Effect of Iron Source and Medium pH on Growth and Development of Sorbus commixta In Vitro.

Sorbus commixta is a valuable hardwood plant with a high economical value for its medicinal and ornamental qualities. The aim of this work was to investigate the effects of the iron (Fe) source and medium pH on the growth and development of S. commixta in vitro. The Fe sources used, including non-chelated iron sulfate (FeSO4), iron ethylenediaminetetraacetic acid (Fe-EDTA), and iron diethylenetriaminepentaacetic acid (Fe-DTPA), were supplemented to the Multipurpose medium with a final Fe concentration of 2.78 mg·L-1. The medium without any supplementary Fe was used as the control. The pH of the agar-solidified medium was adjusted to either 4.70, 5.70, or 6.70. The experiment was conducted in a culture room for six weeks with 25 °C day and night temperatures, and a 16-h photoperiod with a light intensity of 50 mmol·m-2·s-1 photosynthetic photon flux density (PPFD). Both the Fe source and pH affected the growth and development of the micropropagated plants in vitro. The leaves were greener in the pH 4.70 and 5.70 treatments. The tissue Fe content decreased with the increase of the medium pH. The leaf chlorophyll content was similar between plants treated with FeSO4 and those with Fe-EDTA. The numbers of the shoots and roots of plantlets treated with FeSO4 were 2.5 and 2 times greater than those of the control, respectively. The fresh and dry weights of the shoot and the root were the greatest for plants treated with Fe-EDTA combined with pH 5.70. The calcium, magnesium, and manganese contents in the plantlets increased in the pH 5.70 treatments regardless of the Fe source. Supplementary Fe decreased the activity of ferric chelate reductase. Overall, although the plantlets absorbed more Fe at pH 4.70, Fe-EDTA combined with pH 5.70 was found to be the best for the growth and development of S. commixta in vitro.

Antioxidant activity of selected wild Canadian prairie fruits.

BACKGROUND: Canadian prairies are a habitat for unique wild plants. The main object of the present study was to investigate phytochemicals content and antioxidant activity in seven wild Canadian prairie fruits. METHODS: The presence of total phenolics, flavonoids, anthocyanins and antioxidant activity were identified in the extracts according to standard procedure. RESULTS: Wild rose had the highest amounts of total phenolics and total flavonoids, whereas elderberry exhibited the highest amount of anthocyanins. All extracts showed good scavenging activities towards DPPH radicals. The results showed a good linear relationship between oxygen radical absorbance capacity and total phenolics indicating that radicals are scavenged at a greater rate as the total phenolics content increases. Additionally, all extracts when applied at concentration of 800 ppm, showed ability to inhibit oxidation of canola oil. In SOT test the best results were obtained when extract of American mountain ash was used. In general, wild rose followed by American mountain ash demonstrated the highest antioxidant activity among assessed Canadian prairie fruits. CONCLUSIONS: From the results it can be concluded that prairie fruit extracts are a rich source of phenolic compounds and poses a high antioxidant activity, confirmed by assessment with different type of radicals employed.

[Mechanism exploration on synthesis of secondary metabolites in Sorbus aucuparia cell cultures treated with yeast extract].

Suspension cultures cell of Sorbus aucuparia (SASC) was used as materials, the changes of physiological and biochemical indexes of SASC after treatment with yeast extract (YE) were detected, and the synthetic mechanism of secondary metabolites in SASC treated with YE was preliminarily explored. The results were as follows: under the assay conditions, SASC was induced to synthesize five biphenyl compounds, and these compounds content changed differently with induction time prolonging; YE treatment inhibited cell growth, the culture medium pH was gradually reduced after treatment; water-soluble protein content showed a trend of slow decline, which was significantly increased in YE treatment group (YE group) compared with the control group (CK group), the maximum relative content was 147.76% in contrast with CK group; both YE group and CK group were extracellular Ca2+ flow influx, but the YE group flow was significantly slow than CK group. The results indicate that YE induced the cells in a stress state, which was not conducive to the growth of cells and forced the cells to synthesize biphenyl compounds against external stress; water-soluble protein may serve as intracellular enzymes involved in the synthesis of compounds regulation; Ca2+ may as signal molecule mediate cell signal transduction respond to YE stress.

Variation of quantitative composition of phenolic compounds in rowan (Sorbus aucuparia L.) leaves during the growth season.

