Effects of Extraction Methods and Handling on Seed Recovery and Germination of Nauclea Diderrichii (De Wild
Journal of Sustainable Environmental Management. Vol. 8, 99-106, 2016. ISSN: 2141-0267 www.awife.org.ng/publications/jsem.html
Effects of Extraction Methods and Handling on Seed Recovery and Germination of Nauclea diderrichii (De wild. & T.Durand) Merr. Adeniji, I. T., Kazeem-Ibrahim, F., Jegede, O. C., Wahab, W. T., and Osewa O. F. Forestry Research Institute of Nigeria, P.M.B. 5054, Jericho Ibadan. [email protected]/08067386045
ABSTRACT The study was carried out to investigate the effects of extraction methods and handling on seed recovery and germination of Nauclea diderrichii. One (1) kg fresh weight of the fruits of N. diderrichii were measured in six different places immediately after collection to be able to determine the quantity of seeds and were subjected to different extraction and handling methods which serve as treatments. Twenty seeds extracted from each treatment were laid in seed germination chamber and replicated 3 times. The experiment was laid out in Completely Randomized Design. The following parameters were assessed; weight of seeds (g), total germination count and percentage germination. Result showed that T4 gave the highest seeds after extraction (15.19g), T3 (14.86g), T1 (13.63g) T5 (13.56g), T2 (13.15g), T6 gave the least value of 13.08g. Results obtained on the germination percentage showed that T2 has the highest germination percentage (98.33%), T1 (83.33%), T3 75%, T4 (36.67) T5 (21.67%) and T6 (26.67%). Result from the analysis of variance showed that T2 gave the best result (19.67) which was significantly higher than all other treatment. T1 (16.67), T3 (15.00), T4 (7.33), T5 (4.33) and (5.33). It is recommended that foresters and stakeholders working with the seed of the species should process the seed as soon as possible after collection to avoid deterioration.
Keywords: Nauclea diderrichii, Processing, Seed recovery, Seed germination
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Journal of Sustainable Environmental Management. Vol. 8, 99-106, 2016. ISSN: 2141-0267 www.awife.org.ng/publications/jsem.html
INTRODUCTION Nauclea diderrichii is a plant species belonging to the Rubiaceae family. It is found in Angola, the Democratic Republic of the Congo, Ivory Coast, Gabon, Ghana, Liberia, Mozambique, Nigeria, Sierra Leone, and Uganda (Keay1989). Its natural habitat is subtropical or tropical moist lowland forests. It has moderately fast growth rate. The straight, monopodial growth habit of this species has promoted interest in it for the production of transmission poles, bridges, marine construction, veneers and timber for heavy construction, flooring, furniture and carpentry work, The pulp of the fruit is edible, but not much eaten and mainly as a famine food. In Nigeria the leaves are fed to livestock. The root, bark and wood are used for making yellow dye. It is a good shade tree, used for crops as well as other timber trees and its bark has some pharmaceuticals use (Adeoye and Waigh, 1985, Dupuy and Mil, l993 Opuni-Frimpong and Opuni-Frimpong, 2012). In Africa, both exotic and indigenous species have been planted with exotic species dominating (Pandey, 1995). This is particularly true of Nigeria where exotic species account for over 80% of total plantation (Onyekwelu, 2001). The dominance by exotic species is attributed to their ease of establishment, rapid growth rate and general management. However there is empirical evidence that local consumer in Nigeria have preference for product of indigenous species (Akindele and Afuwape, 1998, Onyekwelu, 2001). Records indicated that in the 60s, Nauclea diderrichii was one of the dominant species in Nigeria (FAO, 1981) but the advert of large scale plantation with exotic lead to a situation where Nauclea diderrichii was neglected. Consequently little emphasis was devoted to understanding its growth characteristic and to develop better seed handling methods. According to IUCN (2004), the species was recorded to be vulnerable to extinction and it is still found in the red book as at 2012 (IUCN2012). Like many tropical trees, relatively little is known about the biology of N. diderrichii and this is one of the factors leading to its endangered condition. Flowering occurs during the period from May to December. The fruits have been found all year round, but the heaviest fruiting harvest occurs between October and February. Small size seeds are produced in large fleshy fruits. These seeds are difficult to collect and have short viability (Orwa et al, 2009) Seed processing aim is to achieve clean, pure seed of high germination rate which can be stored and easily handled, that is; it reduces bulkiness. As desirable as processing is, it is known to imply a risk of losing some of the seeds, damage or injury can also occur to seeds if processing is not properly done (Lars 2000). The purpose of extraction and other associated processes is to achieve maximum production of clean seed having high viability (Stein et al, 1974). The processes involved include one or more of the following: maceration and depulping, drying, separation, tumbling and threshing, dewinging and cleaning (FAO, 1985)
