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1.
Oceanic islands are productive habitats for generating new species and high endemism, which is primarily due to their geographical isolation, smaller population sizes and local adaptation. However, the short divergence times and subtle morphological or ecological divergence of insular organisms may obscure species identity, so the cryptic endemism on islands may be underestimated. The endangered weevil Pachyrhynchus sonani Kôno (Coleoptera: Curculionidae: Entiminae: Pachyrhynchini) is endemic to Green Island and Orchid Island of the Taiwan‐Luzon Archipelago and displays widespread variation in coloration and host range, thus raising questions regarding its species boundaries and degree of cryptic diversity. We tested the species boundaries of P. sonani using an integrated approach that combined morphological (body size and shape, genital shape, coloration and cuticular scale), genetic (four genes and restriction site‐associated DNA sequencing, RAD‐seq) and ecological (host range and distribution) diversity. The results indicated that all the morphological datasets for male P. sonani, except for the colour spectrum, reveal overlapping but statistically significant differences between islands. In contrast, the morphology of the female P. sonani showed minimum divergence between island populations. The populations of P. sonani on the two islands were significantly different in their host ranges, and the genetic clustering and phylogenies of P. sonani established two valid evolutionary species. Integrated species delimitation combining morphological, molecular and ecological characters supported two distinct species of P. sonani from Green Island and Orchid Island. The Green Island population was described as P. jitanasaius sp.n. Chen & Lin, and it is recommended that its threatened conservation status be recognized. Our findings suggest that the inter‐island speciation of endemic organisms inhabiting both islands may be more common than previously thought, and they highlight the possibility that the cryptic diversity of small oceanic islands may still be largely underestimated.  相似文献   
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The rise of the early intervention paradigm in psychotic disorders represents a maturing of the therapeutic approach in psychiatry, as it embraces practical preventive strategies which are firmly established in mainstream health care. Early intervention means better access and systematic early delivery of existing and incremental improvements in knowledge rather than necessarily requiring dramatic and elusive breakthroughs. A clinical staging model has proven useful and may have wider utility in psychiatry. The earliest clinical stages of psychotic disorder are non-specific and multidimensional and overlap phenotypically with the initial stages of other disorders. This implies that treatment should proceed in a stepwise fashion depending upon safety, response and progression. Withholding treatment until severe and less reversible symptomatic and functional impairment have become entrenched represents a failure of care. While early intervention in psychosis has developed strongly in recent years, many countries have made no progress at all, and others have achieved only sparse coverage. The reform process has been substantially evidence-based, arguably more so than other system reforms in mental health. However, while evidence is necessary, it is insufficient. It is also a by-product as well as a catalyst of reform. In early psychosis, we have also seen the evidence-based paradigm misused to frustrate overdue reform. Mental disorders are the chronic diseases of the young, with their onset and maximum impact in late adolescence and early adult life. A broader focus for early intervention would solve many of the second order issues raised by the early psychosis reform process, such as diagnostic uncertainty despite a clear-cut need for care, stigma and engagement, and should be more effective in mobilizing community support. Early intervention represents a vital and challenging project for early adopters in global psychiatry to consider.  相似文献   
4.
应用白僵菌防治玉米螟的田间试验   总被引:4,自引:0,他引:4  
玉米螟是我省粮食作物上的重要害虫,利用化学农药(滴滴涕、六六六)治螟,已在生产上推广使用(邱式邦等,1963;农安县柴岗公社农业站等,1966)。随着近年来防治面积的扩大,使用农药数量日益增多。同时,从国内、外发展趋势表明,由于大量生产和使用有机氯等化学农药防治害虫带来了一系列不良后果(如残毒,抗药性及环境污染等问题),因此,迫切要求研究治螟的新方  相似文献   
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SEVERAL reports1–3 have suggested that cholinergic ligands bind to acetylcholinesterase at sites distinct from the active centre. Changeux et al.4 demonstrated that acetylcholine binds to non-catalytic sites as well as to the active centre of the enzyme. Atropine arid 1-hyoscyamine have also been shown to interact with the enzyme at a region distinct from the active site5, 6. We have therefore investigated whether acetylcholine and atropine are bound to the same site and whether this site is related to the acetylcholine receptor.  相似文献   
6.
The stability of soil organic matter (SOM) pools exposed to elevated CO2 and warming has not been evaluated adequately in long‐term experiments and represents a substantial source of uncertainty in predicting ecosystem feedbacks to climate change. We conducted a 6‐year experiment combining free‐air CO2 enrichment (FACE, 550 ppm) and warming (+2 °C) to evaluate changes in SOM accumulation in native Australian grassland. In this system, competitive interactions appear to favor C4 over C3 species under FACE and warming. We therefore investigated the role of plant functional type (FT) on biomass and SOM responses to the long‐term treatments by carefully sampling soil under patches of C3‐ and C4‐dominated vegetation. We used physical fractionation to quantify particulate organic matter (POM) and long‐term incubation to assess potential decomposition rates. Aboveground production of C4 grasses increased in response to FACE, but total root biomass declined. Across treatments, C : N ratios were higher in leaves, roots and POM of C4 vegetation. CO2 and temperature treatments interacted with FT to influence SOM, and especially POM, such that soil carbon was increased by warming under C4 vegetation, but not in combination with elevated CO2. Potential decomposition rates increased in response to FACE and decreased with warming, possibly owing to treatment effects on soil moisture and microbial community composition. Decomposition was also inversely correlated with root N concentration, suggesting increased microbial demand for older, N‐rich SOM in treatments with low root N inputs. This research suggests that C3–C4 vegetation responses to future climate conditions will strongly influence SOM storage in temperate grasslands.  相似文献   
7.
