Skip to main content

Paulo de Oliveira

Universidade de Évora, Biologia, Faculty Member

Followers

223

Following

6

Co-author

1

Public Views

Born in 1960 and raised in Lisbon, Portugal.
Degree in Biology, University of Lisbon, Portugal, 1983.
Graduate student at the ETH-Zürich, Switzerland, 1984-1986.
Graduate student at the University of Porto, Portugal, 1988-1993.
Guest Assistant at CESPU, Porto, 1991-1992.
Assistant at the Biology Department, University of Évora, Portugal, 1993-2006.
Assistant Professor, ibidem, since 2006.
Current activity: Teaching Genetics, Molecular Biology, Evolution, Developmental Biology. Research on Ectomycorrhizas, Mycology, Human Biology, Pedagogy.
Address: University of Évora, Biology Department
Mitra Campus
Apartado 94
7002-554 ÉVORA
Portugal

less

Escuela Nacional de Antropologia e Historia

Guadalupe Sanchez

Instituto Nacional de Antropología e Historia

Instituto Nacional de Antropología e Historia

Ana Fabiola Guzman Camacho

Joaquin Arroyo-Cabrales

Juan Ignacio Macias Quintero

Universidad Autónoma de Aguascalientes

University of Southampton

Guillermo Acosta Ochoa

UNAM Universidad Nacional Autónoma de México

InterestsView All (10)

Uploads

Papers by Paulo de Oliveira

Evidence of human occupation in Mexico around the Last Glacial Maximum

Nature, 2020

Mycorrhiza-Like Structures in Rooted Microshoots of Pinus Pinea L

IV International Symposium on Acclimatization and Establishment of Micropropagated Plants, 2010

Peninsula, being Portugal the largest edible seed producer in the world. The induction and improv... more Peninsula, being Portugal the largest edible seed producer in the world. The induction and improvement of in vitro rhizogenesis of microshoots of Pinus pinea was developed in our laboratory using a co-culture system with ECM fungi. In the acclimation phase in mixed substrates, or in rhizotrons, anatomical and morphological studies were done to observe the evolution of the root system in microshoots from the co-culture system vs. control plants. Extensive dichotomous and coralloid branching of lateral roots occurred spontaneously in inoculated and control plants as well. Moreover, similar branching occurred in liquid culture of excised seedling roots without the presence of ECM fungi. The striking similarity of these organs with pine ectomycorrhizas prompted their anatomical analysis; however the presence of Hartig net was not confirmed. These results suggested that the development of ECM-like structures might have occurred spontaneously.

Adventitious rooting of conifers: influence of physical and chemical factors

Trees, 2010

In conifers, vegetative propagation of superior genotypes is the most direct means for making lar... more In conifers, vegetative propagation of superior genotypes is the most direct means for making large genetic gains, because it allows a large proportion of genetic diversity to be captured in a single cycle of selection. There are two aims of vegetative propagation, namely large-scale multiplication of select genotypes and production of large numbers of plants from scarce and costly seed that originates from controlled seed orchard pollinations. This can be achieved, in some species, either through rooted cuttings or rooted microshoots, the latter regenerated through tissue culture in vitro. Thus far, both strategies have been used but often achieved limited success mainly because of difficult and inefficient rooting process. In this overview of technology, we focus on the progress in defining the physical and chemical factors that help the conifer cuttings and microshoots to develop adventitious roots. These factors include plant growth regulators, carbohydrates, light quality, temperature and rooting substrates/media as major variables for development of reliable adventitious rooting protocols for different conifer species.

Sustained in vitro root development obtained in Pinus pinea L. inoculated with ectomycorrhizal fungi

Forestry, 2003

Stone pine (Pinus pinea L.) is an economically important forest tree in Mediterranean climates an... more Stone pine (Pinus pinea L.) is an economically important forest tree in Mediterranean climates and has been the target for selection efforts through micropropagation. Previous attempts on microshoots, derived from mature seed cotyledons, reached incipient rooting after induction with a combination of auxin and hypertonic shock, but their development in vitro was not sustained. At this stage, co-culturing plantlets with some fungi isolated from ectomycorrhizas succeeded in overcoming this barrier, enabling satisfactory development in vermiculite and later in soil. About half of the fungal isolates tested helped the plants resume root growth. Although control plants (in the absence of fungi) developed roots at a later stage, i.e. during the post-transplanting acclimation in vermiculite, their growth was weaker. The root systems of some inoculated plants had ectomycorrhizas from the introduced fungi being carried over when the plants were transferred from the co-cultures to vermiculite. In conclusion, co-culturing rooted microshoots with ectomycorrhizal fungi can be an effective means to overcome the difficulties encountered in the use of micropropagation methods on this species.

