Vegetation Changes Associated With Invasion by Phytophthora cinnamomi of Defined Plots in the Brisbane Ranges, Victoria, 1975-1985

1986 ◽  
Vol 34 (6) ◽  
pp. 633 ◽  
Author(s):  
G Weste
Keyword(s):  
Slow Growth ◽  
Phytophthora Cinnamomi ◽  
Vegetation Changes ◽  
Bare Ground ◽  
Shrub Species ◽  
Slow Growth Rate ◽  
Ground Flora ◽  
Resistant Species ◽  
Open Forest ◽  
Vigorous Growth

Changes in plant species composition over a 10 year period were measured by biennial counts of numbers and areas on seven quadrats at each of three sites; one site pathogen free, one in the process of invasion by Phytophthora cinnamomi and one diseased since 1970. Susceptible species died and field-resistant species increased. Partly susceptible species fluctuated in growth. The plant community changed from open forest with sclerophyllous understorey dominated by Xanthorrhoea australis to open forest with large gaps and sedge-dominated ground flora. Tree numbers increased by 25% on the pathogen-free site but decreased by 42.9 and 45.3% on the two infested sites. Susceptible shrub species increased 10% on pathogen-free quadrats but decreased in both numbers and diversity with infestation. The high percentage of bare ground on the old diseased site was gradually colonised by graminoids and legumes. At the end of the 10 year period P. cinnamomi could no longer be isolated from this site, tree crowns showed vigorous growth and seedlings of some susceptible species were observed. The epidemic caused by P. cinnamomi in the Brisbane Ranges may be finite, with peak death periods in 1979 for the invaded site and in 1972 for the old diseased site. The bare ground was later colonised by field-resistant species and the disease potential of the pathogen declined. Regeneration has commenced on the old diseased site and may eventually become complete for the tree stratum, but incomplete for the understorey because Xanthorrhoea australis, formerly dominant, has a very slow growth rate.

Vegetation Changes Associated With Invasion by Phytophthora cinnamomi on Monitored Sites in the Grampians, Western Australia

1986 ◽  
Vol 34 (3) ◽  
pp. 251 ◽  
Author(s):  
J Kennedy ◽  
G Weste
Keyword(s):  
Species Composition ◽  
Endemic Species ◽  
Plant Density ◽  
Phytophthora Cinnamomi ◽  
Soil Surface ◽  
Tree Canopy ◽  
Vegetation Changes ◽  
Bare Ground ◽  
Forest Regions ◽  
Steep Slopes

The effects of invasion by Phytophthora cinnamomi were measured on sites representing the larger forest regions of the Grampians. Changes were obvious at first, with the death of more than 50% of the species including large plants such as Xanthorrhoea australis, but soon became dificult to detect as susceptible species were replaced by field-resistant graminoids. Reductions were assessed in species heterogeneity and plant density during 1976, at the onset of disease and from 1977 to 1984. Susceptible species disappeared from infested forest and no re-emergence was observed. Less-susceptible plants such as some Euca/yptus spp. declined in number, regeneration and size, due to deaths or dieback of the branches. Reductions in tree canopy and the loss of structural dominants of the understorey caused changes in the flora which are likely to persist. The survival of rare, susceptible endemic species may be endangered. On dry, steep slopes the dead plants were not replaced and the amount of bare ground increased causing erosion of the soil surface. Some graminoid species increased in abundance on level, infested sites, resulting in a different species composition but with both species heterogeneity and plant density numerically similar to the previous flora.

