Question

Plants which have tap root system and cotyledons in their seeds

Answer 1

Plants with tap root system i.e. dicots show reticulate venation in their leaves. Plants with fibrous root system i.e. monocots show parallel venation in their leaves. However this rule is not universal to all plants, eg. Ferns always have fibrous root system but their leaves show special type of dichotomous or reticulate venation rather than parallel venation.

Please note the fact that leaf & leaf venation pattern is a primary tissue of plant, whereas roots show secondary growth and sometimes anomalous growth in adult plants. Apart from natural co-occurrence, there is no convincing explanation to establish relationship between root system & leaf venation pattern. It seems both have been evolved independently. Plants with fibrous root system with parallel venation are considered highly advanced, adaptive & versatile.

Answer 2

1. Taproot, main root of a primary root system, growing vertically downward. Most dicotyledonous plants (see cotyledon), such as dandelions, produce taproots, and some, such as the edible roots of carrots and beets, are specialized for food storage.

2. Upon germination, the first structure to emerge from most seeds is the root from the embryonic radicle.

3.This primary root is a taproot. In plants in which the taproot persists, smaller lateral roots (secondary roots) commonly arise from the taproot and may in turn produce even smaller lateral roots (tertiary roots).

4.This serves to increase the surface area for water and mineral absorption.

5.In other plants, the initial taproot is quickly modified into a fibrous, or diffuse, system, in which the initial secondary roots soon equal or exceed the primary root in size and there is no well-defined single taproot.

6. Fibrous root systems are generally shallower than taproot systems.