Summer wood is:
(1) the same as heartwood.
(2) found to the outside of each annular ring of xylem.
(3) found to the inside of each annular ring of xylem.
(4) formed throughout the growing season.
Read the different components from I to IV in the list given below and tell the correct order of the components with reference to their arrangement from outer side to inner side in a woody dicot stem
I. Secondary cortex
III. Secondary phloem
The correct order is
(1) III, IV, II, I
(2) I, II, IV, III
(3) IV, I, III, II
(4) IV, III, I, II
Identify the wrong statement in context of heartwood.
(a) Organic compounds are deposited in it
(b) it is highly durable
(c) It conducts water and minerals efficiently
(d) It comprises dead elements with highly lignified walls
Which of the following facilitates opening of stomatal aperture :-
(a) Contraction of outer wall of guard cells
(b) Decrease in turgidity of guard cells
(c) Radial orientation of cellulose microfibrils in the cell wall of guard cells
(d) Longitudinal orientation of cellulose microfibrils in the cell wall of guard cells
Which of the following is made up of dead cells?
(a) Xylem parenchyma
The vascular cambium normal gives rise to.
(a) phelloderm (b) primary phloem
(c) secondary xylem (d) periderm
Cortex is the region found between
(a) Epidermis and stele
(b) Pericycle and endodermis
(c) Endodermis and pith
(d) Endodermis and vascular bundle
The balloon-shaped structures called tyloses
(a) Original in the lumen of vessels
(b) characterise the sapwood
(c) are exetentions of xylem parenchyma cells into vessels
(d) are linked to the ascent of sap through xylem vessels
Specialised epidermal cells surrounding the guard cells are called ?
(a) subsidiary cells
(b) bulliform cells
(d) complementary cells
Vascular bundles in monocotyledons are considered closed because
(a) a bundle sheath surrounds each bundle
(b) cambium is absent
(c) there are no vessels with performations
(d) xylem is surrounded all around by phloem