Pollen diagrams from interior Labrador

1970 ◽  
Vol 48 (11) ◽  
pp. 1957-1975 ◽  
Author(s):  
Alastair Morrison
Keyword(s):  
Primary Succession ◽  
Vegetation Changes ◽  
Bare Ground ◽  
Radiocarbon Dates ◽  
River Watershed ◽  
Pollen Diagrams ◽  
Glacier Ice ◽  
Lake Waters

Six pollen zones can be distinguished in interior Labrador. The earlier zones represent the primary succession of vegetation from bare ground to boreal woodland or forest, which occupied about 500 years between 5700 and 5200 B.P. There have been only minor fluctuations in the nature of the vegetation since 5200 B.P. Radiocarbon dates show that the zones are contemporaneous over that part of the Lake Plateau within the Churchill River watershed, but similar vegetation changes occurred 1000 years earlier in the Kaniapiskau basin, further north, in New Quebec. These two areas must have been freed of a cover of glacier ice or lake waters immediately before 5700 B.P. and 6700 B.P. respectively.

Time-Energy Budgets During Reproduction and the Evolution of Single Parenting in the Superb Lyrebird

1986 ◽  
Vol 34 (3) ◽  
pp. 351 ◽  
Author(s):  
A Lill
Keyword(s):  
Growth Rate ◽  
Brood Size ◽  
Slow Growth ◽  
Bird Species ◽  
Egg Laying ◽  
Energy Budgets ◽  
Brood Care ◽  
Single Parenting ◽  
Slow Growth Rate ◽  
Small Brood

Estimated expenditures on brood-care by unassisted female superb lyrebirds, obtained through time-energy budgeting, were compared with published values for other bird species. With the exception of nestbuilding, estimated daily expenditures were relatively low, due mainly to the small brood size and low level of parental attentiveness. It is suggested that the traits which reduce daily brood-care expenditures, particularly the small brood size and extremely slow growth rate, may have evolved as adaptations which enabled deserted females operating close to maximal capacity to cope with single-parenting. Male parental involvement could probably increase the growth rate of the young, but not brood size; moreover, egg- laying was sufficiently asynchronous to afford multiple mating opportunities to parentally emancipated males. However, the slow growth rate of the young results in relatively large overall brood-care expenditures for females. Investments by males of up to 50% of daylight hours and 45% of BMR on singing at the height of the mating season were comparable with those of partially emancipated, polygynous males of other species. They probably reflect the high level of competition to control good display areas and to advertise status and quality to widely spaced females.

scholarly journals Effect of physiological age of stem and IBA treatment on rooting of branch cuttings of Taxus baccata L.

1970 ◽  
pp. 01-07
Author(s):  
Saumitro Das ◽  
L.K. Jha
Keyword(s):  
Growth Rate ◽  
Large Scale ◽  
Slow Growth ◽  
Physiological Age ◽  
Taxus Baccata ◽  
Practical Solution ◽  
Slow Growth Rate ◽  
Rooting Response ◽  
Himalayan Yew ◽  
Rooting Capacity

The natural population of Taxus baccata L. (Himalayan Yew) throughout the Indian Himalayan Region is greatly reduced due to its extensive and reckless exploitation for “Taxol” an anticancer drug. The effects of overexploitation are exacerbated by the species poor regeneration process, slow growth rate and prolonged seed dormancy. Therefore vegetative propagation by branch cuttings seems to be only practical solution for its large scale multiplication. A study was conducted on six candidate trees (CTs) to examine the effect genotype, physiological age of stem, IBA treatment on rooting of Taxus baccata cuttings. Results revealed that rooting behaviour of cuttings was significantly affected by all the factors under study. Among the six CTs studied, CT 2 (from BSI, Shillong) had given the highest rooting response (46.28%). The juvenile cuttings have the higher rooting capacity; however the callusing was more prominent in mature cutting. The influence of IBA treatment was also significant for rooting where 1000 was most effective for stimulating rooting juvenile cuttings and 2000 ppm in mature cuttings.

scholarly journals The mitochondrial AAA protease FTSH3 regulates Complex I abundance by promoting its disassembly

2021 ◽  
Author(s):  
Aneta Ivanova ◽  
Abi S Ghifari ◽  
Oliver Berkowitz ◽  
James Whelan ◽  
Monika W Murcha
Keyword(s):  
Complex I ◽  
Nadh Dehydrogenase ◽  
Slow Growth ◽  
Nadh:Ubiquinone Oxidoreductase ◽  
Temperature Sensitive ◽  
Wild Type ◽  
Forward Genetic Screen ◽  
Slow Growth Rate ◽  
Partial Restoration ◽  
Screen Approach

