Phenolic Compounds Influence Seed Dormancy of Palicourea rigida H.B.K. (Rubiaceae), a Medicinal Plant of the Brazilian Savannah

Marielle C. Inácio, Rita Maria Moraes, Patrícia C. Mendonça, Lucas J. F. Morel, Suzelei C. França, Bianca W. Bertoni, Ana M. S. Pereira

Departamento de Biotecnologia de Plantas Medicinais, Universidade de Ribeir?o Preto, Ribeir?o Preto, Brazil.
Departamento de Horticultura, Universidade Estadual Paulista Julio de Mesquita Filho, Botucatu, Brazil.
National Center for Natural Products Research, School of Pharmacy, The University of Mississippi, Oxford, USA.

DOI: 10.4236/ajps.2013.41017                

Abstract

Palicourea rigida H.B.K. (Rubiaceae), a medicinal species commonly known as douradinha, has wide distribution across ecosystems in Central and South America. This species exhibits seed dormancy delaying germination until optimal conditions for seedling growth and development are in place. While dormancy ensures species survival, it also presents a technical problem for developing P. rigida’s plant production program. Thus, the objective of this study was to investigate if secondary metabolites present in seeds influence the seed dormancy of P. rigida. Mature fruits were harvested from the native habitat, in the savanna region of the State of Minas Gerais during February 2009, 2010 and 2011. The content of phenolic compounds in the seed of P. rigida was measured, and the allelopathic effects were assessed using the germination of lettuces as model to detect phytotoxicity. The P. rigida seeds geminated at rates varying between 7% and 31% with a Seed Germination Index (SGI) of 0.09. Data suggest that the phenolic compounds present in the seeds may be responsible for seed dormancy.

Keywords

Cerrado; Douradinha; Medicinal Plant; Conservation

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	J. G. Melo, E. L. C. Amorin and U. P. Albuquerque, “Native Medicinal Plants Commercialized in Brazil—Priorities for Conservation,” Environment Monitoring and Assessment, Vol. 156, No. 1-4, 2009, pp. 567-580. doi:10.1007/s10661-008-0506-0
[2]	J. M. Baskin and C. C. Baskin, “A Classification System for Seed Dormancy,” Seed Science Research, Vol. 14, No. 1, 2004, pp. 1-16. doi:10.1079/SSR2003150
[3]	C. C. Baskin and J. M. Baskin, “Seed Dormancy in Trees of Climax Tropical Vegetation Types,” Tropical Ecology, Vol. 46, No. 1, 2005, pp. 17-28.
[4]	B. Kucera, M. A. Cohn and G. Leubner-Metzger, “Plant Hormone Interactions during Seed Dormancy Release and Germination,” Seed Science Research, Vol. 15, No. 4, 2005, pp. 281-307. doi:10.1079/SSR2005218
[5]	W. E. Finch-Savage and G. Leubner-Metzger, “Seed Dormancy and the Control of Germination,” New Physiologist, Vol. 171, No. 3, 2006, pp. 501-523. doi:10.1111/j.1469-8137.2006.01787.x
[6]	V. E. G Rodrigues and D. A. Carvalho, “Etnobotanical Survey of Medicinal Plants in the Dominion of Meadows in the Region of the Alto Rio Grande—Minas Gerais,” Ciência e Agrotecnologia, Vol. 25, No. 2, 2001, pp. 102-123.
[7]	E. A Rosa, B. C. Silva, F. M Silva, C. M. A Tanaka, R. M Peralta, C. M. A. Oliveira, L Kato, H. D Ferreira and C. C Silva, “Flavonoids and Antioxidant Activity in Palicourea rigida Kunth, Rubiaceae,” Revista Brasileira de Farmacognosia, Vol. 20, No. 4, 2010, pp. 484-488. doi:10.1590/S0102-695X2010000400004
[8]	S. Lopes, G. L. Von Poser, V. A Kerber, F. M. Farias, E. L Konrath, P. Moreno, M. E Sobral, J. A. S. Zuanazzi and A. T. HENRIQUES, “Taxonomic Significance of Alkaloids and Iridoid Glucosides in the Tribe Psychotrieae (Rubiaceae),” Biochemical Systematics and Ecology, Vol. 32, No. 12, 2004, pp. 1187-1195. doi:10.1016/j.bse.2004.04.015
[9]	L. J. F. Morel, D. M. Baratto, P. S. Pereira, S. H. T. Contini, H. G. Momm, B. W. Bertoni, S. C. Fran?a and A. M. S. Pereira, “ Loganin Production in Palicourea rigida H.B.K. (Rubiaceae) from Populations Native to Brazilian Cerrado,” Journal of Medicinal Plants Research, Vol. 5, No. 12, 2011, pp. 2559-2565.
[10]	M. F Siqueira, “A Terra Mais Quente,” Pesquisa Fapesp, Vol. 96, 2005, pp. 34-37.
[11]	Brasil, Ministério da Agricultura, Pecuária e Abastecimento, “Regras para análise de sementes/Ministério da Agricultura, Pecuária e Abastecimento. Secretaria de Defesa Agropecuária,” Mapa/ACS, Brasília, 2009, 399 Pages.
[12]	J. D. Maguire, “Speed of Germination Aid in Selection and Evaluation for Seeding Emergence and Vigor,” Crop Science, Vol. 2, No. 2, 1962, pp. 176-177. doi:10.2135/cropsci1962.0011183X000200020033x
[13]	D. F. Ferreira, “Sisvar 5. 1-Análises estatíSticas Por Meio do Sisvar para Windows,” Universidade Federal de Lavras, Lavras, 2005. Available at http://www. dex. ufla. br/~danielff/softwares. htm
[14]	M. M. Ramirez-Rodrigues, M. L Plaza, A. A. M. O Balaban and M. R. Marshall, “Physicochemical and Phy-to-chemical Properties of Cold and Hot Water Extraction from Hibiscus sabdariffa,” Journal of Food Science, Vol. 76, No. 3, 2011, pp. 428-435. doi:10.1111/j.1750-3841.2011.02091.x
[15]	H. Shimomura, Y. Sashida, H. Nakata, A. Yamamoto, Y. Kawakubo and J. Kawasaki, “Germination and Growth Inhibitors in Fruits of Gardenia jasminoides,” Plant Cell Physiology, Vol. 24, No. 1, 1983, pp. 123-126.
[16]	C. E. Pereira, E. V. R. V Pinho, D. F Oliveira and A. L. P Kikuti, “Germination Inhibitors Determination in the Spermoderm of Coffee (Coffea Arabica L.) Seeds,” Revista Brasileira de Sementes, Vo. 24, No. 1, 2002, pp. 306-311.
[17]	R. W. Willemsen and E. L. Rice, “Mechanism of Seed Dormancy in Ambrosia artemisiifolia,” American Journal of Botany, Vol. 59, No. 3, 1972, pp. 248-257. doi:10.2307/2441425
[18]	Z. H. Ali, Q. Wang, X Ruan, C. D. Pan and D. A. Jiang, “Phenolics and Plant Allelopathy,” Molecules, Vol. 15, No. 12, 2010, pp. 8933-8952. doi:10.3390/molecules15128933
[19]	L. Kong, F. Wang, J. Si, B. Feng and S. Li, “Water- Soluble Phenolic Compounds in the Coat Control Germination and Peroxidase Reactivation in Triticum aestivum Seeds,” Plant Growth Regulators, Vol. 56, No. 3, 2008, pp. 275-283. doi:10.1007/s10725-008-9307-2