Clerodane diterpenoids from the roots of Portulaca pilosa

Three trans-clerodane diterpenoids, pilosanol A, B and C, the last compound being a glucoside, have been isolated from the roots of Portulaca pilosa. They show a marked contrast in skeletal type with the constituents of aerial part. Evolutionary changes in the biosynthetic abilities of Portulaca species is discussed.     

Protective effect of Agrimonia pilosa polysaccharides on dexamethasone‐treated MC3T3‐E1 cells via Wnt/β‐Catenin pathway

A water‐soluble polysaccharide (APP‐AW) was isolated from Agrimonia pilosa and prepared to three sulphated derivatives (S1, S2 and S3). The results showed that pre‐treatment with APP‐AW, S1, S2 and S3 each at the concentration of 50 μg/mL for 48 hours was able to prevent cytotoxicity induced by 1 μmol/L dexamethasone (Dex) in MC3T3‐E1 cells via inhibition of apoptosis, which is in line with the findings in flow cytometry analysis. Meanwhile, the decreased ALP activity, collagen content, mineralization, BMP2, Runx2, OSX and OCN protein expression in DEX‐treated MC3T3‐E1 cells were reversed by the addition of APP‐AW, S1, S2 and S3. Moreover, APP‐AW, S1, S2 and S3 rescued DEX‐induced increase of Bax, cytochrome c and caspase‐3 and decrease of Bcl‐2, Wnt3, β‐catenin and c‐Myc protein expression in MC3T3‐E1 cells. Our findings suggest that pre‐treatment with APP‐AW, S1, S2 and S3 could significantly protect MC3T3‐E1 cells against Dex‐induced cell injury via inhibiting apoptosis and activating Wnt/β‐Catenin signalling pathway, thus application of these polysaccharides may be a promising alternative strategy for steroid‐induced avascular necrosis of the femoral head (SANFH) therapy.     

Chemical Characterization and Phytotoxic Effects of the Aerial Parts of Ruzigrass (Urochloa ruziziensis)

Studies of the phytotoxic effects between plants can be a crucial tool in the discovery of innovative compounds with herbicide potential. In this sense, we can highlight ruzigrass (Urochloa ruziziensis), which is traditionally used in the crop rotation system in order to reduce weed emergence. The aim of this work was to characterize the secondary metabolites of ruzigrass and to evaluate its phytotoxic effects. In total, eight compounds were isolated: friedelin, oleanolic acid, α‐amyrin, 1‐dehydrodiosgenone, sitosterol and stigmasterol glycosides, tricin and p‐coumaric acid. Phytotoxic effects of the crude methanolic extract and fractions of ruzigrass were assessed using germination rate, initial seedling growth, and biomass of Bidens pilosa, Euphorbia heterophylla and Ipomoea grandifolia. Chemometric analysis discriminated the weed species into three groups, and B. pilosa was the most affected by fractions of ruzigrass. The phytotoxic activities of 1‐dehydrodiosgenone, tricin, and p‐coumaric acid are also reported, and p‐coumaric acid and 1‐dehydrodiosgenone were active against B. pilosa.     

Effects of co-cropping Bidens pilosa (L.) and Tagetes minuta (L.) on bioaccumulation of Pb in Lactuca sativa (L.) growing in polluted agricultural soils

Polluted agricultural soils are a serious problem for food safety, with phytoremediation being the most favorable alternative from the environmental perspective. However, this methodology is generally time-consuming and requires the cessation of agriculture. Therefore, the purpose of this study was to evaluate two potential phytoextractor plants (the native species Bidens pilosa and Tagetes minuta) co-cropped with lettuce growing on agricultural lead-polluted soils. The concentrations of Pb, as well as of other metals, were investigated in the phytoextractors, crop species, and in soils, with the potential risk to the health of consumers being estimated. The soil parameters pH, EC, organic matter percentage and bioavailable lead showed a direct relationship with the accumulation of Pb in roots. In addition, the concentration of Pb in roots of native species was closely related to Fe (B. pilosa, r = 0.81; T. minuta r = 0.75), Cu (T. minuta, r = 0.93), Mn (B. pilosa, r = 0.89) and Zn (B. pilosa, r = 0.91; T. minuta, r = 0.91). Our results indicate that the interaction between rhizospheres increased the phytoextraction of lead, which was accompanied by an increase in the biomass of the phytoextractor species. However, the consumption of lettuce still revealed a toxicological risk from Pb in all treatments.     

刺枝野丁香和穗花野丁香(茜草科)名称之合格发表

刺枝野丁香Leptodermis pilosa Diels var．acanthoclada Lo和穗花野丁香L．pilosa Diels vat．spicatiformis Lo发表时没指明模式,是不合格发表的名称。现通过指定模式,将它们的名称作合格发表。还对此2新变种及其近缘类群提供了分类检索表和地理分布图。     

