Studies on the floral anatomy and scent chemistry of Titan Arum (Amorphophallus titanum, Araceae)

Authors: RAMAN, VIJAYASANKAR - University Of Mississippi; TABANCA, NURHAYAT - University Of Mississippi; DEMIRCI, BETUL - Anadolu Universtiy; KHAN, IKHLAS - University Of Mississippi

Submitted to: Turkish Journal of Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/19/2016
Publication Date: 1/17/2017
Citation: Raman, V., Tabanca, N., Demirci, B., Khan, I.A. 2017. Studies on the floral anatomy and scent chemistry of Titan Arum (Amorphophallus titanum, Araceae). Turkish Journal of Botany. 41:63-74.

Interpretive Summary: The inflorescence of Titan arum (Amorphophallus titanum) is the largest of its kind in the world. It is also commonly called as ‘corpse flower’ or ‘carrion flower’ due to the characteristic putrid odor of its bloom. This plant is rare, endangered and found naturally only in the evergreen forests in Sumatra Island, Indonesia. It is occasionally grown in a few botanical gardens and it blooms rarely. Last year, two plants of titan arum bloomed at the botanical garden of the University of Mississippi. The present paper provides anatomical descriptions of various parts of the inflorescence illustrated with light and scanning electron microscopy images and also analyzes the composition of the floral scent. During the study, we found various shapes of calcium oxalate prismatic crystals in the floral parts for the first time. We collected the volatile compounds from various parts of the inflorescence using a Headspace-Solid Phase Microextraction (HS-SPME) technique and analyzed the chemical components, GC-MS. The major volatile compounds present in the floral scent included butyl acetate, y-butyrolactone, isovaleric acid, tetradecane, butyric acid, benzylalcohol, 4-hydroxy-4-methyl-2-pentanone, and 3-hydroxy-2-butanone.

Technical Abstract: Titan arum (Amorphophallus titanum)is popularly known for its world's largest unbranched inflorescence. It is also commonly called 'corpse flower' or 'carrion flower' due to the characteristic, putrid odor of the bloom. The present study illustrates detailed anatomy and micromorphology of various parts of the inflorescence and also analyzes the chemistry responsible for the odor. Micrographs of light and scanning electron microscopy were prepared and discussed. This study recognizes two types of raphide crystals, the Lemna type and the Agave type, and also reports various shapes of prism crystals in this plant for the first time. The volatile compounds from different parts of the inflorescence were collected by a Headspace­ Solid Phase Microextraction (HS-SPME) technique and the samples were analyzed by GC-MS. The major volatile compounds found in the appendix were isovaleric acid (21.6%), butyric acid (17.0%), benzyl alcohol (16.2%) and y-butyrolactone (12.1%). The male flowers contained y­ butyrolactone (27.0%), tetradecane (13.4%) and 4-hydroxy--4-methyl-2-pentanone (10.5%) and the female flower exhibited tetradecane (19.9%),4-hydroxy--4-methyl-2-pentanone (13.0%) and 3-hydroxy-2-butanone (10.6%). In the spathe, butyl acetate (44.1%) and 3-hydroxy-2- butanone (12.9%) were present. The volatile composition in titan arum showed variations across different parts of the inflorescence. The application of HS-SPME-GC-MS was used to determine volatile compounds from the natural floral scent of the fresh bloom of titan arum.