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APOGAMY & APOSPORY.pptx

This document discusses apogamy and apospory in plants. It defines apogamy as asexual reproduction in ferns where a haploid gametophyte develops into a haploid sporophyte without gamete fusion. Apospory is defined as the development of a diploid gametophyte from the vegetative cells of a diploid sporophyte, without meiosis or spore formation. The key difference between the two is that apogamy produces a haploid embryo while apospory produces a diploid embryo. Causes of each include environmental stresses that prevent normal sexual reproduction. Similarities include that both are asexual reproductive processes that occur in bryophytes and involve alternation of generations

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Gondawana University, Gadchiroli BRAMHAPURI, DIST. CHANDRAPUR Seminar Topic APOGAMY & APOSPORY Presented By M.Sc. – Ist (BOTANY) I st Sem. Guided By
CONTENT • Introduction • Definition • Difference Between Apospory and Apogamy • Causes of Apogamy • Causes of Apospory • Similarities Between Apogamy and Apospory
INTRODUCTION In apogamy, the sporophyte in some ferns develops from the gametophyte. In apospory, gametophyte develops directly from the vegetative cells of the sporophyte. Apogamy occurs without syngamy, therefore the haploid gametophyte (n) develops into a haploid sporophyte(n), instead of a diploid sporophyte (2n).
DEFINITION Apogamy :- Apogamy is a unique process of asexual reproduction in ferns, in which the development of haploid sporophyte(n) occurs from a haploid gametophyte(n) without the fusion of gametes.
APOSPORY (DEFINITION)- • Apospory is the process of formation of the diploid gametophyte (2n) from the vegetative cells of the sporophyte (2n), without meiosis and formation of spores. • It was first discovered in the year 1884 by Druery, in the plant Athyrium foemina var. clarissima jones. The aposporous gametophyte that has formed in this variety developed from its sporangium stalk and head. • Pteris aquiline, Asplenium dimorphum, Osmunda javanica are the plants in which apospory occurs naturally.
DIFFERENCE BETWEEN APOSPORY AND APOGAMY Apogamy Apospory Apogamy is an asexual method of reproduction in plants where the gametophyte develops from the sporophyte Apospory is also an asexual method of reproduction where sporophyte develops from the gametophyte. Produces a diploid gametophyte Produces a haploid embryo Gametes are formed without the formation of gametophytes The embryo is formed without the process of fertilization
CAUSES OF APOGAMY • The chances of occurrence of apogamy are high in those plants whose prothallus have aged.When the gametophyte fails to produce gametes, there will be fewer chances for fusion. • Hence, Apogamy will occur in such a situation where the failure of sex organ formation occurs.Apogamy happens in those situations, when the plants fail to carry out normal fertilisation (sexual reproduction), either due to certain abnormal physiological conditions or environmental conditions.
CAUSES OF APOSPORY • Causes of Apospory occurs in those pteridophytes who suffer from the deficiency of mineral nutrition due to the lack of minerals in the soil.If the leaves of pteridophyte develop under dim light, chances of occurrence of apospory become high.
SIMILARITIES BETWEEN APOGAMY AND APOSPORY • Asexual reproduction takes place during both apogamy and apospory.Both of them take place in plants.The gametophyte and sporophyte share the same ploidy level in both phenomena. • Both of them take place mainly in bryophytes.The formation of gametes does not occur in apogamy and apospory.Both of them participate in the alternation of generation (alteration of a sexual phase, i.e., gametophyte and an asexual phase, i.e., sporophyte) in the life cycle of an
APOGAMY & APOSPORY.pptx
APOGAMY & APOSPORY.pptx