NEET2014BotanyAnatomy of Flowering PlantsActual
An old piece of dicot stem and a dicot root is given to a candidate during practical examination. Which of the following anatomical structures can be used to distinguish between the two?
Options
- ASecondary xylem
- BSecondary phloem
- CProtoxylem
- DCortical cells
Correct answer
C. Protoxylem
Step-by-step solution
The first formed primary xylem elements are called protoxylem and the later formed primary xylem is called metaxylem. In stems, the protoxylem lies towards the centre (pith) and the metaxylem lies towards the periphery of the organ. This type of primary xylem is called endarch. In roots, the protoxylem lies towards periphery and metaxylem lies towards the centre. Such an arrangement of primary xylem is called an exarch.