Determination of seed viability of eight wild Saudi Arabian species by germination and X-ray tests

Our purpose was to evaluate the usefulness of the germination vs. the X-ray test in determining the initial viability of seeds of eight wild species (Salvia spinosa, Salvia aegyptiaca, Ochradenus baccatus, Ochradenus arabicus, Suaeda aegyptiaca, Suaeda vermiculata, Prosopisfarcta and Panicumturgidum) from Saudi Arabia. Several days were required to determine viability of all eight species via germination tests, while immediate results on filled/viable seeds were obtained with the X-ray test. Seeds of all the species, except Sa.aegyptiaca, showed high viability in both the germination (98–70% at 25/15 °C, 93–66% at 35/25 °C) and X-ray (100–75%) test. Furthermore, there was general agreement between the germination (10% at 25/15 °C and 8% at 35/25 °C) and X-ray (5%) tests that seed viability of Sa.aegyptiaca was very low, and X-ray analysis revealed that this was due to poor embryo development. Seeds of P.farcta have physical dormancy, which was broken by scarification in concentrated sulfuric acid (10 min), and they exhibited high viability in both the germination (98% at 25/15 °C and 93% at 35/25 °C) and X-ray (98%) test. Most of the nongerminated seeds of the eight species except those of Sa.aegyptiaca were alive as judged by the tetrazolium test (TZ). Thus, for the eight species examined, the X-ray test was a good and rapid predictor of seed viability.     

Seed viability of five wild Saudi Arabian species by germination and X-ray tests

Our objective was to evaluate the usefulness of the germination vs. the X-ray test in determining the initial viability of seeds of five wild species (Moringa peregrina, Abrus precatorius, Arthrocnemum macrostachyum, Acacia ehrenbergiana and Acacia tortilis) from Saudi Arabia. Usually several days were required to determine the viability of all five species via germination tests. However, X-ray test will give immediate results on filled/viable seeds. Seeds of all species, except Acacia ehrenbergiana and Acacia tortilis showed high viability in both germination (96–72% at 25/15 °C, 94–70% at 35/25 °C) and X-ray (100–80%) test. Furthermore, there was a general agreement between the germination (19%, 14% at 25/15 °C and 17% and 12% at 35/25 °C) and X-ray (8%, 4%) tests in which seed viability of Acacia ehrenbergiana and Acacia tortilis was very low due to insect damaged embryo as shown in X-ray analysis. Seeds of Abruspreca torius have physical dormancy, which was broken by scarification in concentrated sulfuric acid (10 min), and they exhibited high viability in both the germination (83% at 25/15 °C and 81% at 35/25 °C) and X-ray (96%) tests. Most of the nongerminated seeds of the five species except those of Acacia ehrenbergiana and Acacia tortilis, were alive as judged by the tetrazolium test (TZ). Thus, for the five species examined, the X-ray test was proved to be a good and rapid predictor of seed viability.     

How far a protected area contributes to conserve habitat species composition and population structure of endangered African tree species (Benin,West Africa)

The Pendjari Biosphere Reserve located in the Sudanian zone of Bénin, is a protected area well managed, but mainly aimed at wild animal conservation. This study assessed its effectiveness to conserve habitat species composition and population structure of three endangered African tree species: Afzelia africana Sm., Pterocarpus erinaceus Poir. and Khaya senegalensis (Desv.) A. Juss. We randomly sampled 120 plots in the protected and surrounding unprotected habitats by inventorying plant species. For the three target species, we estimated adult and juvenile densities and recorded size classes. According to floristic composition four habitats groups were recognized in relation to human disturbance, vegetation type, and moisture. These were protected savannas, unprotected savannas, old fallows and gallery forests. The estimated adult densities of A. africana were similar between protected (14 ± 1.2 tree/ha) and unprotected savannas (17 ± 0.9 tree/ha) while for P. erinaceus the adult density was significantly higher in protected (12 ± 3.7 tree/ha) than in unprotected savannas (5 ± 1.9 tree/ha). Estimated adult density of K. senegalensis was also significantly higher in protected gallery forest (40 ± 5.8 tree/ha) than in unprotected one (29 ± 4.8 tree/ha). Juvenile densities of A. africana, K. senegalensis and P. erinaceus were higher in protected habitats than in unprotected ones but the difference was not significant. Skewness coefficient indicated that populations of investigated trees were declining in their protected habitats. However, in the case of A. africana and K. senegalensis populations seemed to be mostly threatened in the protected area. We concluded that although the studied protected area is effective to conserve some habitats species compositions, protection is not sufficient to guarantee future conservation of some threatened tree species.     

