Observations on the fine structure of the root nodule endophyte of Hippophaë rhamnoides L.

Summary Electron microscopy of ultra-thin sections of Hippophaë rhamnoides root nodules has been carried out in order to elucidate the nature of the endophyte. The organism is seen as a branching, septate filament approximately 0.6 microns in diameter bearing on its terminal ends spherical sub-divided vesicles 3–4 microns in diameter. In the mature nodule the vesicles are the most prominent endophyte form and appear to be formed by swelling of the hyphal tips. It is concluded that the endophyte is an actinomycete closely related to but not identical with that of Alnus glutinosa.     

The formation of vesicles in the developmental cycle of the nodular endophyte of Hippophaë rhamnoides L.

Summary The mature vesicle of the Hippophaë rhamnoides root nodule endophyte is spherical, approximately 3–4 m in diameter and exhibits a high degree of apparently random septation. Electron micrographs are presented which show that this vesicular form in the endophytic development within the host cell originates as a swelling of the hyphal tip. The young vesicle is non-septate and in general attains a minimum diameter of 3 m before septation becomes evident. The number of septa then increases with vesicle maturity.     

The of gamma-radiation for induction of apomixis in sea-buckthorn (Hippophaë rhamnoides L.)

The results of studying of the induced apomixis in pollen of sea-buckthorn irradiated by the 60Co gamma-Radiation are considered. Was established that the most effective dose for pollination of the experimental plants is 50 k Gy. In total, from 46 seedlings 19 cases of apomictic origin were revealed, 7 individuals were found to be haploid (n = = 12) and 19 ones were diploid (2n = 24) of maternal origin. Was supposed that apomictic plants (19 seedlings) have parthenogenetic origin. The reason for such conclusion is that the irradiated anomalous pollen tubes despite not having spermia, are entering embryo sac and stimulate the development of apomictic embryo from non-fertilized female gametes. Apparently, pollen tubes cause the induction of DNA replication in the ovules and the development of parthenogenetic plants. Consequently, the described method can be used for the regulation of parthenogenesis in sea-buckthorn to change natural ratio (1 : 1) of male to female plants in desirable quantity.     

Changes in Triacylglycerol Composition in Maturing Sea Buckthorn (Hippophaë rhamnoides) Seeds

Sea buckthorn (Hippophaë rhamnoides L.) seeds on the 29th, 53rd, 80th, and 107th day after pollination were used for determining, by lipase hydrolysis, the qualitative and quantitative composition of the triacylglycerol (TAG) positional types, groups, and positional species, as well as the factor of selectivity of incorporation of unsaturated fatty acids, octadecenoic, linoleic, and linolenic, into the sn-2-position of TAGs. Until the 80th day after pollination, there was a predominant formation of triunsaturated TAGs, which included linolenic and linoleic acid residues. After the 80th day, the absolute content of these major components of total TAGs markedly decreased, and an increase in total TAG content was mainly accounted for by the rise in the level of those TAG species, which included saturated fatty acids, palmitic and stearic (monosaturated–diunsaturated and disaturated–monounsaturated), as well as in the level of sn-2-octadecenoyl species belonging to the triunsaturated and palmito–diunsaturated types of TAGs. At each maturation stage, the quantitative dynamics of separate TAG species was determined by the content of fatty acid species available for TAG formation and the factor of selectivity of these species. The decrease in the content of a certain group of triunsaturated TAGs found here seems to be caused by their metabolization during seed maturation.     

Die vordringlichsten Zuchtziele bei Sanddorn (Hippophaë rhamnoides L.)

Ohne ZusammenfassungMit 9 Textabbildungen Hans Lembke zum 75. Geburtstag.     

Nematodes (Longidorus sp. andTylenchorhynchus microphasmis loof) in growth and nodulation of sea buckthorn (Hippophaë rhamnoides L.)

Summary Hippophaë rhamnoides seedlings were grown in sterilized and unsterilized soil from a decliningH. rhamnoides scrub, to which different numbers ofLongidorus sp. andTylenchorhynchus microphasmis were added. In sterilized and unsterilized soil, retardation of growth, content of dry matter in the shoots, and incidence of deformed short lateral roots of test plants were positively correlated with counts of both nematode species. Nitrogen content in the shoots, nodulation on the roots of test plants and increase increase in nematodes were negatively correlated with the initial number of both nematode species in sterilized soil. In unsterilized soil, an unknown biotic factor was present that reduces growth ofH. rhamnoides, nodulation and multiplication of the nematodes. This factor seems to interact with the nematodes in reducing growth ofH. rhamnoides.Deceased.     

