Abstract

The leaflets of all the species of genus Oxytropis DC. (Leguminosae) in Turkey have been studied by using scanning electron microscope to investigate stomata, trichome and leaf surface morphology. All taxa have amphistomatic leaflets. Four taxa have mesomorphic stomata, the others are xeromorphic. Leaflets adaxial surface have dense epicuticular wax. O. engizekensis Duman et Vural and O. persica Boiss. have subbifurcate trichome, the others are simple.

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INTRODUCTION

The legumes are the third largest family of flowering plants and second only to the cereals in their economic importance (Heywood et al., 2007). The genus Oxytropis DC has 13 species two of endemic in Turkey (Davis, 1970; Guner et al., 2000).

Oxytropis DC belongs to the tribe Galegeae of Papilionoideae in the Leguminosae, comprises about 300-400 species occurring in cold mountainous regions of Europe, Asia and North America and is most numerous in Central Asia (Barneby, 1952). It is classified 181 species into 4 subgenera and 19 sections by Bunge (1874).

The studies of epidermal and cuticular characters of leaves and seed have played an important role in taxonomy (Stace, 1965, 1966; Hardin, 1979; Wilkinson, 1979; Barthlott, 1981, 1984; Soladoye, 1982). The SEM reveals new structural categories and refined details with high systematic impact.

The epidermal characters are surprisingly little affected by the environmental conditions in which a plant grows; there is evidence for a strong genetic control over these characters (Cutler and Brandham, 1977).

Plant surfaces represent, the relationship between plants and their environment. Extracellular membrane, the cuticle covers the primary above ground organs such as flowers, legumes, leaves and stems of all lower and higher land plants. The cuticle is mainly composed of a three-dimensional network of cutin and integrated and superimposed lipids called waxes. Superimposed waxes are also called epicuticular waxes. Plant waxes are composite materials of aliphatic hydrocarbons and their derivatives with carbon chain lengths between 20 and 60 atoms (Koch and Ensikat, 2008). In particular, plant waxes that are deposited on the cuticular surface are referred to as epicuticular waxes (Koch et al., 2006).

The aim of this study is to investigate how leaf micromorphology separates of the Oxytropis taxa. The study based on scanning electron microscope.

MATERIALS AND METHODS

Materials of the studied species and their collection localities are shown in Table 1. Leaves of 13 species collected from field trip. Adaxial and abaxial surfaces of dry leaves were maintained. All part of small leaflets and apex of the large leaflets were studied. The dense hairy leaflets hairs were erased with scalpel for investigating leaflet surface and stomata. Adaxial and abaxial surfaces of dry leaves were maintained onto stubs and coated with gold and examined by JEOL JSM-6060 scanning electron microscope at 10 kV, allocated at Gazi University.

The species Latin names and researchers, short descriptions, abaxial and adaxial surface of leaves and stomata structure are in Table 1.

Table 1:	Studied taxa, their collection locations and collecting numbers

RESULTS AND DISCUSSION

Oxytropis kotschyana Boiss. and Hoh.: Caulescent; ascending; 25-50 cm; leaves 6-15 pairs of leaflets, leaflets ovate-lanceolate to narrowly elliptic, 20-40x5-10 mm; corolla lavender-blue; beak 2-4 mm; legume oblong-linear, 35-45 mm (Fig. 1).

Trichomes are simple and 1-2 celled, striate-verrucae, 10±1.4 μm² on the lamina and margin of the leaves. Leaflets are amphistomatic. Stomata is mesomorphic, 25±4.5 μm². The adaxial surface consists epicuticular waxes.

O. pallasii Pers.: Caulescent; prostrate or ascending; 8-15 cm; leaves 8-12 pairs of leaflets, leaflets narrow elliptic to oblong-elliptic, 8-14x2.5-4 mm; corolla yellowish white; beak 2.5 mm; legume oblong, 30-35x3-4 mm (Fig. 2).

Trichomes are simple and 1-2 celled, striate-verrucae, 17±3.9 μm² on the lamina and margin of the leaves. Leaflets are amphistomatic. Stomata is mesomorphic, 15±3.7 μm². The adaxial surface consists epicuticular waxes.

O. pilosa (L.) DC: Caulescent; erect; up to 50 cm; leaves 8-12 pairs of leaflets, leaflets narrow elliptic to oblong elliptic, 8-14x2.5-4 mm; corolla yellow; beak 2.5 mm; legume oblong, 15-20x4-5 mm (Fig. 3).

Trichomes are simple and 1-2 celled, striate-verrucae, 17±3.9 μm² on the lamina and near the margin but very decrease toward base. Leaflets are amphistomatic. Stomata is mesomorphic, 20±4.1 μm². The adaxial surface consists epicuticular waxes.

O. savellanica Boiss.: Acaulescent; leaves 7-10 pairs of leaflets, leaflets oblong or elliptic, 9-30 mm; corolla violet or purple; beak 0.5-1.5 mm; legume oblong, 10-12x4-4.5 mm (Fig. 4).

