COMPARATIVE STUDIES OF THE MORPHOLOGICAL AND REPRODUCTIVE MECHANISM OF NIGERIAN PASSIFLORA FOETIDA L. AND PASSIFLORA EDULIS F. ELIZABETH OLUWATOMI OLUDARE SCP16/17/H/0335 B.Sc. (Botany), Ife A M.Sc. RESEARCH THESIS WRITTEN IN THE FACULTY OF SCIENCE AND SUBMITTED TO THE POSTGRADUATE COLLEGE, OBAFEMI AWOLOWO UNIVERSITY, ILE-IFE, NIGERIA, IN PARTIAL FULFILLMENT OF THE REQUIRMENTS FOR THE AWARD OF THE DEGREE OF MASTER OF SCIENCE (M.Sc.) IN BOTANY 2019 © Obafemi Awolowo University, Ile-Ife, Nigeria For more information contact [email protected] ABSTRACT The study investigated Passiflora foetida L. and Passiflora edulis F. morphological characteristics and reproductive mechanism under different localities. This was carried out with a view to describing and identifying the two Passiflora species and their reproductive mechanisms. Seedlings of the two Passiflora species used for the study were collected from Olonade in Ile-Ife, Osun State. Viable seeds collected from matured plants were germinated. Established seedlings were transplanted 6 weeks after germination into 7 litre plastic bucket filled with top soil at the rate of one plant per bucket with 10 replicates each and later transplanted to the field behind Chemical Engineering Lecture Theatre in Obafemi Awolowo University Ile-Ife. The plants were scored for both quantitative and qualitative morphological characteristics. For each species, the following pollination mechanisms were investigated on 50 flowers in the open and bagged treatments: Emasculation, Natural pollination, Manual self-pollination, Geitonogamy and Cross pollination. Pollination of the two Passiflora species was also studied with respect to type of foragers that visited the plants and the activities of each forager during each visit. Data obtained from quantitative morphological characteristics and the pollination treatments were analyzed using Descriptive and Inferential analyses while data obtained from pollination experiments were subjected to two-way analysis of variance. The results showed that the two species have hermaphroditic flower with ovate leaf shape and alternate leaf arrangement. The leaf surface of P. foetida is pubescent while that of P. edulis is glaborous, and the fruits of P. edulis turned yellow when matured but fruits of P. foetida remained green when matured. Flower opening (anthesis) in P. foetida began from 5 am-6 am © Obafemi Awolowo University, Ile-Ife, Nigeria For more information contact [email protected] Page i and closes between 10:00 am-11 am, while in P. edulis anthesis began from 1:10 pm-3:00 pm and closes 10:00 pm-10:14 pm. All opened treatments of the P. foetida and P. edulis species produced more fruit than their corresponding bagged treatments. Autonomous self-pollination produced the maximum fruit set (92%) in P. foetida while in P. edulis cross-pollination treatment was the most effective method of pollination (78%) for maximum fruit set. Floral visitors were not observed on P. foetida, while in P. edulis floral visitors such as Xylocopa caffra, Xylocopa frontalis, Dactylurina staudingeri, Trigona fuscipennis were observed to visit the plant from 8 am–7:00 pm for pollen and nectar. Bees during their visit, were often seen foraging on the nectars or pollen of flowers, while doing this, pollens got attached to their back and legs. Hence, movement of these foragers from one flower to another makes them simultaneously pollinate the stigma of flowers. The study concluded that the two species varied in their vegetative and floral morphological characteristics. Passiflora foetida is primarily adapted to reproduction by autogamy while Passiflora edulis exhibit mixed mating system of autogamy and out-crossing which is enhanced by bees that visit the flowers. © Obafemi Awolowo University, Ile-Ife, Nigeria For more information contact [email protected] Page ii CHAPTER ONE INTRODUCTION 1.1 Background to the Study The passion-flower family, Passifloraceae, in the order Malpighiales, is an angiosperm which include 27 genera and about 975 species distributed mainly in America, but also in warm Africa (Stevens, 2012). Passifloraceae is highly developed in the Neotropics and in Africa (Ulmer and MacDougal, 2004). Passiflora is the largest genus in the family, with 525 species, many of which are highly prized for their showy, unusual flowers. Many members of the family climb or get attached by means of tendrils borne in the leaf axil, though others are herbaceous or woody vines, shrubs, and trees, mostly of warm regions. The leaves are often spirally arranged along the stem and are stipulate. Other characteristics include petals, stamens, the presence of radially symmetrical male, female, or bisexual flowers with three to five sepals (MacDougal, 1994). Passiflora species are usually propagated by seed, due to its low cost and ease of seedling production (Coelho de Araújo et al., 2007). The flowers usually have a one-chambered ovary composed of three to five carpels (ovule-bearing segments), with numerous ovules attached to the inner ovary walls. The stamens are usually found below