Most vascular plants depend to some extent on vesicular-arbuscular (V-A) mycorrhizae for mineral uptake, although a few species do not. Some mycotrophic cannot grow without mycorrhizae; others better in fertile soils, but benefit from poor soils. Thus, the mycorrhizal fungus content and fertility of soil influence occurrence plant species. Because V-A fungi carbon, because they produce spores which may survive only short time lowland humid tropics, community composition turn affects soil....

In experiments with plants grown in pots, vesicular—arbuscular mycorrhizal increased seedling growth of 23 to 28 species from a lowland tropical rain forest region. Mycorrhizae improved survival six and cotyledon retention five species. also the size bacterial nodules proportion nodulated among three leguminous Growth seedlings lacking mycorrhizae slowed greatly or ceased after attainment sizes correlated average seed dry mass. Removing cotyledons individuals two that are dependent on...

Earthquakes occasionally denude large areas of tropical forest: for example, 54 square kilometers in Panama 1976 and 130 New Guinea 1935. Earthquake rates Guinea, but not Panama, are sufficiently high so that substantial disturbed, nonclimax forest may accumulate. In earthquake-caused landslides as important tree falls the disturbance regime.

Bat—generated seed shadows of two mature Andira inermis (W. Wright) DC. trees in the deciduous forest lowlands Guanacaste Province, Costa Rica, are highly heterogeneous; very unequal numbers seeds deposited beneath used as feeding roosts. It is calculated that a 45—g Artibeus jamaicensis bat may potentially obtain many 1,766 joules [= 422 calories] per fruit round trip 270 m between parent tree and roost. Seed predation by Cleogonus weevils was found to be highest below tree, intermediate...

Summary Arbuscular mycorrhizal ( AM ) fungi interconnect plants in common networks CMN s) which can amplify competition among neighbors. Amplified might result from the supplying mineral nutrients preferentially to hosts that abundantly provide fixed carbon, as suggested by research with organ‐cultured roots. We examined whether s supplied 15 N large, nonshaded, whole plants. conducted an intraspecific target–neighbor pot experiment Andropogon gerardii and several intact, severed or...

Summary Arbuscular mycorrhizal fungi can interconnect plant root systems through hyphal common networks, which may influence the distribution of limiting mineral nutrients among interconnected individuals, potentially affecting competition and consequent size inequality. Using a microcosm model system, we investigated whether members A ndropogon gerardii monocultures compete via networks. We grew . seedlings with isolated in individual, adjacent containers while preventing, disrupting or...

We quantitatively assessed rodent dispersal of vesicular—arbuscular mycorrhizal fungi in a lowland tropical rain forest. examined fecal pellets from seven species the genera Proechimys, Oryzomys, and Mesomys trapped each month August 1983 through July 1984 at Cocha Cash field station Manu National Park, Peru. found sporocarps Sclerocystis coremioides spores four Glomus 69.3% samples, with 37.5% samples containing 2—4 fungus species. There were median numbers 8.6 S. 712 spores/0.1 g feces....

Vesicular-arbuscular mycorrhizae can be indispensable for establishment and growth of tree seedlings in infertile lowland wet tropical soils. Persistence mycorrhizal fungi after disturbance, however, is problematic to assess. We used a greenhouse bioassay employing Psidium guajava L. Allium cepa estimate the most probable number fungus propagules two Costa Rican soils (Oxic Dystropepts) with different vegetation histories. collected at La Selva Biological Station from sites secondary forest,...

Course-based undergraduate research experiences (CUREs) are an effective way to integrate into science curriculum and extend a large, diverse group of early-career students. We developed biology CURE at the University Miami (UM) called UM Authentic Research Laboratories (UMARL), in which groups first-year students investigated novel questions conducted projects their own design related themes faculty instructors. Herein, we describe implementation student outcomes this long-running CURE....

Although rain forest is characterized as pyrophobic, pyrophilic giant eucalypts grow emergents in both temperate and tropical Australia. In Australia, such depend on extensive, infrequent fires to produce conditions suitable for seedling growth. Little known, however, about constraints seedlings of eucalypts. We tested whether Eucalyptus grandis experience edaphic similar their counterparts. hypothesized that phosphorous addition would alleviate constraints. grew a factorial experiment...

Eucalyptus tetrodonta, a co-dominant tree species of tropical, northern Australian savannas, does not invade adjacent monsoon rain forest unless the is burnt intensely. Such facilitation by fire seedling establishment known as "ashbed effect." Because ashbed effect might involve disruption common mycorrhizal networks, we hypothesized that in absence fire, intact arbuscular (AM) networks inhibit E. tetrodonta seedlings. Although mycorrhizas predominate forest, savannas (including adult...

Arbuscular mycorrhizas can alter competitive interactions between plants that markedly differ in their dependence upon mycorrhizas, but little is known about how affect intra- and inter-specific competition similarly dependent plant species. We conducted experiments pots all pairs of the facultatively mycotrophic crop species, chili ( Capsicum annuum L.), maize Zea mays zucchini Cucurbita pepo L.). used a two-species yield-density model to analyze separate effects mycorrhizal inoculation,...