Hybrids between cork oak and holm oak: Isoenzyme analysis

International Journal of Forest Genetics (For. Gen.), 2003

Hybrids between cork oak and holm oak occur in a large range of overlap between these two species... more Hybrids between cork oak and holm oak occur in a large range of overlap between these two species in Portugal, and the subsequent crosspollination involving the hybrids and cork oak has been postulated to result in some of the worst cork-producing trees in Portugal. A methodological framework was set for the routine large scale detection of hybrid genotypes using isoenzyme analysis. The effectiveness of isoenzyme markers enabling the discrimination of the hybrid trees from both parent species was probed on the ...

Hybrids between cork oak and holm oak: Isoenzyme analysis

by Carola Meierrose and Paulo de Oliveira

International Journal of Forest Genetics (For. Gen.), 2003

Hybrids between cork oak and holm oak occur in a large range of overlap between these two species... more Hybrids between cork oak and holm oak occur in a large range of overlap between these two species in Portugal, and the subsequent crosspollination involving the hybrids and cork oak has been postulated to result in some of the worst cork-producing trees in Portugal. A methodological framework was set for the routine large scale detection of hybrid genotypes using isoenzyme analysis. The effectiveness of isoenzyme markers enabling the discrimination of the hybrid trees from both parent species was probed on the ...

Mushroom Poisoning (editors translation of the original 'Intoxicação por ingestão de cogumelos' in Portuguese)

The diversity of toxicity syndromes caused by mushroom inges-tion entails, on one hand, a many-si... more The diversity of toxicity syndromes caused by mushroom inges-tion entails, on one hand, a many-sided and flexible approach to diagnosis that can benefit from any information obtained from the patients or company, and on the other hand, a need to identify, in collaboration with mycologists, the causative species. The known syndromes are systematised and a proposal is made for the implementation of detailed enquiries that standardise the information. A model form to serve as starting point for the design of such enquiries is included.

Adventitious rooting of conifers: influence of physical and chemical factors

Abstract In conifers, vegetative propagation of superior genotypes is the most direct means for m... more Abstract In conifers, vegetative propagation of superior genotypes is the most direct means for making large genetic gains, because it allows a large proportion of genetic diversity to be captured in a single cycle of selection. There are two aims of vegetative propagation, namely large-scale multiplication of select genotypes and production of large numbers of plants from scarce and costly seed that originates from controlled seed orchard pollinations.

Mycorrhiza-like Structures in Rooted Microshoots of Pinus pinea L.

Abstract: Pinus pinea L.(stone pine) is one of the major plantation species in Iberian Peninsula,... more Abstract: Pinus pinea L.(stone pine) is one of the major plantation species in Iberian Peninsula, being Portugal the largest edible seed producer in the world. The induction and improvement of in vitro rhizogenesis of microshoots of Pinus pinea was developed in our laboratory using a co-culture system with ECM fungi. In the acclimation phase in mixed substrates, or in rhizotrons, anatomical and morphological studies were done to observe the evolution of the root system in microshoots from the co-culture system vs.

