广西种子植物小资料

几年来,我所在中草药资源调查工作中,发现一些我国及广西未曾记录过的植物,现整理成文,以供有关部门参考。本文引用的标本均收藏在广西中医药研究所植物标本室(GXMI)。 山椒子水番挑(博白)番落技科Annonaceae Uvar花a grandiflora Roxb.in FI.Ind.2:665.1524;李秉滔,植物分类学报14(1):98.2976,蒋英,李秉滔,中国植物志30(2):26,图版10. 1979。 广西东南部:博白县,浪平公社,水库边1971年5月9日,王鉴均2247外北流县,隆盛公社,天堂,坡地疏林中,1977年9月26日北流调查队8一44口7。 分布:广东南部,广西东南部;印度、缅甸、泰国、越南、马来…     

Lanzia berggrenii及其相关种的系统发育地位(英文)

系统发育分析结果表明,尽管Lanzia berggrenii能在寄主中形成基物子座,但与膜盘菌属的核心种关系较近,而与蜡盘菌科成员关系较远,应该归属于膜盘菌属。在广义的膜盘菌属的系统树中该种及在新西兰发现的4个新种构成一个单系群,分别命名为Hymenoscyphus haasticus,H. kiko,H.ohakune和H.waikaia。它们的共同特征:基物均为南青冈叶片,侧丝顶端分枝形成类似囊层被的结构,覆盖于子实层上部。Lanzia berggrenii var.metrosideri应为膜盘菌属中一个独立的种,即Hymenoscyphus metrosideri。     

Biotic resistance to an invasive spider conferred by generalist insectivorous birds on Hawai’i Island

A central problem for ecology is to understand why some biological invasions succeed while others fail. Species interactions frequently are cited anecdotally for establishment failure, but biotic resistance is not well supported by quantitative experimental studies in animal communities. In a 33-month experiment on Hawaii Island, exclusion of native and alien forest birds resulted in a 25- to 80-fold increase in the density of a single non-indigenous spider species (Theridiidae: Achaearanea cf. riparia). Caged plots held large aggregations of juveniles and more large-bodied individuals, suggesting potential reproductive individuals are more susceptible to bird predation. Most examples of biotic resistance involve competition for limiting resources among sessile marine animals or terrestrial plants. The present results show that generalist predators can limit the success of introductions, even on oceanic islands, generally assumed less resistant to invasion.     

Intra‐floral resource partitioning between endemic and invasive flower visitors: consequences for pollinator effectiveness

1. Sympatric flower visitor species often partition nectar and pollen and thus affect each other's foraging pattern. Consequently, their pollination service may also be influenced by the presence of other flower visiting species. Ants are solely interested in nectar and frequent flower visitors of some plant species but usually provide no pollination service. Obligate flower visitors such as bees depend on both nectar and pollen and are often more effective pollinators. 2. In Hawaii, we studied the complex interactions between flowers of the endemic tree Metrosideros polymorpha (Myrtaceae) and both, endemic and introduced flower‐visiting insects. The former main‐pollinators of M. polymorpha were birds, which, however, became rare. We evaluated the pollinator effectiveness of endemic and invasive bees and whether it is affected by the type of resource collected and the presence of ants on flowers. 3. Ants were dominant nectar‐consumers that mostly depleted the nectar of visited inflorescences. Accordingly, the visitation frequency, duration, and consequently the pollinator effectiveness of nectar‐foraging honeybees (Apis mellifera) strongly decreased on ant‐visited flowers, whereas pollen‐collecting bees remained largely unaffected by ants. Overall, endemic bees (Hylaeus spp.) were ineffective pollinators. 4. The average net effect of ants on pollination of M. polymorpha was neutral, corresponding to a similar fruit set of ant‐visited and ant‐free inflorescences. 5. Our results suggest that invasive social hymenopterans that often have negative impacts on the Hawaiian flora and fauna may occasionally provide neutral (ants) or even beneficial net effects (honeybees), especially in the absence of native birds.     

