The present work deals with population-based meiotic studies on eight species belonging to four genera of the family Commelinaceae from different regions of Kangra Valley which is well known for its rich floristic diversity. At the world level, different cytotypes for four species such as Commelina hasskarlii (2n = 22, 60), C. kurzii (2n = 60), Murdannia nudiflora (2n = 24) and M. spirata (2n = 24) have been recorded for the first time at various ploidy levels. Additionally, from India, the new chromosome count for Tradescantia pallida (2n = 24) has been reported at the tetraploid level. The course of meiosis has been found to be normal in all the populations of Commelina benghalensis, C. paludosa, Murdannia nudiflora and M. spirata while four species, Commelina hasskarlii, C. kurzii, Cyanotis cristata and Tradescantia pallida have shown a normal to abnormal meiotic course in different populations. These meiotic abnormalities have revealed a clear effect on the pollen size and pollen fertility.
During the research interaction of indole-3-acetic acid (IAA) and methyl jasmonate (JA-Me) in epinasty and/or hyponasty, as well as petiole growth of Bryophyllum calycinum were investigated. Exogenously applied IAA as a lanolin paste was extremely effective to induce epinasty and/or hyponasty accompanied with petiole elongation in intact B. calycinum. Application of IAA around or to the upper side of the petiole was much more effective than that to the lower side, suggesting that petiole epidermal cells on the adaxial side of B. calycinum are more sensitive and/or susceptive to IAA than those on the abaxial one. This is supported by the fact that not only the second curvature but also the first one in B. calycinum was enhanced by application of IAA to the upper side of the petiole. The degree of epinasty and/or hyponasty induced by IAA is strongly related to the increase of petiole growth. On the other hand, JA-Me significantly inhibited IAA-inducing epinasty and/or hyponasty, and petiole growth in intact B. calycinum. When detached leaves with petioles were placed leaf blade face down, clear petiole bending was observed. However, no petiole bending was found when detached leaves were placed leaf blade face up. Exogenously applied IAA to petioles was significantly effective to induce and/or stimulate petiole bending in placing detached leaves of B. calycinum face down but ethephon was not, suggesting that transport and/or movement of endogenous auxin produced in the leaf blade are necessary to induce petiole bending in detached leaves of B. calycinum and that ethylene derived from exogenously applied IAA does not play an important role in epinasty and/or hyponasty, and petiole bending in B. calycinum. The mechanisms of IAA-enhancing and JA-Me-inhibiting epinasty and/or hyponasty, and petiole growth are intensively discussed.
Exposure of green algae Chlorella vulgaris to short-term UV-B radiation (280 nm – 315 nm) induced several changes in the function of photosystem II (PS II) studied by means of chlorophyll fluorescence (FL) and oxygen evolving. The intensity of photosynthetic oxygen evolving intensity of algae suspension decreased in a similar way to the FL parameter values in proportion to the applied dose of UV-B radiation (0.0, 3.2, 6.4, 12.8 kJ·m-2). The correlation between photosynthetic oxygen evolving intensity and FV/FO ratio was better than that between photosynthetic oxygen evolving intensity and FV/FM. The vitality index (Rfd) in the UV-B irradiated algae strongly decreased, compared to the control, which indicates inhibition of potential CO2 fixation and cooperation between light and dark reactions of photosynthesis. It may indicate damage of Rubisco.
Hordeum murinum L. is a polyploid complex of thermophilic, annual, zoochoric grasses of Mediterranean–Irano- Turanian origin that is commonly present in Europe. H. murinum complex includes three annual and most often autogamous taxa: glaucum, leporinum and murinum. The variation of nuclear microsatellites, chloroplast microsatellites and chloroplast SNP-based PCR-RFLP markers of H. murinum from Europe was analyzed in order to investigate its migration. The chloroplast markers revealed three distinct haplotypes. Two of them are characteristic of leporinum and murinum. A geographical pattern of haplotypes has been detected, however it does not correspond to the known patterns of migration routes in the Holocene. Geographic distribution of genotypes defined by nuclear microsatellites has shown a geographic trend that may link the migration of leporinum and murinum with the spread of Neolithic agriculture in Europe. This study also confirms genetic distinction of glaucum, as well as genetic uniformity of murinum and leporinum.
