Dependence of the dwarf sundew (Drosera brevifolia) on burrowing crayfish disturbance

Plant Ecology - Disturbance is necessary for the survival of most species of carnivorous plants to reduce competition and expose bare soil for germination. Historically, fire was the most...     

Structure prediction and network analysis of chitinases from the Cape sundew,Drosera capensis

BackgroundCarnivorous plants possess diverse sets of enzymes with novel functionalities applicable to biotechnology, proteomics, and bioanalytical research. Chitinases constitute an important class of such enzymes, with future applications including human-safe antifungal agents and pesticides. Here, we compare chitinases from the genome of the carnivorous plant Drosera capensis to those from related carnivorous plants and model organisms.MethodsUsing comparative modeling, in silico maturation, and molecular dynamics simulation, we produce models of the mature enzymes in aqueous solution. We utilize network analytic techniques to identify similarities and differences in chitinase topology.ResultsHere, we report molecular models and functional predictions from protein structure networks for eleven new chitinases from D. capensis, including a novel class IV chitinase with two active domains. This architecture has previously been observed in microorganisms but not in plants. We use a combination of comparative and de novo structure prediction followed by molecular dynamics simulation to produce models of the mature forms of these proteins in aqueous solution. Protein structure network analysis of these and other plant chitinases reveal characteristic features of the two major chitinase families.General significanceThis work demonstrates how computational techniques can facilitate quickly moving from raw sequence data to refined structural models and comparative analysis, and to select promising candidates for subsequent biochemical characterization. This capability is increasingly important given the large and growing body of data from high-throughput genome sequencing, which makes experimental characterization of every target impractical.     

Feeding on prey increases photosynthetic efficiency in the carnivorous sundew Drosera capensis

Backround and Aims

It has been suggested that the rate of net photosynthesis (A_N) of carnivorous plants increases in response to prey capture and nutrient uptake; however, data confirming the benefit from carnivory in terms of increased A_N are scarce and unclear. The principal aim of our study was to investigate the photosynthetic benefit from prey capture in the carnivorous sundew Drosera capensis.

Methods

Prey attraction experiments were performed, with measurements and visualization of enzyme activities, elemental analysis and pigment quantification together with simultaneous measurements of gas exchange and chlorophyll a fluorescence in D. capensis in response to feeding with fruit flies (Drosophila melanogaster).

Key Results

Red coloration of tentacles did not act as a signal to attract fruit flies onto the traps. Phosphatase, phophodiesterase and protease activities were induced 24 h after prey capture. These activities are consistent with the depletion of phosphorus and nitrogen from digested prey and a significant increase in their content in leaf tissue after 10 weeks. Mechanical stimulation of tentacle glands alone was not sufficient to induce proteolytic activity. Activities of β-D-glucosidases and N-acetyl-β-D-glucosaminidases in the tentacle mucilage were not detected. The uptake of phosphorus from prey was more efficient than that of nitrogen and caused the foliar N:P ratio to decrease; the contents of other elements (K, Ca, Mg) decreased slightly in fed plants. Increased foliar N and P contents resulted in a significant increase in the aboveground plant biomass, the number of leaves and chlorophyll content as well as A_N, maximum quantum yield (F_v/F_m) and effective photochemical quantum yield of photosystem II (Φ_PSII).

Conclusions

According to the stoichiometric relationships among different nutrients, the growth of unfed D. capensis plants was P-limited. This P-limitation was markedly alleviated by feeding on fruit flies and resulted in improved plant nutrient status and photosynthetic performance. This study supports the original cost/benefit model proposed by T. Givnish almost 30 years ago and underlines the importance of plant carnivory for increasing phosphorus, and thereby photosynthesis.     

Dynamics of long-leaved sundew Drosera intermedia populations at two extremes of a hydrological gradient

Densities of Drosera intermedia were low in two studied habitats (10–25 ramets m⁻¹), a path through a wet heath (short inundation in spring, low soil moisture in summer) and a pool edge (longlasting inundation, high soil moisture in summer). The low densities could be explained by the observed low recruitment and high adult mortality.
The low recruitment resulted from: (1) a high first year mortality of the large number of seedlings that emerged each year in the path population, caused by summer drought and cover with algae after heavy rainfall; (2) the absence in two years out of three of seedling emergence at the pool edge, due to the longlasting inundation. In neither population any seedlings survived to flower; (3) low vegetative reproduction rate.
Adult mortality during the growing season was caused by drought, which did not occur at the pool edge. Rapid senescence in autumn, caused by summer drought on the path and by a rapid submersion after heavy rainfall at the pool edge, was associated with a high winter mortality.     

