Andrea Santo

Light, temperature, dry after-ripening and salt stress effects on seed germination of Phleum sardoum (Hackel) Hackel

Phleum sardoum is an endemic psammophilous species of Sardinia, growing exclusively on coastal sandy dunes. The effect of glumes on seed germination, germination requirements at constant (5–25°C) and alternating (25/10°C) temperatures, both in the light (12/12 h) and in the dark were evaluated, as well as the effect of a dry after-ripening period (90 days at 25°C), the salt stress effect (0–600 mmol NaCl) and its recovery on seed germination. The presence of glumes reduced final germination percentages. For fresh naked seeds, high germination percentages were observed at 10°C. Dry after-ripening increased germination rate at low temperatures, but did not affect final germination percentages. NaCl determined a secondary salt-induced dormancy which recovery interrupted only partially. Our results highlighted that this species has its optimum of germination during autumn–winter when, under a Mediterranean climate, water availability is highest and soil salinity levels are minimal.

The Aichi Biodiversity Target 12 at regional level: an achievable goal?

The Aichi Biodiversity Target 12 aims to prevent the extinction risk of known threatened species and to improve their conservation status by 2020. We present the integrated strategy implemented in the last 10 years for the keystone plant species of Sardinia (Italy, W. Mediterranean Basin), which includes the following activities: conservation status assessment (following the IUCN protocol), ex situ conservation, in situ monitoring and active protection measures. To date, an average of 51.8% of keystone plant species have been subjected to the latter first three activities while, due to the higher costs, only few active conservation measures have been carried out. Considering the activities realised since 2004, we have also predicted the conservation effectiveness towards 2020 and have elaborated an index to evaluate it. Halfway through the strategic plan, we argue that more efforts are needed to guarantee the effective conservation of all threatened plants in Sardinia.

Influence of aerial seed banks on germination response in three desert plant species

Aims To determine if the germination response of desert plant species to a period of aerial storage in field conditions (i.e. mature seeds that remain attached to the parent plant) is comparable to seeds harvested at maturity and stored in ambient laboratory conditions, to better understand the role of aerial seed bank in the germination ecology of desert plants, using one annual and two perennial species. Methods Seeds of three desert plants (Anastatica hierochuntica, Blepharis ciliaris and Scrophularia deserti) that matured in June 2014, were collected from wild plants in June and November 2014, and germinated under two photoperiods (0, 12 hours light) and three thermoperiods (night/day temperatures of 15/25, 20/30 and 25/35 degrees C). Important Findings Seeds of B. ciliaris and S. deserti had significantly higher germination percentages when harvested and stored for five months, compared to being stored in the aerial seed bank. Germination percentages of these two species increased with decreasing temperature and in the presence of light. These results indicate that these species use a combination of aerial and soil seed banks to maintain a percentage of viable seeds through favourable germination periods. Germination percentages of A. hierochuntica were high under all tested circumstances, indicating that this species relies mainly on the aerial seed bank to maintain a percentage of viable seeds through favourable germination periods. This study shows that the population survival strategies of an aerial seed bank are species-specific. These results have practical implications for conservation and habitat restoration for these species, and also for their propagation since early collection of mature fruits and ex situ storage will result in greater germination percentages of some species.

Variability on morphological and ecological seed traits of Limonium avei (De Not.) Brullo & Erben (Plumbaginaceae)

Limonium avei is an annual species occurring in the salt‐marshes and in limited surfaces of rocky areas around the Mediterranean coasts. Seed lots from five populations of this species, along a latitudinal gradient, were analyzed using an image analysis system to detect differences in seed morphology among populations. Germination requirements at constant (5–25°C) and alternating temperatures (25/10°C), both in light and in darkness, were evaluated for all populations, as well as the effect of the calyx removal on final seed germination and its rate. Morpho‐colorimetric analysis clearly identified seeds from different populations, habitats and substrates without misattributions among them. The calyx slowed the germination process, influencing both final germination and rate with respect to naked seeds. Seeds from all populations germinated with significantly higher percentages in the light, with respect to those incubated in the darkness, and showed rapid germination (time in days to reach 50% of germination: 0.5 days) at the warmer tested temperature (25°C). High germination (>80%) was also detected for seeds of all the investigated populations, except for those from the Apulian region (South Italy, ca. 60%). Our results highlight that L. avei has a high variability in seed morphology, probably habitat induced, and a fast germination response for all populations. Rapid germination may be an adaptive strategy that allows L. avei seeds to take advantage of transient favorable conditions during the germination stage, to ensure seedling establishment under the unpredictable rainfall pattern in the Mediterranean climate.

Different ecological strategies during the seed germination phase of nine grasses inhabiting the hyper-arid Arabian desert: ECOLOGICAL STRATEGIES IN DESERT GRASSES

The effect of photoperiod, thermoperiod and their interaction on seed germination and its rate was studied for nine grasses growing in the Arabian desert. Germination tests were conducted under two photoperiods and three thermoperiods. Germination of light‐incubated seeds of Hyparrhenia hirta, Pennisetum divisum, Stipacapensis, Centropodia forsskaolii, Stipagrostis plumosa, Cymbopogon parkeri and Panicum turgidum was significantly higher than that detected in the darkness. Photoperiod did not influence the seed germination of Aristida adscensionis and Imperata cylindrica. Seeds of all species, except P. divisum, C. parkeri and I. cylindrica, germinated indepen dently of the tested temperature. Our results indicate that species belonging to the same family and growing in the same hyper‐arid desert habitat may influence and act in different ways during the seed germination phase, causing species‐specific effects, and therefore might affect the ecology of each taxon in this harsh environment.

Effects of storage, mucilage presence, photoperiod, thermoperiod and salinity on germination of Farsetia aegyptia Turra (Brassicaceae) seeds: implications for restoration and seed banks in Arabian Desert

Abstract Seed viability and germination are key factors in the success of restoration efforts, especially when stored seeds are used. However, the effect of seed storage on germination of most of the native Arabian species is not well documented. We investigated the effect of storage time and role of the seed mucilage in regulating germination, dormancy, salinity tolerance and consequential survival strategy of F. aegyptia in an unpredictable arid desert setting. Effect of light and temperature during germination was studied under two photoperiods and two thermoperiods using intact and de-mucilaged seeds. Presence of mucilage and thermoperiod did not affect the germination. However, seed collection year and photoperiod had a highly significant effect on the germination. Increasing salinity levels decreased the germination of F. aegyptia but ungerminated seeds were able to germinate when salinity stress was alleviated. Seed storage at room temperature enhances the germination percentage, indicating that F. aegyptia seeds have physiological dormancy and it can be alleviated by after-ripening at dry storage. In addition, F. aegyptia seeds show ability to germinate at lower salinity concentration and remain viable even at higher saline conditions, indicating their adaptability to cope with such harsh environmental conditions.