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In the upcoming years, the challenge of the exponential growth in tree planting activities matching climate crisis, which requires the use of targeted and adapted plant material, calls for creating an updated framework of the Italian forest nursery sector, for both basic materials (BM) and for forest reproductive materials (FRM). The present paper aims at highlighting pros and cons of the public nursery system and, at the same time, characterizing the current organization and production capacity in quantitative and qualitative terms. Our effort was focused on recovering information, topic for the development of the sector, which has been gradually weakened in the last decades. The research was carried out in two steps: (a) analysis of the online available sources; (b) diagnostic analysis by questionnaire to the nursery sector managers. The specific objectives were: (i) describing the state of the art of the available MBs; (ii) qualifying and quantifying the seedlings production (active nurseries, management of nurseries in the regions, typology and types of FRM produced and species); (iii) understanding the real and potential users of BM and FRM; and (iv) assessing the usability of information related to the nursery chain. The picture at national scale is definitively fragmented from all points of view: availability of BM, usability of available information, production capacity of FRM, rationalization and innovation of growing systems, computerization. Although virtuous cases were found, the Italian forest nursery sector generally needs a profound revitalization to cope with the imminent increasing demand for target material. [ABSTRACT FROM AUTHOR]

The assessment of seed zones or regions of provenance (RoP) to preserve local adaptation of tree species is an effective tool for the correct management of forest reproductive materials. The RoP for a species or sub-species is the area or group of areas subject to sufficiently uniform ecological conditions in which stands or seed sources show similar phenotypic or genetic characters, taking into account altitudinal boundaries where appropriate. However, the delineation of RoPs is commonly based on estimates of intrinsic environmental homogeneity, mainly climate and/or soil characteristics. The integration of genetic data into RoP maps is an important strategy to obtain a sound tool for managing forest reproductive materials. A study on Quercus suber (cork oak) in Sardinia (Italy) was carried out with the aim of determining ecological regions of provenance, investigating the genetic diversity among populations at the regional scale and identifying possible areas of interest for valorising the available germplasm. Identification of these areas was performed by Reserve Selection Analysis, which allows to identify priority areas by assessing the minimum number of sites required to include all the genetic diversity estimated by genetic analysis. Four spatial clusters were obtained based on environmental data: the northern and northern-eastern parts of the island were included in the Northern RoP; the second RoP covered the western part; and the third RoP enclosed the south-eastern region. The last group was distributed on the central part of the island (Central RoP) and includes the higher elevations. The sampled populations showed a low differentiation among populations and low diversity. According to the Reserve Selection Analysis, four conservation priority areas were identified. These indications can be useful at the local level because these sites can be proposed as stands for seed collection for future plantations. [ABSTRACT FROM AUTHOR]

Tamarix trees are considered of particular interest for afforestation and reforestation of degraded areas prone to salinity and drought. In this study, a comparison of the performance and physiological responses of two species of Tamarix grown in saline and dried soils was carried out. Stem cuttings of T. aphylla and T. jordanis were collected from a location in the Negev desert and the plantlets obtained were subjected to four different soil treatments under semi-controlled conditions for 14 days. The treatments were: fresh water (C); salt (S: 150 mM of NaCl); drought (D: 50% field capacity); and a combined stress (DS: 150 mM of NaCl + 50% FC). Results showed a higher tolerance to salt stress of T. jordanis as compared with T. aphylla. The maintenance of high amount of cell carbohydrates, the high capacity of carbon assimilation and the active growth were considered as markers of salt tolerance in Tamarix spp. T. aphylla showed better performances in terms of growth and biomass production than T. jordanis in dry conditions. The high accumulation of sugars found in the leaves of T. aphylla under mild drought is considered a mechanism of acclimatization. The combined stress (salt+drought) lowered the performance of plants as compared to salt and drought stress applied alone. The possible role of the accumulation of proline observed in the leaves of both species under stressful conditions is discussed. [ABSTRACT FROM AUTHOR]