Salt stress causes severe reduction in the growth and yield of rice plants. The ability to maintain cellular ion homeostasis is of importance to help the plant survive under salt stress. Salt overly sensitive 1 (SOS1), a plasma membrane Na+/H+ antiporter, has been proven to play critical roles in Na+ exclusion out of the cell, hence contributing to salt tolerance in plants. In this study, we analyzed the natural nucleotide polymorphisms occuring within the entire coding sequence as well as the upstream region of the OsSOS1 gene by comparing the sequences of two contrasting rice genotypes, namely, Nipponbare (salt-sensitive) and Pokkali (salt-resistant). In total, six nucleotide polymorphisms were identified in the coding sequence, and 44 nucleotide substitutions, 225-bp-insertion and 65-bp-deletion were observed in the upstream region of the OsSOS1 gene. Futher in silico analysis revealed that two out of six nucleotide polymorphisms in the coding sequence were non-synonymous (A1600G, G2204A) which led to two amino acid substitutions (T534A, S735N, respectively) positioned in the C-terminal domain of OsSOS1 transporter, but caused no effect on protein properties. In the upstream region of OsSOS1 gene, 44 single nucleotide polymorphisms and two INDELs were identified, in which nucleotide substitutions at position -1392, -1389, -822, -583, +57 and an insertion at position -1035 caused change in cis-regulatory elements. Analysis of OsSOS1 expression revealed that salt induced the expression of the gene in the roots, but not in the leaves in both investigated rice cultivars.
An efficient system of micropropagation via somatic embryogenesis from root-derived callus was established in Arabica coffee (Coffea arabica L.). Twenty-six callus lines were induced on MS (Murashige and Skoog, 1962) medium supplemented with combinations of NAA (0, 0.1, 0.5, 1 and 2 mg/L) plus BA (0, 1 and 2 mg/L), or 2,4-D (0, 0.1, 0.5, 1 and 2 mg/L) plus TDZ (0, 1 and 2 mg/L). Subsequently, two types of somatic embryos were obtained from callus cultures and named S-type and I-type embryos. The S-type embryos were obtained from an 18-monthold callus line which was induced and maintained at 2 mg/L TDZ and 0.1 mg/L 2,4-D near the end of each period of the subculture. These embryos have a developmental barrier, which did not pass through the torpedo stage and could be overcome by a supplement of 2 or 5 mg/L BA. The I-type embryos were induced from 3-month-old callus when transferred onto induction media, i.e., MS supplemented with TDZ (2 and 5 mg/L) plus 2,4-D (0 and 0.1 mg/L). The significantly highest response, i.e., 13.3 embryos per callus clump was obtained at 2 mg/L TDZ. In this study, the results reveal that TDZ has a crucial effect on embryogenic callus induction, proliferation and subsequent somatic embryogenesis.