Citrate transporters play a critical role in aluminium-stimulated citrate efflux in rice bean (Vigna umbellata) roots

BACKGROUND AND AIMS: Aluminium (Al) stimulates the efflux of citrate from apices of rice bean (Vigna umbellata) roots. This response is delayed at least 3 h when roots are exposed to 50 microm Al, indicating that some inducible processes leading to citrate efflux are involved. The physiological bases responsible for the delayed response were examined here. METHODS: The effects of several antagonists of anion channels and citrate carriers, and of the protein synthesis inhibitor, cycloheximide (CHM) on Al-stimulated citrate efflux and/or citrate content were examined by high-pressure liquid chromatography (HPLC) or an enzymatic method. KEY RESULTS: Both anion channel inhibitors and citrate carrier inhibitors can inhibit Al-stimulated citrate efflux, with anthracene-9-carboxylic acid (A-9-C, an anion channel inhibitor) and phenylisothiocyanate (PI, a citrate carrier inhibitor) the most effective inhibitors. A 6 h pulse of 50 microm Al induced a significant increase of citrate content in root apices and release of citrate. However, the increase in citrate content preceded the efflux. Furthermore, the release of citrate stimulated by the pulse treatment was inhibited by both A-9-C and PI, indicating the importance of the citrate carrier on the mitochondrial membrane and the anion channel on the plasma membrane for the Al-stimulated citrate efflux. CHM (20 microm) also significantly inhibited Al-stimulated citrate efflux, confirming that de novo protein synthesis is required for Al-stimulated citrate efflux. CONCLUSIONS: These results indicate that the activation of genes possibly encoding citrate transporters plays a critical role in Al-stimulated citrate efflux.     

Allometric Models for Predicting Aboveground Biomass in Two Widespread Woody Plants in Hawaii

Allometric models are important for quantifying biomass and carbon storage in terrestrial ecosystems. Generalized allometry exists for tropical trees, but species‐ and site‐specific models are more accurate. We developed species‐specific models to predict aboveground biomass in two of the most ubiquitous natives in Hawaiian forests and shrublands, Metrosideros polymorpha and Dodonaea viscosa. The utility of the M. polymorpha allometry for predicting biomass across a range of sites was explored by comparing size structure (diameter at breast height vs. tree height) of the trees used to develop the models against trees from four M. polymorpha‐dominated forests along a precipitation gradient (1630–2380 mm). We also compared individual tree biomass estimated with the M. polymorpha model against existing generalized equations, and the D. viscosa model with an existing species‐specific model. Our models were highly significant and displayed minimal bias. Metrosideros polymorpha size structures from the three highest precipitation sites fell well within the 95% confidence intervals for the harvested trees, indicating that the models are applicable at these sites. However, size structure in the area with the lowest precipitation differed from those in the higher rainfall sites, emphasizing that care should be taken in applying the models too widely. Existing generalized allometry differed from the M. polymorpha model by up to 88 percent, particularly at the extremes of the data range examined, underestimating biomass in small trees and overestimating in large trees. The existing D. viscosa model underestimated biomass across all sizes by a mean of 43 percent compared to our model. The species‐specific models presented here should enable more accurate estimates of biomass and carbon sequestration in Hawaiian forests and shrublands.     