Genetic variation and clonal diversity in populations of Nelumbo nucifera (Nelumbonaceae) in central China detected by ISSR markers

To obtain accurate estimates of population structure for purposes of conservation planning for wild lotus (Nelumbo nucifera Gaertn.) in central China, genetic diversity among and within six populations, and clonal diversity within another two populations of the species were analyzed. The genetic diversity was high (percentage of polymorphic bands, PPB = 90.0%; Shannon's information index, I = 0.383 ± 0.234) at the species level, but low within individual study populations (PPB = 35.8%; Shannon's information index I = 0.165 ± 0.241). The mean coefficient of gene differentiation (G_st) was 0.570, indicating that 43.0% of the genetic diversity resided within the population. Analysis of molecular variance (AMOVA) indicated that 50.47% of the genetic diversity among the study populations was attributed to geographical location while 12.3% was attributed to differences in their habitats. An overall value of mean estimated number of gene flow (N_m = 0.377) indicated that there was limited gene flow among the sampled populations. The level of clonal diversity found within the populations was considerably high (Simpson's diversity index, D = 0.985) indicating that clonal diversity contributes to a major extent to the overall genetic variation in the genetic structure of N. nucifera. On the basis of the high G_st and D values detected in this study we recommend that any future conservation plans for this species should be specifically designed to include those representative populations with the highest genetic variation for both in situ conservation and germplasm collection expeditions.     

Effects of various salts on the germination of three perennial salt marsh species

We studied the germination responses of Arthrocnemum macrostachyum, Juncus acutus and Schoenus nigricans to saline stress caused by different salt types. The germination percentage and mean time to germination data were obtained by incubating seeds for 30 d in 1, 2, 3, 4 or 5% saline solutions of NaCl, MgCl₂, MgSO₄ and Na₂SO₄ at 30/20 °C and with a 12 h photoperiod. A. macrostachyum was the most tolerant species to salinity during the germination (65% in 2% NaCl). S. nigricans showed the lowest germination (none germinated in salt and only 26% in distilled water). J. acutus showed intermediate behaviour between the two above species, its germination being inhibited by high salt concentrations. The sulphates had less inhibitory effect than the equivalent chloride concentrations.     

Temperature requirements for seed germination of Pereskia aculeata and Pereskia grandifolia

Pereskia aculeata and Pereskia grandifolia have been studied widely due to their high nutritional and therapeutic values. However, little is known about the biological requirements of their seeds for the various germination factors. Thus, this experiment aimed to evaluate the thermal effects on the germination of these species at the temperatures of 24 °C, 27 °C, 30 °C, 33 °C and 36 °C. After verification of the existence of differences in the performance of germination, a non-linear regression was carried out, relating the germination to temperature and identifying its point of maximum efficiency. We found that the lowest synchronization indexes of germination were observed close to 30 °C. The best germination response of the P. aculeata and P. grandifolia was observed at 30 °C and 33 °C, respectively, with greater germination strength and fewer days to attain 63.21% of germinations. The results obtained from the germination of P. aculeata and P. grandifolia can be described by the Weindull distribution model with three parameters, as proposed by Carneiro and Guedes (1992).     

Smoke-water effect on the germination of Amazonian tree species

Smoke stimulates seed germination of a range of species from ecosystems that may or may not be fire prone. We evaluated the effects of smoke-water on germination of ten tree species of economic value in the Amazon region. Two materials were burnt to produce smoke-water: germination paper and the wood of Cecropia palmata Willd. Seven dilutions of the solutions were tested. Seeds of nine forest trees were germinated under controlled laboratory conditions (25 °C ± 2 °C) in the laboratory. Bertholletia excelsa Humb. & Bonpl., was tested in the nursery (approximately 25–36 °C) because of its large seeds. Irrespective of the material burned, smoke-water significantly increased seed germination of three species: Cordia goeldiana Hub., Ochroma pyramidale (Cav. ex Lam.) Urb. and Jacaranda copaia (Aubl.) D. Don. and there was a significant inhibitory effect on Swietenia macrophylla King. Germination was accelerated by smoke in J. copaia, B. excelsa and Bellucia grossularioides (L.) Triana. The most pronounced effect was observed in B. excelsa, as the mean germination time of 108 d (control) was reduced to 76 d with smoke-water made from germination paper (dilution of 1:25) and to 61 d with the one from Cecropia wood (dilution of 1:250). For five of the ten species studied, smoke-water either increased or accelerated seed germination, irrespective of the materials used for its production. Seeds with low vigour and prolonged germination time seemed to be more receptive to smoke.     

