Ipomoea tricolor, the Mexican morning glory or just morning glory,[1] is a species of flowering plant in the family Convolvulaceae, native to the tropics of the Americas, and widely cultivated and naturalised elsewhere.

Ipomoea tricolor
Ipomoea tricolor 'Heavenly Blue'
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Solanales
Family: Convolvulaceae
Genus: Ipomoea
Species:
I. tricolor
Binomial name
Ipomoea tricolor

Description edit

It is an herbaceous annual or perennial twining liana growing to 2–4 m (7–13 ft) tall. The leaves are spirally arranged, 3–7 cm (1–3 in) long with a 1.5–6 cm (122+12 in) long petiole. The flowers are trumpet-shaped, 4–9 cm (2–4 in) in diameter, most commonly blue with a white to golden yellow centre.

Heavenly blue, and many other species of morning glory, contain ergine.

Cultivation and uses edit

In cultivation, the species is very commonly grown misnamed as Ipomoea violacea, actually a different, though related, species. I. tricolor does not tolerate temperatures below 5 °C (41 °F), and so in temperate regions is usually grown as an annual. It is in any case a relatively short-lived plant. It prefers a warm, sheltered, sunny position such as a south- or west-facing wall.

Ingesting any part of the plant may cause discomfort.[2]

Numerous cultivars of I. tricolor with different flower colours have been selected for use as ornamental plants; widely grown examples include:

  • ‘Blue Star’
  • ‘Flying Saucers’
  • ‘Heavenly Blue’
  • ‘Heavenly Blue Improved’
  • ‘Pearly Gates’
  • ‘Rainbow Flash’
  • ‘Skylark’
  • ‘Summer Skies’
  • ‘Wedding Bells’

The cultivar 'Heavenly Blue' has gained the Royal Horticultural Society's Award of Garden Merit.[2][3]

Weed control edit

Ipomoea tricolor has phytotoxic effects which inhibit seedling growth in weeds. In Mexico, farmers promote the growth of I. tricolor as a cover plant. It prevents weeds and unwanted plants from growing. When it is time to plant crops, this plant is incorporated into the soil. Although it is toxic to weeds, it does not affect crops such as sugarcane.[4]

Toxic treatments aimed at discouraging entheogenic use edit

Commercial seeds are sometimes treated with toxic methylmercury (although the use of methylmercury has been banned in the US and the UK since the 1980s), which serves as a preservative and a cumulative neurotoxic poison that is considered useful by some to discourage recreational use of the seeds as an entheogen (hallucinogen). There is no legal requirement in the United States to disclose to buyers that seeds have been treated with a toxic heavy metal compound.[5] According to the book Substances of Abuse, in addition to methylmercury, the seeds are claimed to be sometimes coated with a chemical that cannot be removed with washing that is designed to cause unpleasant physical symptoms such as nausea and abdominal pain. The book states that this chemical is also toxic.[6]

Colour change edit

In Ipomoea tricolor 'Heavenly Blue', the colour of the flower changes during blossom according to an increase in vacuolar pH.[7][8][9] This shift, from red to blue, is induced by chemical modifications affecting the anthocyanin molecules present in the petals.

References edit

  1. ^ Brickell, Christopher, ed. (2008). The Royal Horticultural Society A-Z Encyclopedia of Garden Plants. United Kingdom: Dorling Kindersley. p. 570. ISBN 9781405332965.
  2. ^ a b "RHS Plant Selector - Ipomoea tricolor". Royal Horticultural Society. Retrieved 22 September 2020.
  3. ^ "AGM Plants - Ornamental" (PDF). Royal Horticultural Society. July 2017. p. 53. Retrieved 13 March 2018.
  4. ^ Anaya, A (1995). "Allelopathic potential of Ipomoea tricolor (Convolvulaceae) in a greenhouse experiment". National Library of Medicine. Journal of Chemical Ecology. doi:10.1007/BF02228313. Retrieved 16 March 2024.
  5. ^ Dunn Chace, Teri (2015). Seeing Seeds: A Journey into the World of Seedheads, Pods, and Fruit. Portland OR: Timber Press. ISBN 978-1604694925.
  6. ^ Potter, James (2008). Substances of Abuse. Redding CA: Jubilee Enterprises. p. 157. ISBN 978-1930327467.
  7. ^ Yoshida, Kumi; Kawachi, Miki; Mori, Mihoko; Maeshima, Masayoshi; Kondo, Maki; Nishimura, Mikio; Kondo, Tadao (2005). "The Involvement of Tonoplast Proton Pumps and Na+(K+)/H+ Exchangers in the Change of Petal Color During Flower Opening of Morning Glory, Ipomoea tricolor cv. Heavenly Blue". Plant and Cell Physiology. 46 (3): 407–415. doi:10.1093/pcp/pci057. ISSN 1471-9053. PMID 15695444.
  8. ^ Yoshida, Kumi; Kondo, Tadao; Okazaki, Yoshiji; Katou, Kiyoshi (1995). "Cause of blue petal colour". Nature. 373 (6512): 291. Bibcode:1995Natur.373..291Y. doi:10.1038/373291a0. ISSN 0028-0836. S2CID 29952543.
  9. ^ Yoshida, Kumi; Miki, Naoko; Momonoi, Kazumi; Kawachi, Miki; Katou, Kiyoshi; Okazaki, Yoshiji; Uozumi, Nobuyuki; Maeshima, Masayoshi; Kondo, Tadao (2009). "Synchrony between flower opening and petal-color change from red to blue in morning glory, Ipomoea tricolor cv. Heavenly Blue". Proceedings of the Japan Academy, Series B. 85 (6): 187–197. Bibcode:2009PJAB...85..187Y. doi:10.2183/pjab.85.187. ISSN 0386-2208. PMC 3559195. PMID 19521056.

External links edit