Nota Su A Cer Lobelii Ten

Summary

Acer Lobelii Ten. has often been considered as a variety of Acer platanoides, the A. clears this doubtful position and points to the characters which differentiate A. Lobelii from other similar species.

A. Lobelii and A. cappadocicum (Acer laetum), belonging to the same series Picta, have a great affinity while great differences exist in the case of A. platanoides.

A. Lobelii has thicker leaves than A. platanoides which have whole lobes, the fruits are smaller and the calix is extremely hairy, petiole red on the lower side. The twigs are covered by a very whithe bloom. The bark of adult branches is bright green in colour and smooth, sometimes with white streaks while that of A. platanoides is grey or greyish-brown.

The bark of the trunks of A. Lobelii is also smooth with few orizontal fissures and ash-white in colour, A. platanoides has instead a bark with fine vertical fissures and which is grey in colour.

The two maples differ also for some biological characters: A. Lobelii freely produces root shoots while A. platanoides does not; in the former the flowers appear at the same time as the leaves while in the latter the leaves appear after the flowers.

The vegetation area of A. Lobelii is restricted to the Mediterranean basin and it can be considered exclusive of Italy where it grows in some places in Campania, Lucania and Calabria.

The whole of the morphological, dendrological and physiological characters point to the fact that A. Lobelii Ten. can not be considered as a variety of A. platanoides but as a definite species. Furthermore A. Lobelii, as A. cappadocicum, has to be considered as a relict of the tertiary era, while A. platanoides belongs to a following period.     

Primi Dati Sull'andamento Stagionale delle Temperature del Troneo di Olivo

Abstract

Temperatures recorded in a olive-tree stem in 1961–1962. — In the Botanical Garden of Bari a temperature recorder has been placed, bearing 6 electrothermometers with platinum resistences having a sensitivity of 2,4 mm/C[ddot], with a recording approximation of 0,1 C[ddot].

The olive tree under examination is a grown-up tree, which has been pruned according to the local methode, and it belongs to a local breed named « Ogliarola leccese ».

— Five thermometers have been employed as follows: 1^rst in the air, hanging from the stem, m. 1,30, high; 2^nd into the outer bark, cm, 0,5 deep; 3^rd into the cambium, cm. 1,5 deep; 4^th into the sap-wood, cm. 6 deep; 5^th into the hearth-wood, cm. 22 deep.

— The thermometers were all placed on the east side of the stem.

— The figures and the graphs of the paper show that:

a) The whole stem of the specimen under examination has a mean temperature which is higher than that of the surrounding air.

b) The outer bark gets warmer than the air, during the day-time; during the night it gives up heat outside and inside, namely towards the stem tissues, particularly to the bark-cambium-sapwood zone, and also as far as the hearth wood zone.

c) The whole living zone of the stem (bark-cambium-sapwood) generally keeps temperature values intermediate between those of the outer bark and those of the air. The temperature values vary along the year.

d) In spring the cambium is warmer than the outer bark.

e) In winter cambium and sapwood generally have the same temperature. The temperature values recorded in this season are much lower than those of the outer bark and almost the same of those of the air.

f) The behaviour of temperature in cambium and sapwood is probably ruled by biological factors.

g) The hearth-wood keeps generally warmer than the air and cooler than other outer tissues. Its thermic rhytm is almost reversed in comparison with that of the outer tissues.

Il seems that hearth wood acts as an useful heat collector and distributor towards the living outer tissues during the diurnal and seasonal temperature remissions, at least in mild climates as that of Bari.     

The novel paclitaxel-producing system: establishment of Corylus avellana L. hairy root culture

Hazelnut (Corylus avellana L.), contains a valuable medicinal substance known as Paclitaxel®, which is one of the most effective anticancer drugs. The original plants produce negligible amount of paclitaxel; therefore, tissue culture techniques, especially hairy root culture, could be one of the most practical methods to enhance the amount of paclitaxel. The main goal of this study was to assess the induction of hairy roots in C. avellana. The effects of different strains of Agrobacterium rhizogenes including c58c1pRiA₄, K599, and 15834, and six culture media, MS (Murashige and Skoog), half-strength MS, quarter-strength MS, WPM (woody plant media), half-strength WPM, and quarter-strength WPM, were evaluated. The results showed that the maximum amounts of the rooted explants were obtained with c58c1pRiA4 strain in quarter-strength WPM medium. The investigations of explant type (leafstalk, petiole, lamina, and stem) and different propagation media (quarter-strength WPM, half-strength MS, and half-strength SH ((Schenk and Hildebrandt) medium) showed that the leafstalk was the most optimal explant for hairy root induction, and half-strength SH was the best culture medium for growth of the hairy roots in liquid medium. HPLC analyses confirmed the presence of paclitaxel (3.2 μg g⁻¹ (DW)) in hairy root extracts.