Effect of yak rumen content treatments on seed germination of 11 alpine meadow species on the Qinghai-Tibetan Plateau

The Qinghai-Tibetan Plateau is located in the ‘Third Pole’ of the world, characterized by a harsh environment. Despite this, the alpine meadow ecosystem have developed over a wide area but serious grassland degradation is threatening the ecological environment on the Plateau. Recruitment of new plants to the population, via germination and establishment, is vital to plant community survival. Previous work on the seeds in this area has mainly focused on community-wide germination strategies, seed germination characteristics and their correlations with seed size and seed mass. However, there have been no studies on the effects of soaking in rumen contents on the plant seed germination characteristics of alpine meadow species. The present study had two main objectives: (i) to determine the effect of fresh rumen content from yaks on seed germination characteristics and seedling growth of species common to the eastern Tibetan Plateau alpine meadow, and (ii) to develop an effective method to enhance seed germination. Seeds of 11 common species were collected together with fresh rumen content from three yaks that grazed there. Seed germination tests were conducted after they had been soaked in rumen content for one of six soaking periods (12, 24, 36, 48, 60 or 72 h). The seeds were incubated under natural light conditions of 8 h light at 25 °C and 16 h darkness at 15 °C, for the germination period of 34 days. The results showed that seed germination and seedling growth were affected by soaking time, seed coat completeness and seed type. After soaking in rumen content, the germination percentages of scarified (peeled or with the seed coat cut through) seeds of some species (true seeds Oxytropis ochrocephala and Medicago ruthenia var inschanica, nutlet Carex enervis, achenes Anemone rivularis and Polygonum sibiricum) and complete seeds of C. enervis, and A. rivularis were improved but the duration of soaking was also important. Seed germination of caryopsis Achnatherum inebrians (a toxic grass) was significantly inhibited by any exposure to rumen fluids. Scarified seeds generally had higher germination percentages than complete ones after treatment, but with the increase in soaking time, germination percentages declined and scarified seeds were more sensitive to the treatment than the complete seeds. After soaking in yak rumen content, the germination indices of scarified M. ruthenia at 12 h treatment, O. ochrocephala and achene Rumex acetosa at 12–24 h treatment, nutlet Kobresia humilis at 24 h treatment, P. sibiricum at 24–48 h treatment, C. enervis at 12–48 h treatment and A. rivularis at 12–60 h treatment were significantly higher than the control (P < 0.05), while the germination indices of complete C. enervis seeds at 12 h and 36 h treatment, and A. rivularis at 12–60 h treatment were significantly higher compared with the control. The germination indices of other species gradually decreased with the increase in soaking time. We concluded that yak rumen digestion could enhance, inhibit or not affect seed germination and seedling growth of the alpine meadow species, which might influence seedling recruitment, interspecific competition, and the plant community structure of the eastern Tibetan Plateau alpine meadow. Overall, yak digestion has a positive effect on alpine meadow seed germination and seed dispersal.     

Nitrate and phosphate uptake kinetics of the harmful diatom Eucampia zodiacus Ehrenberg,a causative organism in the bleaching of aquacultured Porphyra thalli

The diatom Eucampia zodiacus Ehrenberg is a harmful diatom which indirectly causes bleaching of aquacultured Nori (Porphyra thalli) through competitive utilization of nutrients during bloom events. In the present study, we experimentally investigated the nitrate (N) and phosphate (P) uptake kinetics of E. zodiacus, Harima-Nada strain. Maximum uptake rates (ρ_max), which were obtained by short-term experiments, were 0.777 and 0.916 pmol cell^?1 h^?1 for nitrate and 0.244 and 0.550 pmol cell^?1 h^?1 for phosphate at 9 and 20 °C, respectively. The half-saturation constants for uptake (K_s) were 2.59 and 2.92 μM N and 1.83 and 4.85 μM P at 9 and 20 °C, respectively. Although the maximum specific uptake rate (V_max; V_max = ρ_max/Q₀, Q₀; minimum cell quota) and V_max/K_s for nitrate at 9 °C are about 1/2 of those obtained at the optimum temperature (20 °C), they are still higher than those obtained for many other phytoplankton at their optimum temperature conditions for uptake. These results suggest that E. zodiacus utilizes nitrogen efficiently at low water temperature, and it is one of the important factors causing the serious damage to Porphyra thalli by bleaching due of this species. For phosphate, the K_s values of E. zodiacus were higher than those reported for other species; the V_max and V_max/K_s values were much lower than those of other diatoms such as Skeletonema costatum (Greville) Cleve. These results suggest that E. zodiacus is disadvantaged compared to other diatom species during competitive utilization of phosphate.     