佩妃延腹榕小蜂的产卵行为

榕树与传粉榕小蜂之间的互惠共生关系是协同进化研究领域中的热点之一。榕树除了与传粉榕小蜂共生外,它还为许多非传粉榕小蜂提供食物和生境。佩妃延腹榕小蜂Philotrypesis pilosa Mayr腹部第8～9节背板极度延伸,形似长长的产卵鞘,其后更长的才是真正的产卵鞘。它将产卵针刺入榕果的果壁,产卵于果内。该蜂是对叶榕Ficus hispida L. 的传粉榕小蜂Ceratosolen solmsi （Mayr）的盗食性寄生蜂。我们利用数码照相机记录了佩妃延腹榕小蜂产卵的全过程,详细描述了其产卵行为。发现了前人没有发现的下列行为特点： (1）当雌蜂找到合适的产卵位点时,身体呈倒立状,后足扶持产卵鞘到选定的产卵位点;2）从开始插入产卵针到产卵鞘向后弹出,腹部第8～9节背板延伸部分与产卵鞘之间有两次大幅度的靠拢与分开,第一次靠拢与分开是保证产卵针以最佳的垂直角度插入果内,第二次是使产卵鞘向后弹出,将暴露在外的产卵针顺利地插入果内;3）雌蜂产卵针沿榕果直径方向（最短距离）插入果壁;4）前足与后足比中足发达,与整个产卵过程中支撑身体的行为有关 。     

Seasonal Dynamics of Plant Diversity on lnselbergs in the Ivory Coast (West Africa)

Inselbergs are isolated monolithic outcrops which are characterized by large areas of exposed crystalline rock. Due to harsh edaphic and microclimatic conditions, inselbergs are completely differentiated from their surroundings. Consequently they host a very distinct vegetation which is being investigated on a global scale over a six year period. The seasonal dynamics of Selected plant communities (Afrotrilepis pilosa mat, shallow depression, ephemeral flush vegetation) on granitic inselbergs in the Comoe National Park (NE Ivory Coast) were studied during the rainy period from May to November 1991 by recording all vascular plant species at 12 intervals. For the habitats investigated, the seasonal vegetation dynamics were related to the rainfall pattern. Maximum values both in species diversity and richness were attained in the first third of the rainy period. Drought in August and September caused a decline in species number and diversity in the shallow depression and ephemeral flush vegetation, resulting in mortality of more than 20% of the species. The individual communities studied differed considerably in species diversity and richness. We conclude that ephemeral flush and shallow depression communities are more species rich than the mat community which is dominated by the highly competitive and specialized K-strategist Afrotrilepis pilosa (a poikilohydric Cyperaceae) due to stochastic climatic perturbations which allow the maintenance of species rich non-equilibrium assemblages with r-strategists as major components.     

Development of a positive preference–performance relationship in an oligophagous beetle: adaptive learning?

The relationship between oviposition preference and larval performance is a central topic in insect–plant biology. In this study, we investigate whether the oligophagous flea beetle, Altica fragariae Nakane (Coleoptera: Chrysomelidae), exhibits a positive preference–performance relationship, and whether oviposition preference develops over time. We tested the beetles using four sympatric plant species: Duchesnea indica (Andrews) Focke (the normal host plant), Agrimonia pilosa Ledeb. (a secondary host plant), and Potentilla chinensis Ser. and Sanguisorba officinalis L. (host plants of two related Altica species) (all Rosaceae). In no‐choice experiments, both oviposition rate and offspring fitness parameters (eclosion rate, development time, and body mass) were highest on D. indica. Oviposition rate was much lower on P. chinensis than on A. pilosa, whereas offspring fitness parameters did not differ significantly between these two host plants. Offspring fitness were lowest for S. officinalis, and adult females refused to oviposit on this acceptable non‐host in a no‐choice situation. Repeated two‐choice experiments showed that the proportion of oviposition on one of the novel host plants decreased significantly over time when the alternative host plant was D. indica. In repeated two‐choice experiments using A. pilosa and P. chinensis, females mainly fed on A. pilosa but distributed their eggs equally over the two host plants, in accordance with the lack of difference in offspring fitness on those hosts. Together, these results showed that A. fragariae females develop a positive preference–performance relationship over time. We suggest that A. fragariae achieves this through adaptive learning of oviposition preference: not only does the female learn to discriminate among the host plants when there is a fitness difference for her offspring, but the female also fails to discriminate when there is no fitness difference.     

How does the C4 grass Eragrostis pilosa respond to elevated carbon dioxide and infection with the parasitic angiosperm Striga hermonthica?

Eragrostis pilosa (Linn.) P Beauv., a C₄ grass native to east Africa, was grown at both ambient (350 μmol mol⁻¹ and elevated (700 μmol mol⁻¹) CO₂ in either the presence or absence of the obligate, root hemi-parasite Striga hermonthica (Del.) Benth. Biomass of infected grasses was only 50% that of uninfected grasses at both CO₂ concentrations, with stems and reproductive tissues of infected plants being most severely affected. By contrast, CO₂ concentration had no effect on growth of E. pilosa , although rates of photosynthesis were enhanced by 30–40% at elevated CO₂. Infection with S. hermonthica did not affect either rates of photosynthesis or leaf areas of E. pilosa , but did bring about an increase in root:shoot ratio, leaf nitrogen and phosphorus concentration and a decline in leaf starch concentration at both ambient and elevated CO₂. Striga hermonthica had higher rates of photosynthesis and shoot concentrations of soluble sugars at elevated CO₂, but there was no difference in biomass relative to ambient grown plants. Both infection and growth at elevated CO₂ resulted in an increase in the Δ¹³C value of leaf tissue of E. pilosa , with the CO₂ effect being greater. The proportion of host-derived carbon in parasite tissue, as determined from δ¹³C values, was 27% and 39% in ambient and elevated CO₂ grown plants, respectively. In conclusion, infection with S. hermonthica limited growth of E. pilosa , and this limitation was not removed or alleviated by growing the association at elevated CO₂.