Three shelf-derived boulders in debris flow conglomerates of the Downes Point Member of the Shallow Bay Formation of western Newfoundland yielded the first record of an Upper Cambrian shelf-margin ...trilobite fauna from the Elvinia Zone (Steptoean; Jiangshanian) in eastern North America. The fauna is dominated by the "catillicephalid" Buttsia Wilson, 1951, and resembles trilobite biofacies from microbial buildups in the Gatesburg Formation of Pennsylvania. It is correlative with the Cliffia latagenae Subzone, which is the youngest Steptoean biostratigraphic unit in the Gatesburg. New taxa are Triorygma burkhalteri gen. et sp. nov. and Buttsia trema sp. nov.
From a fresh root of
Trema guineensis
(Ulmaceae), endophytic fungi were isolated, among which a taxon belonging to the new species
Diaporthe cameroonensis
. This strain was fermented in shake flask ...batch cultures and the broth was extracted with ethyl acetate. From the crude extract, a hemiketal polyketide
1
, and an acetylated alternariol
2
were isolated, along with fifteen known secondary metabolites. Their structures were established by extensive NMR spectroscopy and mass spectrometry analyses, as well as by comparison with literature data of their analogs.
Nodule symbiosis with diazotrophic Frankia or rhizobium occurs in plant species belonging to ten taxonomic lineages within the related orders Fabales, Fagales, Cucurbitales, and Rosales. Phylogenomic ...studies indicate that this nitrogen-fixing nodulation trait has a single evolutionary origin. In legume model plants, the molecular interaction between plant and rhizobium microsymbiont is mapped to a significant degree. A specific LysM-type receptor kinase, LjEPR3 in Lotus japonicus and MtLYK10 in Medicago truncatula, was found to act in a secondary identity-based mechanism, controlling intracellular rhizobium infection. Furthermore, LjEPR3 showed to bind surface exopolysaccharides of Mesorhizobium loti, the diazotrophic microsymbiont of L. japonicus. EPR3 orthologous genes are not unique to legumes. Surprisingly, however, its ortholog EXOPOLYSACCHARIDE RECEPTOR (EPR) is pseudogenized in Parasponia, the only lineage of non-legume plants that nodulate also with rhizobium.
Analysis of genome sequences showed that EPR3 orthologous genes are highly conserved in nodulating plants. We identified a conserved retrotransposon insertion in the EPR promoter region in three Parasponia species, which associates with defected transcriptional regulation of this gene. Subsequently, we studied the EPR gene of two Trema species as they represent the sister genus of Parasponia for which it is assumed it lost the nitrogen-fixing nodulation trait. Both Trema species possess apparently functional EPR genes that have a nodulation-specific expression profile when introduced into a Parasponia background. This indicates the EPR gene functioned in nodulation in the Parasponia-Trema ancestor.
We conclude that nodule-specific expression of EPR3 orthologous genes is shared between the legume and Parasponia-Trema lineage, suggesting an ancestral function in the nitrogen-fixing nodulation trait. Pseudogenization of EPR in Parasponia is an exceptional case in nodulating plants. We speculate that this may have been instrumental to the microsymbiont switch -from Frankia to rhizobium- that has occurred in the Parasponia lineage and the evolution of a novel crack entry infection mechanism.
To clarify the mechanism underlying successful invasion by tree species into xeric sites on Japan's Bonin Islands, we compared the water use of an alien species, Psidium cattleianum, which is rapidly ...expanding on ridge sites with shallow soil, with that of a native species, Trema orientalis. We hypothesized that there is a trade-off between leaf shedding with low cavitation resistance (frequent xylem cavitation plus refilling ability) and leaf osmotic adjustment with high cavitation resistance (cessation of xylem cavitation plus canopy leaf retention), indicating contrasting strategies for drought tolerance and water use in semi-arid regions. We examined leaf turnover, leaf gas exchange, leaf water potential and water distribution in stem xylem conduits using cryo-scanning electron microscopy for the saplings of both species under three cycles of artificial drought and sudden pulse irrigation. Invasive P. cattleianum saplings were highly resistant to cavitation in stem xylem conduits, retained their leaves and exhibited effective leaf osmotic adjustment under the drought treatment. In contrast, native T. orientalis saplings exhibited xylem cavitation, conspicuous leaf shedding and less effective leaf osmotic adjustment under the drought treatment. Leaf gas exchange rate recovered more rapidly in P. cattleianum saplings than in T. orientalis saplings immediately following pulse irrigation after a period without irrigation, especially in the first drought cycle. Embolized conduits in T. orientalis were refilled by pulse irrigation, and leaf gas exchange rate recovered following refilling. The two tree species showed contrasting strategies for drought tolerance and water use along a trade-off axis. Cavitation avoidance and effective leaf osmotic adjustment in P. cattleianum saplings under drought conditions partially support their survival at the xeric ridge sites on the Bonin Islands. Our results help to explain the success of P. cattleianum in its invasion of a sub-arid environment.
