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Abstract Detail

Pollination Biology

Little, R John [1].

Flowers in Motion: Nyctinasty in Viola banksii, an Australian native.

Nyctinastic flowers are those that close up at night after being open all day. Also included are flowers that open up at night, after being closed all day. A few of the species reported in literature or observed by the author to exhibit nyctinasty include one or more species of Anemone, Crocus, Eschscholzia, Hibiscus, Malva, Magnolia, Mentzelia, Mirabilis, Nymphaea, Oenothera, Oxalis, Stellaria, Taraxacum, Tribulus, and Tulipa. This study adds Viola to the list. A comprehensive list of nyctinastic flowers is apparently lacking. Research on nastic movements has primarily focused on leaves of various species. There appear to be few published studies involving flowers. Theories for the selective advantage of flowers closing at night include protection of pollen and/or nectar, protection of floral part from night-foraging insects, etc. Nyctinasty can be viewed as one component of a species’ pollination strategy. In 2011, I discovered that flowers of Viola pinetorum, collected on a mountain top in southern California, fold up at night then reopen in the morning. Later that year in Australia, I observed that flowers of Viola silicestris also close up at night. In 2013, I observed that flowers of Viola banksii, a species native to Australia and sold in nurseries in CA, are nyctinastic (open during day, closed at night). In 2014, I began a study to monitor the sleep movements of V. banksii flowers. During the same time of my study in CA, a colleague in Australia began a similar set of observations on V. banksii flowers in Brisbane, Queensland, using an identical humidity and temperature gauge as I used. This report focuses only on V. banksii flowers observed in CA. Four sets of observations, consisting of photographs of 10 flowers, one taken in the morning and another in the evening, were made for 6-8 days in June and July 2014. The goal was to answer basic questions, e.g., how many times does a flower open and close? How many days does a flower remain viable? Are nyctinastic movements influenced by humidity or temperature? Do flowers close on cloudy or rainy days? Initial results show that about 77% of flowers completely close up (sleep) at night on the same day they first opened; 89% if partial closures are counted. About 16% close twice, always on consecutive days. About 5% do not close up. Flowers appear viable for 5-6 days.

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1 - 16 PEBBLE RIVER CIRCLE, Sacramento, CA, 95831, USA

Viola banksii.

Presentation Type: Oral Paper
Session: 36, Pollination Biology
Location: 203/Savannah International Trade and Convention Center
Date: Wednesday, August 3rd, 2016
Time: 11:15 AM
Number: 36012
Abstract ID:923
Candidate for Awards:None

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