The present investigation evaluates the effect of the culture medium, IAA concentration, type of explant and culture period on the in vitro induction of adventitious roots in sunflower ...(Helianthusannuus). To this end, hypocotyls and plumules were cultured for 7 or 14 days on two types of media containing IAA (0.1, 0.3 or 0.9 mg l−1)—Murashige et Skoog’s medium at half concentration of macronutrients (MS 1/2) and White’s at full concentration. The type of medium and explant exerted the greatest influence on root induction. The adventitious root formation was greater in plumules than in hypocotyls irrespective of the medium, length of culture period or IAA concentration. The adventitious roots formed quickly in plumules on MS 1/2. After 7 days the plantlets could be transplanted to sterilized peat moss. The optimal IAA concentration for adventitious root formation was 0.9 mg l−1, although the longest roots were obtained at 0.3 mg l−1 IAA.
Background and aims - Invasive alien (exotic) species are one of the most serious threats to the conservation of biodiversity on the planet. This is especially true on islands, given the fragility of ...their ecosystems and high levels of endemicity in both species and ecosystems.
The problem is particularly acute in the Canary Islands, a biodiversity 'hot spot', where there is widespread high endemicity and unique biodiversity. This paper presents the first comprehensive inventory of alien plant species in Anaga Rural Park (ARP) (Tenerife, Canary Islands, Spain) a
Natural Protected Area, currently proposed as a UNESCO Biosphere Reserve. Anaga is also outstanding for including a relict Tertiary era laurel-forest ecosystem that hosts a large number of palaeoendemics. Methods - Surveys were conducted along itineraries through the different
ecosystems of ARP to determine the alien plant species in areas with different levels of human impact. Key results - Two hundred and sixteen alien species were identified, belonging to 53 families and 141 genera, especially concentrated in the most anthropic areas, noting the
possibly competitive coexistence of aliens and local endemics of importance in the ecosystem. This is the first overall comprehensive study on the importance of alien species in ARP. Surveys confirmed how human infrastructure and activities significantly favour the presence and diversity of
exotic species. Using multivariate statistical analysis, significant differences were found between the species diversity of alien flora and the proximity of anthropic areas. The presence of Cuscuta campestris Yunck was detected, being a second record for the Canaries and the first
for ARP. Conclusions - A large number of alien plant species inhabit ARP, affecting all its ecosystems. This is largely the result of the human activities within it, and poses a risk to its conservation and the survival of numerous endemic taxa s. str.
En una riera de la comarca del Baix Camp (Tarragona) hemos encontrado ocho especies de cactáceas alóctonas naturalizadas. De ellas, tres son nuevas para Europa, dos nuevas para España, una nueva para ...la provincia de Tarragona y, finalmente, otras dos sin ser novedad florística requieren aclaraciones en lo concerniente a su estatus en Cataluña. Este hallazgo representa la mayor biodiversidad de cactáceas citada hasta el momento para toda Cataluña, para toda la Península Ibérica e incluso para toda Europa. La introducción de especies exóticas en general y de cactáceas en particular se ve favorecida en esta comarca de la costa mediterránea por el desarrollo de una jardinería basada casi exclusivamente en elementos foráneos y en la existencia de una climatología muy favorable.
During the floristic work carried out in 2004 in the Baix Camp region of Tarragona (NE Spain) we found four new species of alien naturalised Cactaceae. Of these, three are reported for the second ...time from Europe and the other is new to Catalonia region. Southern Catalonia, with eleven species of Cactaceae, harbours the highest diversity of the family in Europe. Our results demonstrate that this diversity is even higher than previously believed. The introduction of these exotic taxa is, once again, due to the development of gardening based exclusively on foreign elements, to the unscrupulous and uncontrolled dumping of their remains in the natural environment, and to the existence of a favourable climate.
The authors report on the finding of eight new alien cacti naturalised in the Baix Camp (Tarragona). Three of these are new records for Europe, two are new records for Spain and one is a first record ...for Tarragona province. Two further species are not new floristic records however some revision of their status in Catalonia is required. Discussed is the extensive use of alien plant species in garden design in the area and the mildness of the local climatic conditions which has resulted in the greatest accumulation of naturalised cacti in Europe.
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