A Study on Intoxications Caused by Macrofungi in the Alto Alentejo Region (congress proceedings)

The present communication reports on the first results aiming at the knowledge on poisoning with ... more The present communication reports on the first results aiming at the knowledge on poisoning with macrofungi in Alto Alentejo, and the respective causes. As starting point, cases classified as this type of poisoning, in the Emergency Service of the Espírito Santo Hospital (Évora) archives, were studied. Based on the clinical files, provisional determinations of possible intoxication syndromes were made, and then complemented by enquiries with the patients, from which an identification of the poisoning species was attempted, along with the recording of similar occurrences and possible informants. The diagnoses based on the clinical files could thus be confirmed, clarified or even corrected. Most of the analysed occurrences were associated with the consumption of Amanita ponderosa Mal. & Heim and generally produced the phalloid syndrome through the co-ingestion of A. verna (Bull.:Fr.)Lamark. The enquiries also allowed the recording of customs of collection and consumption of macrofungi in general

Opportunity for hybridization between two oak species in mixed stands as monitored by the timing and intensity of pollen production

The opportunity of cross-pollination in mixed stands of two oak species (cork oak and holm oak) w... more The opportunity of cross-pollination in mixed stands of two oak species (cork oak and holm oak) was studied by characterizing individual phenologies of flowering. In the spring of 1998 at one stand consisting of 64 marked trees, there was a period of 19 days when maximal pollen release in one species and stigma receptivity in the other occurred simultaneously, enabling interspecific gene flow in either direction. This happened in spite of an average time separation of 22 days between the two species, reflecting a considerable intraspecific variation in the timings of flowering. Flowering intensities (as estimated from male flower abundance) were high, but fruiting intensities were comparatively low. Shortly after pollination, considerable abortion of female flowers and early fruits was recorded. In 2000, the interspecific overlap of phenologies was drastically reduced due to a delay in cork oak flowering. On the other hand, the individual timings were repeatable for most trees, at least in holm oak. Two other mixed stands were subject of parallel studies, with similar results in all traits except for a less dramatic reduction in fruiting intensities. In spite of the high opportunity for cross-pollination in 1998, and given the lack of hybrids among the progenies from the subsequent fruiting season (Oliveira et al., 2003. For. Gen. 10: 283), it can be concluded that the prerequisite of cross-pollination is clearly insufficient for hybridization to succeed. Post-pollination processes must play an important role in the maintenance of reproductive isolation between the two species.

Intoxicação por ingestão de cogumelos (Mushroom poisoning)

The diversity of toxicity syndromes caused by mushroom ingestion entails, on one hand, a many-sid... more The diversity of toxicity syndromes caused by mushroom ingestion entails, on one hand, a many-sided and flexible approach to diagnosis that can benefit from any information obtained from the patients or company, and on the other hand, a need to identify, in collaboration with mycologists, the causative species. The known syndromes are systematised and a proposal is made for the implementation of detailed enquiries that standardise the information. A model form to serve as starting point for the design of such enquiries is included.

Adventitious rooting of conifers (review)

In conifers, vegetative propagation of superior genotypes is the most direct means for making lar... more In conifers, vegetative propagation of superior genotypes is the most direct means for making large genetic gains, because it allows a large proportion of genetic diversity to be captured in a single cycle of selection. There are two aims of vegetative propagation, namely large-scale multiplication of select genotypes and production of large numbers of plants from scarce and costly seed that originates from controlled seed orchard pollinations. This can be achieved, in some species, either through rooted cuttings or rooted microshoots, the latter regenerated through tissue culture in vitro. Thus far, both strategies have been used but often achieved limited success mainly because of difficult and inefficient rooting process. In this overview of technology, we focus on the progress in defining the physical and chemical factors that help the conifer cuttings and microshoots to develop adventitious roots. These factors include plant growth regulators, carbohydrates, light quality, temperature and rooting substrates/media as major variables for development of reliable adventitious rooting protocols for different conifer species.

Macrofungi Diversity As a Measure of Comparison Between Different Modes of Forest Exploitation (congress proceedings)

Studies on the diversity of macrofungi in forest ecosystems are hindered by the erratic fruiting ... more Studies on the diversity of macrofungi in forest ecosystems are hindered by the erratic fruiting behaviour of many species and by disturbances arising in the required long periods of observation. The present study is a first implementation of a comparative approach based on the parallel observation of stands representative of different forest models (oak grove, either seminatural, with agriculture or with herd grazing, pine woods, mixed oak-pine). From the sampling of 94 species during Spring and Autumn 2003 in the Chamusca county, it appeared that the diversity of macrofungi was relatively low in the stands with agriculture or grazing - the latter practically without fruiting by ectomycorrhizal species, which were predominant in all other models. The mixed stands did not present sporophores characteristic of pine, appearing rather as a replicate of the seminatural groves. Most species were not shared between forest models, which suggests that a greater number of stands, in the short run, may allow a more efficient sampling of the existing diversity