Effects of dietary supplementation with sea buckthorn (Hippophaë rhamnoides) seed and pulp oils on atopic dermatitis

A placebo-controlled, double-blind study was conducted to investigate the effects of seed and pulp oils of sea buckthorn (Hipphophae rhamnoides) on atopic dermatitis. Linoleic (34%), alpha-linolenic (25%), and oleic (19%) acids were the major fatty acids in the seed oil, whereas palmitic (33%), oleic (26%), and palmitoleic (25%) acids were the major fatty acids in the pulp oil. The study group included 49 atopic dermatitis patients who took 5 g (10 capsules) of seed oil, pulp oil, or paraffin oil daily for 4 months. During follow-up dermatitis improved significantly in the pulp oil (P < 0.01) and paraffin oil (P < 0.001) groups, but improvement in the seed oil group was not significant (P = 0.11). Supplementation of seed oil increased the proportion of alpha-linolenic acid in plasma neutral lipids (P < 0.01), and increases of linoleic, alpha-linolenic, and eicosapentaenoic acids in plasma phospholipids were close to significant (0.05 < P < 0.1). Pulp oil treatment increased the proportion of palmitoleic acid (P < 0.05) and lowered the percentage of pentadecanoic acid (P < 0.01) in both plasma phospholipids and neutral lipids. In the seed oil group, after 1 month of supplementation, positive correlations were found between symptom improvement and the increase in proportions of alpha-linolenic acid in plasma phospholipids (Rs = 0.84; P = 0.001) and neutral lipids (Rs = 0.68; P = 0.02). No changes in the levels of triacylglycerols, serum total, or specific immunoglobulin E were detected. In the pulp oil group, a significant (P < 0.05) increase in the level of high density lipoprotein cholesterol, from 1.38 to 1.53 mmol/L was observed.     

Nodulation and nitrogen-fixation byHippophaë rhamnoides L. in the field

Summary 1. The extent of nodulation and nitrogen fixation by a population ofHippophaë rhamnoides bushes occurring on a sand dune system on the east coast of England has been studied.2. Nodules were found on all plants (the latter ranged from 3 to 16 years in age) and using the isotope N¹⁵ it was confirmed that these nodules fixed nitrogen. The nodules on the youngest plants were most active in fixation but because of the greater total nodule mass older plants fixed the largest quantities of nitrogen.3. Large increases in total nitrogen (i.e. soil plus plant nitrogen) occurred with increase in age of the plants, such nitrogen increases ranging from 27 kg per hectare per annum in the presence of bushes 0 to 3 years old to 179 kg per hectare per annum in the presence of bushes 13 to 16 years old.4. The N¹⁵-technique indicated that a proportion of the nitrogen accumulated was due to fixation byHippophaë but nitrogen contributions from other sources could not be ruled out.5. The levels of nitrate-nitrogen and ammonium-nitrogen in the soil underHippophaë showed a marked seasonal variation, increasing to a maximum in the winter and to a minimum in the summer. These levels were in general inversely related to the level of average monthly rainfall. Because of the low levels of combined nitrogen in the soil during the summer months it seems unlikely that combined nitrogen should markedly inhibit fixation in this situation.     

Out of the Qinghai-Tibet Plateau: evidence for the origin and dispersal of Eurasian temperate plants from a phylogeographic study of Hippophaë rhamnoides (Elaeagnaceae)

Numerous temperate plants now distributed across Eurasia are hypothesized to have originated and migrated from the Qinghai-Tibet Plateau (QTP) and adjacent regions. However, this hypothesis has never been tested through a phylogeographic analysis of a widely distributed species. Here, we use Hippopha? rhamnoides as a model to test this hypothesis. We collected 635 individuals from 63 populations of the nine subspecies of H. rhamnoides. We sequenced two maternally inherited chloroplast (cp) DNA fragments and also the bi-paternally inherited nuclear ribosomal ITS. We recovered five major clades in phylogenetic trees constructed from cpDNA and internal transcribed spacer (ITS) sequence variation. Most sampled individuals of six subspecies that are distributed in northern China, central Asia and Asia Minor/Europe, respectively, comprised monophyletic clades (or subclades) nested within those found in the QTP. Two subspecies in the QTP were paraphyletic, while the placement of another subspecies from the Mongolian Plateau differed between the ITS and cpDNA phylogenetic trees. Our phylogeographic analyses supported an 'out-of-QTP' hypothesis for H. rhamnoides followed by allopatric divergence, hybridization and introgression. These findings highlight the complexity of intraspecific evolutions and the importance of the QTP as a center of origin for many temperate plants.     

