Chronic photoinhibition in seedlings of tropical trees

Seedlings of five canopy species of tropical trees from Costa Rica and Puerto Rico were grown in full shade (midday range of photosynthetic photon flux density [PPFD], 100–140 μmol m^?2 s^?1), partial shade (midday PPFD, 400–600 μmol m^?2 s^?1) and full sun (midday PPFD, 1 500–1 800 μmol m^?2 s^?1) for 3 months. The species were Ochroma lagopus (Bombacaceae), a pioneer species; Inga edulis (Fabaceae), found in secondary forest; and Dipteryx panamensis (Fabaceae), Hampea appendiculata (Malvaceae), and Manilkara bidentata (Sapotaceae), three species characteristic of primary forest. After the plants were placed in the dark overnight, chlorophyll fluorescence characteristics were measured for recently expanded and mature leaves. The ratio of variable fluorescence to maximum fluorescence (F_v/F_m) was used to estimate the degree of chronic photoinhibition. Only individuals of one species, Dipteryx panamensis, showed significant depression of F_v/F_m after long-term exposure to full sun. The depression was highly correlated with quantum yield of O₂ evolution which also declined after exposure to full sun. The decline may have been related to foliar N concentration. Although all plants were supplied with ample nutrients, foliar N did not increase significantly for Dipteryx seedlings in full sun, whereas it did for Ochroma and Inga. Leaf age affected F_v/F_m only in the cases of Manilkara, where it was slightly lower in recently expanded leaves, and of Dipteryx where it interacted with the effects of light regime. We conclude that chronic photoinhibition is not common in seedlings of canopy trees of tropical rain forests except when availability of mineral nutrients may be limiting.     

Hunger‐dependent and sex‐specific antipredator behaviour of larvae of a size‐dimorphic mosquito

1. Modification of behaviours in the presence of predators or predation cues is widespread among animals. The costs of a behavioural change in the presence of predators or predation cues depend on fitness effects of lost feeding opportunities and, especially when organisms are sexually dimorphic in size or timing of maturation, these costs are expected to differ between the sexes. 2. Larval Aedes triseriatus (Say) (Diptera: Culicidae) were used to test the hypothesis that behavioural responses of the sexes to predation cues have been selected differently due to different energy demands. 3. Even in the absence of water‐borne predation cues, hungry females (the larger sex) spent more time browsing than did males, indicating a difference in energy needs. 4. In the presence of predation cues, well‐fed larvae of both sexes reduced their activity more than did hungry larvae, and males shifted away from high‐risk behaviours to a greater degree than did females, providing the first evidence of sex‐specific antipredator behaviour in foraging mosquito larvae. 5. Because sexual size dimorphism is common across taxa, and energetic demands are probably correlated with size dimorphism, this research demonstrates the importance of investigating sex‐specific behaviour and behavioural responses to enemies, and cautions against generalising results between sexes.     

Okeanomyces, a new genus to accommodate Halosphaeria cucullata (Halosphaeriales, Ascomycota)

The taxonomic affinity of Halosphaeria cucullata to Halosphaeria is reassessed based on a recent collection of this fungus. Halosphaeria cucullata is characterized by immersed, darkly coloured ascomata, clavate asci which deliquesce very early in development, and cylindrical ascospores with or without a polar cap-like appendage at one end. In a phylogenetic analysis of the LSU rDNA sequences from members of the Halosphaeriaceae, H. cucullata did not form a monophyletic clade with H. appendiculata , the type species of the genus. These results suggest that H. cucullata should not be included in Halosphaeria . Okeanomyces gen. nov. is proposed to accommodate this fungus.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 146 , 223–229.     

定量蛋白质组学筛选及分析山慈菇酯提物抗4T1乳腺癌的新启示

探讨山慈菇酯提物(ethyl acetate extract of Cremaara appendiculata,Cr Ap)作用于4T1乳腺癌癌组织中差异蛋白的表达变化,筛选Cr Ap抗4T1乳腺癌的靶点.采用定量蛋白质组学串联质量标签(TMT)标记技术对Cr Ap作用的4T1乳腺癌癌组织进行检测,并筛选4T1组织中...     

