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Highlights • Propagation by single-node stem cutting of giant reed (Arundo donax) was attempted. • Nutrients availability on the node plays a key role in rooting development. • In open field, the best period for node excision is July followed by May. • Nodes whose diameter exceed 2 cm showed higher rooting and plantlets development. • IBA resulted effective in promoting rooting in the worst excision dates. Abstract Giant reed (Arundo donax L.) is a warm-season, fast growing lignocellulosic crop suitable to Mediterranean and semi-arid environments. However, its sterility limits a cost-effective propagation along with environmental impacts associated with rhizome processing. In the present study, the effects of intrinsic (node size and node chemical composition) and extrinsic factors (node pretreatment with growth regulators) on root and shoot development were investigated under different excision time of node-cuttings in a controlled and open field conditions. Results indicated that nutrients availability of the propagation material plays a key role in rooting development. To enhance the success of giant reed propagation by single node stem-cuttings, the best period for node excision is July in open field trial, followed by the late spring (May). Nodes whose diameter exceed 2 cm resulted in higher rooting and plantlets development even in the less favorable excision dates. However, when big nodes are adopted in controlled environments even winter periods are eligible, being particularly useful for spring open field transplants of rooted plantlets. Among the growth regulators used in the present study, indole-3-butyric acid - IBA (in controlled environment) resulted effective in promoting rooting particularly in the worse excision date (April); in open field, IBA significantly improved rooting in the excision dates of February and May in the big nodes, and only in February in the small ones. NAA (1-naphthaleneacetic acid) was almost ineffective in enhancing rooting as compared to the control. The present study might open a new perspective to overcome one of the most significant drawbacks to establish giant reed, namely its agamic propagation. [ABSTRACT FROM AUTHOR]

Carob is a valuable leguminous species for its productions but also for forestation of arid and degraded areas threatened by soil erosion and desertification processes. However, large-scale cultivation of this species is hampered by the difficult propagation by cuttings or seeds. Researches to evaluate genotype tolerance to saline and drought stress during germination and first plant establishment, are also inhibited by the scarce seed germination. In this study, carob seeds, from wild and domesticated carob genotypes collected in a representative area of the Mediterranean basin (Sicily, Italy), were subjected to germination tests under isotonic solutions of polyethylene glycol (PEG) and sodium chloride (NaCl) at −0.5, −1.0, −1.5 MPa. Before germination tests, a 20 min pre-treatment with 96% sulphuric acid was necessary to overcome seed coat dormancy which does not permit germination. Differences in drought and salinity tolerance were determined in the different genotypes during germination. All genotypes exhibited a higher sensitivity to drought stress as compared to salinity stress. The observed differences in some genetically inherited germination characteristics (i.e. base Ψb(50)s and hydrotimes) suggest genetic differences even in seeds of individual old trees situated in close areas, as previously found in other countries of the Mediterranean basin. A greater sensitivity to stress was determined during early radicle growth, an essential feature for early plant establishment in marginal dry areas. In this paper, a protocol to test germination under simulated stress conditions (drought and salinity stress) was established. Including in the analysis other parameters representative of early embryo growth (i.e. radicle elongation), this protocol may be useful to select genotypes for breeding programs towards the selection of tolerant cultivars or rootstocks. It may be also applied to other leguminous species with a difficult germination. [ABSTRACT FROM AUTHOR]

The agronomic use of olive mill wastewaters (OMWs) is limited by some constraints, such as high salinity, acidity, and phenolic compounds that exert phytotoxic and antimicrobial effects. Many researches have been focused on OMW polyphenol effects on germination, but only few on the combined effects of salinity and acidity. In this paper, on Lolium multiflorum Lam., the effects on germination of pH and osmotic potentials similar or higher to those found in OMWs have been investigated. The studied salinity and pH levels did not affect final germination of L. multiflorum , but in some cultivars they significantly enhanced T 50 and consequently reduced initial root growth. Thus, in this species moderately tolerant to salinity, the reduction of germination determined by OMWs cannot be attributed to the osmotic stress and/or to the low pH, but mainly to polyphenols. This research emphasizes the possibility of obtaining good crop establishments after spreading OMWs on soil, choosing herbaceous species tolerant to salinity once polyphenols have been inactivated. [ABSTRACT FROM AUTHOR]

Tissue culture methods offer the potential for large-scale propagation of giant reed ( Arundo donax L.), a promising crop for energy biomass. In previous trials, giant reed resulted particularly suitable to in vitro culture. In this paper, with the final goal of enhancing the efficiency of in vitro production process and reducing costs, the influence of four different culture media (agar or gellan-gum solidified medium, liquid medium into a temporary immersion system-RITA ® or in a stationary state) on in vitro shoot proliferation of giant reed was evaluated. Giant reed exhibited a particular sensitivity to gelling agents during the phase of secondary shoot formation. Gellan gum, as compared to agar, improved the efficiency of in vitro culture giving more shoots with higher mean fresh and dry weight. Moreover, the cultivation of this species into a liquid medium under temporary immersion conditions or in a stationary state, was comparatively as effective as and cheaper than that into a gellan gum medium. Increasing 6-benzylaminopurine (BA) up to 4 mg l −1 also resulted in a further enhancement of secondary shoot proliferation. The good adaptability of this species to liquid medium and the high multiplication rates observed indicate the possibility to obtain from a single node at least 1200 plantlets every six multiplication cycles (about 6 months), a number 100 fold higher than that obtained yearly per plant by the conventional methods of vegetative multiplication. In open field, micropropagated plantlets guaranteed a higher number of survived plants, secondary stems and above ground biomass as compared to rhizome ones. [ABSTRACT FROM AUTHOR]