Late Quaternary history of Hippophaë rhamnoides L. (Elaeagnaceae) inferred from chalcone synthase intron (Chsi) sequences and chloroplast DNA variation

Fossil pollen records indicate that Hippophaë rhamnoides (Sea Buckthorn) was widespread on late‐ and early postglacial raw soils throughout much of central and northern Europe, but that Early Holocene reforestation restricted populations to northern coastal habitats, or along mountain streams in the Alps, Pyrenees, and Carpathians. We used sequence variation at the nuclear chalcone synthase intron (Chsi), in conjunction with chloroplast DNA–restriction fragment length polymorphism data, to investigate the intraspecific phylogeny, phylogeographic structure, and expansion demographic history of this dioecious and wind‐pollinated shrub at its range‐wide scale in Europe and Asia Minor. Four major Chsi phylogroups of unresolved relationships were identified with estimated divergences ～172 000 years ago. Large‐scale phylogeographic structures of nuclear and cytoplasmic markers were congruent in identifying (i) southeastern Europe as the most likely source of colonization into central Europe and Scandinavia, and (ii) the area just north of the Alps as a contact zone between populations from the Alps and the east/central European‐Scandinavian lineage. Coalescence‐based analyses (i.e. nested clade analysis and mismatch distributions) of Chsi variation were able to detect at least four major episodes of population growth, all within about the last 40 000 years. In particular, these analyses identified a nearly synchronized timing of population expansions in various parts of the species’ range in central‐eastern Europe/Asia Minor, most likely correlating with the Younger Dryas Stadial (～13 000–11 600 years ago). It remains to be established whether the phylogeographic history of H. rhamnoides, and particularly its rapid response to the rapid environmental changes of the Younger Dryas cold snap, is unique to the species, or whether it is shared with other cold‐tolerant shrub (or grassland) species known from late‐glacial raw soils in Europe.     

Effect of dietary supplementation with sea buckthorn (Hippophaë rhamnoides) seed and pulp oils on the fatty acid composition of skin glycerophospholipids of patients with atopic dermatitis

Sea buckthorn (Hippopha? rhamnoides) seed and pulp oils have traditionally been used for treating skin diseases in China and Russia, but are not widely used in other countries. A placebo-controlled, parallel study was carried out to investigate the effects of these oils on the fatty acid composition of skin glycerophospholipids of patients with atopic dermatitis. Sixteen patients ate 5 g of sea buckthorn seed oil, pulp oil, or paraffin oil daily for 4 months. Skin fatty acids were analyzed with gas chromatography before and after treatment. The seed oil slightly increased the proportion of docosapentaenoic acid (22:5n-3) and decreased the proportion of palmitic acid (16:0) in skin glycerophospholipids (0.05 < P < 0.1). The levels of the other fatty acids remained stable. The results show that the fatty acid composition of skin glycerophospholipids is well buffered against short-term dietary modification.     

Vesicle formation during electro-fusion of mesophyll protoplasts of Kalanchoë daigremontiana

Following electro-fusion of plant protoplasts the volume of the fused cell is the sum of the volumes of the parent cells. As shown for mesophyll protoplasts from leaves of Kalanchoë daigremontiana, the excess in membrane material arising from the reduction in membrane area is removed-at least to a larger extent — by the formation of vesicles which are visible in the light microscope. These vesicles, which may have been formed by the fusion of sub-microscopic vesicles, are observed in the contact zone of the fusing cells. The mechanism of the formation of vesicles during electro-fusion is discussed.     

Mycorrhizal improvement in non-leguminous nitrogen fixing associations with particular reference toHippophaë rhamnoides L.

