Biology Quiz - 2, General Knowledge - Railways MCQ

Plants growing on sand are called psammophytes. Here's why:

- Psammophytes: These are plants specially adapted to thrive in sandy soils. They have developed mechanisms to cope with water scarcity, shifting substrates, and nutrient-poor conditions.

- Other Options:
- Chasmophytes: Plants growing in rock crevices.
- Oxylophytes: Plants growing in acidic soils.
- Lithophytes: Plants growing on rocks.

Psammophytes have adaptations like deep root systems to access water and stabilize themselves in loose, sandy environments.

With the help of examples, explain the various types of vascular bundles.

In angiosperms the vascular bundles are mainly of three types (i) radial (ii) conjoint (iii) concentric.

(i) Radial : Presence of radial vascular bundles is the characteristic feature of roots. Those vascular bundles in which xylem and phloem are present on different radii are known as radial vascular bundles. In between xylem and phloem bundles parenchymatous cells are present.

(ii) Conjoint : In these vascular bundles xylem and phloem are present on the same radii. Conjoint vascular bundles may be collateral (phloem is present only outer to xylem) or bicollateral (phloem is present on both sides of xylem). If cambium is present between xylem and phloem then the vascular bundle is known as open, otherwise it is called closed.

(iii) Concentric : Those vascular bundles in which one type of vascular tissue is surrounded by another type are known as concentric vascular bundles. These bundles may be amphivasal or leptocentric(phloem is completely surrounded by xylem) or amphicribal or hardocentric (xylem is completely surrounded by phloem). Amphivasal bundles are found in Dracaena and Yucca. Amphicribal bundles are found in stamens of many dicots etc.

Radical vascular bundles are those in which xylem and phloem occur on the different radii.