洛阳地区黄胸木蜂访花植物种类及访花行为

【目的】明确黄胸木蜂Xylocopa appendiculata的访花植物种类和访花行为, 为进一步开发和利用木蜂资源奠定基础。【方法】 2009-2011年连续3年, 在洛阳地区黄胸木蜂的活动期3-10月, 采用目测、 拍照等方法记录其访花植物及访花行为, 记录和统计访花植物的生物学特征; 测量访花植物种类被盗蜜后盗蜜口的大小。【结果】在洛阳地区黄胸木蜂访花植物种类为27科52种, 主要的访花植物有25种。采访的植物种类中, 忍冬科和豆科植物最多, 分别为9种和8种, 占采访植物种类的17.31%和15.38%; 其中黄胸木蜂盗蜜的植物有16种, 占其采访植物种类的30.77%。在采访的植物种类中, 黄胸木蜂喜欢采访中等花型、 两侧对称的紫色、 黄色和白色花。在不同植物上, 黄胸木蜂的盗蜜口大小和访花频率不同, 黄胸木蜂在臭牡丹上的盗蜜口最大, 为9.43±1.91 mm, 蝟实上的盗蜜口最小, 为3.46±0.98 mm; 在紫薇上的访花速度最快, 访花频率为25.71±2.36朵/min; 在蜀葵上的单花停留时间和访花间隔时间均最长, 单花停留时间5.89±3.34 s, 访花间隔时间为2.63±2.04 s。【结论】在洛阳地区黄胸木蜂访花植物种类多、 访花时间长。对于不同的植物种类, 黄胸木蜂的访花行为和访花频率有差异。     

悬游双眉虫(原生动物,纤毛门)无性生殖期间的形态发生

应用蛋白银染色技术研究了悬游双眉虫青岛种群无性生殖期间皮层结构和核器的演化过程,其主要特征为:后仔虫口原基独立地出现于紧靠虫体左侧第一根横棘毛的皮层下小龛,其中毛基粒不参与其它棘毛原基的形成;老的口围带发生后半部的局部重建而非整个的由前仔虫简单继承;在前仔虫中,波动膜原基来自老结构的反分化,而在后仔虫中则来自口原基;所有棘毛原基均为独立发生并与老结构没有任何关系;在前仔虫中,口棘毛(即左侧第一根额棘毛)来自于波动膜的反分化,而在后仔虫中则为独立发生;背触毛列于老的结构当中产生,并由最右一列原基演化出3根尾棘毛;两大核片段的改组带从一端向另一端移动 ,并随着两者的融合而消失.文中同时对前人有关该属发生模式的若干存疑问题做了探讨 [动物学报 54(3):517-524,2008].     

Does differential predation permit invasive and native mosquito larvae to coexist in Florida?

Abstract.  1. The hypothesis that selective predation on larvae of the invasive Aedes albopictus (Skuse) could account for its stable coexistence with the native mosquito species and inferior competitor Ochlerotatus triseriatus (Say) in Florida treeholes and container systems was tested experimentally.
2. Functional responses of the two dipteran predators Toxorhynchites rutilus (Coquillett) and Corethrella appendiculata (Grabham) were evaluated separately for A. albopictus and O. triseriatus prey. Both predators exhibited type II functional responses and consistently consumed more of the invasive species. Handling time of T. rutilus feeding upon O. triseriatus was significantly longer than when preying upon the invasive species.
3. When either predator species was offered varying ratios of the two prey species, A. albopictus was consumed preferentially. The absence of a prey ratio effect on preference indicated that switching probably does not occur.
4. The higher maximum feeding rate upon, and preference for, A. albopictus suggests that differential predation may foster coexistence of the invasive and native mosquito prey species in Florida.     

贵州兰科新资料

报道了贵州兰科2个种。贵州杜鹃兰Cremastra guizhouensis Q.H.Chen&S.C.Chen系一新种,与杜鹃兰C.appendiculata（D.Don）Makino相近,区别点在于本新种具长达10-14cm的圆筒状假鳞茎和在唇瓣中裂片上有1枚平滑的胼胝体。另一个种为线叶美冠兰Eulophia siamensis Rolfe ex Downie,首次报道也产于中国。     

Behavioural responses of larval container mosquitoes to a size-selective predator

Abstract.  1. The hypothesis that size-selective predation and species-specific prey behaviours facilitate the coexistence between larvae of invasive Aedes albopictus (Skuse) and U.S.A.-native Ochlerotatus triseriatus (Say) was tested experimentally with the predator Corethrella appendiculata (Grabham).
2. Larval behaviours associated with a higher risk of predation were identified, and prey behavioural responses were tested in either the physical presence of predators or in water containing predation cues. Larvae that thrashed on container bottoms had a higher risk of being captured by fourth instar C. appendiculata than did larvae resting on the water surface. Ochlerotatus triseriatus , but not A. albopictus , adopted low-risk behaviours in response to water-borne cues to predation. Both prey species reduced risky behaviours in the physical presence of the predator, but O. triseriatus showed a stronger response.
3. The vulnerability of 2nd and 3rd instar prey to predation was compared, and behavioural responses were correlated with prey vulnerability. Second instars of both species were more vulnerable to predation by C. appendiculata than were 3rd instars, and the 3rd instar A. albopictus was more vulnerable than O. triseriatus of the same stage. All instars of O. triseriatus showed a similar reduction of risky behaviours in response to the presence of C. appendiculata despite 4th instar prey being relatively invulnerable to size-selective predation.
4. Weaker predator avoidance, coupled with superior competitive ability, of invasive A. albopictus is likely to contribute to its coexistence with O. triseriatus in containers of the south-eastern U.S.A., where C. appendiculata can be abundant.