Occimum gratissimum (fever plant) is a crop with a wide range of use as a medicinal plant and as a spice. In spite of

its huge economic importance, the plant is only grown in homestead. The study investigated the effects of light, temperature

and water treatments on the germination of the seeds. The incubation of seeds at 25 °C under light condition,

coupled with leaching in running water for 12 hours was found to release the dormancy in the seeds of Occimum gratissimum

Obembe, Olawole O.

English

Covenant University Repository

Obembe, et al, Seed pretreatments enhance germination in Occimum gratissimum (lameaceae)∙  46  ∙Seed pretreatments enhance germination in Occimum gratissimum (lameaceae)Olawole O Obembe1,*, DA Agboola21Department of Biological Sciences, College of Science and technology, Covenant University, Canaan Land, P.M.B. 1023, Ota, Ogun State, Nigeria; 2Department of Biological Sciences, College of Natural Sciences, University of Agri-culture, P.M.B. 2240, Abeokuta, Nigeria Received January 28, 2008AbstractOccimum gratissimum (fever plant) is a crop with a wide range of use as a medicinal plant and as a spice. In spite of its huge economic importance, the plant is only grown in homestead. The study investigated the effects of light, tem-perature and water treatments on the germination of the seeds. The incubation of seeds at 25 °C under light condition, coupled with leaching in running water for 12 hours was found to release the dormancy in the seeds of Occimum gratis-simum. [Life Science Journal. 2008; 5(1): 46 – 48] (ISSN: 1097 – 8135).Keywords: medicinal plants; endangered species; occimum; germination; dormancy1  IntroductionOccimum gratissimum (O. gratissimum) (linn), the fever’s plant belong to the group of labiates herbs with about 180 genera and 3500 species (Lancer and Hill, 1991; Masefield et al, 1973; Sofowora, 1982). The aro-matic leaves add flavor to soups and sauces. O. gratis-simum produces a volatile oil which has anti-microbial properties (Moundipa et al, 2005; Sofowora, 1982); as such it is being used as a vegetable spice for meat seasoning in Nigeria. Its efficacy in the control of food storage insects and as a fungicide has also been explored (Awuah, 1996; Eze et al, 2006). Its leaf extract is gener-ally believed to cure respiratory infections (Agusiobo, 1984; Lasisi and Ajuwon, 2002). Additionally, it is also used in the treatment of epilepsy, high fever and mental illness (Abdulrahman, 1992; Oliver, 1980; Osifo, 1992). Furthermore, O. gratissimum is being used for the cure of diarrhoea, headache, ophthalmic (ocular) diseases, skin diseases, pneumonia, cough, fever, conjunctivitis, as well as digestive disorders (Obuekwe and Obuekwe, 2002;Onajobi, 1986; Sidhu et al, 2007; Sofowora, 1993). In India, it is believed to be used for aromatic baths of fu-migations for the treatment of rheumatism and paralysis.O. gratissimum is an erect perennial shrub, about 1.5 m in height and propagates only by seeds. In spite of its enormous economic and industrial potentials, no deliberate attempt has been made to cultivate the crop as it is still grown as a garden plant. With development and its allied ecological problems such as bush burning moving to the rural areas, the compound farm concept is threatened, and as such under-utilized species like O. gratissimum are most endangered. Hence, there is need to engage in more research activities that would enhance its, conservation, improvement and processing. A preliminary report indicated frequent loss of viabil-ity in the seeds of O. gratissimum (Ojeifo and Denton, 1993). In this study, the effect of seed pretreatments on dormancy status of O. gratissimum was explored.2  Materials and MethodsThe seeds of O. gratissimum were collected from the parent stands. A white table spread of 1 m2 was spread at the base of the stand. Various terminal racemes on many branches on the stand were gathered by hand and shaken *Corresponding author. Tel: 234-8060-164341; Email: obembe@covenan-tuniversity.comPage 87Obembe, et al, Seed pretreatments enhance germination in Occimum gratissimum (lameaceae)at the direction of the white table spread. The small seeds were then collected from this spread and then were sun-dried, de-husked and stored in the refrigerator.Seeds of