Question

A stele consisting of numerous closed vascular bundles is called as

• A. Eustele
• B. Dictyoctele
• C. Atactostele
• D. Solenostele

Answer 1

The correct option is C Atactostele

Solenostele - if the cylinder of vascular tissue contains no more than one leaf gap in any transverse section i.e. has non-overlapping leaf gaps. This type of stele is primarily found in fern stems today. Dictyostele - if multiple gaps in the vascular cylinder exist in any one transverse section. The numerous leaf gaps and leaf traces give a dictyostele the appearance of many isolated islands of xylem surrounded by phloem. Each of the apparently isolated units of a dictyostele can be called a meristele. Among living plants, this type of stele is found only in the stems of ferns. Eustele - in this arrangement, the primary vascular tissue consists of vascular bundles, usually in one or two rings around the pith. In addition to being found in stems, the eustele appears in the roots of monocot flowering plants. The vascular bundles in a eustele can be collateral with the phloem on only one side of the xylem or bicollateral with phloem on both sides of the xylem, as in some Solanaceae. There is also a variant on the eustele found in monocots like maize and rye. The variation has numerous scattered bundles in the stem and is called an atactostele (characteristic of monocot stem). Thus, option C is correct and other options are wrong.