Abstract ATP is generated in mitochondria by oxidative phosphorylation. Complex I (NADH:ubiquinone oxidoreductase or NADH dehydrogenase) is the first multisubunit protein complex of this pathway, oxidising NADH and transferring electrons to the ubiquinone pool. Typically Complex I mutants display a slow growth rate compared to wild-type plants. Here, using a forward genetic screen approach for restored growth of a Complex I mutant, we have identified the mitochondrial ATP dependent metalloprotease, Filamentous Temperature Sensitive H 3 (FTSH3), as a factor that is required for the disassembly of Complex I. An ethyl methanesulfonate-induced mutation in FTSH3, named rmb1 (restoration of mitochondrial biogenesis 1), restored Complex I abundance and plant growth. Complementation could be achieved with FTSH3 lacking proteolytic activity, suggesting the unfoldase function of FTSH3 has a role in Complex I disassembly. The introduction of the rmb1 to an additional, independent, and extensively characterised Complex I mutant, ndufs4, resulted in similar increases to Complex I abundance and a partial restoration of growth. These results show that disassembly or degradation of Complex I plays a role in determining its steady-state abundance and thus turnover may vary under different conditions.

Ustilago bullata. [Descriptions of Fungi and Bacteria].

1981 ◽  
Author(s):  
J. E. M. Mordue
Keyword(s):  
Geographical Distribution ◽  
Latent Infection ◽  
Slow Growth ◽  
Poor Survival ◽  
Head Smut ◽  
Slow Growth Rate ◽  
North And South America ◽  
North And South ◽  
Leaf Distortion ◽  
Infection Hypha

Abstract A description is provided for Ustilago bullata. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Agropyron, Bromus, Brachypodium, Elymus, Festuca, Hordeum, Sitanion. DISEASE: Causes head smut of grasses particularly species of Bromus and Agropyron. Sori develop at the base of spikelets and usually involve the ovary but glumes are usually unaffected, phyllody of floral parts also occurs. Latent infection with very reduced sori production can also occur. Infected seedlings show stunting and poor survival, older plants show slow growth rate and leaf distortion has been observed (56, 265). GEOGRAPHICAL DISTRIBUTION: Europe, North and South America, W. Asia (USSR, Poland, Iraq), India, Kenya, Australia, New Zealand. TRANSMISSION: Teliospores are released from the inflorescence sori to contaminate soil and seed. Teliospores have remained viable (in artificial storage) for 12 years. Germination results in the production of a metabasidium and sporidia, plasmogamy then produces a dikaryotic infection hypha. Seedlings and older shoots become infected, the former producing completely infected plants, but the latter producing separately diseased tillers (see Falloon, 1979).

Embryonic oxygen consumption and growth of Laysan and black-footed albatross

1982 ◽  
Vol 242 (1) ◽  
pp. R121-R128 ◽  
Author(s):  
T. N. Pettit ◽  
G. S. Grant ◽  
G. C. Whittow ◽  
H. Rahn ◽  
C. V. Paganelli
Keyword(s):  
Oxygen Consumption ◽  
Slow Growth ◽  
Egg Mass ◽  
Low Oxygen ◽  
O2 Uptake ◽  
Prolonged Incubation ◽  
Slow Growth Rate ◽  
Air Space ◽  
Embryonic Metabolism ◽  
Pulmonary Respiration