Hybrids between cork oak and holm oak: Isoenzyme analysis

Hybrids between cork oak and holm oak occur in a large range of overlap between these two species... more Hybrids between cork oak and holm oak occur in a large range of overlap between these two species in Portugal, and the subsequent crosspollination involving the hybrids and cork oak has been postulated to result in some of the worst cork-producing trees in Portugal. A methodological framework was set for the routine large scale detection of hybrid genotypes using isoenzyme analysis. The effectiveness of isoenzyme markers enabling the discrimination of the hybrid trees from both parent species was probed on the nursery-grown progenies derived from reference "pure" populations, selected mixed stands and hybrid individuals. No spontaneous hybrid was detected among 1141 seedlings originating in the mixed stands, thus suggesting that the incidence of hybridization is quite low. The seedlings derived from 3 hybrids confirmed that the discriminant isoenzyme loci recombined and segregated the parental types, and a strong preference for mating with cork oak in two of these hybrids was suggested. A substantial increase of the fixation index F within a single generation for the polymorphic cork oak phosphoglucose isomerase locus may indicate that a significant proportion of seedlings derive from short-range pollen, a factor that might weigh on the formation of hybrids between these two species.

Sustained in vitro root development obtained in Pinus pinea inoculated with ectomycorrhizal fungi

Stone pine (Pinus pinea L.) is an economically important forest tree in Mediterranean climates an... more Stone pine (Pinus pinea L.) is an economically important forest tree in Mediterranean climates and has been the target for selection efforts through micropropagation. Previous attempts on microshoots derived from mature seed cotyledons reached incipient rooting after induction with a combination of auxin and hypertonic shock, but their development in vitro was not sustained. At this stage, co-culturing plantlets with fungi isolated from ectomycorrhizas succeeded in overcoming this barrier, enabling the satisfactory development in vermiculite and later in soil. About half of the fungal isolates tested helped the plants resume root growth. Although control plants (in the absence of fungi) were found to develop roots during the post transplanting acclimation in vermiculite, their growth was weaker. The root systems of some inoculated plants had ectomycorrhizas from the introduced fungi being carried over when the plants were transferred from the co-cultures to vermiculite. In conclusion, co-culturing rooted microshoots with ectomycorrhizal fungi can be an effective means to overcome the difficulties encountered in the use of micropropagation methods on this species.

Inbreeding in Plants (in Portuguese)

This review of inbreeding in plants analyses the (genealogical) concept of identity by descent an... more This review of inbreeding in plants analyses the (genealogical) concept of identity by descent and the computation of relationship coefficients, followed by the two perspectives for the F parameter as measure of inbreeding at the population level: as a coefficient of fixation measuring the distortion, in relation to the Hardy-Weinberg model, of genotype distributions in real populations, due to the fact that they are finite; and as correlation between gametes, where the compensatory effects of other factors (such as mutation, migration and selection) on gene fixation can also be taken into account, sometimes resulting in genotype distributions, in finite populations, that mimic those predicted by that model. An example of the computation of genetic identity and diversity in populations is included. The genetic and physiological bases for inbreeding depression (the decrease in fitness often observed in inbred individuals) are analysed, and the implications of this knowledge on the management of genetic resources and plant breeding are addressed.

Arabidopsis thaliana in Genetics Teaching (in Portuguese)

Preâmbulo Morfologia e fisiologia Genética Formulário e protocolos

Inventory of ectomycorrhizal fungi associated with a «relic» holm-oak tree (Quercus rotundifolia) in two successive winters