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Journal of Sustainable Environmental Management. Vol. 8, 99-106, 2016. ISSN: 2141-0267 www.awife.org.ng/publications/jsem.html
Seeds of N. diderrichii are extracted by sun drying fruit then pounding the fruit in a mortar after which the shredded fruit will be sieved through a series of grid with decreasing mesh size to recover the seed (Orwa et al, 2009, Opuni-Frimpong, and Opuni-Frimpong, 2012). This method of extraction may cause injury to the seed which may not be obvious because of its seed size. Nauclea diderrichii is a popular commercial timber species, yielding very durable wood with good mechanical properties. It has good prospects for wider-scale planting for timber production because it combines excellent wood properties with fair growth rates. Its density in the natural forest is low, and to ensure sustainable exploitation of the species, more research is needed on appropriate management systems in natural forest and on the establishment of commercial plantations. Therefore the aims of the study are to determine the amount of seeds that can be obtained from different extraction methods and handling, assess the germination potential of seeds from each extraction methods and handling used and determine the best methods that can be adopted for easy Nauclea diderrichii extraction. MATERIALS AND METHODS The study was carried out at Forestry Research Institute of Nigeria, Jericho Hill, Ibadan, Oyo- State, in the rain forest zone of south-western Nigeria. Fresh fruits of Nauclea diderrichii of about equal sizes were collected from FRIN Headquarters premises. One (1) kg fresh weight of the fruits was measured immediately after collection so as to separate each to treatment group and these were subjected to six (6) different extractions and handling methods which serve as treatments. The extraction methods are as follow: T1- shred and sun dried to constant weight T2- shred and shade dried under room temperature (32°C) to constant weight T3- fermented, shred and sun dried to constant weight T4- fermented, shred and shade dried under room temperature (32°C) to constant weight T5- sun dried to constant weight and later pound T6- shade dried to constant weight and later pound The seeds were extracted by sieving through a series of grid with decreasing mesh size. Seeds from each treatment were weighed with sensitive weighing balance to know the amount of seed recovered from each treatment. Twenty seeds were counted with the aid of magnifying lens from each treatment. The seeds were placed inside Petri dishes (90mm in diameter) lined with Whatman No. 1 single layer filter papers and then placed in seed germinator chamber at 25°C ± 2°C set in the seed laboratory of Forestry Research Institute of Nigeria. Seeds were daily observed to check for germination for 28 days. The experiment was laid out in Completely
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Randomized Design. Each treatment was replicated 3 times with 20 seeds in each replicate .The parameters assessed were weight of seeds (g), total germination count and percentage germination. Data were also analyzed using analysis of variance (ANOVA) and mean separated with Duncan Multiple Range Test at 5% level of probability. RESULTS AND DISCUSSION Results of the seed recovery showed that T4 gave the highest seeds after extraction (15.19) followed by T3 (14.86). The higher amount may be due to the fact that the seed seems to absorb moisture during fermentation which might have increase the size of the seed (Table 1). T1 gave (13.63) followed by T5 (13.56), T2 (13.15), T6 gave the least value of 13.08 (Table 1). Results obtained on the germination percentage showed that (T2) has the highest germination percentage (98.33%), followed by (T1) (83.33%).The high germination observed may be due to the fact that extraction was done immediately after collection, this is in accordance to Lars (2000) who stated that processing should as much as possible be done immediately after fruit collection to avoid damage to the seeds. Treatment 3 gave 75%, this can also be attributed to sun drying the treatment was subjected to prevent further fermentation. Treatments 5 and 6 gave 21.67% and 26.67% respectively. Their low germination percentages may be attributed to fermentation and possibly mechanical damages they might have sustained during handling and processing by pounding. Jahufer and Borovoi (1992) stated that various degrees of damages on seed coat, endosperm and embryo could be detected on seeds after processing; these injuries affect germination, seedling development, susceptibility to disease, plant growth and development. This is indicated in Table 2 as there is reduction in the germination percentage of the seeds after going through different seed processing and extraction methods. Result from the follow up test of analysis of variance showed that T2 gave the best result (19.67a) which was significantly higher than all other treatment. T1 gave (16.67b) and T3 gave (15.00b) these were significantly lower than T2 but significantly higher than T4, T5 and T6. Treatment 4 gave (7.33c) which was significantly lower than T3 but significantly higher than T5 that gave (4.33d).T6 gave (5.33cd) which was not significantly higher than T4 and T5 (Table4)