The constraints placed on diffusive gas exchange by the eggshell and the adaptive features of embryonic respiration and metabolism in large Laysan and black-footed albatross eggs (300 g) during prolonged incubation (65 days) were examined in naturally incubated eggs on Sand Island, Midway, in the Northwestern Hawaiian Islands. A low eggshell gas conductance and slow growth rate were associated with a relatively low oxygen consumption (MO2) throughout incubation. Just prior to internal pipping (IP) of the inner shell membrane and penetration of the air space, the MO2 (pre-IP MO2) was approximately 1,250 ml O2 (STPD).day-1 for both species, resulting in air cell O2 and CO2 tensions of 106 and 40 Torr, respectively. During the 4- to 5-day pipping-to-hatching interval, O2 uptake increases rapidly as pulmonary respiration is initiated. Hatchling O2 consumption averaged 3,700 ml O2 (STPD).day-1 or about three times the pre-IP MO2. Data support the hypothesis that embryonic metabolism among Procellariiformes is related to the extent to which the incubation period deviates from the expected value based on initial egg mass.

scholarly journals Validity of 14C Ages of Carbonates in Sediments

Radiocarbon ◽  
1986 ◽  
Vol 28 (2A) ◽  
pp. 464-472 ◽  
Author(s):  
Yijian Chen ◽  
Henry Polach
Keyword(s):  
Slow Growth ◽  
Major Error ◽  
Warm Climate ◽  
Climatic Effects ◽  
Atmospheric Contamination ◽  
Slow Growth Rate ◽  
Carbonate Formation ◽  
Stable Isotopic ◽  
The Times ◽  
Carbonate Nodule

This review is based on geologic surveys carried out in Australia and China as well as on more than 300 14C dates published in Radiocarbon, Evaluated are the origins and pathways of carbonate formation, stable isotopic composition, carbonate nodule growth rates and paleo-climatic effects. The three identified δ 13C abundance peaks are unrelated to environment and carbon source whilst 14C ages group themselves into periods corresponding to past humid warm climate. It is concluded that the major error in caliche dating is due to incorporation of old limestone whilst error on nodule dating is related to their slow growth rate, Thus, caliche antedates and nodules postdate the times of their deposition. Delta 13C values cannot be used to correct for limestone or atmospheric contamination effects.

scholarly journals Regrowth of Mycobacterium tuberculosis Populations Exposed to Antibiotic Combinations Is Due to the Presence of Isoniazid and Not Bacterial Growth Rate

2019 ◽  
Vol 63 (12) ◽  
Author(s):  
Charlotte L. Hendon-Dunn ◽  
Henry Pertinez ◽  
Alice A. N. Marriott ◽  
Kim A. Hatch ◽  
Jon C. Allnutt ◽  
...  
Keyword(s):  
Growth Rate ◽  
Mycobacterium Tuberculosis ◽  
Time Course ◽  
Bacterial Population ◽  
Slow Growth ◽  
Bacterial Growth Rate ◽  
Content Type ◽  
Slow Growth Rate ◽  
Antibiotic Efficacy ◽  
Fast Growth Rate

ABSTRACT Modulation of the growth rate in Mycobacterium tuberculosis is key to its survival in the host, particularly with regard to its adaptation during chronic infection, when the growth rate is very slow. The resulting physiological changes influence the way in which this pathogen interacts with the host and responds to antibiotics. Therefore, it is important that we understand how the growth rate impacts antibiotic efficacy, particularly with respect to recovery/relapse. This is the first study that has asked how growth rates influence the mycobacterial responses to combinations of the frontline antimycobacterials, isoniazid (INH), rifampin (RIF), and pyrazinamide (PZA), using continuous cultures. The time course profiles of log-transformed total viable counts for cultures, controlled at either a fast growth rate (mean generation time [MGT], 23.1 h) or a slow growth rate (MGT, 69.3 h), were analyzed by the fitting of a mathematical model by nonlinear regression that accounted for the dilution rate in the chemostat and profiled the kill rates and recovery in culture. Using this approach, we show that populations growing more slowly were generally less susceptible to all treatments. We observed a faster kill rate associated with INH than with RIF or PZA and the appearance of regrowth. In line with this observation, regrowth was not observed with RIF exposure, which provided a slower bactericidal response. The sequential additions of RIF and PZA did not eliminate regrowth. We consider here that faster, early bactericidal activity is not what is required for the successful sterilization of M. tuberculosis, but instead, slower elimination of the bacilli followed by reduced recovery of the bacterial population is required.

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