Sex in plants


Q.12. How does sex takes place in plants?

Ans. Plants execute simple sexual behaviour than animals which is entirely their instinctive nature. This behaviour is essential for their survival and came into existence after many trials and errors. The sexual behaviour of a. form of life is of a particular type because it is its intrinsic nature and property to behave as such. One aspect that affects the mode of sex in plants is that they are stationary and the two strains or genders of a species cannot come in contact with each other by movement except in the primitive type of plants.

Life came into existence by the formation of protoplasm and nucleic acid which are the basic materials of life. The chromosome containing nucleic acids which in turn possess genes are the penultimate forms of life. Most forms of life have genetic material present in deoxyribonucleic acids (D.N.A.) though a few have it in ribonucleic acid (R.N.A.). Viruses constitute the simplest and the most primitive form of sex life and are in fact a link between the living and non-living coming into existence from non-living organic substance. Then developed the bacteria which were without true nucleus. Mutation, hybridization and cross breeding give rise to new species spontaneously in nature for the sake of their genetic survival as the means of adaptation. Artificial new species have been produced by cloning genes of different varieties by human being sex . Survival of life is possible by reproduction. Sex ethics includes reproduction by binary fission and a sexual means in the broad sense of the term. The wider meaning of sex is equivalent to all means of propagation of an individual life.

Binary fission which is in fact a variant of vegetative reproduction is seen in primitive form of viruses and as a normal mode of reproduction in bacteria. A sexual boredom reproduction in the primitive form which is in fact a mode of self propagation in bacteria, becomes a developed normal phenomenon in fungi, algae, bryophytes and pteridophytes Vegetative reproduction occurs in algae, bryophytes.. pteridophytes and gymnosperms, sexual reproduction is seen in undeveloped primitive form in bacteria, in improved form in fungi and algae, and becomes fully developed in bryophytes, pteridophytes gymnosperms and angiosperms. The commonest mode of reproduction is by binary fission in bacteria and viruses, vegetative method in algae, asexual form in fungi and pteridophytes and sexual behavior means in bryophytes gymnosperms and angiosperms. The adult plants of viruses, bacteria, fungi, algae and bryophytes are haploid while that of pteridophytes, gymnosperms and angiosperms diploid. Alternation of generation is seen in bryophytes, pteridophytes and gymnosperms in which the haploid gametophytic sexual generation alternates with the diploid sporophytic a sexual generation. The main adult plant is haploid gametophyte in bryophytes while it is diploid sporophytic in pteridophytes and gymnosperms. Bryophytes reproduce sexually with the asexual generation being less significant, pteridophytes reproduce asexually with the sexual generation being less significant while gymnosperms again reproduce sexually with the asexual generation being less conspicuous. Angiosperms are the most developed groups of plants having flowers as their reproductive sex organs which are diploid and reproduce sexually by fusion of male and female gametes. In higher plants and animals, male gametes do not possess cytoplasm and only nuclei take part in fertilization.