THE IRANIAN JOURNAL OF BOTANY
Year:2018 | Volume:24 | Issue:1 |Papers Count:10

In this research, pollen grains of ten species and two subspecies of the genus Hypericum in Iran belonging to four sections were studied using light and scanning electron microscopy. The pollen grains are monad, isopolar to subisopolar and heteropolar, prolate, subprolate, spheroidal and prolate-spheroidal in shape, small to medium in size. The outline of pollen grains varies from round to triangular, quadrangular and ovate from polar view and elliptical, tetrahedral, quadrangular, round and ovate from equatorial view; 3 and 4 syncolporate to 3, 4 and 6 zonocolporate. Based on exine sculpturing, pore shape, size and muri thickness, the examined species are divided in two main types including scrobiculate and micro reticulate and 2 subtypes including small pore / thick muri and large pore / thin muri. The pores are arranged from irregular to regular-irregular with regular intervals. The current result revealed taxonomically important palynological data of the genus Hypericum. These traits can be used for infrageneric classification, especially at sectional and species levels.

This study aims to assess the pollen characteristics of Iranian Onagraceae based on SEM techniques to evaluate the possibility of giving them a role in systematic analysis. Pollen grains of the studied taxa included radially symmetrical, tetrad tetra-hederal, isopolar, triangular to triangular-spheroidal, 3-zonoporate, with viscin threads, rugulate-granulate, granulate, verrucate and striate sculpturing. Polar axis ranged between 30 and 80 μ m. Equatorial axis showed variation from 40 to 90 μ m. Moreover, arm diameter ranged between 8. 85 to 18. 83 μ m, pore diameter 8. 72 to 21. 69 μ m. PCOA and Cluster analysis of pollen characteristics did not clearly show sectional divisions based on Flora Iranica as well as Flora of Iran. There are not significant differences in size, shape, pore structure and arm characteristics to delimit all species in Onagraceae. Moreover, Pollen grains are not efficient for generic delimitation in the studied taxa in Iran. Therefore, even though that the examined taxa cannot be distinguished exclusively by pollen, it may be a useful tool for delimitation some taxa in Onagraceae along with other evidence.

A comparative trichrome micromorphological study of 24 Silene species representing eight sections, was made using light and scanning electron microscopy. To check the consistency of trichome types on different parts of a certain species, micromorphological studies were focused on stem, leaf and calyx surface. Two basic types of trichomes were distinguished: glandular and non-glandular. Two different subtypes were recognized within the non-glandular type representing unbranched non-glandular and branched non-glandular trichomes. The study shows that although trichomes are not useful in delimiting Silene sections, they provide a set of reliable characters for separation of species within sections. The presence or absence of trichomes, and trichome types could be used as diagnostic character for identification of some species.

Phylogenetic relationship and seed morphological characters of 11 species belong to Medicagoid Trigonella, six non Medicagoid and one species of each genera of Medicago and Melilotus were estimated before based on ITS sequences by using Baysian inference and maximum parsimony. In this paper, scanning Electron Microscope and stereomicroscope for seed morphological characters were used. Seed morphology results indicated that majority of Medicagoid Trigonella species belong to Bucerates and Lunatae sections placed in two close subclusters and joined together as did by Baysian analysis results. Both studies confirmed that Medicago radiata is sister for these species. Our results confirm that using molecular and morphological characters data are reliable evidence in systematic discriminations of the taxa.

Middle Asia is one of the major centers of origin and diversity of the family Apiaceae. Secretory system and other anatomical peculiarities of many endemic Apiaceae are still poorly investigated. Comparative anatomical study of plant secretory structures has a great theoretical and practical importance in relation to taxonomy, ecology and pharmacology. The paper provides the results of structural investigation of the secretory system of five endemic and medicinal species of Apiaceae from Middle Asia (Sphaerosciadium denaense, Ferula foetida, F. varia, F. kyzylkumica, Dorema sabulosum). It was revealed that different representatives of the family Apiaceae growing in various habitats have a secretory system represented with terpenoid keeping schizogenous secretory ducts. Desert plants (F. foetida, F. varia, F. kyzylkumica, D. sabulosum) have larger secretory ducts producing more of terpenoids, than a mesophilous relic mountain species S. denaense. The most characteristic structural features of secretory system of S. denaense are small diameter of lumen, small epithelial cells, and the absence of ducts around the xylem of the medullary bundles in the stem and petioles. The structural features of secretory system are specific to each of the investigated plants. The topography and dimensions of secretory ducts are a diagnostic character applied in species identification.

Four species belonging to two subgenera of Iranian Allium species were chromosomally and karyotypically assessed, using squash technique and feulgen stain. Ploidy level of A. longivaginatum, A. hooshidaryae and A. remediorum (2n = 2x = 16) are reported for the first time. Results indicated that A. rotundum is tetraploid (2n=4x= 32). Two chromosome types (‘ ‘ m’ ’ , ‘ ‘ sm’ ’ ) formed different karyotypic formulas. Mean chromosome length varied from 7. 8-13. 56 μ m. The results show that Allium longivaginatum has the most asymmetrical karyotype.

The present study considers assessment of morphometry and genetic diversity of 24 populations of Hypnea. Statistical analyses indicated that characters such as algal branching in habit, size of alga and Position of tetrasporange sorus had the most important role in intera-specific variation. In both morphometry and genetic diversity analysis, grouping of the populations separated the studied species into four distinct clusters and groups but populations were spread in clusters. Analysis revealed significant genetic difference among populations and some degree of genetic admixture and gene exchange among the studied populations.

A freshwater red algae, Compsopogon caeruleus was collected from current water canal on south of Tehran, Iran for the first time. It lives as epiphyte on Cladophora sp. (green algae) in cold water canal at a temperature of 8-10° C and at high speed at a depth of 30-50 cm. Thallus was macroscopic filamentous, grey to greyish– green, in the growing season abundantly branched. Branches made an acute angle with the axis (about, 20-70° ). Thallus is 180-1000 μ m in diameter and 2-10 cm long. In mature thallus, cortex had 1– 2 polygonal or irregular cell layers with short spine-like branchlets. Cortical cells were established in regular or irregular rows. Chloroplasts were parietal. Monosporangia were cortical and semi-spherical to irregular.