Parthenocarpy and Parthenogenesis

The natural or artificial production of fruit without fertilisation of ovules which lack seeds said to be parthenocarpy. It is an unisexual reproduction .  Examples  are Watermelon, Pineapple, Banana etc. The process or strategy of development or growth of embryos without fertilisation is called parthenogenesis, it occurs mainly in animals and also in plant species. Examples are rotifers, daphnia, nematodes (invertebrates animal) . Birds, snakes, sharks , and lizards (vertebrates).

Parthenocarpy

The development of fruit actually takes place from the flower which contains the male and female reproductive parts of a plant. After fertilisation, the ovary evolves into a fruit and the ova becomes its seed. The plump and soft region of the fruit is nothing but an ovary.

The parthenocarpy process was introduced in 1902. The parthenocarpy fruits like cucumber, banana, pineapple etc. contain gibberellic acid, which results in the maturation of ovaries without fertilisation leading to the products like seedless big and pulpy fruits.

The process of the development of fruits without fertilisation is called ‘parthenocarpy’. These fruits are devoid of embryo and endosperm and do not have seeds within that is why they are also called ‘virgin or seedless fruits’.

Types of Parthenocarpy

• Vegetative parthenocarpy
• Stimulative parthenocarpy
• Stenospermocarpy

Vegetative parthenocarpy – In vegetative parthenocarpy, it takes place without pollination which therefore results in no seed within seeds. It can be seen in pears and fig.

Stimulative parthenocarpy – This stimulative parthenocarpy occurs when the ovipositor of a wasp is inserted into the ovary of a flower and can also happen by plant growth regulators that are present in syconium of unisexual flowers.

Stenospermocarpy – In this unique type of parthenocarpy, fertilisation takes place and the seed develops but finally aborts. This unique type of parthenocarpy can be seen in seedless grapes and watermelons. 

These partially developed seeds are extracted from the fruit and grown into plants with the help of tissue culture techniques.

Benefits of Parthenocarpy

• Reduction of the complete cost of cultivation
• This process results in quality improvement with seedless fruit
• It is a healthy process and results are achieved easily
• Improvement of crop yield without using chemicals or organic pesticides
• Protection of plants from pesticides
• Fruits produced are larger due to natural plant growth regulators

Parthenogenesis

Parthenogenesis mainly occurs in animals and also in some plant species. It forms by asexual reproduction and this development of the embryo takes place without fertilization. No sex chromosomes also can reproduce from parthenogenesis 

In animals from an unfertilized egg cell and in plants it occurs from apomixis. Apomixis is the formation of seeds without fertilisation.

Types of Parthenogenesis

• Natural parthenogenesis
• Artificial parthenogenesis

Natural Parthenogenesis –  In some organisms it is a constant process which occurs naturally. It occurs naturally in bees. It can also be divided into two complete and incomplete parthenogenesis.

Artificial Parthenogenesis – When the fertilised eggs develop parthenogenetically by means of different chemicals and physical means known as artificial parthenogenesis.

Benefits of Parthenogenesis

• Parthenogenesis process saves time and energy because a female that reproduces using parthenogenesis has no need for a male
• Without the need for males, parthenogens can reproduce faster than species that reproduce sexually which increases the population size
• Reproduction can be done in times of scarcity because females also do not have to expend energy to search for male
• Parthenogenesis results in genetic stability because organisms produced via this have a genetic code that comes from individuals instead of two combinations
• Parthenogenesis also promotes medical research

Parthenocarpy and Parthenogenesis: Difference

1. Parthenocarpy occurs only in plants, whereas Parthenogenesis occurs in invertebrate animals and lower plants.
2. In Parthenocarpy development of fruit takes place without fertilisation, whereas in Parthenogenesis development of a new organism takes place without fertilisation of an ovum.
3. In Parthenocarpy seedless fruits are produced, whereas in Parthenogenesis female clones are produced and cannot reproduce sexually.
4. Parthenocarpy is a unisexual reproductive method, whereas Parthenogenesis is also a unisexual reproductive method.
5. Parthenocarpy results in the production of seedless fruits, whereas Parthenogenesis results in the production of haploid organisms.
6. Examples of Parthenocarpy in banana, seedless watermelon, pineapple etc., whereas examples of Parthenogenesis are honey bees, rotifers, some lizards and birds.
7. In Parthenocarpy unfertilized ovule develops into a seedless fruit, whereas in Parthenogenesis unfertilized ovule develops into a new organism.

Conclusion

Both Parthenocarpy and Parthenogenesis are a form of asexual reproduction which occurs without fertilization. Parthenocarpy occurs only in plants where the development of fruit takes place and Parthenogenesis occurs mainly in animal and some plant species where the development of new organisms takes place without fertilisation.