A novel mechanism controls anther opening and closing in Paris polyphylla var. Yunnanensis

The phenomena of anther opening and closing in Paris polyphylla var. yunnanensis (Franch) Hand.-Mazz were described in detail, and the effects of ecological factors on those phenomena related to anther opening, closing and the fly-pollination mechanism were discussed. Anthers of P. polyphylla var. yunnanensis open in the morning and close in the evening every day during an over 20 days’ period of anthesis. Light was detected as the main factor controlling this daily anther opening and closing. Anther opening can be reversed in response to rain and re-opens when rain stops. Relative humidity (RH) has a slight effect on anther opening and closing. Flower spans can be prolonged under laboratory conditions. This novel behavior of anther is likely to be a mechanism to enhance the male fitness in this species, of which has no inherited structure to protect pollen from the perianth.