Abstract: The effects of reduced water potential (ψ) in NaCl and pre-osmopriming in PEG, on seed germination and early radicle growth at different temperatures were assessed in the laboratory for sweet sorghum [Sorghum bicolor (L.) Moench] cv. Roce. Five salt solutions (with a ψ of 0-control, −0.22, −0.42, −0.82 or −1.23MPa) and four temperatures of 10, 15, 25 or 35°C were used for germination tests. Daily and final germination, seed moisture at 4 and 24h of imbibition and radicle length 2 days after initial germination were recorded. Sorghum seeds seem to be more tolerant to reduced ψ at optimum temperature. Indeed, at 25°C, down to −0.82MPa seed germination was not affected. The increase in incubation temperature to 35°C determined a greater seed water content and a faster germination than at 25°C at all ψ s, despite the lower final germination percentage. With the lowering of temperature to 15°C, germination percentage significantly declined with the decrease of ψ and at −0.82MPa it reduced to less than 50%. At 10°C seeds failed to germinate at ψ <−0.22MPa due to combined depressive effects of reduced ψ and low temperature. Seed priming enhanced germination and shortened the delay in germination time due to the increase in saline stress, at suboptimal temperatures only. This effect could be explained by the faster water absorption occurring in primed seeds as compared to those unprimed, at these temperatures, regardless of salt concentration of the solution. Root growth was more sensitive than germination to salt stress. Indeed, the increase in NaCl concentration adversely affected root elongation at all temperatures. The beneficial effects of PEG-osmopriming were evident on root growth at all temperatures except the optimal one. From a practical point of view, when early sowings of sweet sorghum are requested, the use of primed seeds is suggested, as PEG-osmopriming is helpful in overcoming the negative effect imposed by reduced water potential upon seed germination under suboptimal thermal conditions. When saline water is available for irrigation at sowing, it may be useful to sow when optimal or nearly optimal temperature may be encountered in the soil in order to avoid the combined stress of temperature and salinity. [Copyright &y& Elsevier]

Summary: Light and temperature-response curves and their resulting coefficients, obtained within ecophysiological characterization of gas exchanges at the leaf level, may represent useful criteria for breeding and cultivar selection and required tools for simulation models aimed at the prediction of potential plant behaviour in response to environmental conditions. Leaf-scale gas exchanges, by means of an IRGA open-flow system, were measured in response to light intensity (8 levels from 0 up to 2000μmolm−2 s−1), CO2 concentrations (ambient—350μmolmol−1 and short-term enriched—700μmolmol−1) and air temperature (from 7 up to 35°C) on three Vicia faba L. genotypes, each representing one of the three cultivated groups: major, equina and minor. The net assimilation rate response to light intensity was well described by an exponential rise to max function. The short-term CO2 enrichment markedly increased the values of light response curve parameters such as maximum photosynthetic rate (+80%), light saturation point (+40%) and quantum yield (+30%), while less homogenous behaviour was reported for dark respiration and light compensation point. For each light intensity level, the major and minor genotypes studied showed assimilation rates at least a 30% higher than equina. The positive effects of short-term CO2 enrichment on photosynthetic water use efficiency (WUE) indicate a relevant advantage in doubling CO2 concentration. In the major and minor genotypes studied, similar assimilation rates, but different WUE were observed. The optimum leaf temperature for assimilation process, calculated through a polynomial function, was 26–27°C and no relevant limitations were observed in the range between 21 and 32°C. Analysis at the single leaf level provided both rapid information on the variations in gas exchange in response to environmental factors and selection criteria for the screening of genotypes. [Copyright &y& Elsevier]

The investigation of natural products in medicinal chemistry is essential today. In this context, acetylcholinesterase (AChE) inhibitors comprise one type of the compounds most actively studied in the search for an effective treatment of symptoms of Alzheimer’s disease. This work describes the isolation of a natural compound, solanocapsine, the preparation of its chemical derivatives, the evaluation of AChE inhibitory activity, and the structure–activity analysis of relevant cases. The influence of structural variations on the inhibitory potency was carefully investigated by modifying different reactive parts of the parent molecule. A theoretical study was also carried out into the binding mode of representative compounds to the enzyme through molecular modeling. The biological properties of the series were investigated. Through this study valuable information was obtained of steroidal alkaloid-type compounds as a starting point for the synthesis of AChE inhibitors. [ABSTRACT FROM AUTHOR]

Abstract: Constructed wetlands (CWs) could play a strategic role in wastewater reclamation and reuse in arid and semiarid regions, such as the Mediterranean area. The aim of this study was to analyse the phytoremoval effectiveness of Phragmites australis and spontaneous plant species (SPS) in two CW systems: a horizontal (H-SSF) and a vertical (V-SSF) subsurface flow. P. australis showed a higher biomass growth than SPS and always covered 100% of the bed''s surface. The H-SSF system was more suitable for enhancing biomass growth of P. australis (4701 gm −2 as compared to 3088 gm −2 detected in the V-SSF CWs) whereas V-SSF of SPS (1700 gm −2 and 100% total cover as compared to 240 gm −2 and 40% total cover observed in H-SSF). SPS included species belonging to different botanical families in relation to the system adopted. Some of these species (i.e. Phalaris spp. and Chrysantemum segetum) were dominant in aboveground floral composition. Beds with SPS showed the same efficiency of the Phragmites ones in TSS, COD and pathogen removal. Phragmites was more effective than SPS in removing BOD5 (in horizontal system), total phosphorus and nitrates. V-SSF systemwas more effective than H-SSF in removing total nitrogen. SPS presence did not decrease the efficiency of unplanted beds. Irrespective of the different plant species covering the beds, CWs were overall efficient in removing pollutants confirming their potential as an economic alternative to traditional urban wastewater treatments in small and medium-sized communities. [Copyright &y& Elsevier]