The dynamics of mediterranean shrubs species over 12 years following perturbations

The response of woody species to experimental burning, cutting andploughing was studied for a period of twelve years in a shrub community in NWSpain. The treatments represent the perturbations most frequently imposed bymanon these shrub communities throughout history. The response to burning is muchfaster than the response to cutting. The response to ploughing is slower due tothe regeneration mechanism that species use: germination. In general, thedominant species, Erica australis, influences theregeneration patterns of the rest of the species, which make up the community.There is a significant increase in the cover of woody species until the fourthyear, and of herbaceous species until the third year. Subsequently,Erica australis attains dominance, returning to itsoriginal spatial occupancy and cover values, removing the herbaceous speciesandnegatively influencing the growth of woody ones like Halimiumumbellatum, Halimium alyssoides and Quercuspyrenaica. Both Erica australis andChamaespartium tridentatum regenerated by sprouting in theburnt and cut plots, and by germination in the ploughed plot.Arctostaphylos uva-ursi only recovers after burning andploughing. Halimium alyssoides, Halimium umbellatum, Ericaumbellata and Calluna vulgaris regenerate bygermination in the three plots. Differences in cover values and spatialoccupancy during the first years of succession tend to be eliminated twelveyears after treatment and most of the species tend to recover their initialcover values. These shrubland communities have a high degree of resilience dueto the strong sprouting potential of the component species.     

Excised or intact inflorescences? Methodological effects on parasitoid wasp longevity

The development of accurate and repeatable experimental techniques is a cornerstone of any research program. Indeed, the first stage in developing a conservation biological control program typically involves ranking the suitability of various plant species as food resources for the target species of natural enemy in the laboratory or glasshouse. Herein the choice of flower presentation method is a highly relevant consideration. It is unclear whether excised flowers with their peduncles submerged in water will generate similar effects on the life history traits of a natural enemy compared with those using flowers remaining intact on a rooted plant. Either method has been used in 86 previous studies, yet none has quantified this effect. It is possible that both plant nectar content and production are altered as a result of changes in the physiological condition of the excised flowers. A laboratory test was designed to assess the influence of flower presentation method (excised or intact inflorescences) and different types of nectar (artificial and natural) on the longevity of the wasp Aphidius ervi, an important parasitoid of aphids. Distinct differences were revealed in the suitability of the nine flower species and three control treatments on parasitoid wasp longevity, with buckwheat being the most suitable plant. However, apart from coriander, flower presentation method and wasp gender generally did not affect parasitoid longevity for the set of species tested. As there was little evidence that parasitoid wasp longevity would be altered on excised flowers, and because of reasons pertaining to improved logistical and experimental requirements, the use of excised flowers is cautiously recommended to researchers for further laboratory evaluations of the effects of nectar provision on parasitoid fitness.     

保鲜剂对夏季香石竹切花衰老的延缓作用

香石竹切花瓶插期间花瓣中ＳＯＤ和蛋白质在前期上升,然后比处理组提前３天呈下降趋势。采后花瓣中ＣＡＴ、可溶性总糖和蔗糖均为下降。经由蔗糖、８－羟基喹啉和植物生长调节剂或钴镍盐组成的保鲜剂能延缓切花花瓣中ＳＯＤ、ＣＡＴ活性的下降,阻碍蛋白质、可溶性总糖和蔗糖的降解速度,同时使切花的瓶插寿命延长、含水量增加。     

New evidence for hominin carcass processing strategies at 1.5 Ma, Koobi Fora, Kenya

Reconstruction of early Pleistocene hominin carcass acquisition and processing behaviors are necessarily based at least in part on butchered fossil bones. This paper provides zooarchaeological and taphonomic analyses and behavioral interpretations of three approximately 1.5 million-year-old archaeofaunas from areas 1A and 103 in the Okote Member of the Koobi Fora Formation, northern Kenya: FwJj14A, FwJj14B, and GaJi14. These sites are all located in similar paleoenvironmental contexts, near shallow water with swampy, seasonally flooded areas, and some evidence for more wooded or gallery forest settings. Both individual specimen--and assemblage-level analyses of butchery-marked bones indicate that the hominins appear to have practiced similar butchery strategies at all of these sites, with butchery (defleshing, disarticulation, and marrow extraction) of both high- and low-ranked skeletal elements with no apparent preference for prey size, skeletal region, limb class, or limb portion. Only four tooth-marked specimens, including one likely crocodile-tooth-marked bone, are preserved in all three archaeofaunas. A paucity of limb epiphyses suggests that bone-crunching hyenids may have deleted these portions subsequent to hominin butchery. Strangely, there are no stone tools preserved with the 292 cut-marked and 27 percussion-marked faunal specimens (out of a total of 6,039 specimens), suggesting that raw material availability may have conditioned hominin lithic discard patterns at these locales. These assemblages increase our knowledge of the dietary behavior and ecology of Homo erectus, and provide support for variability in early Pleistocene hominin carcass foraging patterns.     

