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Seeds of 30 species of Moehringia and 12\ud representatives of the Caryophyllaceae were examined\ud with the Scanning Electron Microscope. High\ud diversity was found in seed coat micromorphology,\ud and a number of novel morphological features have\ud been observed. Comparison with other representatives\ud of the Caryophyllaceae has provided new\ud insight into the potential taxonomic value of\ud discrete morphological characters. Though many\ud characters appear informative within Moehringia,\ud they are affected by a high level of homoplasy when\ud considered in a wider phylogenetic context. Smooth\ud seed is the common condition in Moehringia, except\ud for Eastern Balkan and Iberian species that maintain\ud a secondary ornamentation of the testa cells\ud resembling the plesiomorphic Caryophyllaceaetype.\ud Five types of strophioles were recognized, in\ud accordance with previous literature. Among these,\ud the strophiole of the Iberian species appears very\ud distinctive and a proper strophiole could not be\ud verified in M. glochidisperma and M. fontqueri

The development of isidia in thalli of Pseudevernia furfuracea from the Carnic Alps (North-eastern Italy), and the effects of these structures on CO 2 gas exchanges were investigated. The ontogenetic events were studied by comparison of sections stained with different histochemical tests and SEM observations. A high cell turnover rate in both symbiotic partners is the first sign of isidium development, followed by an increased aplanosporogenesis of algae and growth of neighbouring medullary hyphae which become oriented upwards. Large nuclei and an intense cytoplasm activity characterize the mycobiont cells. The surface of very young isidia shows an irregular structure of spherical to ovoid protruding tips of perpendicular cortical hyphae, that are later organised in a pseudomeristematic area similar to that observed in the apex of growing lobes. CO 2 gas exchange measurements carried out in the laboratory confirmed the high metabolic activity of isidia. At optimal water content and favourable light conditions, isolated isidia had rates of gross photosynthesis and dark respiration that were twice those of non-isidiate lobes. Isolated isidia also had a very low CO 2 saturation point, probably because of their favourable surface/volume ratio, and a high light saturation, probably linked to their high content of photosynthetic pigments. The different roles played by isidia in the biology of Pseudevernia furfuracea, and particularly their rejuvenating effect on aged lobes, are discussed, and the presence of thalloconidia is briefly mentioned.

Main conclusionThe heterologous expression ofAtPCS1in tobacco plants exposed to arsenic plus cadmium enhances phytochelatin levels, root As/Cd accumulation and pollutants detoxification, but does not prevent root cyto-histological damages.High phytochelatin (PC) levels may be involved in accumulation and detoxification of both cadmium (Cd) and arsenic (As) in numerous plants. Although polluted environments are frequently characterized by As and Cd coexistence, how increased PC levels affect the adaptation of the entire plant and the response of its cells/tissues to a combined contamination by As and Cd needs investigation. Consequently, we analyzed tobacco seedlings overexpressing Arabidopsis phytochelatin synthase1 gene (AtPCS1) exposed to As and/or Cd, to evaluate the levels of PCs and As/Cd, the cyto-histological modifications of the roots and the Cd/As leaf extrusion ability. When exposed to As and/or Cd the plants overexpressing AtPCS1 showed higher PC levels, As plus Cd root accumulation, and detoxification ability than the non-overexpressing plants, but a blocked Cd-extrusion from the leaf trichomes. In all genotypes, As, and Cd in particular, damaged lateral root apices, enhancing cell-vacuolization, causing thinning and stretching of endodermis initial cells. Alterations also occurred in the primary structure region of the lateral roots, i.e., cell wall lignification in the external cortex, cell hypertrophy in the inner cortex, crushing of endodermis and stele, and nuclear hypertrophy. Altogether, As and/or Cd caused damage to the lateral roots (and not to the primary one), with such damage not counteracted by AtPCS1 overexpression. The latter, however, positively affected accumulation and detoxification to both pollutants, highlighting that Cd/As accumulation and detoxification due to PCS1 activity do not reduce the cyto-histological damage.Electronic supplementary materialThe online version of this article (doi:10.1007/s00425-015-2428-8) contains supplementary material, which is available to authorized users.

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Daphne gnidium is a circum-Mediterranean\ud evergreen shrub. Flower and pollen features related to\ud pollination mechanism were analyzed, and the seasonal\ud presence of insects visiting the plant was monitored. The\ud morphology and functionality of flowers are compatible\ud with entomophily, as are pollen viability, which is maintained\ud for a few hours only after anthesis, and the very short\ud stigmatic receptivity. The reproductive fitness of the species\ud is low and the ripening process often fails (35% collapsed\ud embryos). While male organ functionality is fairly regular,\ud the female organ often shows developmental arrest. The\ud complex or transient evolutionary traits displayed by\ud D. gnidium are comparable to those of Thymelaea hirsuta\ud and other members of the Thymelaeaceae

Summary 1. Introduction. 1.1 Biodiversity in metal-contaminated sites. 1.2 Selecting native fungi and plants for bioremediation. 2. Case study – Multidisciplinary investigations on biodiversity into a sulphide-rich waste-rock dump. Conclusion: The enormous potential of native fungi and plants that are able to colonize metal-contaminated soils need to be studied in-depth in order to preserve the natural genetic resources of metalliferous habitats and to increase our basic knowledge about the natural adaptation mechanisms of hyperaccumulators in order to employ them in phytoremediation purposes