Journal of Science Research (2014) Vol. 13: 23-36 Comparative Leaf Morphology and Anatomy of some Nigerian Rattans (Arecaceae – Calamoideae Beilschm.) 1Jayeola, A.A. 2*Aworinde, D.O. and 3Ogundairo, B.O. Abstract Collections of 14 species of rattan palms were made from forest habitats along the coastal areas and major forest zones in Nigeria. The aim was to study the leaf morphological and anatomical characters of the palms with a view to facilitating their identification. Morphological characters as well as anatomical features were examined. Analysis of variance (ANOVA) indicated significant differences (p≤0.05) among morphological characters such as trichome length, internode length, cirrus length and leaf width. Trichomes were present in all the species except in Ancistrophyllum novum Burr. and Laccosperma robustum (Burr.) [J. Dransf.] Presence of uniseriate epidermis, ergastic substances, sunken stomata and peripheral arrangement of vascular supply was noted and the significance of this is discussed in relation to the family Arecaceae. The high demand of rattan products has been a serious concern with respect to the sustainability of rattan species worldwide. Conservation methods to ensure continued use of rattan palms might be to sensitize farmers, foresters and users on the overall biology of rattan palms and their cultivation techniques. Key words: Anatomy, Rattan palms, Taxonomy, Nigeria. Introduction The rattans of Africa are represented by the Most, admittedly crude, ecological three endemic genera Laccosperma (G. Mann preferences for rattan species have generally & H. Wendl.) Drude, Eremospatha (G. Mann been identified during taxonomic inventory & H. Wendl.) H. Wendl. and Oncocalamus work, yet these broad ecological summaries (G. Mann & H. Wendl.) as well as by a single are invaluable as a basis for establishing representation of the Asian genus Calamus cultivation procedures. Linn. In Nigeria, they are represented by 14 Generally, rattan species are found in a species and are of vast economic importance. wide variety of forest and soil types. Some The range of rattans extends from the sea species are common components of the forest level to more than 300m elevation, from under-storey; others rely on good light equatorial rainforests to monsoon savannas penetration for their growth; hence, some and the foothills of Himalayas [1]. Thus, the species are found in gap vegetation and may large number of rattan species is matched by respond well to canopy manipulation. Other great ecological adaptation and diversity. species grow in swamps and seasonally inundated forest, whereas others are common on dry ridge tops. Taxa such as Calamus deeratus (G. Mann & H. Wendl.), C. 1Jayeola, A.A. 2*Aworinde, D.O. and 3Ogundairo, pilosellus Becc., Laccosperma secundiflorum B.O. (G. Mann & H. Wendl.) Kuntze, L. leave (G. 1Department of Botany, University of Ibadan, Ibadan, Oyo State, Nigeria Mann & H. Wendl.) Kuntze and 2Department of Biological Sciences, Ondo State Eremospatha wendladiana Dammer ex Becc. University of Science and Technology, Okitipupa, were found in a wide array of forest types, Ondo State, Nigeria ranging from dry to wet habitat and 3 Department of Biological Sciences, Federal occupying all the strata of the habitat whereas University of Agriculture Abeokuta, Ogun State, Nigeria others exhibited restricted distribution. The *Corresponding Author E-mail: petiole in most rattan palms is somewhat [2] [email protected] variable in length . Usually, it is much ISSN 11179333 24 Journal of Science Research (2014) Vol. 13: 23-36 longer in juvenile than in mature leaves and it also been used for items such as belts, may be absent altogether. The petiole, where wristlets, lashing of articles such as axe-head present, and the rachis are often heavily or other instrument heads to their handle [3]. armed with spines and has been speculated In spite of their diverse indigenous uses, little that the spine is not necessarily adapted for is known about their leaf micro-morphology. the climbing process but appear to function as The objective of this work was to elucidate a means of trapping light from the forest the leaf anatomical characters of the rattan canopy probably for the primary purpose of palms with a view to facilitating their nutrients accumulation [3]. identification, even from leaf fragments. In terms of utilization, [4] stated that the largest demand for canes is for making Materials and Methods furniture, for which they provide both frames The leaf specimens used were obtained from and decorative trimmings and facings. [5] living collections made from forest habitats noted that the unsplit canes are utilized as along the coastal areas and major forest zones broom handles, sewer rods, walking sticks, in Nigeria between the years 2006 and 2008 ski sticks and snow brooms, while split canes during the periodic field trips (Fig. 1; are used for chair seats and in basketry Table 1). works.