O. gratissimum were subjected to germina-tion tests. De-husked seeds were surface-sterilized in 10% (w/v) chlorox for 30 seconds and rinsed in several changes of distilled water. Fifty seeds were planted in each of the 9 cm diameter petri dishes lined with moist sterile filter. The experiment was carried out under light and dark at 29 ± 1 °C. Light was supplied by four 40 watt white fluorescent lamps at a distance of 1 m (1,200 lux). The petri dishes for the dark condition were wrapped completely with aluminum foil and kept in a dark cup-board. Fifty seeds were also planted for germination. The set up was subjected to combinations of light/dark and temperature requirements of 10 °C, 15 °C, 25 °C, 30 °C, 35 °C and 40 °C. Observations were made for up to day 10 of incubation. Radicle emergence of up to 1.5 mm was taken as a visible sign of germination. Dormancy breaking by leaching in water was inves-tigated. Seed lots were wrapped in clean sieve-cloth, placed in a beaker and put under running tap water for 12, 24, 36 and 48 hours. Control seeds were not leached. The seeds were then tested for germination at 25 °C un-der light condition.Statistical analysis: All experiments were repeated 5 times. Data were statistically analyzed by the SAS soft-ware using a completely randomized design and means were compared at the P = 0.05 level of significance using Duncan’s multiple range test (SAS GLM, P < 0.05; SAS Institute, 1989).3  Results and DiscussionGermination test showed that the seeds of O. gratis-simum were in a state of dormancy (Table 1). Seeds ger-minated poorly especially in the dark with a maximum of 40% after 10 days (Table 1). Germination of seeds of O. gratissimum was enhanced under light conditions. 70% seed germination was observed as from the 6th up to the 10th day after sowing. The optimum temperature for seeds subjected to com-bination of light and temperature treatments was 25 °C (Table 2). Light-induced germination was also observed in Ocimum basilicum seeds (Dawoud et al, 2003). It has long been established that light sensitivity of seeds oper-ates through the phytochrome pigment systems (Black, 1972; Donohue, 2007). The dormancy challenge on the germination of O. gratissimum appears to be a combi-nation of hard seed coat, the presence of germination inhibitors and a light requirement. Hence the release of dormancy from these seeds can only be achieved when the restriction to the entry of water and oxygen is elimi-nated and that the inhibiting substances are prevented from affecting the biochemistry of germination in these seeds. This would consequently trigger other processes that lead to embryo germination.Table1. Percentage germination of O. gratissimum seeds after 10 days incubation under light and dark at 29 ± 1 °C.Period (days)Percentage germinationLight* Dark*2 0.0 ± 0.0d 0.0 ± 0.0c4 20 ± 45c 0.0 ± 0.0c5 40 ± 3.7b 0.0 ± 0.0c6 70 ± 2.4a 30 ± 5.6b8 70 ± 2.4a 40 ± 2.8a10 70 ± 2.4a 40 ± 2.8a*Mean ± SE. a,,b,c,d are not significantly different (P = 0.05) according to Duncan's multiple range test. Data are means of 5replicates.    Table 2. Percentage germination of O. gratissimum seeds incubated under varying temperatures for 10 days.Temperature (°C)Percentage germinationLight* Dark*10 50 ± 4.6d 25 ± 5.6b 15 65 ± 3.4bc 20 ± 2.6b20 80 ± 4.6a 45 ± 4.8a25 70 ± 4.7b 50 ± 3.6a30 60 ± 4.2cd 20 ± 3.4bc35 35 ± 4.6e 15 ± 2.1c*Mean ± SE. a,,b,c,d are not significantly different (P = 0.05) according to Duncan's multiple range test. Data are means of 5replicates.The leaching of seeds in running water for 12 hours, coupled with sowing at the optimum temperature and light conditions gave 100% germination (Table 3). It is plausible that germination inhibitors in the seeds, which act by blocking the enzymes sites, have been leached out by the running water. Çırak et al (2007) also reported the release of exogenous dormancy in the seeds of a Hypericum species by presoaking the seeds in water for 24 hours. It was, however, surprising to note that further treatment for longer period under running water for 24 – 48 hours had deleterious effects on the seeds (Table 3). On the whole, this study has indicated that O. gratissi-mum germination test should be conducted at 25 °C pref-∙  47  ∙ Page 88 Life Science Journal, Vol 5, No 1, 