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Research Project
Mediterranean Institute for Agriculture, Environment and Development
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Publications
Exploring the Applicability of Calorespirometry to Assess Seed Metabolic Stability Upon Temperature Stress Conditions—Pisum sativum L. Used as a Case Study
Publication . Rodrigues, Lénia; Nogales, Amaia; Hansen, Lee D.; Santos, Fátima; Rato, Ana Elisa; Cardoso, Hélia
The availability of phenotyping tools to assist breeding programs in the selection of highquality
crop seeds is of obvious interest with consequences for both seed producers and
consumers. Seed germination involves the activation of several metabolic pathways,
such as cellular respiration to provide the required ATP and reducing power. This
work tested the applicability of calorespirometry, the simultaneous measurement of
heat and CO2 rates, as a phenotyping tool to assess seed respiratory properties
as a function of temperature. The effect of temperature on seed germination was
evaluated after 16 h of seed imbibition by calorespirometric experiments performed
in isothermal mode at 15, 20, 25, and 28 C on the seeds of three cultivars of peas
(Pisum sativum L.) commonly used in conventional agriculture (cvs. ‘Rondo’, ‘Torta de
Quebrar’, and ‘Maravilha d’América’). Significant differences in metabolic heat rate and
CO2 production rate (RCO2) as well as in the temperature responses of these parameters
were found among the three cultivars. A seed germination trial was conducted during
the 6 days of imbibition to evaluate the predictive power of the parameters derived
from the calorespirometric measurements. The germination trial showed that the optimal
germination temperature was 20 C and low germination rates were observed at extreme
temperatures (15 or 28 C). The cv. ‘Torta de Quebrar’ showed significantly higher
germination in comparison with the other two cultivars at all three temperatures. In
comparison with the other two cultivars, ‘Torta de Quebrar’ has the lowest metabolic
heat and CO2 rates and the smallest temperature dependence of these measured
parameters. Additionally, ‘Torta de Quebrar’ has the lowest values of growth rate and carbon use efficiency calculated from the measured variables. These data suggest
that calorespirometry is a useful tool for phenotyping physiologic efficiency at different
temperatures during early germination stages, and can determine the seeds with the
highest resilience to temperature variation, in this case ‘Torta de Quebrar’
Condensed tannins as antioxidants in ruminants : effectiveness and action mechanisms to improve animal antioxidant status and oxidative stability of products
Publication . Soldado, David; Bessa, R.J.B.; Jerónimo, Eliana
Condensed tannins (CTs) are widely distributed in plants, and due to their recognized
antioxidant activity are considered as possible natural antioxidants for application in ruminant
diets. A wide range of CT-rich sources has been tested in ruminant diets, and their effects on
animal antioxidant status and oxidative stability of their products are reviewed in the present work.
Possible mechanisms underlying the CT antioxidant effects in ruminants are also discussed, and
the CT chemical structure is briefly presented. Utilization of CT-rich sources in ruminant feeding
can improve the animals’ antioxidant status and oxidative stability of their products. However,
the results are still inconsistent. Although poorly understood, the evidence suggests that CTs can
induce an antioxidant effect in living animals and in their products through direct and indirect
mechanisms, which can occur by an integrated and synergic way involving: (i) absorption of CTs
with low molecular weight or metabolites, despite CTs’ poor bioavailability; (ii) antioxidant action on
the gastrointestinal tract; and (iii) interaction with other antioxidant agents. Condensed tannins are
alternative dietary antioxidants for ruminants, but further studies should be carried out to elucidate
the mechanism underlying the antioxidant activity of each CT source to design effective antioxidant
strategies based on the use of CTs in ruminant diets.
