(i) State the adverse effects of continued secondary growth on stem? (ii) In which parts of stem resins and tannis get deposited? (iii) How the tyloses are formed?
kavitaEnlightened
(i) State the adverse effects of continued secondary growth on stem? (ii) In which parts of stem resins and tannis get deposited? (iii) How the tyloses are formed?
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(i) Due to continued secondary growth for many years,
the older parts of the stem have a part of its secondary
xylem becoming non-functional.
(ii) It is always the central portion of xylem from which
the vessels and tracheids progressively become filled
with resins and tannins produced by adjacent living
cells as a secondary metabolite.
(iii) The xylem elements of many woody trees are blocked
by bladder-like in growths of neighbouring
parenchymatous cells, thus blocking the continuity of
these conducting elements. Such bladderlike
ingrowths are called tyloses. As a result, the
conducting elements become non-functional.