SYSTEMATIC SIGNIFICANCE OF FOLIAR CHARACTERS IN THE DELIMITATION OF PASSIFLORA L. (PASSIFLORACEAE) AT THE LOWER TAXONOMIC LEVELS

* VL Beena 1 and S Suhara Beevy 2 . 1. Research Scholar, Department of Botany, University of Kerala, Kariavattom, Thiruvananthapuram, Kerala, India. 2. Assistant Professor, Department of Botany, University of Kerala, Kariavattom, Thiruvananthapuram, Kerala, India. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History


ISSN: 2320-5407
Int. J. Adv. Res. 4 (9), 2205-2215 2206 reported by Viana et al. [7]. Krosnick [8] suggested the role of floral morphology in discriminating the species of Passiflora. However, investigations on the foliar characteristics is sparse except that of Tangarife et al. [9] who reported foliar variations in a few species of Passiflora from Columbia. The significance of leaf morphological and epidermal characters in plant systematics has been proved in Alternanthera Frpsk.(Amaranthacae) [10], Cassia sensu (Cesalpineaceae) [11], Senna (Fabaceae) [12] and Cassiinae (Leguminosae) and in Hybanthus (Violaceae) [13]. The present investigation makes use of foliar features to evaluate the role of those characters in the delimitation of the genus at the inter and intra specific levels.

Materials and Methods:-
Leaf morphological and trichome characteristics of 27 taxa of Passiflora belonging to eight species, five varieties and two hybrids collected from different parts of the states of Kerala and Tamil Nadu were analysed for the study. The plants were maintained in the Botanical Garden, Department of Botany, University of Kerala for the investigation. Details of the accessions and the places of collection are provided in Table 1. Both the qualitative (28) and quantitative (11) characters were analyzed and each character state had been scored ( Table 2). Fifth leaf of the flowering branch was examined for the study to ensure uniform treatment, and the mean value of 10 observations were analysed. The data were subjected to Analysis of Variance (ANOVA) at the level of significance p<0.05, and was used to test the significant differences among the taxa. Discriminant function analyses such as cluster analysis and scatter plot were carried out to check out the character differences among the taxa. Morphology of foliar trichomes and glands were examined with the help of Stereo microscopic (Olympus SZ) observations and a taxonomic key was prepared based on the findings.

Result and Analysis:-
Details of the qualitative characters analysed in the 27 taxa of eight species are are given in Table 3. Foliar variations at the inter specific and intra specific levels were evident from the qualitative data analyzed (Table 3 & Fig 1). Analysis of Variance performed on quantitative traits (Table 2) showed significant variations (P<0.05) at the inter and intra specific levels. Mean standard deviation, range, and coefficient of variation and F values of the quantitative traits were also undertaken ( Table 3). A range of values were found as the average means of lamina length (6.03cm to 6.63cm), lamina width(4.88cm to 5.38cm), petiole length (2.23cm to2.88cm), frequency of stomata in the upper and lower epidermis (74.92µm to 78.70µm and 33.76µm to 36.44µm), length and width of stomatal complex (16.97 µm to 17.82µm &13.42µm to 13.68µm), length and width of guard cells (18.14µm -18.56µm & 5.09µm -5.55µm), length and width of stoma (9.77µm -9.97µm & 3.21µm -3.98µm). Among these, laminar width (LMW) showed maximum coefficient of variation (38.3372%), whereas F value (155.274) and width of guard cell (WGD) had minimum coefficient of variation (16.12%) and F value (14.773).
The Principal Component Analysis (PCA) revealed that the characters were distributed among three principal axes (Fig 2) which accounted for approximately 99.672% of the total variance. The first principal component with Eigen value 17.432 explained 64.563%variance (Table 4). It was found that leaf lobing, leaf arrangement, petiole grove, leaf texture, leaf size, leaf shape, leaf margin, marginal sheath spacing, order of marginal sheath, lob tip gland, leaf color, tooth apex, sinus shape, leaf tip, leaf base, nature of hair, venation, stomata, and leaf pubescence were the highest loaded traits and had positive values. The second component accounted for 13% of the variability with dominance of characters like leaf lobing, leaf arrangement, petiole grove, leaf texture, leaf size, leaf color, leaf shape, leaf margin, order of margin sheath, marginal sheath spacing , tooth apex, sinus shape, leaf tip, leaf base, lob tip gland, nature of hair, and venation. The third principal component accounted for 6% of the variability with dominance of characters like leaf lobing, leaf color, leaf shape, leaf margin, order of margin sheath, leaf tip, leaf trichome and lobe tip gland. The most loaded characters that accounted for more variability in PC1, PC2 and PC3 included leaf lobing, leaf color, leaf shape, leaf margin, marginal sheath spacing, order of margin sheath, sinus shape, leaf tip, leaf trichome, lob tip gland and leaf pubescence, which distinguished the different taxa of the genus Passiflora at the inter and intra specific levels.
UPGMA dendrogram based on morphological differentiation of the accessions (Fig 3) revealed two principal clusters at an Euclidian distance 1.40. The first principal cluster consisted of P.coccinia, P.vitifolia, P.trifaciata and P.subpeltata along with two accessions of P.edulis var. edulis (acc4 & acc5), whereas the second cluster possessed two sub clusters. All the varieties of P.foetida were grouped together in the second sub cluster along with the species, P.apoda and P.quadrangularis. However close relationship among the accessions of P.foetida var.foetida (acc 7, acc 8, acc 9, acc 12, acc 13 and acc14) was evident even though the accessions 10 and 11 differed 2207 extensively from the others. It was observed that the accession P. foetida var. gossippifolia was a connecting link between P. foetida var.foetida and P. foetida var.hispida. The two hybrid varieties of Passiflora (P.'manapany' and P.'canelle'), were clustered together with the varieties of P.edulis var. flavicarpa and P.edulis var. panamared, but the accessions of P.edulis var.edulis (acc 4 and acc 5) were seen grouped in the sub cluster of the second principal cluster.
A taxonomic key constructed based on the foliar features and the trichome characteristics distinguished the taxa at the inter and intra specific levels.  Laminar width area(cm) LMW 3 Length of guard cell (µm) LGD 4 Width of guard cell (µm) WGD 5 Length of stomatal complex (µm) LSC 6 Width of stomatal complex (µm) WSC 7 Length of stomata (µm) LSto 8 Width of stomata (µm) WSto 9 Lower stomatal density(mm) LSD 10 Upper stomatal density (mm) USD

