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- Schnürer, Johan, 1957-, et al.
(författare)
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Fungi, bacteria and protozoa in soil from four arable cropping systems
- 1986
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Ingår i: Biology and Fertility of Soils. - New York : Springer. - 0178-2762 .- 1432-0789. ; 2:3, s. 119-126
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Tidskriftsartikel (refereegranskat)abstract
- The effects of four cropping systems on soil microorganisms were investigated during 3 years. The cropping systems were B0, barley without nitrogen fertilizers; B120, barley with 120 kg N ha-1 year-1; GL, grass ley receiving 200 kg N ha-1 year-1; and LL, lucerne ley without nitrogen fertilizer additions. At samplings in September during three consecutive years no differences were found between treatments. Total fungal lengths ranged between 0.7 and 2.0 × 103 m and bacterial numbers between 3.5 and 7.2 × 109 g-1 dry wt. soil.Twenty samplings over 3 years in B120 and in GL indicated higher numbers of bacteria and protozoa during the growing season, except for periods with moisture stress. No clear seasonal trends were found for the fungi. When comparing mean values for the 20 samplings, the grass ley contained significantly (P < 0.05) higher numbers of amoebae. Means of the bacterial numbers and biomass, total and FDA-active hyphal lengths were also higher or equal (FDA-active hyphae) but not significantly so.Seventy-nine per cent of the bacterial biomass and 73% of the total fungal lengths were found in the top soil, where also 85% of the oxygen was consumed.
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| 2. |
- Waara, Sylvia, 1958-, et al.
(författare)
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Somatic hybridization between anther-derived dihaploid clones of potato (Solanum tuberosum L.) and the identification of hybrid plants by isozyme analysis
- 1989
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Ingår i: Theoretical and Applied Genetics. - Heidelberg : Springer Berlin/Heidelberg. - 0040-5752 .- 1432-2242. ; 77:1, s. 49-56
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Tidskriftsartikel (refereegranskat)abstract
- Green mesophyll protoplasts of the dihaploid potato line 198∶2 (Solanum tuberosum L.) were fused with herbicide-bleached mesophyll protoplasts of the dihaploid potato line 67∶9 using a polyethylene glycol protocol. Heterokaryons were identified under a fluorescence microscope using the dual fluorescence of carboxyfluorescein-stained, herbicide-bleached protoplasts and the autofluorescence of green mesophyll protoplasts. About 20% of the protoplasts survived the fusion treatment, and the fusion frequency was 3%-4%. Unfused and fused protoplasts were mass cultured for 6 weeks after which vigorously growing calli were selected and transferred to shoot regeneration medium. Somatic hybrids were identified by a combination of five isozyme markers, and the ploidy level was determined by flow cytometry. Out of 15 calli that regenerated shoots, 6 plants derived from 2 different calli were identified as hexaploid somatic hybrids, while one morphologically deviant plant from a third callus was identified as a mixoploid that had lost some enzyme markers after 4 months of culturing.
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