An efficient micropropagation system for Taraxacum pieninicum using seedling explants germinated in vitro is described. Shoot tips and fragments of cotyledons, hypocotyls and roots were isolated from several-day-old seedlings. The highest response, 100% frequency with 12.3 axillary shoots/explant, was from shoot tips on medium supplemented with 0.5 mg L-1 BA and 0.05 mg L-1 NAA. In subsequent subcultures the number of shoots was significantly higher on all explants cultured on medium containing 0.25 and 0.5 mg L-1 BA, and the multiplication rate was highest (20 shoots/explant) in the 4th passage. Shoots rooted on MS and 1/2 MS medium; the highest rooting frequency was 90% and the highest number of roots 2.7/shoot. Rooted plants showed 96.2% survival in sterile soil:sand, and 100% survival in hydroponic culture. Regenerated plants flowered in the second year after acclimatization and yielded viable seeds. This protocol for obtaining complete plants through micropropagation may prove useful for conservation of the genetic resources of this and other endangered species
cAMP is a second messenger which plays a regulatory role in a wide variety of biological processes in organisms ranging from prokaryotes to higher eukaryotes, but knowledge of its role in macroalgae and vascular plants is limited. We modified cAMP levels in the macroalga Chara vulgaris thallus and studied the effects on thallus growth and gametangia development: db-cAMP (permeable analog of cAMP), adenylate cyclase (AC) activator, forskolin and theophylline (cAMP phosphodiesterase (PDE) inhibitor) were used to elevate cAMP levels, and the AC inhibitors 2'-dAdo and 2'-d3'-AMP were used to decrease them. The results suggest that in Chara vulgaris the cAMP pathway may regulate both vegetative thallus growth and gametangia development, and that these effects may depend on this second-messenger level. Elevated cAMP stimulated thallus growth and delayed gametangia development; decreased cAMP inhibited thallus growth and accelerated maturation of both antheridia and oogonia. These results suggest that the cAMP pathway participates in regulation of developmental processes in Chara vulgaris and that thallus growth and gametangia development require different cAMP levels in cells.
Morphological description of seeds is a required step for analysis of biodiversity in natural populations and may give clues to adaptive strategies in species evolution. A cardioid is the curve described by a point of one circumference rolling around another circumference of equal radius. Models based on adjustment of seed shape with cardioid curves have been described for Arabidopsis thaliana and the model legumes Lotus japonicus and Medicago truncatula. In this work the model is applied to analyze seed morphology in populations of two subspecies of Capparis spinosa growing in Tunisia. Adjustment of seed images to cardioid curves, followed by statistical analysis of similarity in the complete images as well as in each of four quadrants, allows an accurate description of seed shape. The results show differences in morphology between subspecies. Seeds of subsp. rupestris present higher diversity of shape than seeds of subsp. spinosa. This may indicate primitiveness of C. subsp. rupestris seeds, associated with nonspecialization. The results are discussed in relation to the ecological strategies of both subspecies in their evolution.
This paper is both a review and a study. It discusses the taxonomic status of Yellow Archangel (Galeobdolon luteum Huds.) from historical and contemporary perspectives, and gives a comprehensive list of synonyms for the discussed genera, species and lower taxonomic units, including their publication details. In the study it is postulated that G. luteum should be included in the genus Lamium. The hypothesis is verified by a comparative analysis between the representatives of the genera Galeobdolon and Lamium in four DNA regions: ITS, accD, rpoC1 and trnH-psbA. The analysis supported the determination of phylogenetic relationships among the studied taxa: G. luteum is not genetically distant enough from Lamium to be considered a separate genus, and integration of Galeobdolon and Lamium is legitimate.
This study used ISSR markers to assess the genetic diversity of a collection of 15 genotypes of Salix purpurea and 6 interspecific hybrids, employing 40 of 60 tested ISSR primers generating polymorphic amplification products. The PCR-ISSR method was adapted for S. purpurea by optimizing the annealing temperature for each primer. The polymorphism index of ISSR amplification products was 91.8% for all studied genotypes and 70.4% for S. purpurea genotypes. Nei's genetic identity statistics ranged from 0.538 to 0.958. Nei's genetic distance values were used to build a dendrogram (UPGMA) for the investigated genotypes. The dendrogram shows five clusters, and principal coordinate analysis yielded nearly the same genetic relationships among the studied genotypes. The results confirm the usefulness of ISSR markers for determining genetic diversity in S. purpurea.