Holm-oak (Quercus rotundifolia), either as forests or as seminatural stands (the "montado" system... more Holm-oak (Quercus rotundifolia), either as forests or as seminatural stands (the "montado" systems), occupies a vast area of land in Portugal, forming an important ecological and economical reserve that remains very little studied. A «relic» tree of this species, left from a montado stand that was replaced by cereals decades ago and now surrounded by Eucalyptus globulus, was visited during two winter carpophore fruiting seasons to scrutinize the ectomycorrhizal species associated with its root system. The sampled sporophores were identified and mapped relative to the oak trunk. Of thirty nine different higher fungi that have been tentatively identified after four gatherings, twenty nine were probably ectomycorrhizal. Russula sp. (a total of ten species) dominated in the first gathering of each season while Lactarius cremor and Helvella lacunosa dominated in the second of the first and second season, respectively. Practically none of the holm oak-associated mutualistic or facultative species were found in the surrounding Eucalyptus plantation. This study will be continued and extended to other locations in the long term, in order to provide data on the ecology of the holm oak ectomycorrhizal associates and to support the molecular identification of fungal isolates obtained from holm oak ectomycorrhizas.

Evidence of human occupation in Mexico around the Last Glacial Maximum

Nature, 2020

Mycorrhiza-Like Structures in Rooted Microshoots of Pinus Pinea L

IV International Symposium on Acclimatization and Establishment of Micropropagated Plants, 2010

Peninsula, being Portugal the largest edible seed producer in the world. The induction and improv... more Peninsula, being Portugal the largest edible seed producer in the world. The induction and improvement of in vitro rhizogenesis of microshoots of Pinus pinea was developed in our laboratory using a co-culture system with ECM fungi. In the acclimation phase in mixed substrates, or in rhizotrons, anatomical and morphological studies were done to observe the evolution of the root system in microshoots from the co-culture system vs. control plants. Extensive dichotomous and coralloid branching of lateral roots occurred spontaneously in inoculated and control plants as well. Moreover, similar branching occurred in liquid culture of excised seedling roots without the presence of ECM fungi. The striking similarity of these organs with pine ectomycorrhizas prompted their anatomical analysis; however the presence of Hartig net was not confirmed. These results suggested that the development of ECM-like structures might have occurred spontaneously.

Adventitious rooting of conifers: influence of physical and chemical factors

Trees, 2010

In conifers, vegetative propagation of superior genotypes is the most direct means for making lar... more In conifers, vegetative propagation of superior genotypes is the most direct means for making large genetic gains, because it allows a large proportion of genetic diversity to be captured in a single cycle of selection. There are two aims of vegetative propagation, namely large-scale multiplication of select genotypes and production of large numbers of plants from scarce and costly seed that originates from controlled seed orchard pollinations. This can be achieved, in some species, either through rooted cuttings or rooted microshoots, the latter regenerated through tissue culture in vitro. Thus far, both strategies have been used but often achieved limited success mainly because of difficult and inefficient rooting process. In this overview of technology, we focus on the progress in defining the physical and chemical factors that help the conifer cuttings and microshoots to develop adventitious roots. These factors include plant growth regulators, carbohydrates, light quality, temperature and rooting substrates/media as major variables for development of reliable adventitious rooting protocols for different conifer species.

Sustained in vitro root development obtained in Pinus pinea L. inoculated with ectomycorrhizal fungi

Forestry, 2003

Stone pine (Pinus pinea L.) is an economically important forest tree in Mediterranean climates an... more Stone pine (Pinus pinea L.) is an economically important forest tree in Mediterranean climates and has been the target for selection efforts through micropropagation. Previous attempts on microshoots, derived from mature seed cotyledons, reached incipient rooting after induction with a combination of auxin and hypertonic shock, but their development in vitro was not sustained. At this stage, co-culturing plantlets with some fungi isolated from ectomycorrhizas succeeded in overcoming this barrier, enabling satisfactory development in vermiculite and later in soil. About half of the fungal isolates tested helped the plants resume root growth. Although control plants (in the absence of fungi) developed roots at a later stage, i.e. during the post-transplanting acclimation in vermiculite, their growth was weaker. The root systems of some inoculated plants had ectomycorrhizas from the introduced fungi being carried over when the plants were transferred from the co-cultures to vermiculite. In conclusion, co-culturing rooted microshoots with ectomycorrhizal fungi can be an effective means to overcome the difficulties encountered in the use of micropropagation methods on this species.

