Patterns of variation in the yeast florae of exudates in an oak community

1983 ◽  
Vol 61 (12) ◽  
pp. 2984-2995 ◽  
Author(s):  
Jane M. Bowles ◽  
Marc-André Lachance

Yeasts associated with exudates of 16 red oak trees (Quercus rubra) were sampled repeatedly over a 2-year period. The 210 yeasts isolated were assigned to 28 species whose frequencies were characteristic of each habitat. Significant variation among the habitats was detected in the species diversity, composition, nutritional breadth, and physiological specificity of their yeasts. Some exudates were recognized as "typical" sap fluxes by their physical characteristics and their similar yeast florae. Others differed to various degrees in their yeast species composition, or in the physiological structure of their yeast communities. Among the factors linked to the observed variation were features of the adjacent vegetation, colonization by ants, or growth in open parts of the study area.

2006 ◽  
Vol 56 (8) ◽  
pp. 2015-2018 ◽  
Author(s):  
Gábor Péter ◽  
Dénes Dlauchy ◽  
Judit Tornai-Lehoczki

Two methanol-assimilating yeast strains were isolated from a flux of a sessile oak (Quercus petrea) in Hungary and one genetically and phenotypically very similar strain from a flux of a red oak (Quercus rubra) in Canada. The strains exhibited ascomycetous affinity but ascospore formation was not observed. On the basis of the sequence of their D1/D2 domain of the large subunit rDNA, as well as of their physiological characteristics, they represent a novel yeast species of the genus Candida. Therefore Candida floccosa sp. nov. is proposed, with NCAIM Y.01581T (=CBS 10307T=NRRL Y-27951T) as the type strain.


1988 ◽  
Vol 18 (12) ◽  
pp. 1550-1555 ◽  
Author(s):  
David B. Kittredge Jr.

Research in 40- to 60-year-old even-aged mixed hardwood stands in southern New England suggests a stratified canopy structure by species, with red oak crowns occupying the uppermost canopy stratum. The basal area growth of individual red oak trees with crowns in this uppermost canopy stratum is negatively related to the basal area of neighboring oaks with crowns in the same stratum. The total basal area of neighboring trees with crowns in this stratum has no effect on individual oak growth. Similarly, the basal area of trees in lower strata has no significant effect on the growth of oaks with crowns in the uppermost canopy stratum. Crown width of individual oaks is negatively related to the basal area of neighboring oaks with crowns in the uppermost canopy stratum. Also, both the total foliar biomass per tree and the efficiency of that foliage in producing basal area increment are negatively related to the quantity of surrounding oaks with crowns in the uppermost canopy stratum. These results imply that basal area increment of individual red oaks in the overstory depends on the species composition of the mixture (i.e., the proportion of red oaks in the mixture) and the resulting competition for growing space in the canopy.


2006 ◽  
Vol 36 (1) ◽  
pp. 123-131 ◽  
Author(s):  
James J Zaczek ◽  
Kim C Steiner ◽  
Charles W Heuser, Jr. ◽  
Walter M Tzilkowski

Bud grafts, up to three series over 3 years, were made on seedling and tree rootstocks using scions from juvenile and mature northern red oak (Quercus rubra L.). Serial grafts on juvenile rootstock used buds collected from shoots developed from grafted scions of prior years. Rooting trials were performed in years 2 and 3 with shoot cuttings developed in situ on seedlings and trees and developed from successful grafts. Without grafting, cuttings from seedlings rooted more frequently and had more roots than cuttings from trees. Significant variation within maturation groups due to genotype and ontogeny obscured absolute between-group differences. Grafting scions of juvenile origins onto seedling rootstock had little effect on percent rooting and the number of roots for cuttings. Grafting onto seedling rootstock tended to increase rooting and the number of roots for cuttings from mature origins, but the effect was not progressive with increasing grafting series. Grafting onto mature rootstock did not affect rooting of cuttings from juvenile or mature origins collected in the first growing season after grafting, but cuttings from juvenile scions collected in the second growing season exhibited reduced percent rooting compared with cuttings from seedling controls. Results suggest that northern red oak buds are predetermined in their developmental fate relative to rooting parameters and are only minimally influenced by grafting. The true effect of grafting on the subsequent rooting of cuttings may be mediated through processes other than rejuvenation.