Trichomes are simple and 1-2 celled, striate-verrucae, 25±3.7 μm² on the lamina surface and near the margin of the leaves. Leaflets are amphistomatic. Stomata is xeromorphic, 38±4.3 μm². The adaxial surface consists epicuticular waxes.

O. persica Boiss.: Acaulescent; leaves 6-8 pair of leaflets, leaflets linear-elliptic or narrow elliptic, 3-7x1-2 mm; corolla violet or pinkish; beak 1-2 mm; legume ovate, 6-12x3-6 mm (Fig. 5).

Trichomes are simple and 1-2 celled, striate-granulate, psilate-verrucae, striate-verrucae, 40±4.2 μm² on the lamina and near the margin of the leaves. Leaflets are amphistomatic. Stomata is xeromorphic, 10±3.7 μm². The adaxial surface consists epicuticular waxes.

O. engizekensis H. Duman and Vural: Acaulescent; leaves 4-6 pairs of leaflets, leaflets linear-elliptic, 3-7x1-2 mm; corolla white; beak 1-2 mm; legume ovoid-oblong, 10-16x5-8 mm (Fig. 6).

Endemic: Trichomes are simple and 1-2 celled on adaxial surface psilate-granulate ve striate-granulate on abaxial striate-granulate, psilate-granulate or striate, 38±3.4 μm² on the lamina and near the margin of the leaves. Leaflets are amphistomatic. Stomata is xeromorphic, 8±3.4 μm². The adaxial surface consists epicuticular waxes.

O. albana Stev.: Acaulescent; leaves 6-13 pairs of leaflets, leaflets linear-oblong elliptic to oblong-ovate, 2-8x0.5-3 mm; corolla violet or pinkish; beak 1-2 mm; legume oblong, 6-12x3-6 mm (Fig. 7).

Trichomes are simple and 1-2 celled, striate-granulate, 1±1.5 μm² on the midrib and near the margin of the leaves. Leaflets are amphistomatic. Stomata is xeromorphic, 17±5.1 μm². The adaxial surface consists epicuticular waxes.

O. lazica Boiss.: Caulescent; leaves 6-15 pairs of leaflets, leaflets oblong-ovate to narrow oblong-elliptic, 3-10x 1.5-4 mm; corolla white, pale or violet blue; beak 1-2 mm; legume ovate-oblong, 20-25x7-9 mm (Fig. 8).

Fig. 1:	Scanning electron micrographs of leaf surfaces of O. kotschyana, a) Adaxial view, b) Higher magnification of adaxial surface, c) Trichome and d) Stomata

Fig. 2:	Scanning electron micrographs of leaf surfaces of O. pallasii, a) Adaxial view, b) Higher magnification of adaxial surface, c) Trichome and d) Stomata

Fig. 3:	Scanning electron micrographs of leaf surfaces of O. pilosa, a) Adaxial view, b) Higher magnification of adaxial surface, c) Trichome and d) Stomata

Fig. 4:	Scanning electron micrographs of leaf surfaces of O. Savellanica, a) Adaxial view, b) Higher magnification of adaxial surface, c) Stomata and d) Trichome

Fig. 5:	Scanning electron micrographs of leaf surfaces of O. persica, a) Adaxial view, b) Higher magnification of adaxial surface, c) Trichome and d) Stomata

Fig. 6:	Scanning electron micrographs of leaf surfaces of O. engizekensis, a) Adaxial view, b) Higher magnification of adaxial surface, c) Stomata and d) Trichome

Fig. 7:	Scanning electron micrographs of leaf surfaces of O. albana, a) Adaxial view, b) Higher magnification of adaxial surface, c) Trichome and d) Stomata

Fig. 8:	Scanning electron micrographs of leaf surfaces of O. lazica, a) Adaxial view, b) Higher magnification of adaxial surface, c) Trichome and d) Stomata

Trichomes are simple and 1-2 celled, striate-verrucae, 4±1.1 μm² on the midvein and on the leaves. Leaflets are amphistomatic. Stomata is mesomorphic, 30±3.7 μm². The adaxial surface consists epicuticular waxes.

O. argyroleuca Bornm.: Caulescent; leaves 5-7 pairs of leaflets, leaflets elliptic, 5-6x3 mm; corolla violet; beak 1 mm; legume linear, 20-25x4 mm (Fig. 9).

Endemic: Trichomes are simple and 1-2 celled, striate-verrucae, 40±3.7 μm² on the lamina and near the margin of the leaves. Leaflets are amphistomatic. Stomata is xeromorphic, 32±4.8 μm². The adaxial surface consists epicuticular waxes.

O. fominii Grossh.: Caulescent; leaves 8-12 pairs of leaflets, leaflets linear-oblong-elliptic to oblong-ovate, 2-8x0.5-3 mm; corolla violet or pinkish; beak 1-2 mm; linear, 20-25x7-9 mm (Fig. 10).

