Difference between Stem and Root:
1.Roots are the non-green descending axis of the plant that move towards soil.
2.Roots develop from radicle of the embryo. These arc positively geotropic but negatively phototropic.
3. Except in some modified roots (Tinospora, Trapa etc.) all roots are without chlorophyll.
4. Roots are not differentiated into nodes, internodes. buds, leaves etc. In some roots adventitious buds arise for the purpose of reproduction (lpomea, Dahlia etc.)
5. Lateral roots develop endogenously from pericycle.
6. Root hairs are unicellular.
7. Root apex has special protective covering called root cap.
8. The root along with all the branches form the root system.
9. Two types of root systems are found – tap root system and adventitious root system.
10. Tap root originates from radicle and persists for whole life. It produces secondary and tertiary roots in acropetal manner.
11. Adventitious roots are of three kinds fibrous roots of monocotyledonous plants (rice, grass etc.) in which the radicle is replaced by a tuft of fibrous roots. (ii) Cauline roots, which develop from any part of the stem (sweet potato, Oxalis, banyan etc). (iii) Foliar roots, which develop from leaves (Bryophyllum, Bignonia)
12. Some tap roots and adventitious roots undergo modification for the purpose of storage, support, defence and propagation.
13. Fusiform, napiform, conical and some tuberous roots are the modification of tap root system. The store food and therefore fleshy.
14. There are some tap root systems which undergo modification for some special purposes such as f n. breathing (pneumatophor), symbiosis (mycorrhiza) etc.
15. Some adventitious roots undergo modification for storage (tuberous roots, fasciculated root, nodulose root), mechanical support (prop root, stilt root, climbing root, contractile root. root thorn etc.) and for physiological functions (epiphytic root, assimilatory root, parasitic root, reproductive root, etc.)
1. Stem is the ascending part of the plant. It is positively phototropic but negatively geotropic.
2. Stem develops from plumule of the embryo.
3. Stem bears branches, leaves and flowers.
4. Sterns always possess nodes, internodes, axillary and terminal buds.
5. Stem branches arise exogenously.
6. Stem apex bears a bud and not a cap like the root.
7. Stern hairs arc multicellular.
8. Young stems are green in colour due to presence of chlorophyll.
9. According to nature sterns can be classified into herbs, shrubs and trees. 10. According to form sterns can be classified into strong stem and weak stems.
11. Strong stems exhibit various forms such as excurrent (pyramidal form, e.g. Polyalthia lonaolia), deliquescent (dom-shaped, e.g. mango), caudex (unbranched stem, e g, coconut), culms (having hollow internodes, c.g, bamboo), scape (the anal stem produces h underground stem, e.g. ginger, onion).
12. The weak stems may be prostrate or decumbent (prostrate pl4nt in which only apices raised), creeper, stem climbers etc.
13. Stems undergoes various modifications for various purposes. The modified sterns are classified into three categories – underground, sub-aerial and aerial.
14. Underground modified stems such as rhizome (e.g. ginger, turmeric), bulb (e.g. onion) and corm (e.g Amorphophallus) are meant for storage of food.
15. Sub-aerial modified stems such as runner (e.g. Oxalis), stolon (e.g. — Mentha), offset (e.g water hyacinth) and sucker (e.g. Chrysanthemum) are weak stems. Modifications are meant for propagation.
16. Aerial modifications are of various kinds such as stem tendril (e.g. Passiflora), thorn (e.g. Duranta), phylloclade (e.g. Opuntia), bulbil (e.g. Globa bulbifera) etc. These modifications are for giving support to the weak stern (stem – tendril), for defensive purpose (thorn), for photosynthesis (phyllociade), for reproduction (bulbil) etc.
Difference between Stem and Root
|1||Stem Develops from plumule.||Develops from radicle or any part of the body.|
|2||Moves towards light (positively phototropic)||Moves away from light (negatively Phototropic)|
|3||Moves away from gravity (negatively geotropic)||Moves towards gravity (positively geotropic).|
|4||Moves away from the source ofmoisiture (negatively hydrotropic).||Moves towards the source of water (positively hydrotropic).|
|5||Generally green in colour. (when young)||Generally non-green.|
|6||Apical buds present.||Apical bud absent, instead a cap is present at the tip.|
|7||Presence of nodes and internodes.||Nodes and internodes are absent.|
|8||Bears leaves, flowers and fruits.||Does not bear leaves, flowers and fruits.|
|9||Branches develop in a regular fashion.||Branches develop irregularly.|
|10||There is no definite region of hair growth.||Hairs develop at a particular region.|
|11||Hairs are multicellular.||Hairs are unincellular.|
|12||Branches grow exogenously (from outer layer)||Branches grow endogenously (from pericycle).|
|13||Main functions are to bear leaves, flowers and fruit.||Main functions are to fix the plant to the soil and to help absorb water and minerals.|
|14||Stem may take part in synthesis of carbohydrates when young and green.||Never takes part in synthesis of carbohydrate.|
|15||Above ground parts store very little food. Only underground stems store food but do not become too much fleshy.||Roots modified for storage become excessively swollen due to deposition of food.|