Plant Disease ◽  
2019 ◽  
Vol 103 (8) ◽  
pp. 1940-1946 ◽  
Author(s):  
Rachael A. Sitz ◽  
Vincent M. Aquino ◽  
Ned A. Tisserat ◽  
Whitney S. Cranshaw ◽  
Jane E. Stewart

The focus of investigation in this study was to consider the potential of arthropods in the dissemination of the bacterium involved in drippy blight disease, Lonsdalea quercina. Arthropod specimens were collected and tested for the presence of the bacterium with molecular markers. The bacterium L. quercina was confirmed on 12 different insect samples from three orders (Coleoptera, Hemiptera, and Hymenoptera) and eight families (Buprestidae, Coccinellidae, Dermestidae, Coreidae, Pentatomidae and/or Miridae, Apidae, Formicidae, and Vespidae). Approximately half of the insects found to carry the bacterium were in the order Hymenoptera. Estimates of the insects that are contaminated with the bacterium, and likely carry it between trees, is conservative because the documented insects represent only a subset of the insect orders that were observed feeding on the bacterium or present on diseased trees yet were not able to be tested. The insects contaminated with L. quercina exhibited diverse life histories, where some had a facultative relationship with the bacterium and others sought it out as a food source. These findings demonstrate that a diverse set of insects naturally occur on diseased trees and may disseminate L. quercina.


1981 ◽  
Vol 11 (3) ◽  
pp. 689-695 ◽  
Author(s):  
Craig G. Lorimer

Mortality and growth rates of trees in various crown classes and size classes were analyzed from 40-year permanent plot records of slope and ravine forest dominated by chestnut oak (Quercusprinus L.) and northern red oak (Quercusrubra L.). Average 5-year mortality rates for suppressed trees ≥2.5 cm dbh of chestnut oak and red oak in the slope forest were 26 and 45%, respectively. None of the suppressed red oaks survived the 40-year period, compared with 14% of the chestnut oaks and 33% of the red maples (Acerrubrum L.). Mortality of oak trees in the intermediate crown class was less than half that of suppressed trees, but still much higher than that of maples and birches on the tracts. Survival was reasonably high for oaks as long as the top of the crown was receiving direct sunlight, but the expected 40-year survival rate of red oaks in such a position is only 20%, with an average growth rate of 1.0 mm in diameter per year. Curves and equations expressing average mortality and growth rates at various levels of competition are presented for each species.


2017 ◽  
Vol 47 (8) ◽  
pp. 997-1009 ◽  
Author(s):  
Katherine F. Crowley ◽  
Gary M. Lovett

As tree species composition in forests of the northeastern United States changes due to invasive forest pests, climate change, or other stressors, the extent to which forests will retain or release N from atmospheric deposition remains uncertain. We used a species-specific, dynamic forest ecosystem model (Spe-CN) to investigate how nitrate (NO3–) leaching may vary among stands dominated by different species, receiving varied atmospheric N inputs, or undergoing species change due to an invasive forest pest (emerald ash borer; EAB). In model simulations, NO3– leaching varied widely among stands dominated by 12 northeastern North American tree species. Nitrate leaching increased with N deposition or forest age, generally with greater magnitude for deciduous (except red oak) than coniferous species. Species with lowest baseline leaching rates (e.g., red spruce, eastern hemlock, red oak) showed threshold responses to N deposition. EAB effects on leaching depended on the species replacing white ash: after 100 years, predicted leaching increased 73% if sugar maple replaced ash but decreased 55% if red oak replaced ash. This analysis suggests that the effects of tree species change on NO3– leaching over time may be large and variable and should be incorporated into predictions of effects of N deposition on leaching from forested landscapes.


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