Sexual Reproduction In Orchids

In contrast to the method adopted by the orchids in achieving vegetative reproduction, which are very much the same as in other plant families , the process of sexual reproduction shows several peculiarities . As mentioned earlier, in orchids, seeds are produced in thousands and in some cases even in millions . The fertilization of such a large number of ovules is facilitated by the pollen being carried about in packets (pollinia ) in the majority of cases . Moreover , endosperm tissue is entirely lacking in seeds and consequently development of the embryo shows several deviations from the usual angiosperm pattern.

Our information regarding microsporogenesis , megasporogenesis , fertilization , embryogeny etc. in orchids is , to say the least , quite inadequate . Of the 25-35,000 species of existing orchids, less than a hundred species have been studied with regard to the aspects mentioned above . The most detailed work on the embryogeny in orchids is that of Swamy (1948, 1949). The account given below is largely based on his work on 33 species of orchids, the majority of them native to South India .