Sexual system of Garcinia indica Choisy: geographic variation in trioecy and sexual dimorphism in floral traits

• Published in: Plant systematics and evolution Vol. 301; no. 3; pp. 1065 - 1071
• Main Authors: Joseph, K. S, Murthy, H. N
• Format: Journal Article
• Language: English
• Published: Vienna Springer-Verlag 01.03.2015; Springer-Verlag Gmbh; Springer Vienna; Springer Nature B.V
• Subjects: androdioecy; Biomedical and Life Sciences; Bisexuality; Carpels; female flowers; Flowering; Flowering plants; Flowers; Garcinia indica; Geographical Locations; geographical variation; Gynodioecy; Hermaphroditism; Life Sciences; male flowers; males; monoecy; Plant Anatomy/Development; Plant Ecology; Plant Sciences; Plant Systematics/Taxonomy/Biogeography; Plants (botany); Populations; Sexual dimorphism; SHORT COMMUNICATION; Stamens; Trees; Variation; Trioecy; Pistillode; Paths to dioecy; Staminodes
• ISSN: 0378-2697; 1615-6110; 2199-6881
• DOI: 10.1007/s00606-014-1120-y

Most flowering plants are hermaphroditic with both stamens and carpels in the same flower. Other sexual systems are derived from ancestral hermaphroditism through one of the following pathways namely via monoecy, directly from hermaprhoditism, via gynodioecy, via distyly or via androdioecy. Sexual system in the genus Garcinia is highly diverse and includes dioecious, gynodioecious, androdioecious, polygamodioecious, monoecious and andromonoecious species. Garcinia indica Choisy (kokum tree) is reported to be polygamodioecious or gynodioecious. In the present study, sexual variation was estimated in seven populations of Garcinia indica of Western Ghats to determine the extent of variation among the populations and 14 floral traits were studied to assess the sexual dimorphism in floral traits. Four basic kinds of flowers namely, male flowers, male flowers with pistillode, female flowers with staminodes and bisexual flowers, were found in G. indica. These basic kinds of flowers occurred individually on a particular tree, producing unisexual individuals, or in combination of two, forming cosexual individuals. Thus, this species is trioecious, although the percentage of cosexual trees varied in different geographical locations. All the populations included cosexuals except one whereas pure hermaphroditic trees were present only in one. Significant differences were observed in 11 out of the 14 floral traits studied in the seven populations resulting in the diversity of sex forms. Male flowers had larger petal and female flowers were in general smaller than the other kinds. Interestingly, bisexual flowers were not always intermediate in size between male and female flowers.