Summary The roots ofHippophaë rhamnoides which regularly bear actinomycete induced nodules when growing on Scottish sand dunes have also been found to support an endomycorrhizal association withGlomus fasciculatus. Ultrastructural and cytochemical studies carried out on the indigenous infections of establishedHippophaë mycorrhizal roots would support the postulate that transport is indeed occurring between the fungal symbiont and the host plant and vice versa in respect of phosphate and carbohydrate. Experiments using various inoculation regimes, demonstrated the significant improvement in the mycorrhizal/nodulated plants compared to the nodulated-only and the mycorrhizal-only plants with respect to plant growth, uptake of phosphate and nitrogenase activity, when grown in a medium poor in combined nitrogen and soluble phosphate. Preliminary work onAlnus andMyrica species growing in Central Scotland indicates that the mycorrhizae associated with these nodulated root systems exhibit a different interaction pattern which may be dependent on habitat type and associated angiosperm species.     

Long-distance transport of signals during symbiosis: Are nodule formation and mycorrhization autoregulated in a similar way?

Legumes enter nodule symbioses with nitrogen-fixing bacteria (rhizobia), whereas most flowering plants establish symbiotic associations with arbuscular mycorrhizal (AM) fungi. Once first steps of symbiosis are initiated, nodule formation and mycorrhization in legumes is negatively controlled by a shoot-derived inhibitor (SDI), a phenomenon termed autoregulation. According to current views, autoregulation of nodulation and mycorrhization in legumes is regulated in a similar way. CLE peptides induced in response to rhizobial nodulation signals (Nod factors) have been proposed to represent the ascending long-distance signals to the shoot. Although not proven yet, these CLE peptides are likely perceived by leucine-rich repeat (LRR) autoregulation receptor kinases in the shoot. Autoregulation of mycorrhization in non-legumes is reminiscent to the phenomenon of “systemic acquired resistance” in plant-pathogen interactions.Key words: arbuscular mycorrhiza, autoregulation, CLE peptides, mutant, nodulation, split-root systemUnder natural conditions, growth of plants is often limited by the availability of nutrients such as nitrogen and phosphorous. Plants have therefore developed strategies to acquire nutrients with the help of soil microorganisms. Most land plants enter mutualistic root symbioses with arbuscular mycorrhizal (AM) fungi, whereas legumes form special root nodules containing nitrogen-fixing bacteria, so-called rhizobia.^1–4 Establishment and maintenance of symbiosis requires plant resources, such as photosynthetically assimilated carbon. To minimize these costs, host plants are able to control the degree of their symbiotic interactions. Above a critical threshold level further establishment of symbiosis is restricted—a feedback phenomenon termed autoregulation of symbiosis. Autoregulation can be experimentally demonstrated in split-root systems. When legume roots are already infected by rhizobia on one side of a split-root, further nodule development is “systemically” inhibited on the other side. Similarly, prior colonization of split-roots by AM fungi on one half suppresses later fungal root colonization on the other half. Hence, important elements of the symbiotic autoregulation circuit are not only localized in roots, but also in aerial parts of the plant, implicating transport of signals in vascular bundles (Fig. 1). Whereas autoregulation of nodulation in legumes has been studied for many decades,^5–9 the first publications clearly stating a shoot-controlled autoregulation of mycorrhization in split-root systems appeared in 2000 for the non-legume barley (Hordeum vulgare) and thereafter for alfalfa (Medicago sativa) and soybean (Glycine max).^10–13 The data from these split-root experiments are supported by the findings that supernodulating (or hypernodulating) loss-of-autoregulation mutants displayed either an increased degree of AM colonization and/or a higher abundance of arbuscules.^14–16Open in a separate windowFigure 1Proposed model of shoot-controlled autoregulation of symbiosis in a split-root system. Prior infection of root A by rhizobia or AM fungi systemically suppresses later establishment of symbiosis in root B. Expression of specific CLE peptides (and/or other peptide hormones) is induced in response to rhizobial nodulation signals (Nod factors) and perhaps also in response to colonization by AM fungi (stage 1). The CLE peptides (and/or other signals) are then presumed to be transported in the xylem to the shoot, where they are perceived by leucine-rich repeat (LRR) autoregulation receptor kinases (stage 2). As a result of autoregulation signaling in the shoot, an unknown shoot-derived inhibitor (SDI) is produced (stage 3) and transported as a phloem-mobile signal to the root. Perception and action of the SDI signal in roots would then inhibit nodulation and root colonization by AM fungi (stage 4).     

Endogenous NO levels regulate nodule functioning: Potential role of cGMP in nodule functioning?