Endemic: Trichomes are simple and 1-2 celled, striate-verrucae, 24±5.1 μm² on the surface and near the margin of the leaves. Leaflets are amphistomatic. Stomata is xeromorphic, 40±2.8 μm². The adaxial surface consists epicuticular waxes.

O. aucheri Boiss.: Caulescent; leaves 6-10 pairs of leaflets, leaflets oblong-elliptic, c.10x3 mm; corolla pink (drying deep blue); beak c. 2 mm; legume ovate-oblong, 20-30x4-6 mm (Fig. 11).

Trichomes are simple and 1-2 celled, striate-verrucae, 10±3.9 μm² on the lamina and near the margin of the leaves. Leaflets are amphistomatic. Stomata is xeromorphic, 20±5.6 μm². The adaxial surface consists epicuticular waxes.

O. karjaginii Grossh.: Caulescent; leaves 6-10 pairs of leaflets, leaflets oblong-elliptic, 9-15x3-4 mm, corolla violet or pinkish; beak c. 2 mm; legume ovate-oblong, 20-30x5-6 mm (Fig. 12).

Trichomes are simple and 1-2 celled, striate-verrucae, 30±4.7 μm² on the lamina and near the margin of the leaves.

Leaflets are amphistomatic. Stomata is xeromorphic, 25±5.1 μm². The adaxial surface consists epicuticular waxes.

O. lupinoides Grossh.: Caulescent; leaves 7-14 pairs of leaflets, leaflets ovate-oblong-elliptic, 9-16x4-5 mm; corolla pink or lilac (drying deep blue); beak c. (1-) 2-3 mm; legume 20-25x3-4 mm (Fig. 13).

Trichomes are simple and 1-2 celled, striate-verrucae, 15±2.8 μm² on the lamina and near the margin of the leaves. Leaflets are amphistomatic. Stomata is xeromorphic, 30±4.2 μm². The adaxial surface consists epicuticular waxes.

Studied taxa, altitude, flowering time, stomata, stomata number, trichome ornamentation, trichome number and endemism are in Table 2.

Table 2:	Results of taxa, altitude, flowering time, stomata, stomata number, trichome ornamentation, trichome number and endemism

Fig. 9:	Scanning electron micrographs of leaf surfacesof O. argroleuca, a) Adaxial view, b) Higher magnification of adaxial surface, c) Trichome and d) Stomata

Fig. 10:	Scanning electron micrographs of leaf surfaces of O . fominii, a) Adaxial view, b) Higher magnification of adaxial surface, c) Trichome and d) Stomata

Fig. 11:	Scanning electron micrographs of leaf surfaces of O. aucheri, a) Adaxial view, b) Higher magnification of adaxial surface, c) Trichome and d) Stomata

Fig. 12:	Scanning electron micrographs of leaf surfaces of O. karjaginii, a) Adaxial view, b) Higher magnification of adaxial surface, c) Trichome and d) Stomata

Fig. 13:	Scanning electron micrographs of leaf surfaces of O. lupinoides, a) Adaxial view, b) Higher magnification of adaxial surface, c) Trichome and d) Stomata

CONCLUSION

Trichomes are on the lamina and near the margin of the leaves, O. albana and O. lazica on the midrib and near the margin. This study showed that all the species leaflets are amphistomatic. Although, O. savellanica, O. persica, O. engizekensis, O. argyroleuca, O. fominii, O. albana, O. aucheri, O. karjaginii and O. lupinoides leaflets observe xeromorphic stomata, O. kotschyana, O. pallasii, O. pilosa and O. lazica mesomorphic. O. kotschyana, O. pallasii and O. pilosa bloom earlier than the other species (April to May). O. lazica, which blooms later (July to August) also lives in areas where has continuous rainfall. These factors can explain the reason of having mesomorfik stoma.

O. savellanica (38±4.3 μm²) have the most numerous stomata, O. engizekensis (8±3.4 μm²) has the least. O. persica (40±4.2 μm²) and O. argyroleuca (40±3.7 μm²) had the most numerous trichome, O. albana (1±1.5 μm²) had the least. All species have simple trichome, but we show that O. engizekensis Duman et Vural and O. persica Boiss. have subbifurcate trichome. These charachters can be used for separate these two taxa the others.

The trichome ornamentations have some differences from each other, the common type is striate-verrucae. O. persica and O. engizekensis leaflets show different trichome ornamentations between adaxial and abaxial surfaces and between the other taxa. O. persica striate-granulate, psilate-verrucae (adaxial), striate-verrucae (abaxial). O. engizekensis striate-granulate, psilate-granulate or striate (adaxial), striate-granulate, psilate-granulate (abaxial).

This study was useful in confirming the relationship between Oxytropis sp. in Turkey.

How to cite this article:

S. Karaman, Z. Suludere, M. Pinar and Z. Aytac. The Leaflets Micromorphology of the Genus Oxytropis DC. (Leguminosae) in Turkey by SEM.
DOI: https://doi.org/10.36478/brj.2009.7.23
URL: https://www.makhillpublications.co/view-article/1995-4751/brj.2009.7.23