Relationship between cavitation and water uptake in rose stems

Cavitation in rose stems ( Rosa hybrida L.) was assessed in both intact plants and excised flowers, by measurement of ultrasonic acoustic emissions at the stem surface and determination of the air-conductivity of 2.5-cm segments that were attached at one end to air at low pressure (0.01 MPa). On sunny days the stems of intact rose plants showed acoustic emissions and conductivity to air, starting early in the morning. In Cara Mia and Sonia rose plants the cavitations were repaired during the late afternoon; in Madelon plants this repair only occurred overnight. Water flow was seriously impaired in stems of Cara Mia roses cut around midday, on sunny days.
During dehydration of cut roses in air the onset of a high rate of acoustic emissions coincided with a low rate of water uptake when stems were subsequently placed in water. High emission frequency occurred after 2.4 ± 0.7 h, 6.8 ± 4.3 h and 19.8 ± 9.0 h of exposure to air in Cara Mia, Madelon and Sonia roses, respectively. A low rate of water uptake in excised stems placed in water was found after 3–4, 9–12 and 24–36 h of desiccation in air, respectively. The onset of the high emission frequency corresponded with a water potential of −1.7, −2.9 and −3.8 MPa in the three cultivars, respectively.
It is concluded that a high number of cavitations may occur in noncut stems of rose plants, leading to low water uptake immediately after excision, depending on the weather and the cultivar, and that the low rate of water uptake after a period of dry storage, among the three rose cultivars investigated, is correlated with the presence of a high number of cavitated xylem elements.     

烯效唑(S-3307)对非洲菊切花保鲜的影响

以非洲菊(GerberajamesoniiBolus)切花为材料,以保鲜基本液(BP,20gL-1蔗糖 200mgL-1柠檬酸 150mgL-18-羟基喹啉柠檬酸盐)和添加30mgL-1烯效唑(S-3307)的基本液(BP S-3307)作对比实验,通过对切花外部形态观察和切花衰老过程中一些生理生化指标测定,探讨了S-3307对非洲菊切花的保鲜效果。结果表明,S-3307处理使切花的瓶插寿命比对照(蒸馏水)延长了4.3d,比BP处理延长了2.3d,而弯颈率分别仅为对照和BP处理的9.6%和28.8%。说明S-3307可增强切花的吸水能力,增加花枝的鲜重,延缓了切花花瓣中蛋白质的降解和抗氧化酶SOD和CAT活性的下降,并减少了游离脯氨酸和MDA的积累,维持膜结构的相对稳定性,从而延缓了非洲菊切花的衰老和提高了切花瓶插期间的观赏品质。     

Funerary practices of the Iberomaurusian population of Taforalt (Tafoughalt, Morocco, 11–12,000 BP): the case of Grave XII

The Iberomaurusian necropolis of Taforalt (Morocco, 11-12000 BP), excavated by Roche in the 1950s, contains 28 multiple graves. The funerary practices of the Taforalt population have been the focus of a previous work (Mariotti et al., 2009). In the absence of the excavation records of the necropolis, these funerary practices were investigated through the analysis of the contents of each grave and the distribution of intentionally modified specimens (ochre-dyeing, cut marks). Previous research has drawn particular attention to Grave XII (containing three male adults and two juveniles), where many intentionally modified specimens were identified. The present study focused specifically on the human remains recovered from Grave XII. Analysis of these remains has provided evidence of interventions, such as dismemberment and defleshing of the cadaver, and the use of ochre to colour the bones. Furthermore, the presence of lesions on two skulls suggests the possibility of intentional killing and cannibalism among the Taforalt population. This study further supports our previous impression of the complex and diversified funerary practices, characterising the social life of the Iberomaurusian population of Taforalt.     

Laboratory acetylene reduction assay for relative measurement of N2-fixing activities associated with field-grown wetland rice plants

Summary A short-term laboratory acetylene reduction assay using cut plant-soil samples incubated in the dark was developed for measuring relative N₂-fixing activities associated with field-grown rice plants. The assay sample consists of rhizosphere soil, root, and cut stem and leaf sheath. The cut plant-soil assay is relatively simple, rapid, and convenient; it reduces, if not eliminates, the problems encountered in whole-plant (field, pot, and water culture) and excised roots assays. Varietal differences in N₂-fixing activity were detected with the new assay technique.