Question
Biology Question on Anatomy of Flowering Plants
The older resin clogged secondary xylem in the central part of the tree trunk and the younger outer secondary xylem which conducts water are __ and __ respectively.
duramen and alburnum
alburnum and duramen
autumn wood and spring wood
spring wood and autumn wood
duramen and alburnum
Solution
In perennial woody trees, the central portion of stem is darker in colour: Further, it is hard and tough due to deposition of resins, tannins, gums and formation of tyloses. This central hard tough, and darker region constitutes heart wood or duramen. The conduction function of heart wood stops due to formation of tyloses in vessels and hence heart wood is mechanical in fundtiori but does not function in water conduction. The outer or peripheral portion of the trunk is lighter incolour and soft which performs the functions of conduction of water and minerals and it is known as sap wood or alburnum.