Sexual phenotype of Capparis herbacea (Capparaceae)
Floral morphology coupled with the morphometry of androecium revealed that Capparis herbacea Willd. has an andromonoecious sexual system, producing both male and perfect flowers on the same plant. Functionally male flowers develop more stamens with larger anthers than bisexual ones (63.6 ± 0.6 and 4.1 ± 0.01 mm; 58.1 ± 0.7 and 3.6 ± 0.02 mm, respectively). The ratio of male to perfect flowers ranges from 0.5 to 2.6 during the flowering season. The development of dense trichomes on the adaxial surface of the cavity made by variegated connate petals is presumably adaptive and serves to protect nectary exudate from evaporation in a hot and dry environment. Air temperatures below 30 °C and successful cross pollination-rather than light and relative humidity-limit florescence time and duration. No preference for flower morphs was observed during pollinator visitations. These data confirm the pollen donation hypothesis regarding the role of male flowers in andromonoecious plants. It is a primary benefit of effective pollination in Capparis herbacea, a species with a short blooming period. Results also indicate that Capparis herbacea is the second member of the section Capparis L., after Capparis spinosa L., in which the coexistence of male and hermaphrodite flowers on the same plant has been reported.
Sexual phenotype of Capparis herbacea (Capparaceae)
Floral morphology coupled with the morphometry of androecium revealed that Capparis herbacea Willd. has an andromonoecious sexual system, producing both male and perfect flowers on the same plant. Functionally male flowers develop more stamens with larger anthers than bisexual ones (63.6 ± 0.6 and 4.1 ± 0.01 mm; 58.1 ± 0.7 and 3.6 ± 0.02 mm, respectively). The ratio of male to perfect flowers ranges from 0.5 to 2.6 during the flowering season. The development of dense trichomes on the adaxial surface of the cavity made by variegated connate petals is presumably adaptive and serves to protect nectary exudate from evaporation in a hot and dry environment. Air temperatures below 30 °C and successful cross pollination-rather than light and relative humidity-limit florescence time and duration. No preference for flower morphs was observed during pollinator visitations. These data confirm the pollen donation hypothesis regarding the role of male flowers in andromonoecious plants. It is a primary benefit of effective pollination in Capparis herbacea, a species with a short blooming period. Results also indicate that Capparis herbacea is the second member of the section Capparis L., after Capparis spinosa L., in which the coexistence of male and hermaphrodite flowers on the same plant has been reported.
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- Bingham R & Orthner A (1998). Efficient pollination of alpine plants. Nature 391: 238–239.
- Cao G & Kudo G (2008). Size dependent sex allocation in a monocarpic perennial herb, Cardiocrinum cordatum (Liliaceae). Plant Ecology 194: 99–107.
- Charnov E (1982). The Theory of Sex Allocation. Princeton: Princeton University Press.
- Cuevas J & Polito V (2004). The role of staminate flowers in breeding system of Olea europaea (Oleaceae): an andromonoecious, wind-pollinated taxon. Annals of Botany (Lond.) 93: 547–553.
- Diggle P (1991). Labile sex expression in andromonoecious Solanum hirtum: floral morphogenesis and sex determination. American Journal of Botany 78: 377–393.
- El-Ghani M, Soliman M, Hamdy R & Bennoba E (2013). Weed flora in the reclaimed lands along the northern sector of the Nile valley in Egypt. Turkish Journal of Botany 37: 464–488.
- Emms S (1993). Andromonoecy in Zigadenus paniculatus (Liliaceae): spatial and temporal patterns of sex allocation. American Journal of Botany 80: 914–92.
- Fakhireh A, Ajorlo M, Shahryari A, Mansouri S, Nouri S & Pahlavanravi A (2012). The autecological characteristics of Desmostachya bipinnata in hyper-arid regions. Turkish Journal of Botany 36: 690–696.
- Hendrix S & Trapp E (1981). Plant herbivore interactions: insect induced changes in host plant sex expression and fecundity. Oecologia (Berl.) 49: 119–122.
- Inocencio C, Alcaraz F, Calderón F & Obón C (2002). The use of floral characters in Capparis sect. Capparis to determine the botanical and geographical origin of capers. European Food Research and Technology 214: 335–339.
- Inocencio C, Rivera D, Obón C, Alcaraz F & Barren J-A (2006). A systematic revision of Capparis section Capparis (Capparaceae). Annals of the Missouri Botanical Garden 93: 122–149.
- Ishii H & Sakai S (2000). Optimal timing of corolla abscission: experimental study on Erythronium japonicum (Liliaceae). Functional Ecology 14: 122–128.
- Krupnick A & Weis A (1999). The effect of floral herbivory on male and female reproductive success in Isomeris arborea. Ecology 80: 135–149.
- May P & Spears E Jr (1988). Andromonoecy and variation in phenotypic gender of Passiflora incarnata (Passifloraceae). American Journal of Botany 75: 1830–1841.
- Miller J & Diggle P (2003). Diversification of andromonoecy in Solanum section Lasiocarpa (Solanaceae): the roles of phenotypic plasticity and architecture. American Journal of Botany 81: 1354–1365.
- Peruzzi L, Mancuso E & Gargano D (2012). Males are cheaper, or the extreme consequence of size/age-dependent sex allocation: sexist gender diphasy in Fritillaria montana (Liliaceae). Botanical Journal of Linnean Society 168: 323–333.
- Solomon B (1985). Environmentally influenced changes in sex expression in an andromonoecious plant. Ecology 66: 1321– 13
- Song Y, Ma K, Bo W, Zhang Z & Zhang D (2012). Sex-specific DNA methylation and gene expression in andromonoecious poplar. Plant Cell Reports 8: 1393–1405.
- Vallejo-Marín M & Rausher M (2007). The role of male flowers in andromonoecious species: energetic costs and siring success in Solanum carolinense. Evolution 61: 404–412.
- Yampolsky C & Yampolsky H (1922). Distribution of sex forms in the phanerogamic flora. Bibliotheca Genetica 3: 1–62.
- Zhang T & Tan D (2008). Adaptive significances of sexual system in andromonoecious Capparis spinosa (Capparaceae). Journal of Systematics and Evolution 46: 861–873.
- Zhang T & Tan D (2009). An examination of the function of male flowers in an andromonoecious shrub Capparis spinosa. Journal of Integrative Plant Biology 51: 316–324.