Hybrids between cork oak and holm oak: Isoenzyme analysis

International Journal of Forest Genetics (For. Gen.), 2003

Hybrids between cork oak and holm oak occur in a large range of overlap between these two species... more Hybrids between cork oak and holm oak occur in a large range of overlap between these two species in Portugal, and the subsequent crosspollination involving the hybrids and cork oak has been postulated to result in some of the worst cork-producing trees in Portugal. A methodological framework was set for the routine large scale detection of hybrid genotypes using isoenzyme analysis. The effectiveness of isoenzyme markers enabling the discrimination of the hybrid trees from both parent species was probed on the ...

Hybrids between cork oak and holm oak: Isoenzyme analysis

by Carola Meierrose and Paulo de Oliveira

International Journal of Forest Genetics (For. Gen.), 2003

Hybrids between cork oak and holm oak occur in a large range of overlap between these two species... more Hybrids between cork oak and holm oak occur in a large range of overlap between these two species in Portugal, and the subsequent crosspollination involving the hybrids and cork oak has been postulated to result in some of the worst cork-producing trees in Portugal. A methodological framework was set for the routine large scale detection of hybrid genotypes using isoenzyme analysis. The effectiveness of isoenzyme markers enabling the discrimination of the hybrid trees from both parent species was probed on the ...

Mushroom Poisoning (editors translation of the original 'Intoxicação por ingestão de cogumelos' in Portuguese)

The diversity of toxicity syndromes caused by mushroom inges-tion entails, on one hand, a many-si... more The diversity of toxicity syndromes caused by mushroom inges-tion entails, on one hand, a many-sided and flexible approach to diagnosis that can benefit from any information obtained from the patients or company, and on the other hand, a need to identify, in collaboration with mycologists, the causative species. The known syndromes are systematised and a proposal is made for the implementation of detailed enquiries that standardise the information. A model form to serve as starting point for the design of such enquiries is included.

Adventitious rooting of conifers: influence of physical and chemical factors

Abstract In conifers, vegetative propagation of superior genotypes is the most direct means for m... more Abstract In conifers, vegetative propagation of superior genotypes is the most direct means for making large genetic gains, because it allows a large proportion of genetic diversity to be captured in a single cycle of selection. There are two aims of vegetative propagation, namely large-scale multiplication of select genotypes and production of large numbers of plants from scarce and costly seed that originates from controlled seed orchard pollinations.

Mycorrhiza-like Structures in Rooted Microshoots of Pinus pinea L.

Abstract: Pinus pinea L.(stone pine) is one of the major plantation species in Iberian Peninsula,... more Abstract: Pinus pinea L.(stone pine) is one of the major plantation species in Iberian Peninsula, being Portugal the largest edible seed producer in the world. The induction and improvement of in vitro rhizogenesis of microshoots of Pinus pinea was developed in our laboratory using a co-culture system with ECM fungi. In the acclimation phase in mixed substrates, or in rhizotrons, anatomical and morphological studies were done to observe the evolution of the root system in microshoots from the co-culture system vs.

A Study on Intoxications Caused by Macrofungi in the Alto Alentejo Region (congress proceedings)

The present communication reports on the first results aiming at the knowledge on poisoning with ... more The present communication reports on the first results aiming at the knowledge on poisoning with macrofungi in Alto Alentejo, and the respective causes. As starting point, cases classified as this type of poisoning, in the Emergency Service of the Espírito Santo Hospital (Évora) archives, were studied. Based on the clinical files, provisional determinations of possible intoxication syndromes were made, and then complemented by enquiries with the patients, from which an identification of the poisoning species was attempted, along with the recording of similar occurrences and possible informants. The diagnoses based on the clinical files could thus be confirmed, clarified or even corrected. Most of the analysed occurrences were associated with the consumption of Amanita ponderosa Mal. & Heim and generally produced the phalloid syndrome through the co-ingestion of A. verna (Bull.:Fr.)Lamark. The enquiries also allowed the recording of customs of collection and consumption of macrofungi in general

Opportunity for hybridization between two oak species in mixed stands as monitored by the timing and intensity of pollen production