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Journal of Sustainable Environmental Management. Vol. 8, 99-106, 2016. ISSN: 2141-0267 www.awife.org.ng/publications/jsem.html
Table 1: Seed recovered from Nauclea diderrichii subjected to different seed processing methods
TREATMENT WEIGHT OF RECOVERED or extracted SEEDS(g)
T1 13.63
T2 13.15
T3 14.86
T4 15.19
T5 13.56
T6 13.08
Table 2: Total germination count and Germination percentage of Nauclea diderrichii as influenced by different processing methods
Treatment Germination percentage % Total germination count
T1 83.33 50
T2 98.33 59
T3 75 45
T4 36.67 22
T5 21.67 13
T6 26.67 16
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Table 3: Analysis of variance on effect of processing on seed germination of Nauclea diderrichii
Source of Degree of Sum of square Mean of square F-cal p level Variation freedom
Treatment 5 636.94 127.39 52.11 3.11*
Error 12 29.33 2.44
Total 17 666.28
*significant at 5% level of probability Table 4: Mean separation of effects of processing on seed germination of Nauclea diderrichii
Treatment Mean
T1 16.67b
T2 19.67a
T3 15.00b
T4 7.33c
T5 4.33d
T6 5.33cd
Mean with the same letter are no significantly different at 5% level of probability by DMRT
CONCLUSION AND RECOMMENDATIONS The study revealed that seeds of Nauclea diderrichii left to ferment before processing may have higher amount of seed recovery after processing, although this may not translate to higher germination percentage. Seeds that were extracted soon after collection have better chances of germination than those that are left to ferment and those left to dry before extraction. Result from follow up test of the analysis of variance showed that seeds that were processed immediately after collection and were not exposed to direct sunlight performed significantly better compared
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Journal of Sustainable Environmental Management. Vol. 8, 99-106, 2016. ISSN: 2141-0267 www.awife.org.ng/publications/jsem.html to other methods used. Hence, seed technologists, foresters and other sakeholders working with the seeds of the species should process the seed as soon as possible after collection. REFERENCES Adeoye, A.O. and Waigh, R.D. (1985). Secoiridoid and triterpenic acid from stem of Nauclea diderrichii an ever green rain forest species. Phytochemistry 22(4):975-978 Akindele, S.O. and Afuwape, J.A. (1998). Wood-base industrial sector review. A consultancy report prepared in the national forest resources study Nigeria1998.74pp Dupuy and Mille (1993). Timber plantation in the tropic of Africa .FAO Forestry paper 98, pp 190 FAO (1981). Tropical forest resource assessment .Forest resources of tropical Africa 11. Nigeria UN3216.1301-78.04.Technical report No2 pp 359-385 IUCN, (2004). IUCN Red List of Threatened Species. Searchable database at http://www.iucnredlist.org.Accessed 11/5/2013 IUCN, (2012). IUCN Red list of threatened species. Version 2012. 2. Web: Accessed 11/16 2013.2012 edition, Clarendon Press Oxford, 176 pp. Jahufer, M . Z. and Borovoi, V.V (1992). The effect of mechanical damage to maize (Zea mays L.) Seed germination, seed morphology and subsequent grain yield. Journal of Applied Seed Production. 10:67-77 Keay, R .W. J., (1989). Trees of Nigeria. 2nd Edition, Clarendon Press Oxford, 176 pp. Lars, S. (2000). Guide to handling of Tropical and Subtropical forest seed. Danida Forest Seed Centre Denmark. Pp. 265 Okojie. O. (1985). Height-diameter relationship for Taungya plantation of Nauclea diderrichii . Journal of Tropical Forestry Research 1:78-83 Opuni-Frimpong, N.Y. and Opuni-Frimpong, E., (2012). Nauclea diderrichii (De Wild. & T.Durand) Merr. Record from PROTA4U. Lemmens, R.H.M.J., Louppe, D. & Oteng-Amoako, A.A. (Editors). PROTA (Plant Resources of Tropical Africa / Ressources végétales de l’Afrique tropicale), Wageningen, Netherlands.
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Orwa, C., Mutua, A., Kindt, R., Jamnadass, R,and Simons, A.,(2009). Agroforestree Database:a tree reference and selection guide version 4.0 (http://www.worldagroforestry.org/af/tree/) Accessed 11/16 2013. Pandey,D.(1995).Forest resources assessment for tropical forest plantation.F.A.O paper, pp 128-181 Stein, W. I., Slabaugh, P. E. and Plummer, A. P. (1974). Harvesting, processing and storage of fruits and seeds. In seeds of woody plants in the United States, Agriculture Handbook No. 450 For. Service, USDA, Washington D.C pp 87.
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