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
A major characteristic of the monocot root is the presence of
(a) open vascuiar bundles
(b) scattered vascular bundles
(c) vasculature without cambium
(d) cambium sandwiched between phloem and xylem along the radius
In a ring girdled plant ?
(a) the shoot dies first
(b) the root dies first
(c) the shoot and root die together
(d) Neither root nor shoot will die
Which one gives the most valid and recent explanation for stomatal movements?
(b) Potassium influx and efflux
(c) Starch hydrolysis
(d) Guard cell photosynthesis
You are given a fairly old piece of dicot stem and a dicot root. Which of the following anatomical structures will you use to distinguish between the two?
(a) Secondary xylem
(b) Secondary phloem
(d) Cortical cells
Interfascicular cambium develops from the cells of ?
(a) medullary rays
(b) xylem parenchyma
Lenticels are involved in
(b) gaseous exchange
(c) food transport
Age of a tree can be estimated by?
(a) its height and girth
(c) number of annual rings
(d) diameter of its heartwood