Question

Sapwood differs from heartwood in being _______ .
(a) Darker and non-conducting
(b) Softer and non-conducting
(c) Lighter and conducting
(d) Hard, darker, and less conducting

Answer 1

Hint: Sapwood and heartwood are different components of wood of plants and trees, distinguishing between the living and dead parts of the wood. They can also be generally distinguished by their color.

Complete answer:

Sapwood	Heartwood
Sapwood is the living and outermost portion of a woody stem or branch.	Heartwood is the central core of the trunk and is dead tissue.
It is used for conducting water and nutrients through plants and the storage of food.	It has almost no moisture or stored food as it is dead tissue, hence, it is non-conductive.
It is generally lighter in color.	It is generally darker in colour because of the release of chemicals from dead cells that give a particular color to the wood.

Additional information:

Sapwood	Heartwood
It is also known as alebernum.	It is also known as duramen.
All wood first starts as sapwood and is formed just under the bark of the stem. It is formed under the cambium, which is responsible for forming the cells on the bark outside as well as the wood inside.	Heartwood is the dead tissue which was previously sapwood.

- The transformation of sapwood to heartwood has multiple processes: all living cells lose protoplasts, water, and food materials in the cell walls are gradually lost, tyloses have formed that block the vessels, lignification of parenchyma occurs, and substances like oils, tannins, and resins are formed.
So, the correct answer is ‘(c) Lighter and conducting’.

Note:
- Trees that do not show a significant difference in the color of the sapwood and the heartwood include firs, beech, aspen, holly, etc.
- Heartwood is used as timber as they have lesser material and lower moisture for pathogens to grow. Sapwood is used more often for pulpwood and for wood that is impregnated with preservatives.
- Heartwood is sometimes aromatic due to the presence of oils and resins.