Nitric oxide is a small gaseous signaling molecule which functions in the regulation of plant development and responses to biotic and abiotic stresses. Recently, we have shown that nitric oxide is required for development of functional nodules. Here, we show that inhibition of nitric oxide synthase enzymatic activity (using N_ω-nitro-L-arginine) reduces nitric oxide content in soybean root nodules and this is coupled by reduction of endogenous cyclic guanosine monophosphate content in the nodules. We postulate that the regulation of soybean nodule development by nitric oxide is transduced via cyclic guanosine monophosphate through activation of nitric oxide-responsive soluble guanylate cyclase. Furthermore, we hypothesize that this signaling cascade is mediated via modulation of the activities of antioxidant metabolic pathways.Key words: cyclic guanosine monophosphate, nitric oxide synthase, nitric oxide, nitrogen fixation, nodulation efficiency, nodule functioning, reactive oxygen species     

Growth,ionic balance,proton excretion,and nitrate reductase activity in Alnus and Hippophaë supplied with different sources of nitrogen

Summary Pre-cultivated, nodulated and non-nodulated plants of black alder (Alnus glutinosa) and sea buckthorn (Hippophaë rhamnoides ssp.rhamnoides) were grown on different N sources, with and without acidity control. Dry matter yields were lowest when plants were supplied with only NO ₃ ^– and were much greater when NH ₄ ⁺ was supplied either alone or in combination with NO ₃ ^– as long as the external pH was controlled; the final yields of the N₂-fixing plants were relatively low, especially withH. rhamnoides. Without acidity control, yields were greatly reduced in the presence of NH ₄ ⁺ .Proton or hydroxyl-ion effluxes, calculated on the basis of plant analyses, agreed well with measured excretion values. Without pH adjustment, the total proton efflux into the external solution was greater inA. glutinosa than inH. rhamnoides.Both species, but particularlyA. glutinosa, displayed the highest nitrate reductase activity in the roots.     

Calcium activation of macrocilia in the ctenophoreBeroë

1. Macrocilia on the lips of the ctenophore Bero? are usually quiescent, but can be activated to beat rapidly and continuously by various stimuli. 2. During feeding, macrocilia beat actively and serve to spread the lips of Bero? over its prey. 3. Vigorous, repetitive mechanical stimulation of the lips evokes widespread activation of macrocilia via a pathway that is probably neural. 4. Extracellular electrical stimulation (DC or bipolar pulse-trains) elicits immediate activation of macrocilia on lip pieces, but not on dissociated cells. 5. Macrocilia on lip pieces are activated to beat by high KCl artificial sea water (ASW), but not by high KCl Ca-free ASW. Continuous beating for long periods is also elicited by high Ca ASW or Mg-free ASW, but not by Ca-Mg-free ASW. Addition of La, Cd, Co or Mn (10 mM) to high KCl ASW reversibly blocks activation. Verapamil, D-600, nifedipine, or BAY K 8644 (10 microM) has no effect on KC1-induced activation, but the anticalmodulin drug W-7 (10 microM) reversibly inhibits beating. 6. Mild heat treatment dissociates macrociliary cells from lip tissue. Such isolated macrociliary cells usually beat continuously in normal sea water, and swim in circular paths. Ca-free ASW, or addition of Co or Mn to ASW, inhibits beating of dissociated cells. High KCl ASW activates beating of quiescent, isolated macrociliary cells. 7. Ca-Mg-free ASW inhibits beating of dissociated macrociliary cells, and return to Mg-free ASW activates motility, allowing one to activate macrocilia on isolated cells simply by addition of Ca.(ABSTRACT TRUNCATED AT 250 WORDS)     

Changes in behaviour associated with pair formation in the polychaete Harmothoë imbricata (L.)

Spacing between individuals in populations of Harmothoë imbricata has been investigated both on the shore and in the laboratory. Males tend to occur closer together than females, and the mean male‐male individual distance measured was less than the mean distance between females; male—female distances for immature worms were intermediate. When worms mature they pair: the male mounts the female and lies across her dorsal surface. There is evidence that after spawning the members of a pair separate. Contact responses between worms have been investigated in the laboratory. Most encounters between immature worms lead to separation, as a result of one or both worms moving rapidly away from the other or fighting; females show more marked avoidance behaviour than males. The majority of male‐male and female‐female encounters between mature worms also lead to separation but in male‐female encounters the male usually mounts the female. A male which has mounted a female becomes highly aggressive and will attack intruding males but not females.