for the stoma to open.

(c) Phellem or cork is a tissue formed on the outer side of cork cambium. It is composed of dead cells.
The cell wall become impermeable due to suberisation.

(c) Vascular cambium located between xylem and phloem in the stems and roots of vascular plants- It produces secondary xylem towards the pith and secondary phloem towards the bark. Phellogen is made of narrow thin-walled and nearly rectangular cells. phellogen cuts off cells on both sides. The outer cells differentiate into cork or phellem while inner cells differentiate into secondary cortex or phelloderm. The phellogen, phellem and phelloderm are collectively known as periderm.

The opening and closing of stomata are caused by influx and efflux of potassium ions (K⁺). The increase of K⁺ results in opening of stoma and decrease of K⁺ causes closing of stoma. The turgidity of guard cells induces to open the pores of stomata found on the surface of leaves.