An effective procedure for producing transformed Centaurium erythraea plants from synthetic seeds is described. Explants were encapsulated in 3% sodium alginate with 3% sucrose. Encapsulated hairy roots were cultured on half-strength Murashige and Skoog (1/2 MS) or Woody Plant (WPM) agar-solidified regeneration media supplemented with 6-benzylaminopurine (BAP) or without the cytokinin. The use of WPM with 0.5 mg/L of BAP gave the best shoot formation frequency (86%) and mean number of shoots (15) per root segment. Shoots rooted with 97% frequency on 1/2 MS without growth regulators. Encapsulated shoot buds were cultured on onethird- strength MS agar medium (1/3 MS) supplemented with indole-3-butyric acid (IBA) (0.05 mg/L). The plantlet conversion frequency was 32%. The encapsulated hairy roots and shoot buds were stored for 4, 6 or 14 weeks at 4°C. Synthetic seeds encapsulated with 3% sodium alginate with 3% sucrose stored at 4°C remained viable for 6 weeks but their developmental parameters significantly decreased. Adding nutrient medium and growth regulator to the alginate matrix increased plantlet recovery from both non-stored and stored synthetic seeds: synthetic seeds retained their viability and ability to form plantlets even after 14 weeks of storage. Regenerated transformed plantlets of C. erythraea were acclimatized in the greenhouse.
We measured the total chlorophyll (Chl a+b) content in seedling leaves of fifteen maize cultivars infested by two studied aphid species (oligophagous Rhopalosiphum padi L., monophagous Sitobion avenae F.) 7 and 14 days after the beginning of infestation, using a SPAD-502 chlorophyll meter. Chlorophyll loss was more severe in R. padi-infested than in S. avenae-infested plants. Chlorophyll depletion was greater after long-term (14 days) than after short-term aphid infestation in the investigated host systems. Seedlings of Złota Karłowa and Tasty Sweet were more damaged by aphid feeding; Ambrozja and Płomyk plants were less damaged by aphid feeding.
Here we report the consequences of telomere erosion in Arabidopsis thaliana, studied by examining seed and pollen production and the course of male meiosis through the last five generations (G5-G9) of telomerase-deficient Arabidopsis mutants. We used a previously described mutant line in which telomerase activity was abolished by T-DNA insertion into the TERT gene encoding telomerase reverse transcriptase. Reduced fertility accompanied by morphological abnormalities occurred in G6, which produced on average 35 seeds per silique (vs. 43 in wild type) and worsened in G7 (30 seeds) and G8 (14 seeds), as did the morphological abnormalities. The last generation of tert mutants (G9) did not form reproductive organs. Analysis of meiosis indicated that the main cause of reduced fertility in the late generation tert mutants of Arabidopsis was the numerous chromosomal end-to-end fusions which led to massive genome rearrangements in meiocytes. Fusion of meiotic chromosomes began in G5 and increased in each of the next generations. Unpaired chromosomes (univalents) were observed in G7 and G8. The study highlights some differences in the meiotic consequences of telomere shortening between plant and animal systems.