While the influence of elevated CO2 on the production, mass and quality of plant seeds has been well studied, the effect of warming on these characters is largely unknown; and there is practically no information on possible interactions between warming and elevated CO2, despite the importance of these characters in population maintenance and recovery. Here, we present the impacts of elevated CO2 and warming, both in isolation and combination, on seed production, mass, quality, germination success and subsequent seedling growth of Austrodanthonia caespitosa , a dominant temperate C3 grass from Australia, using seeds collected from the TasFACE experiment. Mean seed production and mass were not significantly affected by either elevated CO2 or warming, but elevated CO2 more than doubled the proportion of very light, inviable seeds ( P < 0.05) and halved mean seed N concentration ( P < 0.04) and N content ( P < 0.03). The dependence of seed germination success on seed mass was affected by an elevated CO2× warming interaction ( P < 0.004), such that maternal exposure to elevated CO2 or warming reduced germination if applied in isolation, but not when applied in combination. Maternal effects were retained when seedlings were grown in a common environment for 6 weeks, with seedlings descended from warmed plants 20% smaller ( P < 0.008) with a higher root : shoot ratio ( P < 0.001) than those from unwarmed plants. Given that both elevated CO2 and warming reduced seed mass, quality, germinability or seedling growth, it is likely that global change will reduce population growth or distribution of this dominant species.  相似文献   
8.
1.本文主要研究松毛虫卵的两种黑卵蜂(Telenomus dendrolimusi Chu及Teleno-mus sp.,Scelionidae,Hymenoptera)的生物学特性;及1954—55年江苏南京和浙江常山等地林间的寄生情况,同时对松毛虫卵及黑卵蜂的冷藏也进行了试验。 2.两种黑卵蜂中,松毛虫黑卵蜂(Telenomus dendrolimusi Chu)与毒蛾黑卵蜂(Telenomus sp.)不但在形态上有所不同。而且在生活习性及各期虫态对低温的反应上亦各异,证明它们确系不同的两种。毒蛾黑卵蜂在我国系首次记载寄生于松毛虫卵中,现知在江苏南京、江宁,浙江常山及广东广州均有分布,在南京的黑卵蜂中占80%以上。 3.毒蛾黑卵蜂以幼虫态在寄主卵内越冬,利于冬季生存。越冬代成虫羽化时间接近松毛虫第1代卵出现期。且有松毒蛾(Lymantria sp.,Lymantriidae,Lepidoptera)作为补充寄主。这些特性均较松毛虫黑卵蜂为优。 4.室内外饲育结果,知松毛虫黑卵蜂在南京年可发生10—12代,毒蛾黑卵蜂年有8—9代,性比雌蜂占80%左右,毒蛾黑卵蜂破坏寄主卵粒平均为30粒左右比松毛虫黑卵蜂平均15粒左右为高。产卵期较集中,且在室内容易繁殖。 5.从发育1天的松毛虫卵冷藏于4℃冰箱中1个月不影响毒蛾黑卵蜂的寄生发育。毒蛾黑卵蜂在4℃冰箱中冷藏,以老熟幼虫为最好,冷藏1个月后,对其产生后代数无影  相似文献   
9.
Thermogenic flowers produce heat by intense respiration, and the rates of O2 consumption (?o2) in some species can exceed those of all other tissues of plants and most animals. By exposing intact flowers to a range of O2 pressures (Po2) and measuring ?o2, we demonstrate that the highest respiration rates exceed the capacity of the O2 diffusive pathway and become diffusion limited in atmospheric air. The male florets on the inflorescence of Arum concinnatum have the highest known mass‐specific ?o2 and can be severely diffusion limited. Intact spadices of Japanese skunk cabbage Symplocarpus renifolius are diffusion limited in air only when ?o2 is maximal, but not at lower levels. True flowers of the sacred lotus Nelumbo nucifera and the appendix of Arum concinnatum are never diffusion limited in air. ?o2Po2 curves are evaluated quantitatively with the ‘Regulation Index’, a new tool to measure dependence of ?o2 on ambient Po2, as well as the conventional ‘Critical Po2’. The study also includes measurements of Po2 within thermogenic tissues with O2‐sensitive fibre optics, and reveals that the diffusion pathway is complicated and that O2 can be provided not only from the surface of the tissues but also from the pith of the flower's peduncle.  相似文献   
10.
This study examines the extent to which interactions among two common alpine/subalpine plant species and their neighbours at the Bogong High Plains in southern Australia are characterized by competition or facilitation. The two target species were Celmisia pugioniformis (Asteraceae) and Carex breviculmis (Cyperaceae). Biotic interactions were examined using vegetation removal manipulations over three growing seasons at five sites across the altitudinal range of tall alpine herbfield communities. Observations recorded growth and mortality. Results for C. pugioniformis clearly indicated facilitation as a dominant process across all sites and seasons. Plants that had their neighbours removed tended to perform worse than plants that had their neighbours left intact. Growth observations for Ca. breviculmis were less clear, but again suggested facilitation. Mortality was distinctly higher among Ca. breviculmis individuals that had their neighbours removed relative to those with neighbours left intact. Results collectively suggest the removal of neighbours acts to reduce growth and increase mortality in C. pugioniformis and Ca. breviculmis throughout the altitudinal range of tall alpine herbfields at the Bogong High Plains. Facilitative and competitive interactions need to be recognized in efforts aimed at mitigating climate change‐associated impacts on the ecology of alpine plant communities. The extent to which biotic interactions may exacerbate or buffer abiotic change is difficult to predict, emphasizing the need for ecological monitoring.  相似文献   
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