     

Culture studies on Radula flaccida Lindenb. & Gottsche

Abstract

Radula flaccida has been grown on defined inorganic media. Its growth varies with the type and concentration of the media, lower concentrations proving better than higher ones. Basile's medium supported a better growth of the liverwort than that of Diller et al., Müller's medium being least effective. The liverwort was successfully established on leaves and bark of some higher plants, thus proving that it is not ‘host’ specific with respect to leaf types and that it is not exclusively epiphyllous. Its less frequent occurrence on bark may be due to other habitat factors.     

Estimating bark thickness in natural stands of Eucalyptus

Information on bark thickness at various heights is sought to predict damage to trees by forest fires. A procedure which for natural stands of some smooth bark eucalyptus species enables the estimation of bark thickness at different heights from a single girth measurement at one metre height is discussed. The method utilizes the relationships of average girth, average bark thickness, and the regression coefficients of girth and bark thickness at given height positions, with height at one metre. The height positions are determined on a calibrating sample of about thirty trees of different sizes. Furthermore it is shown how the above information can be used to estimate bark volume, and hence bole volume, for Eucalyptus species of some commercial importance such as E. viminalis. Four species are considered: E. viminalis, E. pauciflora, E. mannifera and E. radiata.     

In vitro culture of <Emphasis Type="Italic">Taxus</Emphasis> sp.: strategies to increase cell growth and taxoid production

Interest in Taxus species has increased since paclitaxel, an anticancer drug, was isolated from the bark of Taxus brevifolia (Pacific yew) in the 1960’s. Great effort has been carried out to establish an efficient callus cultures of Taxus species. Culture media must be optimized for each Taxus species, and in general, there is no one method that guarantees success for Taxus cultures. The source of explant, culture medium composition and the growth regulators used appear to affect callus initiation and maintenance. Research effort has focused on obtaining a cell culture that exhibits good growth and a high rate of taxoid accumulation. In this sense, many strategies have been employed to stimulate taxoid production without affecting cell growth. In an attempt to scale-up cell culture, problems such us shear stress, oxygen supply and gas composition have been studied. A more detailed knowledge of the pathway and the fluxes of intermediates towards taxane accumulation will be key factors to obtain cell lines with increased taxane accumulation through metabolic engineering.     

Small Spruce Bark Beetle Ips amitinus (Eichhoff, 1872) (Coleoptera,Curculionidae: Scolytinae): a New Alien Species in West Siberia

The small spruce bark beetle Ips amitinus is a widespread species in many European countries that has been actively spreading into Northern Europe in the recent decades. In Russia, I. amitinus is present in the western, northwestern, and northern regions of the European part, with a tendency for range expansion. The species was first recognized in West Siberia in 2019 by characteristic morphological features and molecular genetic analysis. This bark beetle is abundant on Pinus sibirica in Siberian pine forests located near settlements within Tomsk and Kemerovo provinces, and is also sporadically found on the Siberian spruce Picea obovata. It colonizes the upper trunk and branches of standing and windfall trees. In the outbreak foci this bark beetle causes catastrophic drying of Siberian pines, starting from the crown top. This pattern of tree drying was noted for the first time near settlements in Yashkinsky District of Kemerovo Province in 2014, and now outbreak foci of I. amitinus exist in all the Siberian pine forests in this district. The population growth of I. amitinus was probably facilitated by dry and hot summer weather in the southeast of West Siberia during the last decade, in 2011 and 2012, and also by heavy winter snowfalls leaving numerous snapped tree branches which are easily colonized by the pest. In Tomsk Province, the most active outbreak focus of I. amitinus appeared in 2018 in the Siberian pine forest near Luchanovo and Ipatovo, following an outbreak of the Siberian moth Dendrolimus sibiricus. The invasion of I. amitinus in Siberia may increase the degradation rates not only of the gene-reserve Siberian pine forests but also of other dark coniferous stands.

     

Gradient of photosynthetic pigments in the bark and leaves of lilac (Syringa vulgaris L.)

The concentration of chlorophyll and a carotenoids in the bark of stems of different age and in the leaves of lilac (Syringa vulgaris L.) was determined. The thickness of bark changes with the age of the stems, ranging from 0.73 mm in the current-year stems to 1.22 mm in 3-year-old ones. Chlorophyll and carotenoids were present through the whole thickness of the bark, except the cork. It was found that chlorophyll and carotenoids are located mainly in the outer layer of the bark, immediately under the cork, to a depth of 400 μm. In this layer the chlorophyll a/b ratio is the highest and the content of chlorophyll is four times larger than that of carotenoids. When penetrating deeper into the bark, the content of chlorophyll and carotenoids as well as the chlorophyll a/b ratio diminishes. Investigations of the leaves showed that most of the chlorophyll is found in the palisade parenchyma, the chlorophyll a/b ratio is the highest in the upper layer. The highest concentration of chlorophyll in the bark is 0.44 mg·dm⁻² and in leaves −1.2 mg⁻²·dm⁻². The highest value of the chlorophyll a/b ratio in the bark is 3.8, and the lowest 0.5, while in the leaves it varies from 4.5 to 3.8 Low values of the chlorophyll a/b ratio are due to the shade conditions existing in the bark and they are evidence of very great differentiation of light conditions within it.     

