Entomophily in dioecious species of Ephedra: a preliminary report
Acta botanica neerlandica , Volume 30 - Issue 1/2 p. 151- 153
Studies by Porsch (1910, 1916) have shown that Ephedra campylopoda C. A. Mey. is frequently visited by insects, which collect and/or consume the sugary micropylar exudate of ovules of functionally female plants and of the sterile ovules of morphologically hermaphrodite but functionally male plants. The possible significance of such data in connection with the advent of entomophily during the early evolution of the angiosperms was pointed out by the senior author (Meeush 1978, 1979). Although Porsch adduced some cogent evidence as regards the partial dependence of the Ephedra species on a form of biotic pollen transfer for its sexual reproduction, additional data are required. The junior author (R.J.B.) was going to investigate the anthecology of E. campylopoda in Israel between April and June, 1980. but did not find it in anthesis. However, the strictly dioecious species E. alte C. A. Mey., common in the coastal areas oflsrael, produced large numbers of reproductive organs and plants of both sexes appeared to be regularly visited by a variety of insects (Diptera and Apids). As far as successful pollinations are concerned, the effectiveness of these visits in a dioecious species at first seemed negligible. However, the attractant appeared to be neither pollen nor a micropylar pollination droplet, but a different kind of liquid exudate produced by the reproductive regions of both male and female plants. In the female individuals the pollination droplet is minute or even absent, but the so-called ‘chlamys’ (the outer integument in our interpretation) produces a sweetly tasting nectar, which after a test with Fehling’s reagent proved to contain an appreciable quantity of sugar. The male specimens produce smaller quantities of nectar on the outside of the socalled ‘perianth’ or ‘involucre’. The location and anatomical structure of the secernent parts of these organs are under investigation.
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