The aim of our study was to explore variation peculiarities of qualitative and quantitative composition of phenolic compounds in leaf samples of rowan (Sorbus aucuparia L.) plants growing in natural habitats of Lithuania during their growth season using the HPLC method. In rowan leaf samples, collected during different phenological stages, qualitative and quantitative estimation of neochlorogenic acid, chlorogenic acid, caffeic acid, hyperoside, isoquercitrin, rutin, astragalin, ( - )-epicatechin, procyanidin B1 and procyanidin B2 was performed. Analysis of the qualitative and quantitative composition of phenolic compounds in ethanol extracts of leaf samples of S. aucuparia growing in natural habitats of Lithuania revealed a close relationship between the content of phenolic compounds in S. aucuparia raw plant material and different growth stages.

Variation in the phenolic content and in vitro antioxidant activity of Sorbus aucuparia leaf extracts during vegetation.

Seasonal variation in the antioxidant activity and content of phenolic compounds was studied for the 70% methanol extracts of Sorbus aucuparia leaves harvested monthly over the full course of the growing season. The antioxidant potential of the extracts was evaluated using two complementary in vitro tests: the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical-scavenging assay and the AAPH [2,2'-azobis-(2-amidinopropane)dihydrochloride]-induced [corrected] linoleic acid (LA) peroxidation test. The radical-scavenging capacities of the extracts towards the DPPH radical were in the range of 0.40 to 0.57 millimolar Trolox equivalents/g dry weight of the leaves. They were significantly correlated (r = -0.8480, p < 0.05) with the results of the LA-peroxidation test, indicating the S. aucuparia leaf extracts to be universal antioxidants. Significant linear correlations were also found between the different antioxidant potentials and total phenolic contents as estimated by the Folin-Ciocalteu method and further verified by serial determinations of proanthocyanidins, chlorogenic acid isomers and flavonoids ([r] in the range of 0.81-0.97, p < 0.05). As the best antioxidant capacities and the highest phenolic contents were found for the leaf samples harvested during the three summer months (June, July and August), this period could be considered to be optimal for cost-effective production of natural health products. For the leaf samples collected in July, the values of EC50 and IC50 for the two antioxidant tests were 2.02 and 93.45 µg [corrected] phenolics/mL, respectively. These antioxidant capacities were found to be higher or comparable to those of synthetic and natural phenolic antioxidants, such as BHT (butylated hydroxytoluene), BHA (butylated hydroxyanisole), TBHQ (tert-butylhydroquinone), quercetin and Trolox.

Temperature rather than photoperiod controls growth cessation and dormancy in Sorbus species.

Environmental regulation of growth and dormancy of four Sorbus genotypes was studied in controlled environments. Emphasis was placed on assessment of the presence and nature of the deficient photoperiodic dormancy regulation system that has previously been reported for some woody Rosaceae species. Two genotypes of Sorbus aucuparia L. maintained indeterminate growth for 8 weeks and 9 weeks at temperatures of 15 °C and 21 °C in both 20 h and 10 h photoperiods, while at 9 °C, in the same photoperiodic conditions, they immediately ceased growing. At the higher temperatures, initiation of new leaves (nodes) was unaffected by photoperiod, while internode elongation was significantly enhanced by long days (LD). However, even after prolonged exposure to 9 °C, most plants resumed growth when moved to high temperature and LD, indicating a shallow state of dormancy. Seedlings of Sorbus intermedia (J. F. Ehrh.) Pers. and micro-propagated plantlets of S. commixta Hedl. 'Dodong' were also unaffected by photoperiod during primary growth, but failed to elongate and gradually became dormant regardless of temperature and day-length conditions. However, after chilling and breaking of dormancy, the plants elongated vigorously but changed to a determinate mode of growth. Furthermore, a temperature of 9 °C was found to be fully effective for breaking dormancy in S. intermedia plants. It is concluded that deficient photoperiodic dormancy control seems widespread in the Rosaceae and that, in such plants, both dormancy induction and release is brought about by low temperature. The potential impacts of climate change on such trees are discussed.

[Natural regeneration characteristics of Sorbus pohuashanensis in forest region of eastern Northeast China].

