1,721,014 research outputs found
Analisi strutturale e morfologica fogliare di alcune aree rimboschite a Pinus nigra Arn. nell’Appennino Abruzzese
No full textAnalisi strutturale delle formazioni forestali presenti nel territorio dei Comuni di Anzio e Nettuno (Roma).
No full text
Regeneration of the undergrowth in reafforested areas with Pinus nigra, in the High Aterno Valley (Italy).
No full textDiachronic adjustments of functional traits scaling relationships to track environmental changes. Revisiting Cistus species leaf cohort classification
No full textLeaf functional traits and their relationships can differ between leaf flushes, particularly for species characterized by an extended growing season such as Mediterranean ones. Among them, Cistus spp. are generally reported to display two different leaf cohorts (i.e. summer and winter leaves) during the same growing season. We tested the generality of such leaf cohort classification by analyzing the diachronic adjustments of relationships between different leaf functional traits in 3 Cistus spp. Traits included were: leaf mass per area (LMA), leaf thickness (LT), leaf dry matter content (LDMC) and net photosynthesis on a mass basis (Am). The slopes of the relationships between morphological traits were then regressed against climate variables. The slopes were also regressed against leaf production rate (LPR) and the scores of the positioning as Competitors (%C), Stress tolerators (%S) and Ruderals (%R) in the tertiary CSR scheme. The different leaf flushes reshaped the well-known trait covariation patterns thus reflecting shifts in leaf-level resource-acquisition and -use strategies. This was achieved through an opposite response of the relationships LMA–LT and LMA–LDMC to temperature changes. In fact, the relationship LMA–LT was better modulated in leaves produced at different temperatures, while the LMA–LDMC one was possibly constrained due to the tighter negative relationship LDMC–Am (i.e. higher costs in terms of carbon assimilation). Accordingly, changes in LMA–LDMC coordination were significantly related to %C. Our results provide an evidence that while Cistus spp. leaf cohort classification generally holds, it does not necessarily capture the entire seasonal spectrum of traits covariation. We propose to move forward from the generally accepted winter–summer leaf classification shown in literature providing a new framework that can better describe Cistus species potential response to environmental changes
Physiological, morphological and anatomical leaf traits variation across leaf development in Corylus avellana
No full textThe study analyzed the variations of physiological, morphological and anatomical leaf traits during its development in Corylus avellana L. saplings. Three different phases were identify during leaf development: the first phase (hereafter IP) considered in the developing leaves, the second phase (IIP) in the mature green leaves and the third phase (IIIP) in the senescent leaves. In particular, variations in parameters estimated from the photosynthetic light response curves, in chlorophyll fluorescence variables and in morphological leaf traits were analyzed during the three phases. The principal component analysis (PCA) carried out using all the considered morphological characters (leaf mass per area - LMA, and leaf tissue density - LTD) and physiological traits (the maximum net photosynthetic rates - A(Nmax), dark respiration rates - R-D, light compensation point - LCP, light saturation point - LSP, maximum quantum yield - phi(max), fluorescence-based maximum quantum yield of PSII photochemistry - F-v/F-M and effective quantum yield of PSII photochemistry - phi(PSII)) showed a complete separation among the considered phases. The results showed that the major differences occur between the phases IP and IIP. In particular, a greater variation was found for LMA, A(Nmax), R-D. On the contrary a lower variation was observed for phi(max) which remain quite constant from IP to IIP indicating that chloroplasts present in juvenile leaves are fully functional
Carbon sequestration capability provided by different types of green areas in Rome
No full textCarbon dioxide (CO2) has been recognized as a major driver of climate change accounting for over 80% of all greenhouse gas emissions in the European Union. In particular, urban green areas represent a sink of CO2 due to plants capacity to fix carbon via photosynthesis and store the carbon excess as biomass. However, the plant CO2 sequestration capability occurs at different rates depending on plant species, the relative growth rate and the photosynthetic capability. Rome is among the largest European cities, with a surface area of 1285 Km2, where the green areas represent 35.3% of the total surface. In such context, the main objective of this research was to quantify the plant CO2 sequestration capability (CS, Mg CO2 ha-1 y-1) by green areas of different size, location and vegetation types in Rome. In particular, four historical residences (Villa Pamphjli, 184 ha, Villa Ada Savoia, 160 ha, Villa Borghese, 74 ha, and Villa Torlonia, 14 ha), the Botanical Garden of Rome (12 ha) and the Campus of the Sapienza University of Rome (20.3 ha) were analyzed. The CS of the four historical residences were 780, 998, 664 and 756 Mg CO2 ha-1 y-1 respectively, the Botanical Garden 809 Mg CO2 ha-1 y-1, and the Campus 43.4 Mg CO2 ha-1 y-1. The results highlight the importance of green areas in cities in order to mitigate the atmospheric CO2 concentration increasing. Our data concerning CS capability by green areas might be incorporated in a geographic information system allowing the monitoring of CO2 concentration variations over time, implement strategies to maximize the urban vegetation ecological function and the management practices to fully realize the benefits of the services that green areas can provide
Thermal requirements for seed germination of three invasive alien species (IAS).