The opportunity of cross-pollination in mixed stands of two oak species (cork oak and holm oak) w... more The opportunity of cross-pollination in mixed stands of two oak species (cork oak and holm oak) was studied by characterizing individual phenologies of flowering. In the spring of 1998 at one stand consisting of 64 marked trees, there was a period of 19 days when maximal pollen release in one species and stigma receptivity in the other occurred simultaneously, enabling interspecific gene flow in either direction. This happened in spite of an average time separation of 22 days between the two species, reflecting a considerable intraspecific variation in the timings of flowering. Flowering intensities (as estimated from male flower abundance) were high, but fruiting intensities were comparatively low. Shortly after pollination, considerable abortion of female flowers and early fruits was recorded. In 2000, the interspecific overlap of phenologies was drastically reduced due to a delay in cork oak flowering. On the other hand, the individual timings were repeatable for most trees, at least in holm oak. Two other mixed stands were subject of parallel studies, with similar results in all traits except for a less dramatic reduction in fruiting intensities. In spite of the high opportunity for cross-pollination in 1998, and given the lack of hybrids among the progenies from the subsequent fruiting season (Oliveira et al., 2003. For. Gen. 10: 283), it can be concluded that the prerequisite of cross-pollination is clearly insufficient for hybridization to succeed. Post-pollination processes must play an important role in the maintenance of reproductive isolation between the two species.

Intoxicação por ingestão de cogumelos (Mushroom poisoning)

The diversity of toxicity syndromes caused by mushroom ingestion entails, on one hand, a many-sid... more The diversity of toxicity syndromes caused by mushroom ingestion entails, on one hand, a many-sided and flexible approach to diagnosis that can benefit from any information obtained from the patients or company, and on the other hand, a need to identify, in collaboration with mycologists, the causative species. The known syndromes are systematised and a proposal is made for the implementation of detailed enquiries that standardise the information. A model form to serve as starting point for the design of such enquiries is included.

Adventitious rooting of conifers (review)

In conifers, vegetative propagation of superior genotypes is the most direct means for making lar... more In conifers, vegetative propagation of superior genotypes is the most direct means for making large genetic gains, because it allows a large proportion of genetic diversity to be captured in a single cycle of selection. There are two aims of vegetative propagation, namely large-scale multiplication of select genotypes and production of large numbers of plants from scarce and costly seed that originates from controlled seed orchard pollinations. This can be achieved, in some species, either through rooted cuttings or rooted microshoots, the latter regenerated through tissue culture in vitro. Thus far, both strategies have been used but often achieved limited success mainly because of difficult and inefficient rooting process. In this overview of technology, we focus on the progress in defining the physical and chemical factors that help the conifer cuttings and microshoots to develop adventitious roots. These factors include plant growth regulators, carbohydrates, light quality, temperature and rooting substrates/media as major variables for development of reliable adventitious rooting protocols for different conifer species.

Macrofungi Diversity As a Measure of Comparison Between Different Modes of Forest Exploitation (congress proceedings)

Studies on the diversity of macrofungi in forest ecosystems are hindered by the erratic fruiting ... more Studies on the diversity of macrofungi in forest ecosystems are hindered by the erratic fruiting behaviour of many species and by disturbances arising in the required long periods of observation. The present study is a first implementation of a comparative approach based on the parallel observation of stands representative of different forest models (oak grove, either seminatural, with agriculture or with herd grazing, pine woods, mixed oak-pine). From the sampling of 94 species during Spring and Autumn 2003 in the Chamusca county, it appeared that the diversity of macrofungi was relatively low in the stands with agriculture or grazing - the latter practically without fruiting by ectomycorrhizal species, which were predominant in all other models. The mixed stands did not present sporophores characteristic of pine, appearing rather as a replicate of the seminatural groves. Most species were not shared between forest models, which suggests that a greater number of stands, in the short run, may allow a more efficient sampling of the existing diversity