2008                                                                                                                               http://lsj.zzu.edu.cn∙  48  ∙erably in light. Dormancy in this species can be released by 12 hour washing of the seeds under running tap water.Table 3. Effect of leaching on seed germination in O. gratissimum.Treatment Duration (hour)* Percentage germination (10th day)*Leaching 12 100 + 0.0a24 50 + 5.6c36 30 + 3.4d48 25 + 2.7dControl - 77 + 6.5b*Mean ± SE. a,,b,c,d are not significantly different (P = 0.05) according to Duncan's multiple range test. Data are means of 5replicates.ReferencesAbdulrahman F. Studies in Natural Products. The Moraceae in Afri-can Traditional Medicine and Management of Psychiatry in Borno State. M.Sc. Thesis. Department of Chemistry, University of Maidu-guri. 1992; 89 – 94.Agusiobo ON. Vegetative Gardening. Macmillan Press London. 1984; 344 – 5.Awuah RT. Possible utilization of plant products in grain storage. In: Cardwell KF. (ed) Proceedings of the workshop on mycotoxins in food in Africa. November 6 – 10, 1995 at cotonou, Benin. Interna-tional Institute of Tropical Agriculture, Benin. 1996; 32.Black M, Vlitos AJ. Possible Interrelationships of Phytochrome and Plant Hormones. Phytochrome pp. 517 – 49. (ed. by Mitrakos K & Shropshire Jr. W), Academic Press, New York. 1972.Çırak C, Kevseroğlu K, Ayan AK. Breaking of seed dormancy in a Turkish endemic Hypericum species: Hypericum aviculariifolium subsp. depilatum var. depilatum by light and some pre-soaking treat-ments. Journal of Arid Environments 2007; 68(1): 159 – 64.1.2.3.4.5.Dawoud DA, Ahmed EA, Khalid H, Babiker AGT. Modulation of seed dormancy in Ocimum basilicum by light, gibberellins (GA3) and abscisic acid (ABA). Agricultural Research Corporation, Wad Medani, Sudan. 2003; 7F-11.Donohue K, Heschel MS, Chiang GCK, Butler CM, Barua D. Phy-tochrome mediates germination responses to multiple seasonal cues. Plant, Cell & Environment 2007; 30(2): 202 – 12. Eze SC, Asiegbu JE, Mbah BN, Orkwor GC, Asiedu R. Biocontrol of strorage insect and use as fungicide were explored Agro-Science 2006; 5(1) : 8 – 12 .Lancer RHM, Hill GD. Agricultural Plants, 2nd edition. Cambridge University Press. 1991; 287.Lasisi AO, Ajuwon AJ. Beliefs and perceptions of ear, nose and throat-related conditions among residents of a traditional community in Ibadan, Nigeria. Afr J Med Med Sci 2002; 31(1): 45 – 8.Masefield GB, Wallis M, Harrison SG, Nicholson. Labiate Herbs. In: the Oxford Book of Food Plants. Oxford University Press. 1973; 142.Moundipa PF, Flore KGM, Bilong CFB, Bruchhaus I. In vitro amoe-bicidal activity of some medicinal plants of the bamun region (cam-eroon). Afr J Traditional, Complementary and Alternative Medicines 2005; 2(2): 113  – 21. Obuekwe IF, Obuekwe IC. Indigenous methods used for the manage-ment of diarrhoea in an urban community in Edo State, Nigeria. Jour-nal of Medicine and Biomedical Research 2002; 1(1): 2002.Ojeifo IM, Denton L. Growing Occimum gratissimum in Nigeria: Outlook on the botany, economic importance, cultivation and re-search strategies. In Okojie JA, Okali DUU (eds) Lost crop of Nige-ria: implications for Food security. University of Abeokuta Confer-ence proceeding Series (3) 1993; 216 – 30.Oliver B. Medicinal Plants in Nigeria. Published by Nigerian College of Arts, Science and Technology, lbadan. 1980; 90 – 4.Onajobi FD. Smooth muscle contraction lipidic-soluble principles in chromatography fractions of Ocimum gratissimum. J Ethnopharma-col 1986; 18: 3 – 11. Osifo NG. A System of Traditional Health Care. 1992; 2: 56.Sidhu K, Kaur J, Kaur G, Pannu K. Prevention and cure of diges-tive disorders through the use of medicinal plants. J Hum Ecol 2007; 21(2): 113 – 6.Sofowora LA. Medicinal Plants and Traditional Medicine in Africa. Macmillan London 1982; 68 – 72.Sofowora LA. Medicinal Plants and Traditional Medicine in Africa. Spectrum Books Ltd, Ibadan. 1993; 55 – 716.7.8.9.10.11.12.13.14.15.16.17.18.19.20.Page 89

Seed pretreatments enhance germination in Occimum

gratissimum (lameaceae)

http://eprints.covenantuniversity.edu.ng/362/1/LifeSc_Obembe2008.pdf

Seed pretreatments enhance germination in Occimum gratissimum (lameaceae)

Abstract

Similar works

Full text

Available Versions

Covenant University Repository