The demography of a clonal herbaceous perennial plant, the longleaved sundew Drosera intermedia, in different heathland habitats

Eight populations of longleaved sundew Drosera intermedia Hayne ramets were studied in three hydrologically and phytosociologically differing heathland habitats over a 4 yr period a pool edge, an old path through the wet heath, a seepage area At the extreme sites, with high levels of water table fluctuations (pool edge and dry path), both survival and recruitment were low, resulting in small populations The pool edge populations went extinct At the less extreme sites (wet paths and seepage area), populations were stable, but ramet and genet turnover was higher at the path sites than in the seepage area Demographic variation between populations was explained by differences in adult survival and sexual recruitment (asexual recruitment did not differ clearly), which, in turn, were related to specific biotic and abiotic factors Likely adult mortality causes were summer drought (all habitats), winter frost (path habitat), cover with a crust of iron bacteria after heavy summer rainfall (seepage area) and shading by Sphagnum and algae (pool edge) Low seedhng recruitment was caused by a low germination succes (pool, seepage area) and seedling survival (seepage area, dry path)     

The reproductive behaviour of a clonal herbaceous plant, the longleaved sundew Drosera intermedia, in different heathland habitats

The reproductive behaviour of the longleaved sundew Drosera intermedia Hayne was studied in three hydrologically differing heathland habitats a pool edge, an old path through the wet heath and a seepage area
Sexual reproductive allocation (SRA) (the slope of the regression of sexual biomass on vegetative biomass m a given season) differed strongly between years (related to temperature and precipitation) and habitats Averaged over years, path plants had a higher SRA than plants in the seepage area and at the pool edge
Asexual reproductive allocation, expressed as the size-dependent probability of reproducing asexually, did not differ between habitats in most years
The observations agreed with general life history theory SRA was high in the path habitat where adult survival chances were low and juvenile (= seed, first year seedling) survival was high SRA was lower in the seepage area where adult survival chances were higher and juvenile survival lower At the pool edge, a habitat with high adult mortality and low juvenile establishment, the predicted optimal reproductive behaviour, a high SRA, was not observed due to environmental constraints (inundation)     

Biotic versus abiotic pollination in Oeceoclades maculata (Lindl.) Lindl. (Orchidaceae)

Geographical variation in the reproductive biology of widespread species often occurs at their distributional boundaries. We sought to determine whether such variation has occurred in an invasive orchid, Oeceoclades maculata, across its naturalized range. We compared its reproductive biology in a Brazilian population with that published for a population on the Caribbean island of Puerto Rico. In the state of São Paulo, O. maculata flowers between December and February, at the height of the rainy season. Similar fruit sets were observed in manual self (76%) and cross (70.4%) pollination treatments. The fruit set of plants protected from both pollinators and rainfall was 6.1%, whereas plants exposed only to rainfall had a fruit set of 41.4%, slightly less than the controls (48.3%). Like the Puerto Rico population, reproduction is primarily through rain‐assisted autogamy, but unlike observations made on the island, outcrossing can eventually occur. We observed two butterfly species (Heliconius ethilla narcaea and Heliconius erato phyllis) pollinating O. maculata. Secretory epidermal cells and trichomes of the spur lumen produced 0.7 µL of 25% (sucrose equivalents) nectar per flower each morning, which was stored in a dilated basal portion of the spur and reabsorbed by the afternoon. Thus, geographical variation in reproductive biology exists across the broad invasive range of O. maculata.     

Phenological growth stages of loquat tree (Eriobotrya japonica (Thunb.) Lindl.)

Conservation, characterisation and utilisation of minor fruit tree species is an important objective for diversification of agro-food production. One such fruit tree is the loquat, a tree that originated in China but is well adapted to the Mediterranean area. The conservation and utilisation of suitable germplasm requires an accurate characterisation and evaluation of the material. A first step in characterisation is to use phenotypic traits. This paper describes the phenological growth stages of loquat tree using the extended BBCH scale. Seven principal growth stages (PGS) for bud, leaf and shoot development, inflorescence emergence, flowering, fruit development and fruit maturity and 31 secondary growth stages are described and compared with a previous scale based on Fleckinger classical methodology. An example of application of the extended BBCH scale for characterisation of loquat cultivars from IVIA germplasm collection is reported.     

