Growth efficiency of italian threatened species in response to climatic factors

Predictions of future climate scenarios indicate a likely increased risk of drought in many regions, including the Mediterranean basin. Water stress experiments underline that drought may be a discriminant of species distribution determining change in vegetation in the long time. Therefore, monitoring the conservation status of threatened plant species is a crucial component of global change research programs in order to assess their potential responses to global warming and make informed land management decisions. We are carrying out a conservation project regarding a wide range of species included in the Red Lists of the Italian flora: Rhamnus persicifolia Moris (status LR), Brassica rupestris subsp. hispida Raimondo & P. Mazzola (status LR), Brassica rupestris Raf. subsp. rupestris (status EN) Centaurea cineraria L. subsp. circae (Sommier) Cela Renzoni & Viegi (status LR), Malcolmia littorea (L.) R.Br (status VU), Carex paniculata L. subsp. paniculata (status CR). The study is carried out at the Botanic Garden of Rome, where they are cultivated outdoors. The main objective is to analyse the growth efficiency in response to climatic factors of the considered species. The pronounced sensitivity of photosynthesis to heat can be used to detect early damage in plant tissue. Thus, we employ photosynthesis as a stress temperature indicator. In particular, the relationship between net photosynthesis and temperature gives information about the species tolerance threshold to air temperature. Moreover, we want to determine the most important morphological and physiological factors driving the relative plant growth rate (RGR). RGR is an useful trait to characterise plant species with respect to its potential productivity. Considering that henological events reflect the complex interrelations between plants and their environments highlighting their adaptation, a phenological database, recording vegetative activity, flowering, fruiting and leaf senescence is carried out. Knowing potential growth capability of the wild species is aimed at the conservation of genetic intraspecific variability of native populations, outlining practices for the reintroduction projects.