Isozyme, RAPD and AFLP markers were evaluated and compared for their ability to determine genetic similarity in a set of 18 parental lines of winter oilseed rape F<sub>1</sub> hybrids developed using CMS ogura. Five isozyme systems, 64 RAPD starters and 23 EcoRI+3/MseI+3 AFLP primer combinations generated 597 polymorphic markers. These polymorphic fragments were chosen for estimation of genetic similarity. Of the total number of polymorphic products, polymorphic zymograms constituted only 3.0% of the markers, 57 RAPD primers 37.7%, and 23 AFLP primer combinations 59.3%. The size of RAPD polymorphic products ranged from 564 to 2100 bp. On average there were four amplified bands per primer, with 61.0% polymorphism. The AFLP polymorphic fragments ranged from 72 to 1352 bp in size. AFLP assays generated 15 bands per primer pair on average and detected roughly four times more bands than with RAPD analysis. The genetic similarity coefficients based on all marker data range from 0.52 to 0.84. The correlation of genetic similarities based on RAPD and AFLP markers was 0.58. Estimated genetic similarity based on isozyme data was not correlated with genetic similarity derived from the two DNA-based markers. The dendrogram constructed with the three types of markers taken together grouped all the winter oilseed rape parental lines into several similar clusters. The genomic distribution and frequency of the RAPD and AFLP markers can serve well as estimators of genetic similarity between parental lines of F<sub>1</sub> CMS ogura hybrids
Hylocereus undatus flower is commonly used as food or for medicinal purposes in south China. To study its antioxidant activity and mechanism we used antioxidant and chemical assays to compare two commercial samples from different locations (Shenjing, Qixing). The difference in antioxidant levels corresponded with differences in chemical content (including total phenolics, total flavonoids, kaempferol and quercetin) between Shenjing and Qixing. The antioxidant ability of H. undatus flower seems attributable to total phenolics (mainly total flavonoids). Kaempferol is one of the main bioactive components. H. undatus flower exerts its antioxidant effects through metal chelation and radical scavenging via hydrogen atom (H•) and electron (e) donation.
The systematic position of Sorbus population occurring in the Pieniny Mts. is controversial. To verify its taxonomic status we studied the ITS sequence of closely related species of the S. aria group: Sorbus sp. from the Pieniny Mts., S. aria from the Tatra Mts., S. graeca from the Balkans, and other well-distinguished native Polish Sorbus species (S. aria, S. aucuparia, S. intermedia and S. torminalis). As a reference we examined Sorbus populations closest to the Pieniny Mts. where S. graeca was reported to occur, in Slovakia. The results indicate that the Sorbus plants found in the Pieniny Mts. differ genetically from those in the Tatra Mts. but are identical to those collected from the Vihorlat Mts. in Slovakia and are closely related to S. graeca from the Balkans
Stem structure strongly influences the drought response across a diverse group of temperate and tropical tree species. The stem of Salvadora persica (miswak), used as a chewing stick in the Islamic world, has a number of distinctive xeromorphic characteristics adapting it to arid or semi-arid conditions. The thick periderm is interrupted at points around the stem by transversely oriented lenticels to moderate exchange of vital gases. On the stem surface are 3-dimensional epicuticular crystals of various shape and size, present to protect against UV exposure, insects and pathogens. The secondary xylem contains groups of xylem fibers which consist of thickwalled narrow cells. Vessels are axially oriented without branching for interconnection. The xylem is also composed of parenchyma cells, which are characterized as ray parenchyma and wood parenchyma. The woodparenchyma become crushed in the middle, forming a chamber which is later filled with amorphous inclusions or rhombohedral crystals. SEM-EDX analysis revealed sulphur in wood parenchyma cells, likely a defense against pathogenic microorganisms. Apart from its adaptive value, the sophisticated stem anatomy of Salvadora persica, in combination with its chemistry, makes it an effective tool for oral hygiene.
Allium cepa var. agrogarum L. seedlings grown in nutrient solution were subjected to increasing concentrations of Cd2+ (0, 1, 10, 100 μM). Variation in tolerance to cadmium toxicity was studied based on chromosome aberrations, nucleoli structure and reconstruction of root tip cells, Cd accumulation and mineral metabolism, lipid peroxidation, and changes in the antioxidative defense system (SOD, CAT, POD) in leaves and roots of the seedlings. Cd induced chromosome aberrations including C-mitoses, chromosome bridges, chromosome fragments and chromosome stickiness. Cd induced the production of some particles of argyrophilic proteins scattered in the nuclei and even extruded from the nucleoli into the cytoplasm after a high Cd concentration or prolonged Cd stress, and nucleolar reconstruction was inhibited. In Cd2+-treated Allium cepa var. agrogarum plants the metal was largely restricted to the roots; very little of it was transported to aerial parts. Adding Cd2+ to the nutrient solution affected mineral metabolism. For example, at 100 μM Cd it reduced the levels of Mn, Cu and Zn in roots, bulbs and leaves. Malondialdehyde content in roots and leaves increased with treatment time and increased concentration of Cd. Antioxidant enzymes appear to play a key role in resistance to Cd under stress conditions.