Sorbus pohuashanensis is an important non-timber tree species in Northeast China. Aimed to study the natural regeneration characteristics of this tree species and related affecting factors, representative S. pohuashanensis forests in the forest region of eastern Northeast China were investigated by line sampling method. In this forest region, S. pohuashanensis was regenerated by seed propagation, stump sprouting, and root sprouting. In intact or poor habitat natural forests, the proportions of the S. pohuashanensis seedlings established by each of the three regeneration methods occupied roughly a third, with no significant difference (P > 0.05) among them; while in secondary forests, the frequency of stump sprouts (16.5%) was lower than that in natural forests. Even so, the combination of stump sprouting and root sprouting could likely maintain a stable local population. Root sprouting could make the seedlings spread more than 50 cm away from the stump. The transfer rate from diameter class II (1.0-2.9 cm) to diameter class III (3.0-4.9 cm) was 25.6% in secondary forests, 45.3% in poor habitat natural forests, and 15.9% in intact natural forests, suggesting that the lower transfer rate was the key limiting factor for S. pohuashanensis natural regeneration.

[Sorbus pohuashanensis seed dispersal and germination and their relationships with population natural regeneration].

Sorbus pohuashanensis is an important non-timber tree species in Northeast China, but poor in natural regeneration via seed dispersal. In this paper, a field observation was made on the seed dispersal of S. pohuashanensis, its seedling emergence, and soil seed bank, aimed to study the factors affecting the natural regeneration of this tree species. There were 96.1% of naturally dispersed S. pohuashanensis seeds distributed within the range of 2 m around the stock tree, and 97.0% of the seeds in soil seed bank distributed in litter layer and 0-2 cm surface soil. The seed quantity in soil seed bank differed greatly with seasons, being the maximum [(257.7 +/- 69.2) seeds per square meter] in early November in the year of seed dispersal, and the minimum [only (2.9 +/- 2.9) seeds per square meter] in next July. Temperature was not the limiting factor affecting the seedling emergence of S. pohuashanensis [at 0 degrees C-5 degrees C, the seedling emergence percentage could reach (67.5 +/- 6.6)%], but strongly affected the seedling emergence rate. The most proper soil moisture content for the seedling emergence was 50% , under which, the seedling emergence percentage could reach (74.7 +/- 4.2)%. When the soil moisture content was up to 60%, the seedling mortality was the lowest (32.6% +/- 0.6%). All the results suggested that the seed dispersal pattern of S. pohuashanensis and the spatiotemporal dynamics of soil seed bank could affect the seedling emergence of the tree species, and further, affect the population natural regeneration of S. pohuashanensis via seed dispersal.

[Animal predation and dispersal of Sorbus pohuashanensis fruits and seeds].

Sorbus pohuashanensis is an important non-timber tree species in Northeast China. There are two approaches for its fruit- and seed dispersal, i. e. , natural dispersal and animal dispersal. In this paper, a field observation was conducted to study the characteristics of animal predation and dispersal of S. pohuashanensis fruits and seeds, and the effects of the predation and dispersal on the natural regeneration of the tree species. During the fruit-ripening stage of S. pohuashanensis in 2008 and 2009, there were 8 species of birds visiting S. pohuashanensis fruits, among which, three pulp-eating species Turdus naumanni, Cyanopica cyana, and Dendrocopos leucotos could disperse S. pohuashanensis seeds. The visiting frequency of the three species to S. pohuashanensis fruits was 54%, 12%, and 7%, respectively, and the first stop spot after predation was mainly within 5-10 m away from the visited trees (with a proportion of 68.2%), secondly within 5 m (27.3%), and only 4.5% was out of 10 m. The retention time of S. pohuashanensis fruits in the digestive tract of the bird dispersers was up to 20 min, implying a long potential dispersal distance. Fruit- and seed placement tests showed that the fruits artificially placed in different habitats were disappeared within 6-7 days, and the fruit predators on the ground were mainly rodents and ground-feeding birds, with the predation rates being 50% -70%, while the seed predators on the ground were rodents, ground-feeding birds, and ants, with the predation rates only 1% -5%. S. pohuashanensis could provide food for a variety of frugivorous animals, and in return, the animals could disperse S. pohuashanensis seeds, which might have profound effects on the natural regeneration of S. pohuashanensis.

A comparison of phenological models of leaf bud burst and flowering of boreal trees using independent observations.

