Abstract: In present research anatomical and palynological studies carried out seven species of Silene which growing in north-east of Iran. These species belonged to four sections including Sclerocalycinae, Melandriformes, Auriculatae and Conoimorpha. For comparative anatomy studying, cross sections from stem and leaf were prepared using microtome and differential staining. The characters of secondary xylem and epidermal cell in leaf were studied. For palynology studying, after extraction of the pollen and acetolysis, the ornamentation of the pollen were investigated. The results of anatomy showed, presence of sclerid and fiber, spiral and reticulate vessel. The arrangement of vessel was radial chain pore, solitary and cluster. The arrangement of mesophyll was dorsi-ventral and isolateral. The pollen was spheroid, pantaporate, inaperture, tectate. Finally, a correspondence between morphology and palynology characters was observed.
INTRODUCTION
Silene belongs to Silenoideae subfamily, Caryophyllaceae family, which composes of 700 species around the world (Jurgens et al., 2002; Jurgens, 2004). This genus distributed in Turkey, Russia, Italy, Iraq, Iran, east of Mediterranea, Europe, Japan, Spain and England (Boissier, 1884; Tutin, 1964; Zohary, 1966; Groshkova et al., 1970; Davis, 1965-1985; Anzalone, 1982; Melzheimer, 1988). The number of Silene L. species in Iran is 98 (Melzheimer, 1988), only seven species are found and distributed in North-East of Iran. In present study, stem and leaf anatomy in cross section were investigated. The aim of this present investigation was study of variation in internal structure and identification of Silene species on the basis of micromorphology and internal structure because morphologically identification of this species is difficult. The previous anatomy studying on Caryophyllaceae had been done by Metcalfe and Chalk (1983). Also, the stem anatomy had been carried out Saponaria (Ataslar, 2004). In this part of investigation, the type of sclerenchyma tissue, stoma, arrangement of leaf mesophyll and vessel studied.
The earlier palynology investigation had been done of sect. Auriculatae, Siphonomorpha by Ghazanfar (1984). In the present research, anatomy of stem, leaf and the pollen ornamentation of Silene species growing in North-East of Iran were studied.
MATERIALS AND METHODS
As for the anatomic study, the examined species were collected from the localities in North-East of Iran during May-June 2005-2006 (Table 1). For preparing of cross section of stem and leaf, base of stem and basal leaves
| Table 1: | The localities of studied Silene species |
were selected from 6-7 specimens. The living materials were fixed in FAA then they were dehydrated with ethanol and later, some slices were prepared with microtome. Twelfth- microns thickness was stained with Safranine and Fast-green (Johnson, 1940; Chamberlain, 1990). For the stem maceration, this organ was placed in Jeffery solution for 4 h to soften.
In the palynological study, the pollen was extracted from the anther and dehydrated by glacial acetic acid, then acetolised, coated with sputter finally studied by LM Olympus and SEM LEO1450VP (Erdtman, 1952; Moore et al., 1991). The pollen terminology was adapted from Punt et al. (1994).
RESULTS AND DISCUSSION
Anatomic characters: The results from the anatomic studies showed:
| • | Some (several) parenchymatous layers with small cells under the epidermis. |
| • | Some sclerenchymatous layers with small cells |
| • | Vascular bundles which the arrangement of vessel was variable for example solitary- radial chain pore in S. bupleuroides, S. latifolia subsp. ramosa, radial chain pore in S. noctiflora, S. bupleuroides, S. latifolia subsp. eriocalycinae, S. conoidae (Fig. 1), radial chain pore- cluster in S. latifolia subsp. alba, S. latifolia subsp. persica, S. swertifolia (Fig. 2) and cluster in S. indeprensa, S. gertraudiae (Fig. 3). The sclerid layers observed in S. bupleuroides and S. swertifolia while in S. gertraudiae existed only fiber. In the rest of studied species both of the cells type observed. The results from stem maceration confirmed the presence of vessel with simple perforation plate. |
The results of leaf anatomy showed, the arrangement of mesophyll in perennial species, i.e., S. swertifolia,
| Fig. 1: | Stem cross section of S. noctiflora. The arrow showing radial chain pore (x416) |
S. gertraudiae, S. indeprensa, S. bupleuroides were isolateral (Fig. 4) but in annual and biennial species i.e., S. latifolia, S. noctiflora, S. conoidae were dorsi-ventral (Fig. 5).
| Fig. 2: | Stem cross section of S. swertifolia. The arrow showing Radial chain pore with cluster (x416) |
| Fig. 3: | Stem cross section of S. indeprensa. The arrow showing cluster (x416) |
| Fig. 4: | Leaf cross section of S. gertrauidae. Isolateral mesophyll (x416) |
| Fig. 5: | Leaf cross section of S. conoidae. Dorsi-ventral mesophyll (x416) |
| Fig. 6: | Crenate subsidiary cell in S. latifolia |
| Fig. 7: | Entire subsidiary cell in S. bupleuroides |
The subsidiary cell in S. latifolia, S. noctiflora, S. conoidae were crenate (Fig. 6) and entire in S. indeprensa, S. swertifolia, S. gertraudiae, S. bupleuroides (Fig. 7).
Palynology analysis: The pollen was spheroid minuta and media size, tectate or semi-tectate, pantaporate or inaperture reticulate, scabrate-granulate, occasionally muri with microechinate (Fig. 8-11). The characters were shown in Table 2.
| Fig. 8: | The pollen of S. latifolia. The muri with microechinate |
| Fig. 9: | The pollen of S. noctiflora |
| Fig. 10: | The pollen of S. conoidae |
The anatomy results showed that the glabrous and pubescent species had sclerid and fiber, respectively. The arrangement of mesophyll in annual and biennial species of Melandriformes and Conoimorpha sections growing
| Table 2: | The characters of the pollen of studied Silene species |
| +: Present, -: Absent | |
| Fig. 11: | The pollen of S. gertrauidae |
around the river is dorsi-ventral, but that in perennial species of Auriculatae and Sclerocalycinae sections which growing in stony ground is isolateral. Druse crystals in Saponaria like Silene have been observed by Ataslar (2004). The morphology of pollen in Auriculatae and Siphonomorpha sections has been reported by Ghazanfar (1984). In Siphonomorpha section, ectexine is punctuate (tubulifer/spinolose) but it is composed of punctuate, reticulate, semi- tectate (tubulifer/spinolose) types in Auriculatae. The origin of reticulate ectexine is punctuated. The pollen of some Caryophyllaceae species, like S. noctiflora, has been observed (Punt and Hoen, 1995). Besides, the pollen of S. latifolia subsp. alba has also been investigated (Moore et al., 1991). Their results are similar to present research study. In present research, the ectexine in Sclerocalycinae and Conoimorpha sections is scabrate- granulate, tectate, while that in Melandriformes and Auriculatae sections is semi- tectate and reticulate. Two of studied species i.e., S. indeprensa and S. latifolia had muri with microechinate. Morphologically, S. latifolia is similar to S. noctiflora, also their pollen are similar, but the former species differs from another for having muri with microechinate. Phylogenetically, tectate- perforate gradually changes to form lumina and muri with semi- tectate (Ghazanfar, 1984).
The Melandriformes and Auriculatae sections having semi- tectate and reticulate exine are more advanced than Conoimorpha and Sclerocalycinae sections. In conclusion the results showed that the similarity of their ornamentation to some extant related to their morphology. The sections could be recognized on the basis pollen ornamentation.