Multitemporal land use and cover analysis coupled with climatic change scenarios to protect the endangered Taxon Asphodelus bento-rainhae subsp. bento-rainhae
Publication . Almeida, Alice Maria; Delgado, Fernanda; Roque, Natália; Ribeiro, Maria Margarida; Fernandez, Paulo
Climate change and land use and land cover (LULC) change are impacting the species’
geographic distribution, causing range shifts and reducing suitable habitats. Asphodelus bento-rainhae
subsp. bento-rainhae (AbR) is an endangered endemic plant restricted to Serra da Gardunha (Portugal),
and knowledge of those changes will help to design conservation measures. MaxEnt was used to
model AbR’s current distribution and project it into the future, 2050, using the Shared Socioeconomic
Pathway SSP3-7. The Portuguese LULC maps from 1951–1980, 1995, 2007, and 2018 were used to
assess and quantify LULC changes over time. The results showed that the AbR current predicted
distribution matches its actual known distribution, which will not be affected by future predicted
climate change. The significant LULC changes were observed during the study periods 1951–1980
to 2018, particularly between 1951–1980 and 1995. Scrubland and Agriculture decreased by 5% and
2.5%, respectively, and Forests increased by 4% in the study area. In the occurrence area, Agriculture
increased, and Forests decreased between 1980 and 2018, due to Orchard expansion (34%) and
declines in Chestnut (16.9%) and Pine (11%) areas, respectively. The use of species distribution
models and the LULC change analysis contributed to understanding current and future species
distribution. The LULC changes will have a significant impact on future species distribution. To
prevent the extinction of this endemic species in the future, it is crucial to implement conservation
measures, namely species monitoring, replantation, and germplasm conservation, in addition to
guidelines for habitat conservation.
Co-inoculation with Staphylococcus equorum and Lactobacillus sakei reduces vasoactive biogenic amines in traditional dry-cured sausages
Publication . Dias, Igor; Laranjo, Marta; Potes, Maria Eduarda; Agulheiro-Santos, Ana Cristina; Ricardo-Rodrigues, Sara; Fialho, Ana Rita; Véstia, Joana; Fraqueza, Maria J.; Oliveira, Margarida; Elias, Miguel
Dry-cured sausages are traditional in Mediterranean countries, and Paio do Alentejo (PA)
is one of the most popular in South Portugal. The aim of the present work was to evaluate the effect
of combined starters on the safety and quality of PA preserving its sensory quality. Physicochemical
parameters, namely pH and water activity (aW), microbiological parameters, biogenic amines, color,
texture, and sensory attributes were assessed. Three starter cultures were used, namely Staphylococcus
equorum S2M7 and Lactobacillus sakei CV3C2, both separate and combined with the 2RB4 yeast
strain at a concentration of 106 cfu/g. Dextrose 0.25% was added to the meat batter. Starters had
a significant effect on the reduction of aW values (0.845 to 0.823). The treatment with L. sakei as
well as the co-inoculation of L. sakei with S. equorum effectively reduced the L. monocytogenes counts
to undetectable levels. Sausages co-inoculated with S. equorum S2M7/L. sakei CV3C2 showed a
significant reduction in the content of vasoactive amines, namely tryptamine (26.21 to 15.70) and
-phenylethylamine (4.80 to 3.69). Regarding texture, control PA showed higher hardness values,
and the starters promoted the cohesiveness of the batter while reducing chewiness. The studied
starters did not compromise the sensory characteristics of PA
Carrot AOX2a transcript profile responds to growth and chilling exposure
Publication . Campos, Maria Doroteia; Campos, Catarina; Nogales, Amaia; Cardoso, Hélia
Alternative oxidase (AOX) is a key enzyme of the alternative respiration, known to be
involved in plant development and in response to various stresses. To verify the role of DcAOX1 and
DcAOX2a genes in carrot tap root growth and in response to cold stress, their expression was analyzed
in two experiments: during root growth for 13 weeks and in response to a cold challenge trial of
7 days, in both cases using different carrot cultivars. Carrot root growth is initially characterized by an
increase in length, followed by a strong increase in weight. DcAOX2a presented the highest expression
levels during the initial stages of root growth for all cultivars, but DcAOX1 showed no particular
trend in expression. Cold stress had a negative impact on root growth, and generally up-regulated
DcAOX2a with no consistent effect on DcAOX1. The identification of cis-acting regulatory elements
(CAREs) located at the promoters of both genes showed putative sequences involved in cold stress
responsiveness, as well as growth. However, DcAOX2a promoter presented more CAREs related to
hormonal pathways, including abscisic acid and gibberellins synthesis, than DcAOX1. These results
point to a dual role of DcAOX2a on carrot tap root secondary growth and cold stress response
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Funders
Funding agency
Fundação para a Ciência e a Tecnologia
Funding programme
6817 - DCRRNI ID
Funding Award Number
UIDB/05183/2020