High allozymic diversity in natural populations of Mycoheterotrophic Orchid Gastrodia elata,an endangered medicinal plant in China

Gastrodia elata Blume, a mycoheterotrophic orchid native to the Far East, is an endangered medicinal plant in China. Genetic variation among 19 natural populations of G. elata was examined in central China by using allozyme polymorphism (16 loci in six enzymatic systems). The species exhibited high level of genetic diversity (P = 56.3%, A = 2.2 and H_E = 0.221), which was mainly attributed to its perennial habit and mixed reproduction system (both sexual and asexual). Evident genetic differentiation in G. elata natural populations was suggested by F_ST = 0.241. AMOVA analysis showed 31.3% of the total molecular variation was attributed to inter-population differentiation. Obvious genetic structure and genetic depauperation of some populations indicate forest fragmentation and over-collection have affected genetic variation of G. elata. A conservation strategy, which is conserving populations with great genetic distinction or high level of genetic variation from four management units, is recommended.     

Seed and forage yield,and forage quality determinants of nine legume shrubs in a non-tropical dryland environment

The objective was to identify legume shrub species for development of agroforestry technologies based on seed and forage (leaves and twigs < 10 mm diameter) yield, and determinants of forage quality. Ten individual plants of Bituminaria bituminosa ‘Ecotypes 1’, B. bituminosa ‘Ecotypes 2’, Medicago citrina, and M. arborea from Spain; Colutea istria and Onobrychis aurantiaca from Syria; C. istria from Jordan; Chamaecytisus mollis from Morocco; and Coronilla glauca from France were randomly selected from plots established in a non-tropical dryland environment in northwest Syria in 2000. Five individual plants of each species were cut back to 0.5 m above ground in March 2004. Coppice regrowths were pruned in December 2004 and April 2005 to determine forage yield and proportion of forage in the total above ground biomass (PEFB). Forage samples were analyzed for concentrations of crude protein (CP), lignin(sa), acid detergent fibre (ADFom), neutral detergent fibre (aNDFom), in vitro organic matter (OM) digestibility (IVOMD), and in vitro 24 h gas production (IVGP24h). Matured seeds were hand harvested from the remaining five plants of each species to estimate seed yield. Forage (21–250 kg DM/ha) and seed (0–200 kg DM/ha) yields; PEFB (0.22–0.96); and concentrations of CP (85–115 g/kg DM), lignin(sa) (14–42 g/kg DM), ADFom (94–170 g/kg DM), aNDFom (122–217 g/kg DM), IVOMD (456–617 g/kg OM), and IVGP24h (27–42 ml 200 mg/DM) varied (P<0.05) among shrub species. The IVOMD and IVGP24h were positively correlated (r = 0.75, P<0.032), whereas IVOMD and IVGP24h were negatively correlated with ADFom, lignin(sa) and aNDFom. In terms of forage and seed yields and determinants of forage quality, C. istria from Jordan, M. arborea, B. bituminosa ‘Ecotype-2’, C. istria and O. aurantiaca have higher potential than C. mollis, C. glauca and B. Bituminosa ‘Ecotype-1’ for the development of agroforestry technologies in non-tropical dry areas.     