The relationships between non-radiative energy dissipation and the carotenoid content, especially the xanthophyll cycle components, were studied in sun and shade leaves of several plants possessing C3 (Hedera helix and Laurus nobilis) or C4 (Zea mays and Sorghum bicolor) photosynthetic pathways. Sun-shade acclimation caused marked changes in the organisation and function of photosynthetic apparatus, including significant variation in carotenoid content and composition. The contents of zanthophyll cycle pigments were higher in sun than in shade leaves in all species, but this difference was considerably greater in C3 than in C4 plants. The proportion of photoconvertible violaxanthin, that is the amount of violaxanthin (V) which can actually be de-epoxidised to zeaxanthin, was much greater in sun than in shade leaves. The amount of photoconvertible V was always linearly dependent on the chlorophyll a/b ratio, although the slope of the relationship varied especially between C3 and C4 species. The leaf zeaxanthin and antheraxanthin contents were correlated with non-radiative energy dissipation in all species under different light environments. These relationships were curvilinear and variable between sun and shade leaves and between C3 and C4 species. Hence, the dissipation of excess energy does not appear to be univocally dependent on zeaxanthin content and other photoprotective mechanisms may be involved under high irradiance stress. Such mechanisms appear largely variable between C3 and C4 species according to their photosynthetic characteristics. [ABSTRACT FROM AUTHOR]

Drought and temperature stress can cause considerable gluten protein accumulation changes during grain-filling, resulting in variations in wheat quality. The contribution of functional polymeric components of flour to its overall functionality and quality can be measured using solvent retention capacity (SRC). The aim of this study was to determine the effect of moderate and severe drought and heat stress on SRC and swelling index of glutenin (SIG) in six durum wheat cultivars with the same glutenin subunit composition and its relation with gluten protein fractions from size exclusion high performance liquid chromatography. Distilled water, sodium carbonate and sucrose SRC reacted similarly to stress conditions, with moderate heat causing the lowest values. Lactic acid SRC and SIG reacted similarly, where severe heat stress highly significantly increased the values. SIG was significantly correlated with sodium dodecyl sulphate sedimentation (SDSS) and flour protein content (FPC) under all conditions. Lactic acid SRC was highly correlated with FPC under optimal and moderate heat stress and with SDSS under moderate drought and severe heat. SIG was negatively correlated with low molecular weight glutenins under optimal and drought conditions, and combined for all treatments. The relationship between SRC and gluten proteins was inconsistent under different stress conditions. [ABSTRACT FROM AUTHOR]

Hordeum maritimum With. is a wild salt tolerant cereal present in the saline depressions of the Eastern Tunisia, where it significantly contributes to the annual biomass production. In a previous study on shoot tissues it was shown that this species withstands with high salinity at the seedling stage restricting the sodium entry into shoot and modulating over time the leaf synthesis of organic osmolytes for osmotic adjustment. However, the tolerance strategy mechanisms of this plant at root level have not yet been investigated. The current research aimed at elucidating the morphological, physiological and biochemical changes occurring at root level in H. maritimum and in the salt sensitive cultivar Hordeum vulgare L. cv. Lamsi during five-weeks extended salinity (200 mM NaCl), salt removal after two weeks of salinity and non-salt control. H. maritimum since the first phases of salinity was able to compartmentalize higher amounts of sodium in the roots compared to the other cultivar, avoiding transferring it to shoot and impairing photosynthetic metabolism. This allowed the roots of wild plants to receive recent photosynthates from leaves, gaining from them energy and carbon skeletons to compartmentalize toxic ions in the vacuoles, synthesize and accumulate organic osmolytes, control ion and water homeostasis and re-establish the ability of root to grow. H. vulgare was also able to accumulate compatible osmolytes but only in the first weeks of salinity, while soon after the roots stopped up taking potassium and growing. In the last week of salinity stress, the wild species further increased the root to shoot ratio to enhance the root retention of toxic ions and consequently delaying the damages both to shoot and root. This delay of few weeks in showing the symptoms of stress may be pivotal for enabling the survival of the wild species when soil salinity is transient and not permanent. [ABSTRACT FROM AUTHOR]