Summary

The morphological characters of the whole plant, Leaf architecture and lamina epidermal characteristics (LM & SEM) as well as Molecular data (RAPD-PCR & Isozymes) of 25 taxa of the Caesalpinioideae were investigated. These taxa represent four tribes, 15 genera, 25 species.

The morphological and molecular criteria and their states (679 attributes) were numerically analyzed. The observation obtained led to various conclusions of taxonomic importance, which could be summarized in the following:



Section A: Morphological Characters

1. Whole Plant

Habit: tree or shrubs. Length: varied between tall or medium.Texture: rough, prickly, spiny, Pubescent or glabrous. Leaf Composition: Simple, Bipinnate (paripinnate), oncepinnate (paripinnate) oncepinnate & bipinnate (paripinnate).

Shape of Blade: Suborbicular, elliptic-oblong, oblong, oblong-elliptic, ovate-lanceolate, ovate-elliptic, oblong-ovate, obovate in, cordate, oblanceolate or oblong-lanceolate. Apex of Blade: emarginated, caudate, acute, obtuse, cleft, mucronate, acute-mucronate, retuse or acuminate. Base of Blade: cordate, cuneate or obtuse. Margin of Blade: Serrate in Gleditsia caspica or entire in the rest. Stipules: exstipulate in Cassia fistula, C. grandis & C. marginata, cresentiform, auricle, cordate, spiniform, ovate, lanceolate or linear. Number of Flowers / Inflorescence: Few or many. Length: short or long. Position: leaf opposed, axillary & terminal, axillary or terminal. Type: spike-like, corymbose or raceme. Bracts: ebracteate (Cassia fistula), deltoid, suborbicular, subulate, scaly, ovate, ovate-lanceolate, ovate-oblong or obovate. Calyx Texture: glabrous, tomentose, velvety, pubescent. Colour: red, pink, crimson, scarlet, brown , green or yellow. Sepal Shape: gamosepalous or polysepalous. The sepals may be lanceolate, ovat-lanceolate, ovate, obovate, oblong, oblong-ovate, oblong-obovate or ovate-oblong. Number: four or five. Corolla Texture: glabrous or pubescent. Colour: whitish green, white, yellow, red, lavender, pink or scarlet. Petal Shape: obovate, obovate-elliptic, obovate-oblong, ovate-elliptic, oblong, sub-orbicular, obconical, spathulate or ovate. Number: in all the taxa under investigation the number of petals are five except Gleditsia caspica (four petals) and Ceratonia siliqua & Saraca indica (apetalous). Androecium Fertility: ten fertile stamens, three, five, seven, eight, nine or 12, seven fertile & three sterile, six fertile and four sterile or five fertile & five sterile. Length: as long as petals, shortly exerted, longly exerted or included. Filament Texture: pubescent, hairy, pilose, glandular or glabrous. Form: awl-shaped or Filiform. The latter may be sigmoid or nodulated. Anthers Size: unequal, subequal or equal. Attachement: dorsifixed, basifixed or versatile. Ovary Texture: glabrous, pilose or pubescent. Form: flattened, oblong or terete. Setting: sessile, subsessile or stipitate. Style Length: short or long. Form: flattened, teret or filiform. Curvature: upcurved, straight or incurved. Stigma Form: capitate, sub-capitate, concave, truncate, peltate or simple. Pod Texture: pubescent or glabous. Colour: yellow or Brown. Form: linear, linear-oblong, oblong, terete or elliptic. Dehiscence: dehiscent or indehiscent. Apex: acut, mucronate, cuspidate, tapering or obtuse. Peak: peakless, long or short. Type: membranous, crustaceous, sub-woody or woody. Seed Colour: orange, black, greenish black, green or brown. Form: teret, sub-terete, compressed or flattened. Shape: ovate, obovate, orbicular, suborbicular, elliptic, pear–shaped or oblong.

2. Lamina Architecture

Primary Vein Category: campylodromous or pinnate. Secondary Vein Category: poorly developed in Parkinsonia aculeata, cladodromous, brochidodromous or festooned brochidodromous. Basal Vein Number: one, two, three, four, five, six, seven, 13 or 14. Secondary Vein Spacing: uniform or irregular. Tertiary Vein Category: poorly developed, dichotomizing, alternate percurrent or random reticulate. Tertiary Vein Course: sinuous, straight, admedially ramified or exmedially ramified. Tertiary Vein Angle: obtuse or acute. Quaternary Vein Category: alternate percurrent, dichotomizing, poorly developed or regular polygonal reticulate. Areolation: absent, poorly developed, moderately developed or highly developed. Freely Ending Veins: absent, unbranched, once branching or two or more branching. Marginal Ultimate Venation: absent, fimbrial or looped.