Analysis of the germination rate,mitotic index and karyotype of Chromolaena barranquillensis (Hieron.) R.M. King & H. Rob.—Asteraceae

Chromolaena barranquillensis (Asteraceae) is an endemic plant of northern Colombia that has garnered economic and medicinal interest, because species from the genus Chromolaena have shown diverse biological activities. This study describes, for the first time, the karyotype, germination and mitotic indices of C. barranquillensis (Hieron.) R.M. King & H. Rob. The germination index was between 34% and 56% with an average germination rate of 1.2 ± 0.4 seeds/day. The mitotic index analysis allowed to determine the cell cycle time (4 h, 10 min) and the mitotic hours (3:00–8:00 h and 17:00 h). The mitosis time was 49 min, equivalent to ~ 20% of the cell cycle. Karyotype analysis showed that C. barranquillensis is a hexaploid species with a chromosomal formula 2n = 6x = 60 = 48 m + 12 sm, and the average chromosomal lengths were 1.7 ± 0.1 μm to 0.9 ± 0.3 μm. The Stebbins asymmetry index was 2B, and the total form percentage was ~ 41%. These results uncover differences between C. barranquillensis and Chromolaena odorata, one of the most abundant species found in the world and the most closely related species to C. barranquillensis.     

Copper,zinc superoxide dismutase of Curcuma aromatica is a kinetically stable protein

This study details on cloning and characterization of Cu,Zn superoxide dismutase (Ca–Cu,Zn SOD) from a medicinally important plant species Curcuma aromatica. Ca–Cu,Zn SOD was 692 bp with an open reading frame of 459 bp. Expression of the gene in Escherichia coli cells followed by purification yielded the enzyme with K_m of 0.047 ± 0.008 μM and V_max of 1250 ± 24 units/mg of protein. The enzyme functioned (i) across a temperature range of −10 to +80 °C with temperature optima at 20 °C; and (ii) at pH range of 6–9 with optimum activity at pH 7.8. Ca–Cu,Zn SOD retained 50% of the maximum activity after autoclaving, and was stable at a wide storage pH ranging from 3 to 10. The enzyme tolerated varying concentrations of denaturating agent, reductants, inhibitors, trypsin, was fairly resistant to inactivation at 80 °C for 180 min (k_d, 6.54 ± 0.17 × 10⁻³ min⁻¹; t_1/2, 106.07 ± 2.68 min), and had midpoint of thermal transition (T_m) of 70.45 °C. The results suggested Ca–Cu,Zn SOD to be a kinetically stable protein that could be used for various industrial applications.     

Synthesis and antioxidant evaluation of (S,S)- and (R,R)-secoisolariciresinol diglucosides (SDGs)

Secoisolariciresinol diglucosides (SDGs) (S,S)-SDG-1 (major isomer in flaxseed) and (R,R)-SDG-2 (minor isomer in flaxseed) were synthesized from vanillin via secoisolariciresinol (6) and glucosyl donor 7 through a concise route that involved chromatographic separation of diastereomeric diglucoside derivatives (S,S)-8 and (R,R)-9. Synthetic (S,S)-SDG-1 and (R,R)-SDG-2 exhibited potent antioxidant properties (EC₅₀ = 292.17 ± 27.71 μM and 331.94 ± 21.21 μM, respectively), which compared well with that of natural (S,S)-SDG-1 (EC₅₀ = 275.24 ± 13.15 μM). These values are significantly lower than those of ascorbic acid (EC₅₀ = 1129.32 ± 88.79 μM) and α-tocopherol (EC₅₀ = 944.62 ± 148.00 μM). Compounds (S,S)-SDG-1 and (R,R)-SDG-2 also demonstrated powerful scavenging activities against hydroxyl [natural (S,S)-SDG-1: 3.68 ± 0.27; synthetic (S,S)-SDG-1: 2.09 ± 0.16; synthetic (R,R)-SDG-2: 1.96 ± 0.27], peroxyl [natural (S,S)-SDG-1: 2.55 ± 0.11; synthetic (S,S)-SDG-1: 2.20 ± 0.10; synthetic (R,R)-SDG-2: 3.03 ± 0.04] and DPPH [natural (S,S)-SDG-1: EC₅₀ = 83.94 ± 2.80 μM; synthetic (S,S)-SDG-1: EC₅₀ = 157.54 ± 21.30 μM; synthetic (R,R)-SDG-2: EC₅₀ = 123.63 ± 8.67 μM] radicals. These results confirm previous studies with naturally occurring (S,S)-SDG-1 and establish both (S,S)-SDG-1 and (R,R)-SDG-2 as potent antioxidants and free radical scavengers for potential in vivo use.     