Plasticity in photosynthetic response to nutrient supply of seedlings from a mixed conifer‐angiosperm forest

Abstract We measured the plasticity of the response of photosynthesis to nutrient supply in seedlings of the dominant four conifer and broadleaved angiosperm tree species from an indigenous forest in South‐westland, New Zealand. We hypothesized that the response of conifers to differing nutrient supply would be less than the response for the angiosperms because of greater adaptation to low fertility conditions. In Prumnopitys ferruginea (D. Don) de Laub. the maximum velocity of electron transport, J_max, doubled with a 10‐fold increase in concentration of nitrogen supply. In Dacrydium cupressinum Lamb. the maximum velocity of carboxylation, V_cmax, doubled with a 10‐fold increase in phosphorus supply. In contrast, photosynthetic capacity for the angiosperm species Weinmannia racemosa L.f. was affected only by the interaction of nitrogen and phosphorus and photosynthetic capacity of Metrosideros umbellata Cav. was not affected by nutrient supply. The response of the conifers to increasing availability of nutrient suggests greater plasticity in photosynthetic capacity, a characteristic not generally associated with adaptation to soil infertility, thus invalidating our hypothesis. Our data suggest that photosynthetic response to nutrient supply cannot be broadly generalized between the two functional groups.     

Time of germination and establishment success after fire of three obligate seeders in a Mediterranean shrubland of central Spain

Aim Determining how differences in time of germination can affect plant establishment in plant communities that, after a disturbance, must reestablish from seeds under climatic conditions subject to extremes, such as the Mediterranean. Although early germination may be beneficial for survival in summer, when drought is severe, this may expose the seedlings to winter extremes, thus to higher mortality. Understanding how sensitive is the establishment of different species to temporal patterns of germination will help to understand the factors that control species distribution and community stability in disturbance‐prone environments, as well as its sensitivity to changes in weather patterns as climate changes. Methods An experimental fire was made in early fall in an old Cistus–Erica shrubland in Toledo (central Spain). After fire, germination, survival and growth of the three dominant seeder species (Cistus ladanifer, Erica umbellata and Rosmarinus officinalis) were monitored during the first 3 years after fire. Seedlings were tagged to identify their time of emergence, and divided into cohorts according to their month of germination. Differences in survival of the various cohorts were evaluated by means of a Wilcoxon (Gehan) statistic. Height of surviving, tagged plants was compared among cohorts by means of a Kolmogorov–Smirnov test. Results The year following fire was one of the driest on record, while the next one was one of the wettest. Germination was more abundant during the first than during the second year. Establishment was mainly from first‐year germination, as the majority of second‐year germinated seedlings died. Temporal patterns of germination within a year and between years varied between species. Seedling mortality was highest immediately following germination, not in summer. Mortality was related to time of germination: during a given period of time, the mortality of younger seedlings was higher than that of older ones. However, survival was not highest for the first cohorts. In general, the earlier the seedlings germinated the more vigourous they became, more clearly so for Cistus than for Rosmarinus, but differences tended to disappear with time. Overall, time of germination varied between species and affected differently seedling survival and vigour of the various species. Rosmarinus and Cistus had sufficient survivors to reestablish the initial population. Erica, despite abundant germination, suffered a strong population reduction. Main conclusions Mediterranean shrub species differ in their temporal patterns of germination and survival after fire. The effect of time of germination is complex: germinating early is advantageous since old seedlings fared better than younger ones when confronted with the same rigours. However, germinating early might expose the seedlings to greater hazards and the first cohort might not survive best. The temporal window for establishment is narrow and mainly restricted to the first year after fire. Second year seedlings, irrespective of most favourable conditions, survived very little. Missing the window of establishment might virtually lead to a population collapse, despite having very high germination, as found for Erica.     

密环菌激发子诱导猪苓细胞产生活性氧及其相关酶的变化

研究了蜜环菌激发子处理猪苓细胞后活性氧及产生及相关酶的变化。结果表明：蜜环菌激发子分别处理猪铃菌丝和菌核后,都能引起活性氧迸发,且出现两个迸发高峰,高峰期分别在加入激发子后约10min和90min。与此同时,猪铃菌丝酶活性也发生相应变化,超氧化物歧化酶（SOD）、过氧化物酶（POD）活性下降,过氧化氢酶（CAT）活性没有变化,而苯丙氨酸解氨酶（PAL）活性出现先下降后上升的趋势。