3. Lamina Epidermal Characteristics (LM)

Cell Shape: quadrangular, polygonal, pentagonal, hexagonal or irregular. Anticlinal Wall: straight, sinuous, slightly curved or curved. Trichome Type: wanting, unicellular or bicellular. Stomata Type: paracytic, isotricytic & tetracytic, cyclocytic, anomocytic or paracytic. The taxa under investigation vary between hypostomatic lamina or amphistomatic one. Shape: circular or elliptic. Crystals: wanting, irregular, druses or/and prisms.

4. Lamina Epidermal Characteristics (SEM)

Sculpture: colliculate, ruminate, reticulate, pusticulate or tuberculate. Anticinal Wall Width: broad or narrow Elevation: raised or depressed. Texture: smooth or granular. Periclinal Wall Elevation: depressed or raised. Texture: smooth or granular.

Section B: Molecular Characters

1. RAPD Diversity Aspects

The present investigation was conducted to develop biochemical and molecular genetic fingerprints for the studied taxa and to elucidate relationships among these samples.

Extracted DNA from fresh leaf samples was used to identify the molecular fingerprints. Ten 10-mer arbitrary oligonucleotide primers were used to establish their randomly amplified polymorphic DNA based on polymerase chain reaction (RAPD-PCR) fingerprints. The ten primers were successfully generated reproducible polymorphic products. The primers are SC10-5, SC10-14, SC10-17, SC10-18, SC10-22, SC10-23, SC10-25, SC10-59, SC10-64 and SC11-30. The fingerprints generated by these primers revealed characteristic profiles for each taxa, in terms of number and position of RAPD bands. The results revealed that both the number and size of the amplified products varied considerably with the different primers.

A sum of 323 polymorphic bands was generated by these primers in the taxa under study. In the present study, a total of 91 unique bands were identified out of the polymorphic ones. These unique bands were used to discriminate among the studied taxa. Most samples of the studied taxa were discriminated by one or more unique bands.

2. Isozyme Analysis

Fresh and young leaves were used separately to identify the fingerprint based on polymorphism in isozymes banding patterns.

Polyacrylamide gel electrophoresis was employed to identify the biochemical fingerprint based on five isozyme systems, alcohol dehydrogenase (Adh), aldehyde oxidase (Alo), and esterase (Est) and acid phosphatase (Acph) profiles. Isozymes results revealed a high level of polymorphism among the studied taxa and have proved to be effective in identifying the each of the studied taxa by a unique class pattern, which indicates that biochemical genetic fingerprinting, is a reliable technique to discriminate among these taxa.

Section C: Numerical Analysis

The data obtained from the morphological and molecular attributes (679) of the investigated taxa were subjected to the numerical analysis to produce the dendrogram and comparing it with the current systems of taxonomic classification. The results illustrated that the taxa investigated were split into eight groups, three clusters and two series.

The most important of several conclusions and predictions are obtained as the following:

The suggested current taxonomic treatments agree in far extent with the current systems of classification (Bentham & Hooker, 1862, Post, 1932, Emberger, 1960, Engler, 1964, Willis, 1966, Brenan, 1967, Hutchinson, 1967, Pettigrew & Watson 1977, Smith, 1977, Polhill & Raven, 1983, Watson & Dalwitz, 1983 and Lewis et al., 2005).

Haematoxylum was isolated away from the rest of the related taxa viz. Ceasalpinia, Delonix, Parkinsonia and Peltophorum. And this is confined with Pettigrew & Watson, 1977.

The studied Bauhinia species were nested together in one group and closely related to Cercis, this supported the division of tribe Cercideae into two subtribes, Cercidinae, the subtribe containing Cercis and Bauhiniinae, the subtribe containing Bauhinia by (Wunderlin et al., 1981, 1987).

Although Cassia and Senna group were heterogenous, in far extent the suggested treatment supports the segregation of genus Cassia L. into three subgenera viz. Fistula, Senna and Lasiorhegma by Bentham, (1871) & Taubert, (1891) or subgenera viz. Cassia, Senna and Absus by Randell, (1976).