How plants reproduce asexually and naturally?

 Vegetative Propagation

Stem , leaves , roots are vegetative parts of plants.

Flowers are reproductive parts of the plants which perform sexual reproduction. Vegetative parts are produced much before the reproductive parts in a plant.

Sometimes vegetative propagation happens in plants in addition to the sexual reproduction.

For example in banana flowers utilised for sexual reproduction where as modified stem rhizomes are used in vegetative propagation .

Some plants are vegetatively propagated with the help of roots for example sweet potato.

Some plants are propagated with the help of modified stem. For example Ginger turmeric are propagated by modified stem having buds and stored food. 

Onion and garlic are grown by modified shoot called bulb which have leaves filled with food.

Potatoes which we eat are having nodes for eyes having buds which can grow into new potato if planted in soil. These modified stems of potato are called stem tuber. They also store food . 

Suckers our modified stems in mint and chrysanthemum which are produced from base of another shoot and they grow parallel to the ground coming out of the soil to sprout new shoots . They remain themselves underground most of the part except where they produce aerial shoots .

Offsets are modified stem in aquatic plants producing bunch of leaves at their top and help water hyacinth to cover the surface of water .

Terror of Bengal is the name given to this plant ( Eichornia crassipes )  

 Asexual Reproduction

In this type of reproduction new individuals are produced by a single individual parent . Gametes generally are not required except in special cases ( parthenogenesis ) . 

For example a mother bacterial cell will produce two daughter cells  without involving any gametic cells and second partner . So this is uniparental.

No meiosis will be required in such cases as no gamete is required. 

Daughter cells produced from such type of reproduction are difficult to distinguish from each other as they are morphologically and genetically similar. They may have few variation on account of DNA copying errors . 

Asexual reproduction is seen in both plants and animals in addition to microbes . As we move up the ladder in animal world its occurence decreases and sexual reproduction dominates vehemently .

Different modes of asexual reproduction:

Binary fission : It takes place in bacterial and protozoal cells . Eg. Curd Bacteria , amoeba , paramecium . In this one big cell divides into two nearly equally small daughter cells which will grow like their mother cells in near future . In this nuclear material is divided equally into daughter cells .

Multiple fission : It occurs in plasmodium ( which is a protozoan  parasite causing malaria in humans ) . Single mother cells divide it's nucleus into many nuclei which become surrounded by some cytoplasmic material to form multiple daughter cells instead of only two . 

Budding : In case of yeast and hydra which exhibit budding mechanism to reproduce we find that cell division is required without reducing chromosome number . Mitotic division in parent body leads to bud like growth which continue to grow in size . Ultimately a small body similar to parent is seen attached to its outer surface in hydra .

In yeast divisions just lead to increase in number of daughter cells which remain attached with parent yeast . In yeast actually it is variant of binary fission in which unequal cell division after nuclear division leads to two daughter cells out of which smaller one remain attached to larger daughter cell . 

Sporulation 

During unfavorable conditions amoeba with generally divides by binary fission tend to tide over these conditions by remaining inactive and protected under a resistant coat called cyst wall.  When favourable conditions are back amoeba multiply by multiple fission and the products are released from the cyst which provided shelter from harsh conditions. 

Spore formation in fungi , algae .

Zoospores : these are reproductive structures units which are motile on account of flagella . Flagella vary in number . Zoospores can be dispersed with the help of these flagella .

Immovable spores are also seen in fungi and algae called aplanospores .

Conidia are immovable spores produced on the tip of conidiophores in aspergillus and penicillium .They are generally attached to each other in tandem .

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Regeneration  or reproduction 

In some animals like planaria if we cut the animal into two or more parts they can regenerate whole body from the cut parts . This ability is termed as regeneration .

Other animals  star fish , lizard have limited capacity for regeneration.