Germination response and viability of an endangered tropical conifer Widdringtonia whytei seeds to temperature and light

The tropical conifer Widdringtonia whytei Rendle is an endangered species endemic to Mulanje Mountain in Malawi. A study was conducted for the first time under controlled conditions in order to assess the effects of temperature and light on germination and viability of W. whytei seeds. Seeds incubated at a constant temperature of 20 °C attained the highest cumulative germination percentage (100%) followed by 87% germination under fluctuating temperatures of 15 °C night/25 °C day. No seed germination occurred at temperatures below 15 °C. Seeds that failed to germinate at temperatures below 15 °C showed the highest (> 90%) viability compared to the seeds incubated at 25 °C (60%). Across temperature regimes, germination was significantly higher under light (44.7%) than dark (35.6%) conditions. It is concluded that temperature is one of the critical factors for germination of W. whytei seed. The ability of W. whytei seeds to germinate both in light and darkness implies that the species would unlikely form a persistent soil seed bank, an attribute which is common in species that survive in habitats frequently disturbed by fires.     

Synthesis,EPR, electrochemistry and EXAFS studies of ruthenium(III) complexes with a symmetrical tetradentate N2O2 Schiff base

A series of new hexa-coordinated ruthenium(III) complexes of the type [RuX(Nap-o-phd)(EPh₃)] (where, H₂-Nap-o-phd = N,N′-bis(2-hydroxy-1-naphthaldehyde) o-phenylene diamine; X = Cl or Br; E = P or As) have been prepared by reacting [RuX₃(EPh₃)₃] and [RuBr₃(PPh₃)₂(MeOH)] (where X = Cl or Br; E = P or As) with tetradentate Schiff base ligand (H₂-Nap-o-phd) in 1:1 molar ratio. The complexes have been characterized by elemental analyses, infra red, electronic, electron paramagnetic resonance spectroscopy and cyclic voltammetry. The coordination geometry and structure of the complexes have been investigated by extended X-ray absorption fine structure (EXAFS) spectroscopy and an octahedral structure has been proposed.     

Grazing of cover crops in integrated crop-livestock systems

Conventional agriculture is specializing rapidly into the management of few monoculture crops, threatening crop diversity and questioning the sustainability of extensive cropping systems. The grazing of cover crops in integrated crop-livestock systems could be a feasible biologically based technology to restore crop diversity and mitigate ecological issues in cropping systems. However, there is limited evidence on plausible synergies or trade-offs for the practice, and about how grazing plans could affect the herbage production and services from cover crops. This work assessed the effects of cattle grazing on the primary and secondary production of annual ryegrass (Lolium multiflorum) in an integrated ryegrass–soybean rotation system. Specifically, the prediction for synergistic effects of cattle grazing on the ryegrass herbage production, residual crop cover and animal performance were tested in a 2-year (2014 and 2015) study comprising a randomized complete block design of four grazing intensity treatments, replicated three times. A no-cattle grazing treatment (NG), used as control, or continuous grazing with Holstein heifers (~ 220 kg live weight) at targeted sward heights of 5, 10, 15 and 20 cm (hereafter referred as G₅, G₁₀, G₁₅ and G₂₀, respectively) was applied to ryegrass plots. The herbage production and residual herbage cover of ryegrass, and the average daily gain (ADG, kg/day) and live weight gain per hectare (LWG, kg/ha) of heifers were analyzed by ANOVA (P < 0.05) and compared by the Tukey_HSD test (P < 0.05). Regression models were used to estimate relationships between herbage production, animal performance and sward height. The herbage production was 60% higher (P < 0.01) for the grazing treatments compared to NG. The residual herbage for G₁₅ and G₂₀ was not different than that for NG and increased linearly as sward heights increased, reaching highest values for G₁₅ and G_20. Maximum ADG was 1.10 kg/day for ryegrass grazed at a 20.6 cm height, whereas maximum LWG was 427 kg/ha for ryegrass grazed to a 16.1 cm height. The results support the hypothesis for synergistic effects of using annual ryegrass as a dual forage and service cover crop. Moderate grazing intensity to sward height of 12–18 cm with continuous stocking led to optimized forage production and utilization by dairy heifers.     

