Tag: importance of plants

A.Central wood - The hard fibrous material that forms the main substance of the trunk or branches of a tree or shrub, used for fuel or timber.

B.Heart wood -  The inner or central dark colored non-functional resin clogged wood or secondary xylem formed during secondary growth in dicot stem is called Heart wood or duramen.

C.Alburnum– The outer light coloured functional wood which contains living cells formed during secondary growth in dicot stem is called Alburnum or sap wood.

D.Hardwood – secondary xylem or wood present in broad leaved tropical and temperate forests.

So, the correct option is ‘Heart wood’.

A.Duramen – also called heart wood.

B.Alburnum – also called sap wood.

C.Primary xylem – also called hydromel.

D.Spring wood – also called early wood.

So, correct option is ‘duramen’.

A ring of wood or secondary xylem formed by the association of spring wood and autumn wood is called annual ring. In every year one annual ring formation occurs in dicot stems.

So, the correct option is ‘autumn wood and springwood’.

In dicotyledonous stems, during intra stellar secondary growth, a ring of cambium called vascular cambium is formed.  In the plants growing temperate regions, the activity of vascular cambium is influenced by the existence of maximum seasonal variations. In the spring or early summer, due to the existence of favourable conditions, a large amount of secondary xylem is formed. it is called Springwood or early wood. In the autumn season, due to the presence of unfavourable conditions, less amount of wood is formed. it is called autumn wood or latewood.  Every ring of spring wood and autumn wood together form into an annual ring. In the 26 rings, 13 rings constitute spring wood and 13 rings constitute autumn wood. So total 13 annual rings are present.

A.False – Secondary xylem formed during spring season, during the secondary growth of dicotyledonous stem is called Spring wood or early wood. It is light coloured and high density.

B.False - Secondary xylem formed during spring season, during the secondary growth of dicotyledonous stem is called Spring wood or early wood. It is light coloured and high density.

C.False – Secondary xylem formed during autumn season, during secondary growth of dicotyledonous stem is called autumn wood or late wood. It is dark coloured and high density.

D.True - Secondary xylem formed during autumn season, during secondary growth of dicotyledonous stem is called autumn wood or late wood. It is dark coloured and high density.

So, the correct option is ‘Autumn wood- dark colour, high density’.

In winter, when the cambium is less active and forms fewer xylary elements that have narrow vessels then this wood is called autumn wood or late wood. While, in spring season, cambium is very active and produces a large number of xylary elements having vessels with wider cavities, this wood is called springwood or early wood.

In dicotyledonous stems, during intra stellar secondary growth, a ring of cambium called vascular cambium is formed.  In the plants growing temperate regions, the activity of vascular cambium is influenced by the existence of maximum seasonal variations. In the spring or early summer, due to the existence of favourable conditions, a large amount of secondary xylem is formed. it is called Springwood or early wood. In the autumn season, due to the presence of unfavourable conditions, less amount of wood is formed. it is called autumn wood or latewood.  A spring wood and autumn wood together form into an annual ring. Every annual ring becomes sapwood, it is light coloured, peripheral functional wood and every sap wood gradually transform into heat wood, it is inner or central dark coloured non-functional wood contains resin clogged structures called tyloses. 

So, the correct answer is 'Duramen and alburnum'.

In coniferous gymnosperms, secondary growth takes place by the formation of vascular cambium. it produces secondary xylem or wood towards its innerside and secondary phloem or bast towards outerside. Secondary xylem, shows more number of vessels without pores. So these are called non-porous vessesl. So the wood is called soft wood or non-porous wood.

In dicotyledonous stems, during intra stelar secondary growth, a ring of cambium called vascular cambium is formed.  Vascular cambium produces more amount of secondary xylem towards its innerside, and less amount of secondary phloem towards innerside. In the plants growing temperate regions, the activity of vascular cambium is influenced by existence of maximum seasonal variations. In the spring or early summer, due to the existence of favorable conditions, large amount of secondary xylem is formed. it is called Springwood or early wood. It is lighter in colour with low density. In the autumn season, due to the presence of unfavorable conditions, less amount of wood is formed. it is called autumn wood or late wood. It is darker in colour with higher density.

So, the correct answer is 'Depends on season and region where the plant grows'.

Secondary xylem is of different types is called heteroxylous wood. In this, the formation of sapwood and heartwood takes place. It is mostly found in dicotyledons.

So, the correct option is ‘Angiosperms’.