Discussion:-
The analysis of variance on the quantitative data revealed significant differences among the taxa at P<0.05 level. The highest coefficient of variation (Table 3.) estimated for laminar width (38.3cm), upper stomatal density (36.7), laminar length (30.25cm), and width of stomatal complex (29.23) suggests high degree of variability with regard to these characters. Of those, characters like laminar width and upper and lower stomatal density were found to be useful for distinguishing the taxa at inter specific level. Passiflora foetida var. gossippifolia was characterized by the presence of stomata on the adaxial surface, whereas in P.foetida var. foetida and P.foetida var.hispida they were amphistomatic. The lowest coefficient of variation was observed in characters like length and width of stomata and guard cells in varieties of P. foetida indicating that they had only a minimal role in delimiting the taxa at the intra specific level. The significance of stomata and trichomes in the delimitation of the varieties of P.edulis was reported earlier by Chrochemore et al. [3].
Principal component analysis using qualitative morphological data exhibited significant differences at the inter and intra specific levels among the wild and cultivated species of Passiflora (Table 4). Anlaysis of data revealed that characters like leaf lobing (0.850), leaf trichome(4.637), sinus shape (1.021), and leaf margin (0.850) were highly significant in differentiating the wild and cultivated taxa of Passiflora at the inter and intra specific levels. This may be the reason for the variation observed among the varieties of P.foetida. Researches like Viscosi and Cardini [14], Al-shammary and Gornall [15] and Ogundipe [10] emphasized the significance of foliar characters like lobing, leaf trichome, leaf margin and sinus shape in distinguishing the intra specific variations in legumes, members of Saxifragaceae and in Alternanthera respectively.
UPGMA dendrogram (Fig.2) revealed the close relationships between the two species, P. vitifolia and P.coccinea. This may be due to presence of multicellular trichomes with characteristic leaf lobing, leaf base, leaf color, and leaf shape and teeth apex. The presence of the two accessions of the P. edulis var. edulis (acc 5 and acc 4) in the first cluster and P. edulis var.flavicarpa and var. panamared in the second cluster suggest the significance of foliar morphology in the delimitation of the taxa at the varietal level. The three varieties were clearly demarcated by the color of the leaves and the nature of leaf margin. Even though inter varietal differentiation was noticed in the varieties of P. foetida, the foliar characters did not support the delimitation of varieties at the intra varietal level. However, separation of the accessions (acc10 and acc 11) of P.foetida var.foetida, from the rest of accessions may be due to the presence of anisocytic stomata and dense pubescent leaves. The variations in the foliar morphological characters at the inter specific levels were also noticed in the present investigation. Similarity in the entire leaf margin and the lack of trichomes and hairs in P.subpeltata and P.faciata pointed out the interspecific relationship. The presence of dense pubescence and multicellular trichomes in P.vitifolia and P.coccinea revealed their close relatioships. Simple leaves with entire margin in P.apoda and P. quadrangularis can be the distinguishing character to delimit the species. Occurrence of the two hybrid varieties P.'Manapany' and P.'Cananelle' together in the second subcluster may be due to the characters like leaf arrangement, leaf size, marginal sheath spacing and teeth apex shared by them, but the former was distinct by the presence of trichomes. According to Tangarife et al. [9] clustering of the seven species of Passiflora L. together in a single cluster based on the unique nature of the leaf arrangement and leaf margin.
The data suggest that the inter and intra specific variations in Passiflora may be primarily due to the foliar variations. The study emphasizes the significance of foliar characters in the delimitation of taxa at the inter and intra specific levels. The taxonomic key prepared, based on foliar features supports the findings.