Consider the following plant tissues: [2023]
(A) Axillary buds
(B) Fascicular vascular cambium
(C) Interfascicular cambium
(D) Cork cambium
(E) Intercalary meristem
Identify the lateral meristems among the above.
(A), (C) and (D) only
(B), (C) and (D) only
(A), (B), (C) and (E) only
(A), (B), (D) and (E) only
(2)
Fascicular vascular cambium, interfascicular cambium and cork-cambium are examples of lateral meristems as these are responsible for producing the secondary tissues. Axillary buds are present in the axils of leaves and are capable of forming a branch or a flower. Intercalary meristem is a primary meristem as they appear early in life of a plant and contribute to the formation of the primary plant body.
Given below are two statements. [2023]
Statement I: Endarch and exarch are the terms often used for describing the position of secondary xylem in the plant body.
Statement II: Exarch condition is the most common feature of the root system.
In the light of the above statements, choose the correct answer from the options given below:
Statement I is correct but statement II is false.
Statement I is incorrect but statement II is true.
Both statement I and statement II are true.
Both statement I and statement II are false.
(2)
Endarch and exarch are the terms often used for describing the position of primary xylem in the plant body. Primary xylem is of two types—protoxylem and metaxylem. In roots, protoxylem lies towards the periphery. This arrangement of primary xylem is called exarch.
Phloem in gymnosperms lacks [2019]
both sieve tubes and companion cells
albuminous cells and sieve cells
sieve tubes only
companion cells only
(1)
In gymnosperms, phloem is without companion cells and sieve tubes.
Regeneration of damaged growing grass following grazing is largely due to [2019]
lateral meristem
apical meristem
intercalary meristem
secondary meristem
Tracheids differ from other tracheary elements in [2014]
having Casparian strips
being imperforate
lacking nucleus
being lignified
(2)
Tracheids are elongated, dead cells with hard lignified walls, wide lumens, and narrow walls with spiral, annular, reticulate, scalariform, and pitted thickening but without perforated end walls or septa. That is, they have intact end walls unlike vessels. Vessels are long cylindrical tube-like structures made of many cells, called vessel members, each with lignified walls and a large central cavity. Vessel members are interconnected through perforation in their common walls.