SITE-SPECIFIC CHANGES IN THE BARK TEXTURE OF QUERCUS FALCATA MICHX. (SOUTHERN RED OAK)

A method of measuring bark texture is described. This method is used to show that bark roughness in Quercus falcata Michx. (southern red oak) increases from mesic to xeric sites. This change does not appear to be explained by variability in tree size and age, or by changes in the relative abundances of varieties falcata and pagodaefolia. We suggest that it may be due to postulated relationships between bark texture (or the associated property of outer bark thickness) and tree fire resistance, nutrient conservation or susceptibility to pathogens.     

A study of a population of birches in Glen Gairn

Summary

A small population of birches was studied with a view to measuring the rangeof morphological variation in Betula pendula Roth, and B. pubescens Ehrh. The general morphological features of crown and bark of trees in the area indicated that both species were present. A more detailed study was made of leaf and fruit characters, accepted by other investigators as being useful in discriminating between the species. It was shown that such characters varied continuously throughout the population and no tree was wholly pubescens- like or pendula-like in all characters.

The implications of these results are discussed in relation to the situation in Glen Gairn and to the general taxonomic situation of the British birches.     

ALLELOPATHIC AND HERBICIDAL EFFECTS OF EXTRACTS FROM TREE OF HEAVEN (AILANTHUS ALTISSIMA)

Mature trees of Ailanthus altissima produce one or more potent inhibitors of seed germination and seedling growth. Inhibitor activity is highest in bark, especially of roots, intermediate in leaflets, and low in wood. Crude extracts of Ailanthus root bark and leaflets corresponding to 34 and 119 mg water extractable material/L, respectively, caused 50% inhibition of cress radicle growth. Ailanthus seeds also contain one or more inhibitors. These are bound within the seed by the pericarp but diffuse into water agar when the pericarp is removed. The inhibitor(s) could readily be extracted from Ailanthus tissues with methanol, but not dichloromethane, indicating polar characteristics. Ailanthus leaflets had highest inhibitory activity during expansion in spring, whereas activity of trunk bark peaked just before emergence of leaves. This pattern suggests transport of allelochemicals from bark into new leaves. A comparison of seven plant species for sensitivity to the inhibitor(s) from Ailanthus root bark showed little selectivity, although velvetleaf was somewhat more resistant. The inhibitor(s) from Ailanthus root bark exhibited strong herbicidal effects when sprayed pre- and postemergence on plants in soil in the greenhouse. Postemergence effects were striking, with nearly complete mortality of all species, except velvetleaf, at even the lowest doses tested. The results suggest the allelochemical(s) from Ailanthus may have potential for development as natural-product herbicides.     

Characterization of the photosynthetic apparatus in cortical bark chlorenchyma of Scots pine

Winter-induced inhibition of photosynthesis in Scots pine (Pinus sylvestris L.) needles is accompanied by a 65% reduction of the maximum photochemical efficiency of photosystem II (PSII), measured as F _v/F _m, but relatively stable photosystem I (PSI) activity. In contrast, the photochemical efficiency of PSII in bark chlorenchyma of Scots pine twigs was shown to be well preserved, while PSI capacity was severely decreased. Low-temperature (77 K) chlorophyll fluorescence measurements also revealed lower relative fluorescence intensity emitted from PSI in bark chlorenchyma compared to needles regardless of the growing season. Nondenaturating SDS-PAGE analysis of the chlorophyll–protein complexes also revealed much lower abundance of LHCI and the CPI band related to light harvesting and the core complex of PSI, respectively, in bark chlorenchyma. These changes were associated with a 38% reduction in the total amount of chlorophyll in the bark chlorenchyma relative to winter needles, but the Chl a/b ratio and carotenoid composition were similar in the two tissues. As distinct from winter pine needles exhibiting ATP/ADP ratio of 11.3, the total adenylate content in winter bark chlorenchyma was 2.5-fold higher and the estimated ATP/ADP ratio was 20.7. The photochemical efficiency of PSII in needles attached to the twig recovered significantly faster (28–30 h) then in detached needles. Fluorescence quenching analysis revealed a high reduction state of Q _A and the PQ-pool in the green bark tissue. The role of bark chlorenchyma and its photochemical performance during the recovery of photosynthesis from winter stress in Scots pine is discussed.     