Hybrids between cork oak and holm oak: Isoenzyme analysis

Hybrids between cork oak and holm oak occur in a large range of overlap between these two species... more Hybrids between cork oak and holm oak occur in a large range of overlap between these two species in Portugal, and the subsequent crosspollination involving the hybrids and cork oak has been postulated to result in some of the worst cork-producing trees in Portugal. A methodological framework was set for the routine large scale detection of hybrid genotypes using isoenzyme analysis. The effectiveness of isoenzyme markers enabling the discrimination of the hybrid trees from both parent species was probed on the nursery-grown progenies derived from reference "pure" populations, selected mixed stands and hybrid individuals. No spontaneous hybrid was detected among 1141 seedlings originating in the mixed stands, thus suggesting that the incidence of hybridization is quite low. The seedlings derived from 3 hybrids confirmed that the discriminant isoenzyme loci recombined and segregated the parental types, and a strong preference for mating with cork oak in two of these hybrids was suggested. A substantial increase of the fixation index F within a single generation for the polymorphic cork oak phosphoglucose isomerase locus may indicate that a significant proportion of seedlings derive from short-range pollen, a factor that might weigh on the formation of hybrids between these two species.

Sustained in vitro root development obtained in Pinus pinea inoculated with ectomycorrhizal fungi

Stone pine (Pinus pinea L.) is an economically important forest tree in Mediterranean climates an... more Stone pine (Pinus pinea L.) is an economically important forest tree in Mediterranean climates and has been the target for selection efforts through micropropagation. Previous attempts on microshoots derived from mature seed cotyledons reached incipient rooting after induction with a combination of auxin and hypertonic shock, but their development in vitro was not sustained. At this stage, co-culturing plantlets with fungi isolated from ectomycorrhizas succeeded in overcoming this barrier, enabling the satisfactory development in vermiculite and later in soil. About half of the fungal isolates tested helped the plants resume root growth. Although control plants (in the absence of fungi) were found to develop roots during the post transplanting acclimation in vermiculite, their growth was weaker. The root systems of some inoculated plants had ectomycorrhizas from the introduced fungi being carried over when the plants were transferred from the co-cultures to vermiculite. In conclusion, co-culturing rooted microshoots with ectomycorrhizal fungi can be an effective means to overcome the difficulties encountered in the use of micropropagation methods on this species.

Inbreeding in Plants (in Portuguese)

This review of inbreeding in plants analyses the (genealogical) concept of identity by descent an... more This review of inbreeding in plants analyses the (genealogical) concept of identity by descent and the computation of relationship coefficients, followed by the two perspectives for the F parameter as measure of inbreeding at the population level: as a coefficient of fixation measuring the distortion, in relation to the Hardy-Weinberg model, of genotype distributions in real populations, due to the fact that they are finite; and as correlation between gametes, where the compensatory effects of other factors (such as mutation, migration and selection) on gene fixation can also be taken into account, sometimes resulting in genotype distributions, in finite populations, that mimic those predicted by that model. An example of the computation of genetic identity and diversity in populations is included. The genetic and physiological bases for inbreeding depression (the decrease in fitness often observed in inbred individuals) are analysed, and the implications of this knowledge on the management of genetic resources and plant breeding are addressed.

Arabidopsis thaliana in Genetics Teaching (in Portuguese)

Preâmbulo Morfologia e fisiologia Genética Formulário e protocolos

Inventory of ectomycorrhizal fungi associated with a «relic» holm-oak tree (Quercus rotundifolia) in two successive winters

Holm-oak (Quercus rotundifolia), either as forests or as seminatural stands (the "montado" system... more Holm-oak (Quercus rotundifolia), either as forests or as seminatural stands (the "montado" systems), occupies a vast area of land in Portugal, forming an important ecological and economical reserve that remains very little studied. A «relic» tree of this species, left from a montado stand that was replaced by cereals decades ago and now surrounded by Eucalyptus globulus, was visited during two winter carpophore fruiting seasons to scrutinize the ectomycorrhizal species associated with its root system. The sampled sporophores were identified and mapped relative to the oak trunk. Of thirty nine different higher fungi that have been tentatively identified after four gatherings, twenty nine were probably ectomycorrhizal. Russula sp. (a total of ten species) dominated in the first gathering of each season while Lactarius cremor and Helvella lacunosa dominated in the second of the first and second season, respectively. Practically none of the holm oak-associated mutualistic or facultative species were found in the surrounding Eucalyptus plantation. This study will be continued and extended to other locations in the long term, in order to provide data on the ecology of the holm oak ectomycorrhizal associates and to support the molecular identification of fungal isolates obtained from holm oak ectomycorrhizas.