► Presence of vitamins B1, B2, B6 and PP (vitamers) in dried bee pollen samples. ► Food with high protein value. ► Quality of the bee pollen.
We investigated the concentration of B complex vitamins ...(B1, B2, B6 and PP) including their vitamers, physicochemical composition and botanical origin of dried bee pollen samples from the State of São Paulo, Brazil. The possible influence of pollen types on the proximate composition and vitamin content was also verified. Vitamins, after simultaneous extraction, were quantified by HPLC, with fluorescence detection. The results showed a great concentration difference of B complex vitamins in the samples analyzed. The variations were (dry basis): 0.59–1.09mg/100g for vitamin B1; 1.73–2.56mg/100g for vitamin B2; 6.43–15.34mg/100g for vitamin PP and 0.33–0.68mg/100g for vitamin B6. All samples were considered sources of vitamin B2. For the proximate composition, this was not observed, and the results were: 3.47±0.30% for moisture; 2.98±0.18% for ash; 5.39±0.60% for lipids and 23.38±1.24% for protein. The frequency of the plant families presented showed a total of 10 significant pollen types: Arecaceae, Cecropia, Cestrum, Cyperaceae, Eucalyptus, Ilex, Myrcia, Piper, Vernonia and Trema. The data analyzed served as an indication of the nutritional quality and value for commercial dried bee pollen.
Cannabaceae is a known family because of the production of cannabinoids in laticifers and glandular trichomes of
Cannabis sativa
. Laticifers are latex-secreting structures, which in Cannabaceae were ...identified only in
C. sativa
and
Humulus lupulus
. This study aimed to expand the knowledge of laticifers in Cannabaceae by checking their structural type and distribution, and the main classes of substances in the latex of
Celtis pubescens
,
Pteroceltis tatarinowii
, and
Trema micrantha
. Such information is also updated for
C. sativa
. Samples of shoot apices, stems, leaves, and flowers were processed for anatomical, histochemical, ultrastructural, and cytochemical analyses. Laticifers are articulated unbranched in all species instead of non-articulated as previously described for the family. They occur in all sampled organs. They are thick-walled, multinucleate, with a large vacuole and a peripheral cytoplasm. The cytoplasm is rich in mitochondria, endoplasmic reticulum, dictyosomes, ribosomes, and plastids containing starch grains and oil drops. Pectinase and cellulase activities were detected in the laticifer wall and vacuole, confirming its articulated origin, described by first time in the family. These enzymes promote the complete dissolution of the laticifer terminal walls. The latex contains proteins, lipids, and polysaccharides in addition to phenolics (
C. sativa
) and terpenes (
C. pubescens
,
T. micrantha
)
.
The presence of laticifers with similar distribution and morphology supports the recent insertion of
Celtis
,
Pteroceltis
, and
Trema
in Cannabaceae. The articulated type of laticifer found in Cannabaceae, Moraceae, and Urticaceae indicates that the separation of these families by having distinct laticifer types should be reviewed.
In tropical forests, pioneer tree species regenerate from seeds dispersed directly into canopy gaps and from seeds that persisted in soil seed banks before gap formation. Life‐history models have ...suggested that selection for the long‐term persistence of tree seeds in the soil should be weak because persistence potentially reduces population growth rate by extending generation time and because adult life spans may exceed the return interval of favorable recruitment sites. Here we use accelerator mass spectrometry to carbon‐date seeds of three pioneer tree species extracted from undisturbed seed banks in seasonally moist lowland Neotropical forest. We show that seeds ofCroton billbergianus,Trema micrantha, andZanthoxylum ekmanniigerminate successfully from surface soil microsites after 38, 31, and 18 years, respectively. Decades‐long persistence may be common in large‐seeded tropical pioneers and appears to be unrelated to specific regeneration requirements.