No full textInvasive alien species (IAS) have been introduced
outside their native sites by humans and
becoming part of local flora. The IAS number is
strongly increased worldwide during the past two
centuries, redefining the classical biogeography
boundaries, affecting ecosystem functioning,
human health and economies. IAS represent
one of the main threats to biodiversity and
interconnected ecosystem services.
This work aimed to investigate thermal
requirements for seed germination of Ailanthus
altissima (Mill.) Swingle, Robinia pseudoacacia L.
and Phytolacca americana L. Germination tests
were carried out at the Germplasm Bank (Botanical
Garden of Rome). Seeds were incubated in the
dark, and in the light (12 h light/12 h darkness)
at three range temperatures (15/6, 20/10 and
30/20 °C). For A. altissima and P. americana cold
stratification (4 °C, for 1 month) was investigated
as potential factor improving seed germination.
Differently, no cold stratification was applied to R.
pseudoacacia, which shows pronounced physical
dormancy due to an impermeable seed coat. In
this case a seed piercing to determine a higher
germination was applied.
A. altissima and P. americana showed a higher
germination rate at 30/20 °C than at 20/10 and 15/6
°C. R. pseudoacacia showed a high germination
rate after piercing at 15/6 °C and 20/10 °C, whereas
at 30/20 °C a high seed mortality was observed.
Expanding knowledge on IAS seed germination
is crucial to better understand the invasiveness
process. This information can help to find and
apply incisive and more appropriate actions to
limit the establishment and survival of IAS, whose
invasiveness could benefit from climate change in
progress.Invazivne tujerodne vrste so na območja zunaj
domorodnih območij vnesli ljudje in postajajo del
lokalne flore. Število invazivnih tujerodnih vrst je
v zadnjih dveh stoletjih močno naraslo po vsem
svetu, zaradi česar se na novo določajo klasične
biogeografske meje, to pa vpliva na delovanje
ekosistemov, zdravje ljudi in gospodarstvo.
Invazivne tujerodne vrste so ena od glavnih groženj
biotski raznovrstnosti in povezanim ekosistemskim
storitvam.
Cilj te študije je raziskati toplotne zahteve za klitje
semen vrst Ailanthus altissima ((Mill.) Swingle),
Robinia pseudoacacia L. in Phytolacca americana
L. Testi kalivosti so bili izvedeni v semenski banki
(Botanični vrt v Rimu). Semena so bila inkubirana v
temi in na svetlobi (12 ur na svetlobi/12 ur v temi)
pri treh temperaturnih razponih (15/6, 20/10 in
30/20 °C). Za vrsti A. altissima in P. americana je bila
kot potencialni dejavnik izboljšanja kalivosti semen
raziskana hladna stratifikacija (4 °C, 1 mesec). Za vrsto
R. pseudoacacia, ki ima izrazito fizično dormanco
zaradi nepropustne semenske ovojnice, pa hladna
stratifikacija, nasprotno, ni bila uporabljena. Pri tej
vrsti je bila za določanje večje kalivosti uporabljena
perforacija semen.
Pri vrstah A. altissima in P. americana je bila pri
temperaturnem razponu 30/20 °C ugotovljena večja
kalivost kot pri temperaturnih razponih 20/10 in
15/6 °C. Pri vrsti R. pseudoacacia je bila ugotovljena
večja kalivost po perforaciji pri temperaturnih
razponih 15/6 °C in 20/10 °C, pri temperaturnem
razponu 30/20 °C pa je bila ugotovljena velika
smrtnost semen. Razvijanje znanja o kalivosti
semen invazivnih tujerodnih vrst je ključno za boljše
razumevanje procesa invazivnosti. Te informacije
lahko pomagajo pri iskanju in uvedbi učinkovitih
in primernejših ukrepov za omejitev naselitve
in preživetja invazivnih tujerodnih vrst, saj lahko
na njihovo invazivnost ugodno vplivajo trenutne
podnebne spremembe
Ecologia dei pascoli di Campo Imperatore (Gran Sasso d'Italia) e carta della biomassa vegetale. In “Ricerche di Geobotanica ed Ecologia Vegetale di Campo Imperatore (Gran Sasso d’Italia).
No full textLeaf mass per area (LMA) as possible predictor of adaptative strategies in two species of Sesleria (Poaceae): analysis of morphological, anatomical and physiological leaf traits
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