We compared and tested Thermal Time, Sequential, Parallel and Flexible phenological models of leaf bud burst in birch (Betula pendula Roth. and B. pubescens Ehrh.) and flowering in bird cherry (Prunus padus L.) and rowan (Sorbus aucuparia L.). We used phenological records from Oulainen-Ohineva (64 degrees 13' N, 24 degrees 53' E) in central Finland from 1953 to 2002 to estimate model parameters. We tested the models with data collected in all but six years between 1896 and 2002 in southern and central Finland; we divided this dataset into two 50-year datasets. The use of three datasets enabled us to test the models with data that were independent of the parameter fitting data, facilitating robust evaluation of model performance. Several models that fitted the parameterization data well showed poorer performance when tested with the independent data. This may be because the models were over-parameterized and able to adapt to noise in the data in addition to the phenological phenomenon itself. Simple Thermal Time models performed best with independent data, and Sequential and Parallel models were similar in prediction accuracy. Although Thermal Time models simulated boreal phenological events under current climatic conditions, some precautions are needed with simulations of climatic warming. For example, changed conditions may increase the relative importance of chilling in the timing of bud burst under elevated temperature conditions, which could alter the performance of phenological models.

[Quantitative analysis of different restoration stages during natural succession processes of subalpine dark brown coniferous forests in western Sichuan, China].

By adopting space as a substitute for time, and based on the approaches of inter-specific association, PCA and optimal division, the restoration stages of various secondary forest communities originated from the natural succession processes of bamboo-dark brown coniferous and moss-dark brown coniferous old-growth forests after clear-cut were quantified at different temporal series (20, 30, 30, 40, 50 and 160-200 years). The results showed that Betula albo-sinensis, Salix rehderiana, Acer mono, A. laxiflorum, Prunus tatsienensis, Hydrangea xanthoneura, Tilia chinensis and Salix dolia were the declining species groups with progressive restoration processes from secondary forest to mature moss and bamboo-dark brown coniferous forests, Sorbus hupehensis, S. koehneana and P. pilosiuscula were the transient species groups, and Abies faxoniana, Picea purpurea, Tsuga chinensis and P. wilsonii were the progressive species groups. During the period of 20-40 years restoration, the secondary forests were dominated by broad-leaved tree species, such as B. albo-sinensis, and the main forest types were moss--B. albo-sinensis forest and bamboo--B. albo-sinensis forest. Through 50 years natural succession, the secondary forests turned into conifer/broad-leaved mixed forest dominated by B. albo-sinensis and A. faxoniana, and the main forest types were moss--B. albo-sinensis--A. faxoniana forest and bamboo--B. albo-sinensis--A. faxoniana forest. The remained 160-200 years old coniferous forests without cutting were dominated by old-growth stage A. faxoniana, and the main forest types were moss--A. faxoniana forest and bamboo--A. faxoniana forest.

Heritability of some characteristics of Sorbus torminalis seedling.

This research was conducted to determine the heritability of some characteristics of wild service (Sorbus torminalis L. Crantz) seedling by a half-sib progeny test in north of Iran. The seeds of Sangdeh provenance (1600-1800 m a.s.l.) were collected from twenty individual parent trees and planted in a mountainous nursery (Orimelk, 1550 m a.s.l) as randomized complete block design with three replications. At the end of third growing season heritability of some seedling characteristics was determined with using Falconer method. Analyses indicated that heritability of biggest branch (h2 = 0.003) and branch number (h2 = 0.007) was lower than those of other characteristics measured. Heritability of collar diameter, vitality and total height was h2 = 0.22, h2 = 0.20 and h2 = 0.17, respectively. Among 20 parent trees the genotypes 2, 11, 18, 19 and 20 can be introduced as plus trees for seed providing and seedling production. It can be deduced that for seedling production of Sorbus torminalis in this nursery the parent trees should be benefited from a better collar diameter, vitality and total height in order to occurrence possibility of high-quality progenies.

Plant culture: thirteen seasonal pieces. February--constructing a corymb.

According to Robert Graves' mythological interpretation of the seasonal cycle, February is associated with the rowan tree. Corymb is the systematic name for the rowan inflorescence that produces the distinctive group of orange berries. The corymb, a gently domed cluster, is related to a panicle and an anthela, differing from them in the extent of upgrowth of the inflorescence branches. Soon, molecular biology will provide a gene-driven description of each inflorescence structure. This advance illustrates the progress of science: previous issues of inflorescence classification are not resolved, but a new system, reflecting the availability of new technology, is established. The artist and poet William Blake remarked that it is better to invent a system, than be enslaved by that of another. He also railed against science for its improper restriction to the imagination.