[4] listed the uses of canes to include mats, handicrafts and souvenirs. Rattans have Laccosperma robustum Fig. 1: Geographical distribution of rattan species in Nigeria and the collection sites. ISSN 11179333 Table 1: List of Representative Specimens Studied F.R. = Forest Reserve; C.R.S. = Cross River State. 25 26 Journal of Science Research (2014) Vol. 13: 23-36 The leaves were pressed and identified at the transferred into xylene for 5mins., cleared in Forestry Research Institute of Nigeria clove oil for 10mins. and mounted in DPX® herbarium (FHI) and University of Ibadan mountant. Anatomical descriptions followed herbarium (UIH); voucher specimens were the conventions established by [6] as modified deposited in the herbaria. Fresh specimens by [7]. Data were expressed as mean ± SD, were used for the anatomical investigation. and differences in means were assessed for From five specimens of each of the 14 taxa significance at P≤0.05 by Duncan’s Multiple studied, 1cm2 portions were cut at the apical, Range Test (DMRT) [8]. median and basal regions of the preserved mature leaflets. Samples were revived by Results boiling in water and fixed in formaldehyde Morphology acetic acid (FAA 50%) for 24 hours [6] Quantitative morphological parameters of the followed by dehydration in series of ethanol rattans are presented in Table 2. The leaflet (30-95%). Infiltration was done with width differs among the species of rattans paraplast (soft wax) and tissue mat (hard studied; it ranged from 1.9cm in wax) using tertiary butyl alcohol (TBA) as Ancistrophyllum novum Burr. and base for 24-48 hours at 50°C [6]. Infiltrated Oncocalamus manni H. Wendl. to 24.1cm in specimens were transferred into the Calamus pilosellus Becc. The leaflet widths embedding liquid (melted wax poured into in Laccosperma secundiflorum and improvised moulds) to cast hard blocks. Eremospatha hookeri are not significantly Trimming of the relatively hard polymerised different. The same trend was observed for blocks was done with the aid of disposable Ancistrophyllum novum and Oncocalamus knives. The transverse sections, about 13µm, manni, and Calamus deeratus and were made with Leica 820 II rotary Eremospatha wendladiana. Mean number of microtome available in the pathology paired leaflets of the species differs; this laboratory at the International Institute of ranged from 4.5 in Laccosperma robustum Tropical Agriculture (IITA) Ibadan, Nigeria. (Burr.) J. Dransf. to 48 in Laccosperma Using, one-way disposable knife, each opacum (G. Mann & H. Wendl.) and section was transferred into drops of warm Calamus deeratus (G. Mann & H. Wendl.) distilled water on a clean slide on which The values observed are similar in adhesive had been previously rubbed. The Oncocalamus macrospatha Burr. and O. warm distilled water served in a place of acanthocuenis Drude both having 18 each. water bath for stretching the sections. After Also, the numbers of paired leaflets are drying on a slide warmer (Fisher slide similar in Oncocalamus wrightianus Hutch., warmer SE 2417), slides were de-waxed in O. manni H. Wendl. and Calamus pilosellus xylene and subsequently hydrated through Becc. each having 35. The remaining species ethanol series (5-30%). Staining was done have variable number of paired leaflets which with safranin for 15-20 mins. and could be diagnostic. subsequently rinsed in distilled water and differentiated ethanol series (30-95%); counterstained in fast green for 5secs, ISSN 11179333 Table 2: Quantitative Morphological Parameters of the Rattans Studied Values are mean ± SD; n=3. Means followed by the same alphabet in the same column are not significantly different (Spearman, p>0.05); n.p. = not present. 27 28 Journal of Science Research (2014) Vol. 13: 23-36 Anatomy correct identification of rattans is essential in Photomicrographs of the species studied are establishing priorities for conservation and presented in Plates 1-7. The epidermis is use strategies. composed of rectangular cells with outer The absence of trichomes in Ancistro- thickened wall and few sunken stomata. The phyllum novum and Laccosperma robustum epidermal cells are in longitudinal files and which often is a reflection of physiological are usually square or rectangular. One or response to a combination of environmental more cell layers immediately beneath the factors could be useful for diagnostic purpose epidermis form a colourless hypodermis and at the species level. This is in agreement with often indistinct. The peripheral bundles are [9] who used trichomes to delimit five species sometimes irregularly and