Cholinesterase inhibitory triterpenoids from the bark of Garcinia hombroniana

Abstract

Context: Garcinia hombroniana Pierre, known as manggis hutan in Malaysia is a rich source of xanthones and benzophenones.

Objectives: This study was aimed to isolate and characterize potential cholinesterase inhibitors from the extracts of G. hombroniana bark and investigate their interactions with the enzymes.

Materials and methods: The dichloromethane extract afforded five triterpenoids which were characterized by NMR and mass spectral techniques. Cholinesterase inhibitory assay and molecular docking were performed to get insight of the inhibitory activity and molecular interactions of the compounds. The compounds were also tested for their antioxidant capacity.

Results: The isolated triterpenoids were identified as: 2β-hydroxy-3α-O-caffeoyltaraxar-14-en-28-oic acid (1), taraxerol (2), taraxerone (3), betulin (4) and betulinic acid (5). Compound 1 was the most active dual inhibitor of both AChE and BChE. Compound 1 also showed good antioxidant activities.

Conclusion: Compound 1 had dual and moderate inhibitory activity on AChE and BChE worthy for further investigations.     

A major symbiont shift supports a major niche shift in a clade of tree-killing bark beetles

1. One small clade of bark beetles, out of thousands of species worldwide, has shifted from using phloem to using a combination of phloem and outer bark, or to completely using outer bark. 2. The shift to outer bark has been accompanied by a shift to non-typical bark beetle mutualist fungi in Entomocorticium (Basidiomycota) and Ceratocystiopsis (Ascomycota). 3. This study compared the growth and metabolic capabilities of fungi associated with a nearly phloem-independent species, Dendroctonus brevicomis, with those of mutualist fungi of Dendroctonus ponderosae, a completely phloem-colonising beetle in a sister clade associated with more typical Ascomycota in Grosmannia and Ophiostoma. 4. Only the basidiomycete associated with D. brevicomis could degrade cellulose and lignin, whereas both the ascomycete and basidiomycete could grow in outer bark. Ascomycetes associated with D. ponderosae could not degrade cellulose or lignin or grow in outer bark. 5. Beetles and fungi in these mutualisms may best be considered as co-niche constructors. For niche construction, one organism must modify a resource in a way that enhances its fitness while also influencing fitness of other organisms using the resource. Here, the beetles kill the tree, transport the fungi into the tree, and modify the woody substrate for use by the fungi. They have also evolved mycangia to ensure vertical dissemination of the fungi. In turn, the fungi modify tree tissues and provision nutrients to the host and have evolved traits that support their acquisition and transport by the beetle host in mycangia.     

Host specificity of a Brazilian mistletoe, Struthanthus aff. polyanthus (Loranthaceae), in cerrado tropical savanna

The aim of this study was to determine if the mistletoe Struthanthus aff. polyanthus shows host specificity, and if host abundance and twig architecture influence this specificity in Cerrado (senso strictu). An area of 1.3 ha of natural savanna was sampled for the occurrence of the mistletoe. The twigs of the hosts were classified as vertical or horizontal, and the bark as smooth or rough. We sampled a total of 666 trees in the study site and 118 individuals (17.7%) hosted S. aff. polyanthus. The abundance of mistletoe was significantly affected by the bark type, but not by the twigs inclination. In the cerrado, S. aff. polyanthus seems to be a generalist, with a tendency to be more common on some hosts (Kielmeyera coriacea, Pouteria ramiflora and Styrax ferrugineus), prefering that with rough bark type.     

Adverse Effects of Epiphytic Crustose Lichens upon Stem Photosynthesis and Chlorophyll of Populus tremula L.

Dry cork layer (phellem) in stems of Populus tremula transmitted 35–55 percent of incident irradiation, depending upon moisture content. A cover of crustose Lecanora lichens reduced transmission through phellem to 10 percent or less of incident irradiation. The bark contains photosynthetically active cells. Apparent quantum yield for photosynthetic O₂-evolution was 0.017 in bark covered with dry Lecanora compared with 0.070 in naked bark. The capacity for gross photosynthesis in high light (1090 μmol photons m^?2 s^?1) was reduced by 50 percent in Lecanora-covered bark. Lecanora did not reduce the ratio between variable and maximal chlorophyll a fluorescence (F_v/F_m). Chlorophyll content per unit area was similar in leaves and naked bark of Populus tremula. The chlorophyll content in the bark decreased with increasing chlorophyll content in Lecanora. Chlorophyll a/b ratio was 2.5 in the bark compared with 4.0 in leaves and in Lecanora, and the ratio decreased down the stems. The a/b ratio was 2.3 in Lecanora covered bark compared with 2.6 in naked bark. The changes in bark photosynthesis below a Lecanora crust were probably due to acclimation of bark photosynthesis to shade, since the lichen acids in the measured lichens neither suppressed photosynthetic O₂-evolution nor changed the F_v/F_m in bark disks.