the ovary, and both are borne on the end of a stalk called an androgynophore. Sometimes only the ovary is carried on the stalk and almost all species have seeds that bear a fleshy appendage called an aril. In the passion-flower family there are more whorls of tendril-like structures, called the corona in the flower. The fruits are capsules or berries (www.encyclopediabritinnica.com). © Obafemi Awolowo University, Ile-Ife, Nigeria For more information contact [email protected] Page 1 1.1 Genus Passiflora Passiflora comes from Latin word "Passio" was first discovered by Spanish discoverers in 1529 and was described as a symbol for "Passion of Christ"(Kinghorn 2001; Dhawan et al., 2004). Passiflora is the most important genus in the passion-flower family and it is distributed within tropical and sub-tropical regions. The first report on Passiflora species was made in 1553 by Pedro Cieza during the spanish colonial period in south America (MacDougal and Feuillet, 2004). It is widely cultivated in tropical Africa, South-East Asia and the Caribbean. It is a large genus of herbaceous or woody tendril climber (The Wealth of India, 2001), mostly distributed in the warm temperate and tropical regions of the world, but they rare in Asia, Australia, and tropical Africa (Beninca et al., 2007). Few of the Passiflora species are cultivated for their edible fruits and many have ornamental values (Guire, 1999). More than 350 species was found in tropical regions and rain forests of South America and 60 of them are edible species. Passion fruit is an important fruit crop in many tropical and subtropical countries due to its edible fruits, ornamental use, medicinal properties, antispasmodics and antibacterial properties (Patil et al., 2013). However, Passiflora seeds have low germination percentages due to the fact that they have a hard outer coating covered by a resin that makes it impermeable, inducing exogenous dormancy, which is probably a combination of mechanical and chemical mechanisms (Ellis et al., 1985). Plants of the genus Passiflora are shrubs and herbs, mostly climbers with auxiliary tendrils. Leaves are alternately arranged, sometimes simple, entire, lobed or /and palmate, sometimes compound, imparipinnate; stipules germinate at the base of petioles, rarely absent; tendril axillary, arising from sterile pedicels. © Obafemi Awolowo University, Ile-Ife, Nigeria For more information contact [email protected] Page 2 The high interspecific compatibility in natural and artificial crossings among the diploid species gives a wide genetic variability distributed in different agro-climatic regions. Morphological characters used for taxonomical description of passion fruit have allowed classification up to the species level, but not to an intraspecific discrimination (Dhawan et al., 2004). Although all passion flowers (Passiflora spp.) produce complex flowers with structural similarities, species vary substantially in their flower colour, in details of flower structure and its behaviour. All species in this tropical and subtropical speciose genus have at least one ring of filaments (the corona) around a vertical stalk which gives support to the styles and stamens (the androgynophore) (Burks and Lanza, 2008). 1.3 Passiflora foetida L. Passiflora foetida common names are wild maracuja, bush passion fruit, marya-marya, wild water lemon, stinking passion flower, love-in-a-mist or running pop. It is a species of passion flower that is native to the Southwestern United States (southern Texas and Arizona), Mexico, the Caribbean, Central America, and South America. It has been introduced to tropical regions around the world, such as South-east Asia and Hawaii (www.wikipedia.com). It is a creeping vine, weed, like other members of the genus, and yields an edible fruit (Holm et al., 1997). The specific epithet, foetida, means "stinking" in Latin and refers to the strong aroma emitted by damaged foliage (Nelis and David, 1997). Passiflora foetida is commonly found growing around houses, sheds, along fences, ruderal and in waste areas throughout the tropics and subtropics. It requires warm, moist soil and air for at least half of the year, with moderate to high soil fertility, and also, support for the vines, and free from cultivation for several months. In permanently © Obafemi Awolowo University, Ile-Ife, Nigeria For more information contact [email protected] Page 3 moist soils it may exhibit an annual or a perennial life cycle, while in areas with dry season, it is likely to exist as an annual vine (www.cabi.org/isc). The stems are thin and wiry, covered with minute sticky yellow hairs and older stems become woody. The leaves are three- to five-lobed and viscid-hairy. When the leaves are crushed, they give off a pungent smell that some people consider unpleasant. The flowers are white to pale- cream in colour, about 5–6 cm in diameter. The fruit is globose, 2–3 cm in diameter, yellowish- orange to red when ripe, and has numerous black seeds embedded in the pulp; the fruits are eaten and the seeds dispersed by birds (Radhamani et al., 1995).