Tentacles of in vitro-grown round-leaf sundew (<Emphasis Type="Italic">Drosera rotundifolia</Emphasis>L.) show induction of chitinase activity upon mimicking the presence of prey

Induction of plant-derived chitinases in the leaves of a carnivorous plant was demonstrated using aseptically grown round-leaf sundew (Drosera rotundifolia L.). The presence of insect prey was mimicked by placing the chemical inducers gelatine, salicylic acid and crustacean chitin on leaves. In addition, mechanical stirring of tentacles was performed. Chitinase activity was markedly increased in leaf exudates upon application of notably chitin. Application of gelatine increased the proteolytic activity of leaf exudates, indicating that the reaction of sundew leaves depends on the molecular nature of the inducer applied. In situ hybridization of sundew leaves with a Drosera chitinase probe showed chitinase gene expression in different cell types of non-treated leaves, but not in the secretory cells of the glandular heads. Upon induction, chitinase mRNA was also present in the secretory cells of the sundew leaf. The combined results indicate that chitinase is likely to be involved in the decomposition of insect prey by carnivorous plants. This adds a novel role to the already broad function of chitinases in the plant kingdom and may contribute to our understanding of the molecular mechanisms behind the ecological success of carnivorous plants in nutritionally poor environments.     

Identification of S-genotypes in Chinese cherry cultivars (Prunus pseudocerasus Lindl.)

Self-incompatibility has been studied extensively at the molecular level in Solanaceae, Rosaceae, and Scrophulariaceae, all of which exhibit gametophytic self-incompatibility. In the present study, we successfully isolated nine S-RNase alleles from cultivars of Chinese cherry by PCR amplification from genomic DNA and stylar cDNA combining with cleaved amplified polymorphic sequence marker. Analysis of amino acid sequences revealed five novel S-alleles, S ₂ , S ₄ , S ₆ , S ₈ , and S ₉ , with respective accession numbers in the NCBI database of EF541168, EF541173, EF541172, FJ628598, and FJ628599. Results showed that “Dongtang” and “Yinzhu” contained six S-alleles (S ₁ , S ₃ , S ₅ , S ₇ , S ₈ , and S ₉ ); “Taishanganying” contained four S-alleles (S ₁ , S ₂ , S ₄ , and S ₆ ); “Daiba”, “Dayingzui”, and “Xiaomizi” contained four S-alleles (S ₁ , S ₂ , S ₅ , and S ₈ ); “Laiyangduanzhi”, “Shuangquanchangba”, and “Daqingye” contained three S-alleles (S ₁ , S ₂ , and S ₈ ). It is interesting that different cultivars collected from the same place hold the same S-genotypes. Moreover, pollination tests and pollen tube growth assays showed that nine cultivars were self-compatible. Chinese cherry presented in this article are naturally polyploidy, which is a very useful material for the study of self-compatibility, and much of this information will be valuable for further work on self-(in)compatibility of fruit tree in Rosaceae.     

绵枣儿叶片植株再生体系的建立

1 植物名称 绵枣儿[Scilla scilloides（Lindl.） Druce]。     

Changes in terpene production following nitrogen fertilization of grand fir (Abies grandis (Dougl.) Lindl.) seedlings

Summary Of ten terpenes that comprise most of the volatiles of grand fir foliage only four were affected by addition of nitrogen. Levels of beta-phellandrene, camphene and bornyl acetate and terpinolene were significantly reduced with nitrogen added to the equivalent amount of 44.8 g/m². A quantity of 22.4 g/m² did not affect terpene production. Several populations were examined and these did not respond consistently on a regional basis, yet a significant interaction effect was apparent between treatment and local population response. Overall, total yield of terpenes as a function of fertilization was not altered.     

Mycorrhizal colonization and macronutrient status of cliff-edge Thuja occidentalis and Acer saccharum

This work was done to determine if suppressed growth of stunted old-growth Thuja occidentalis along Niagara Escarpment cliff edges was associated with low concentrations of tissue macronutrients and/or the absence of mycorrhizae, and if the restriction of Acer saccharum from cliff edges could be due to similar limitations Mycorrhizal colonization rates and foliar concentrations of N, P, K, Ca, and Mg were compared between the cliff face, cliff edge, deciduous forest and a swamp for T occidentalis , and between the cliff edge and deciduous forest for A saccharum There were statistically significant differences in tissue nutrient concentrations and mycorrhizal colonization between species but not among habitats This suggests that the stunted growth of T occidentalis on the cliff face, and the absence of A saccharum from the cliff edge are not due to limitations imposed by macronutrients or lack of mycorrhizae     

Development of microsatellite markers from loquat, Eriobotrya japonica (Thunb.) Lindl

Loquat (Eriobotrya japonica) is a minor fruit which has become an interesting alternative into the European fruit industry. This interest resulted in a loquat germplasm collection established at the Instituto Valenciano de Investigaciones Agrarias, Valencia, Spain. Currently, it is the main reservoir of this species outside Asia. We developed and characterized the first 21 polymorphic microsatellite loci from a CT/AG-enriched loquat genomic library. The observed heterozygosity ranged between 0.20 and 1.00, expected heterozygosity ranged between 0.17 and 0.81, three markers were multilocus and eight loci departed significantly from Hardy-Weinberg equilibrium. These markers will facilitate diversity and genetic studies into the species.     