Weeds are one of the main obstacles in the recovery of degraded areas. This research aimed to study the selectivity of herbicides on Trema micrantha (Jamaican nettletree), Schinus molle (Peruvian ...peppertree), and Apuleia leiocarpa (garapeira) seedlings. An experiment was installed in Junqueirópolis and another in Jaboticabal/SP, Brazil. The experimental design used was completely randomized design with four replications. Treatments consisted of clethodim + fenoxaprop-p-ethyl (50 + 50 g a.i. ha-1), sethoxydim (184 g a.i. ha-1), quizalofop-p-ethyl (75 g a.i. ha-1), nicosulfuron (50 g a.i. ha-1), fluazifop-p-butyl (125 g a.i. ha-1), fomesafen (225 g a.i. ha-1), haloxyfop-methyl (48 g a.i. ha-1), bentazon (720 g a.i. ha-1), chlorimuron-ethyl (15 g a.i. ha-1), and control without herbicide. The analyzed characteristics were stem diameter, plant height, and phytointoxication at 7, 14, 21, 28, 35, and 42 days after herbicide application (DAA), in addition to shootdry matter accumulation in seedlings at the end of the study. Nicosulfuron and chlorimuron-ethyl caused intoxication in all the studied tree species. In Jaboticabal, these herbicides impaired the initial growth of Jamaican nettletree seedlings, while no herbicide delayed its initial development in Junqueirópolis.A similar result was obtained regarding dry matter accumulation for garapeira in both cities. The herbicides clethodim + fenoxaprop-p-ethyl and sethoxydim decreased dry matter accumulation in Peruvian peppertree plants in Jaboticabal and Junqueirópolis, respectively, thus not being recommendedtheir use for these species.
RESUMO: As plantas daninhas são um dos principais entraves na recuperação de áreas degradadas. O objetivo deste trabalho foi estudar a seletividade de herbicidas sobre mudas de Trema micrantha (candiúba), Schinus molle (aroeirinha) e Apuleia leiocarpa (garapeira). Foi implantado um experimento no município de Junqueirópolis-SP e outro em Jaboticabal/SP. O delineamento experimental usado foi inteiramente casualizado com quatro repetições. Os tratamentos utilizados foram (50 + 50 g i.a. ha-1): clethodim + fenoxaprop-p-ethyl, sethoxydim (184 g i.a. ha-1), quizalofop-p-ethyl (75 g i.a. ha-1), nicosulfuron (50 g i.a. ha-1), fluazifop-p-butyl (125 g i.a. ha-1), fomesafen (225 g i.a. ha-1), haloxyfop-methyl (48 g i.a. ha-1), bentazon (720 g i.a. ha-1), chlorimuron-ethyl (15 g i.a. ha-1) e controle sem herbicida. As características analisadas foram: diâmetro de caule, altura de plantas e fitointoxicação aos 7, 14, 21, 28, 35 e 42 dias após a aplicação (DAA) dos herbicidas, além do acúmulo de massa seca na parte aérea das mudas ao final do estudo. O nicosulfuron e o chlorimuron-ethyl causaram intoxicação em todas as espécies arbóreas estudadas. Em Jaboticabal, estes mesmos herbicidas prejudicaram o crescimento inicial das plantas de candiúba, enquanto em Junqueirópolis nenhum herbicida retardou o desenvolvimento inicial desta espécie. Resultado semelhante foi obtido quanto ao acúmulo de matéria seca para a espécie garapeira em ambos os municípios. Também houve redução de matéria seca em plantas de aroeirinha quando da utilização dos herbicidas (clethodim + fenoxaprop-p-ethyl) e sethoxydim, em Jaboticabal e Junqueirópolis, respectivamente, o que não permite recomendar estes herbicidas para estas arbóreas.
Drought-induced tree death has become a serious problem in global forest ecosystems. Two nonexclusive hypotheses, hydraulic failure and carbon starvation, have been proposed to explain tree die-offs. ...To clarify the mechanisms, we investigated the physiological processes of drought-induced tree death in saplings with contrasting Huber values (sapwood area/total leaf area). First, hydraulic failure and reduced respiration were found in the initial process of tree decline, and in the last stage carbon starvation led to tree death. The carbohydrate reserves at the stem bases, low in healthy trees, accumulated at the beginning of the declining process due to phloem transport failure, and then decreased just before dying. The concentrations of non-structural carbohydrates at the stem bases are a good indicator of tree damage. The physiological processes and carbon sink-source dynamics that occur during lethal drought provide important insights into the adaptive measures underlying forest die-offs under global warming conditions.
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