L5: Evolution and Diversity of Woody and Seed plants

Which of the following are true about Lignophytes?

• Lignophytes are also called woody plants or Lignophyta.

• They are a monophyletic lineage of

  euphyllous vascular plants that share derived features.

• One of the derived features are vascular cambium which gives

  rise to wood.

• Another is the cork cambium - which produces

  cork.

Growth of the vascular and cork cambia is called _________ because it initiates after the vertical extension of stems and roots due to cell expansion (primary growth).

• secondary growth

• primary growth

• tertiary growth

(a)   is a sheath or hollow cylinder of cells that develops within the stems and roots as a continuous layer between the xylem and phloem in extant eustelic spermatophytes.

The cells of the vascular cambium divide mostly tangentially (parallel to a tangential plane), resulting initially in two concentric layers of cells

• True

• False

One of the layers remains as the vascular cambium and continues to divide indefinitely; the other layer eventually differentiates into either:

• secondary xylem or wood, if

  produced to the inside of the

  cambium.

• primary xylem or wood, if

  produced to the inside of the

  cambium.

• primary phloem, if produced to

  the outside

• secondary phloem, if produced to

  the outside of the cambium

Cells are produced both to the inside and outside of a continuously generated cambium are termed as (a)   .

(a)   is similar to a vascular cambium only it differentiates near the periphery of the stem or root axis.

The cork cambium and its derivatives constitute the (a)   (referred to as

the outer bark).

The outermost layer of the periderm is the (a)   .

Cork cells contain a waxy polymer called _______ (similar to cutin) that is quite resistant to _____ ____.

• suberin, water loss

• cutin, water loss

• wax, water loss

• cuticle, water loss