Exogenous sodium sulfide improves morphological and physiological responses of a hybrid Populus species to nitrogen dioxide

Gaseous nitrogen dioxide (NO₂) can disturb normal plant growth and trigger complex physiological responses. NO₂-induced responses are influenced by biotic or abiotic factors. In this study, we investigated the effects of exogenous sodium sulfide (Na₂S, 5 mmol L⁻¹) on epidermis and stomata related physico-chemical responses of hybrid poplar cuttings (Pouplus alba × P. berolinensis) to gaseous NO₂ (4 μl 1⁻¹) for three time periods (0, 14 and 48 h). We also investigated hydrogen sulfide (H₂S), nitrate-nitrogen and nitrate reductase activity (NR) in control and Na₂S treated plants. Our results showed that NO₂ exposure for 48 h led to the decline of NR, maximal PSII quantum yield (F_v/F_m), net photosynthetic rate (P_n), and dark respiration rate (R_d). The maximum rate for the post-illumination carbon dioxide burst (PIB) occurred in 48-h exposed leaves 13–15 s after darkening. Moreover, NO₂ exposure resulted in a significant increase in nitrogen percentage (from 0 to 33%) and a decrease in the macro and micro-elements of leaf surface. Spraying Na₂S aqueous solution on the leaf surfaces significantly increased the thicknesses of palisade/spongy tissue and H₂S content. Na₂S pretreatment alleviated NO₂-caused toxic effects as indicated by increased NR and higher values of P_n, F_v/F_m, and actual photochemical efficiency in light (ФPSII) compared with the control. Na₂S pretreatment had no significant impacts on PIB-based photorespiration or elements composition of a leaf surface.     

The return of the Iberian wild goat Capra pyrenaica to Portugal: From reintroduction to recolonization

The Iberian wild goat (Capra pyrenaica) is an endemic species of the Iberian Peninsula. Of the four generally accepted subspecies (Capra pyrenaica victoriae, C.p. hispanica, C.p. pyrenaica, C.p. lusitanica) only two subsist (C.p. victoriae, C p. hispanica). The subspecies once found in Portugal, C. p. lusitanica, became extinct in the 19th century. However, the reintroduction of the C. p. victoriae in north-west Spain, led to the natural recolonization of this subspecies into Portugal. Knowledge of the Iberian wild goat in Portugal is still limited, making it difficult to evaluate the major conservation/management needs. To fill this gap, here we describe the historical distribution of the Iberian wild goat in Portugal and summarize the available information on the reintroduction and recolonization process of this species. Additionally, we used line itinerary survey (2011–2012), coupled with Distance Sampling, to estimate current densities, range and population structure of the Iberian wild goat distribution in Portugal. The Iberian wild goat density is 2.78/100 ha (95% CI: 1,72–4,50; CV: 18,36%) and the abundance is of 576 (CI 95%: 356–930; CV: 18,36%). The distribution data shows that the population is divided in three nuclei: 1- Serra do Gerês (13,840 ha); 2–Serra Amarela (1235 ha); 3–Castro Laboreiro (343 ha), in a total area of 15,418 ha. Iberian wild goat population in Portugal has greatly increased in the last years, both in number and distribution range. The demographic data shows a potential for increase in the next years but our current ecological background knowledge still remains limited. Iberian wild goat management will benefit from a long-term project including public awareness, scientific research and management solutions.     

Isolation,spectroscopic characterization,X-ray,theoretical studies as well as in vitro cytotoxicity of Samarcandin

Samarcandin 1, a natural sesquiterpene-coumarin, was isolated as well as elucidated from F. assa-foetida which has significant effect in Iranian traditional medicine because of its medicinal attitudes. The crystal structure of samarcandin was determined by single-crystal X-ray structure analysis. It is orthorhombic, with unit cell parameters a = 10.8204 (5) Å, b = 12.9894 (7) Å, c = 15.2467 (9) Å, V = 2142.9 (2) Å³, space group P2₁2₁2₁ and four symmetry equivalent molecules in the unit cell. Samarcandin was isolated in order to study for its theoretical studies as well as its cellular toxicity as anti-cancer drug against two cancerous cells. In comparison with controls, our microscopic and MTT assay data showed that samarcandin suppresses cancer cell proliferation in a dose-dependent manner with IC₅₀ = 11 μM and 13 for AGS and WEHI-164 cell lines, respectively. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) of the structure was computed by three functional methods and 6-311++G⁷ standard basis set. The optimized molecular geometry and theoretical analysis agree closely to that obtained from the single crystal X-ray crystallography. To sum up, the good correlations between experimental and theoretical studies by UV, NMR, and IR spectra were found.