Relevance of Soil Microbiology to Search for Life on Other Planets

Stotzky, G.

doi:10.1016/s0065-2164(08)70187-4

Cited by 8 publications

(2 citation statements)

References 253 publications

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“…However, it is possible that a temporary lack of available calcium occurs as a result of flooding, disturbing the balance of ion absorption from the soil solution by the roots (Crawford, 1982). High temperatures may drastically affect root physiology and microbial activities in the rhizosphere and rhizoplane (Kappen, 1981, Stotzky, 1968. Our study showed that at relatively high temperatures, damage increased with duration of flooding.…”

Section: Discussionmentioning

confidence: 57%

Reproducible induction of cavity spot in carrots and physiological and microbial changes occurring during cavity formation

Soroker

Bashan

Okon

1984

Soil Biology and Biochemistry

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Summary-Inoculation of carrots with 40 types of bacteria, both aerobic and anaerobic, including clostridia isolated from cavity spots, failed to induce cavity spot in carrots. A combined stress of minimum 6 h flooding and temperatures higher than 28°C clearly induced cavity formation. Sugars, amino acids, lipids and minerals leaked from the carrots after flooding and heating the roots. A longer growth period following stress markedly increased cavity spots. Soil types (sandy loam and loess) and several carrot cultivars tested had no marked effect on spot formation. Cavities were formed in stressed carrots grown in sterilized soil containing only one type of bacterium, a Gram-negative short rod. Scanning electron micrographs revealed that after carrots were subjected to combined stress, microscopic cavities nearly free of bacteria were formed under the epidermis. Proliferation of bacteria was concommitant with the appearance of visible cavities. Cell-free extracts of infected carrots showed higher protease and pectinase-specific activities, as well as significantly higher peroxidase and polyphenoloxidase activities and total phenol content as compared to healthy carrots.

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Section: Discussionmentioning

confidence: 57%

Reproducible induction of cavity spot in carrots and physiological and microbial changes occurring during cavity formation

Soroker

Bashan

Okon

1984

Soil Biology and Biochemistry

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“…An understanding of carbon and nitrogen transformations in nature must be based on a knowledge of the bacterial, fungal, and actinomycete populations present. The study of the role of microorganisms in ecosystems and the forthcoming search for life on other planets (10) has been largely responsible for the increased interest in the development and reevaluation of techniques for studying the biomass, ecology, and activity of organisms in the soil (19).…”

Section: Introductionmentioning

confidence: 99%

The use of fluorescein isothiocyanate in the determination of the bacterial biomass of grassland soil

Babiuk¹,

Paul²

1970

Can. J. Microbiol.

292

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Quantitative recoveries of bacteria added to a number of soils were obtained using fluorescein isothiocyanate (FITC) as a stain. Enzyme fluorescence, using fluorescein diacetate or dibutyrate, could not be adapted for the routine counting of metabolizing organisms in soil. Staining with rose bengal gave recoveries of 60–80%.Soil-extract dilution plates revealed 4 × 107 bacteria/g in the 0–10 cm layer in April and 27 × 107 in October. One-third of this number was observed in the 20–30 cm layer. Actinomycete colonies added another 20% to the counts at the 0–30 cm depth but constituted 70% of the total colonies from the 90–120 cm depth. Microscopic counts indicated 2.2–4.6 × 109 organisms/g of surface soil. The number of bacteria decreased in a linear fashion with depth but no relation was found between the numbers obtained by direct microscopy and those by plate counting. However, each of the methods showed a high relationship between the size of the bacterial population present at each depth on the different sampling dates.The observed bacteria, actinomycete spores, and hyphal segments averaged 0.6 × 1 μ. On this basis, the biomass in the top 30 cm, as determined by direct microscopy, ranged from 30 to 76 g/m2 (dry weight basis). This implies, considering the amount of available energy, that the individual cells have enough energy to divide only a few times each year. Direct microscopic counting yields a quantitative picture of the organisms present but cannot separate between inactive cells, spores, and metabolizing organisms. Data from plate counts probably give a truer indication of metabolically active cells.

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Weitere Verfahren mit Mikroorganismen

Rehm

1980

Industrielle Mikrobiologie

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Relevance of Soil Microbiology to Search for Life on Other Planets

Cited by 8 publications

References 253 publications

Reproducible induction of cavity spot in carrots and physiological and microbial changes occurring during cavity formation

Reproducible induction of cavity spot in carrots and physiological and microbial changes occurring during cavity formation

The use of fluorescein isothiocyanate in the determination of the bacterial biomass of grassland soil

Weitere Verfahren mit Mikroorganismen

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