In vitro propagation and secondary product production by Merwilla plumbea (Lindl.) Speta

Merwilla plumbea is a popular but threatened traditional medicinal plant sold at herbal markets in South Africa. It produces bioactive compounds and contributes to Traditional African Medical systems for the treatment of various diseases. Due to high demand, the plant is recommended for commercial cultivation. We investigated in vitro propagation and secondary compound production in in vitro cultures of M. plumbea, cultivated on Murashige and Skoog (Physiol Plant 15:473–497, 1962) medium supplemented with various plant growth regulators [PGRs: adenine sulphate (Ads), benzyladenine (BA), 2-isopentenyladenine (2iP), meta-topolin (mT), meta-topolin riboside (mTR), thidiazuron (TDZ), kinetin (Kin) and naphthaleneacetic acid (NAA)] and organic elicitors [casein hydrolysate (CH), glutamine (GM), haemoglobin (HB), mebendazole (MBZ), trimethoprim (TMP), yeast extract (YE) and yeast malt broth (YMB)]. A combination of 20?μM GM, 0.45?μM TDZ and 0.054?μM NAA produced the highest number of adventitious shoots per explant (30.6 shoots/explant) after 12?weeks of culture. The regenerated shoots were rooted and the plantlets successfully acclimatized. The total phenolic, flavonoid, gallotannin and condensed tannin contents were determined. The highest levels of flavonoids (50.97?μg CTE/g in shoots) and gallotannins (99.55?μg GAE/g in shoots) were recorded in combinations of 200?mg?l^?1 YE, 0.45?μM TDZ and 0.054?μM NAA and 100?mg?l^?1 YMB, 0.45?μM TDZ and 0.054?μM NAA. These increases were around 3- to 16-fold higher than in naturally-grown plants. This system offers the possibility to use in vitro culture techniques for mass propagation, secondary metabolite and pharmacological studies.     

拟蝶唇兰的组织培养

1植物名称拟蝶唇兰【Psychopsis papilio（Lind1．）H．G．Jones】。 2材料类别幼芽。 3培养条件（1）原球茎诱导培养基：MS＋6-BA2．0mg．L^-1（单位下同）＋NAA0．5：（2）丛生芽诱导及增殖培养基：1g．L。花宝1号＋2g．L。花宝2号＋6-BA2．0＋NAA0．05＋100g．L^-2香蕉汁（花宝1号和花宝2号由美国Hyponex化学公司生产,     

Characterisation of microsatellite markers isolated from Bossiaea ornata (Lindl.) Benth. (Papilionaceae)

Bossiaea ornata is a member of the pea family that occurs in the forest understorey of south-western Australia. We constructed a genomic library and developed eight polymorphic loci to assess genetic variability and structure within the species. Polymorphism was investigated for these markers in 20 individuals from a single population located in the jarrah forest. Expected heterozygosity ranged from 0.765 to 0.889 with a mean of 0.842, and observed heterozygosity ranged from 0.550 to 0.900 with a mean of 0.742. The number of alleles per locus ranged from 7 to 16 and averaged 11.9.     

Water Permeability of the Wood of Grand Fir (Abies grandis (Doug.) Lindl.) in Relation to Infestation by the Balsam Woolly Aphid, Adelges piceae (Ratz.)

The water permeability of sapwood and heartwood of Abies grandis(Doug.) Lindl. was found for normal trees and those infestedby balsam woolly aphid Adelges Piceae (Ratz.). It was determinedas the rate of flow of water through plugs of the wood of standarddimensions and under constant suction. The permeability of normaltrees was less in the inner than the outer sapwood and thisdifference was correlated with a greater void space (gas-filledtracheids) in the inner sapwood. The permeability of the heartwoodwas less than 5 per cent that of the sapwood. Aphid infestationreduced the permeability of the outer sapwood to about the samelevel as normal heartwood. The infested wood had a high percentageof void space and again permeability was negatively correlatedwith void space. But for a given level of void space the infestedwood had a much lower permeability than normal wood. This suggeststhat there was factor additional to the air in the tracheids,which contributed to the low permeability of infested wood.The possible nature of this factor is briefly discussed.