We explored the use of the medicinally important plant Centella asiatica for expression of hemagglutinin-neuraminidase (HN) protein of Newcastle disease virus (NDV) strain AF2240. HN protein is the principal target for subunit vaccine development against NDV. The full-length HN gene was cloned into a plant expression construct driven by the CaMV 35S promoter and C-terminal fusion of green fluorescence protein (GFP) as reporter system. The recombinant expression construct was transformed via particle bombardment into C. asiatica callus. Transformants were screened using GFP and selected on MS medium supplemented with 15 mg/l hygromycin. The ~1.8 kb HN mRNA transcript was detected on the putative transformants using RT-PCR. The presence of HN protein expression was further confirmed through dot blot analysis using anti-NDV chicken serum. Here we report, for the first time, the use of a novel medicinal plant as a new platform for HN protein expression.
The paper describes anatomical and physiological features of photobionts and mycobionts in Bryoria forsteri Olech & Bystrek, Caloplaca regalis (Vain.) Zahlbr., Cetraria aculeata (Schreb.) Fr., Ramalina terebrata Hook f. & Taylor, Sphaerophorus globosus (Huds.) Vain. and Usnea antarctica Du Rietz, collected in the Antarctic under varied weather conditions. Green algae from the genera Lobosphaera and Trebouxia were gathered in depressions of the cortex under the more resistant mycobiont hyphae. In photobiont cells a large amount of highly osmiophilic electron-dense PAS-negative material, lipid-like in character, was of particular interest. Similar material also filled certain areas of the aerial apoplast. A star-shaped chromatophore with central and lateral pyrenoids encompassed most of the photobiont protoplast in all the studied species. Regularly arranged thylakoids with evenly widened lumina along their entire length and osmiophilic lipid droplets adhering to their outer surfaces were visible within the pyrenoid. Inside the chloroplast, large protein inclusions tightly joined with the thylakoids were observed. The mycobionts were closely attached to each other another and with the photobionts by means of an outer osmiophilic wall layer, and formed intramural haustoria. Their protoplasts were filled with PAS-positive polysaccharides and a large amount of lipid-like substances. The photobionts were physiologically active and produced a large amount of electron-dense osmiophilic material, and PAS-positive starch grains were visible around their pyrenoids in the thalli collected in different weather conditions. The permanent reserves of nutritive materials deposited in the thalli enable these organisms to quickly begin and continue indispensable physiological processes in the extreme Antarctic conditions.
Three problems in the taxonomy of Pancratium in Egypt are the lack of publications, a lack of clarity about the relationships between recently distinguished species, and the lack of markers for examining the levels and patterns of variation in rare and endemic species; the latter hinders work in plant conservation genetics. In this study we reassessed the taxonomic status of the Pancratium species of Egypt, and examined morphological and genetic variation within and between species, using specimens from different populations collected throughout its distribution range in the country. Our assessment was based on 38 macromorphological characters mainly representing vegetative parts, flowers, fruits and seeds, in addition to RAPD data. The results revealed five morphologically distinguished Pancratium species in Egypt, of which P. trianthum Herb. is newly recorded. Species identification was confirmed by two phenetic dendrograms generated with 26 quantitative morphological characters and RAPD data, while species delimitation was verified by principal component analysis. The diagnostic floral characters are those of the perianth, corona teeth, pistil, stamens, aerial scape, spathe, and number of flowers. The retrieved RAPD polymorphic bands show better resolution of the morphologically and ecologically closely allied Pancratium species (P. arabicum and P. maritimum), and also confirm the morphological and ecological divergence of P. tortuosum from the other studied species. These results are supported by the constructed UPGMA dendrogram.