OBJECTIVE FORESTRY

Detailed explanation-1: -There are two types of sclerenchyma (Figure 4.4): (1) fibers, which are long, very narrow cells with sharply tapering end walls; and (2) sclereids, which are isodiametric to irregular or branched in shape. Fibers function in mechanical support of various organs and tissues, sometimes making up the bulk of the tissue.

Detailed explanation-2: -Sclerenchyma fibres (Phloem fibres) are present in Metaphloem and usually absent in Protophloem. However, Protophloem can sometimes contain specialized phloem fibres.

Detailed explanation-3: -Sclerenchyma is a type of simple permanent tissue. They have thick walls due to the deposition of lignin on their cell wall. Fibres are elongated thick walled cells which have pointed ends. Since they have very thick cell walls due to the deposition of lignin, they have very narrow lumen.