Morphology and reproductive biology of Maramanjal (Coscinium fenestratum (Gaertn.) Colebr)
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Date
2015
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Department of Plantation Crops and Spices, College of Horticulture, Vellanikkara
Abstract
Coscinium fenestratum (Gaertn.) Colebr. is a critically endangered and highly-traded medicinal plant belonging to the family Menispermaceae, having extensive pharmacological activities. Despite its importance, there are substantial gaps in our understanding of its morphology, reproductive biology and phenology.
With this background, the present study entitled „Morphology and reproductive biology of “Maramanjal” (Coscinium fenestratum (Gaertn.) Colebr.)‟ was undertaken in the Department of Plantation Crops and Spices, College of Horticulture, Vellanikkara, during 2013- 2015. The investigation aimed to study the phenology, flowering, fruitset, and seed viability of Coscinium fenestratum so as to explore the feasibility of its multiplication and conservation. Coscinium fenestratum is a large dioecious perennial growing up to 10 m height and the detailed morphological study revealed that the young and mature shoots in male and female plants were brown in colour with spiral phyllotaxy. The branchlets were observed as brown and tomentose at the young stage, later turning glabrous. The quantitative characters of stem of the male and female plants showed no significant difference. Anatomical studies of stem revealed that the number of vascular bundles differed in the male and female plants. The 1-2 layered interfascicular cambium was observed to originate in between the bundles, in line with the fascicular cambium.
The shape of leaf lamina was found to be narrowly ovate in the male plant and broadly ovate in the female plant. It was noticed that the lamina has acuminate tip and slightly cordate base and is dark green on the glabrous adaxial surface and light green on the tomentose abaxial surface with reticulate-multicosate divergent type venation. The leaf petiole was observed as tomentose with pulvinus. The length of petiole and lamina were significantly different in both the plants. Anatomical studies of leaf
revealed the epidermis as single layered with lower region possessing large number of multicellular and uniseriate trichomes. It was noticed that mesophyll consists of 1-2 layered, thick walled, highly chlorophyllous palisade tissue and 2-4 layered, thin walled and spongy tissue with abundant intercellular spaces. Vascular bundle was seen encircled by a wavy ring of 2-10 layers of sclerenchymatous tissue and collenchyma and parenchyma cells present.
The type of male and female inflorescence was observed as compound raceme, with the yellowish or whitish globose heads borne on long peduncles, developing on old stems in the axils of fallen leaves. The colour of sofly hairy peduncle was noted as light yellow brown in the male and brown in the female inflorescence. The characters like inflorescence length, life-span of a flower head, duration of flower head opening and the days to attain 50% flowering, and the floret diameter were significantly different for the male and female inflorescences.
The zygomorphic sessile floret was found to be having nine tepals in three whorls which are densely hairy outside and glabrous inside. In the male floret, out of the six stamens, three were seen are connate to the middle and the others remain free. The female floret was observed with no distinct style; ovary being superior with axile placentation.
With respect to the reproductive biology, the flowering season of male plant was noticed from late August to late February with the peak anthesis between 7.00 a. m. - 8.00 a. m. Anther dehiscence was found to continue for a period of 20 and half hours. The flowering season of female plant was noticed from early October to mid- October to mid-March with peak anthesis between 7.00 a. m. - 11.00 a. m. The stigma was seen receptive for a period of 26-28 hours. Coscinium fenestratum was observed as anemophilous with a pollen fertility of 57.45%.
Fruit was noticed as a one-seeded drupe, globular and dark brown in colour. With a high fruit set of 93.00%, the per cent of fruits carried to maturity was only 27.33%. The greenish brown kidney shaped subglobose seed was found to be having a special structure called condyle. The per cent of seed germination was recorded as 50%.
Seedling studies revealed that the seeds from Wayanad exhibited better cumulative growth rate than those from Vellanikkara, in terms of number of days for germination, number of days for initiation of first leaf, number of leaves and internode length.
The different phenophases in the male and female plants were identified and recorded. The variation in C/N ratio and starch content in male and female plants showed a similar pattern with the three critical stages considered, such as onset of flowering, peak flowering and termination of flowering.
Berberine detected through Thin Layer Chromatography (TLC) technique was quantified using High Performance Liquid Chromatography (HPLC) technique. Male plant had 1.16% berberine in the stem and 0.95% in the root. Female plant had 1.17% berberine in the stem, 0.82% in the root and 0.10% in the seed.
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