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151.
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154.
Summary Unrelated, unselected 2x haploid-species hybrids that produce 2n eggs, by second division restitution and 2n pollen due to
first division restitution were intercrossed to generate 4x progeny. The 19, 4x families were compared with seven cultivars
for tuber yield, tuber appearance and tuber set. The mean yield of the 4x families was 30% higher than the mean yield of the
cultivars. The best five 4x families outyielded the best five cultivars by 57% and 69% at two locations. Cultivars were superior
for tuber appearance and tuber set. The high yields of the 4x families are due to genetic diversity of the 2x parents and
their ability to transmit that diversity to the 4x progeny utilizing 2n gametes. The potential of the 2x×2x breeding method
is dependent on developing 2x hybrid clones that form 2n eggs and possess desirable tuber types; clones producing 2n pollen
and good tuber quality are available. 相似文献
155.
Werner Schuphan 《Plant foods for human nutrition (Dordrecht, Netherlands)》1970,20(1-2):35-68
The criteria of yield increases is being subjected to a causal examination. Maximum yields — brought about by large nitrogen supply — are being examined with respect to their influence upon disease potential, increase of quality — and non-parasitic defects as well as upon decrease of useful and increase of undesirable compounds. Observations from the world literature as well as our own experiments with vegetables over many years, particularly with spinach serve as evidence. Stimulation of diseases and pests through overnourishment with nitrogen refer particularly to rust, downy mildew, septoria and botrytis organisms as well as to lice and mites. Amongst non-parasitic diseases one has to list a great number of quality defects, a lessening of resistance against mechanical damage at harvest and during transport, a reduction in quantity of commercial grades, flavour losses and above all a decline of keeping in winter storage. Exessive nitrogen supply also results in a decline in content of valuable constituents and increase in biogenic toxicants as well as in plant components to undesirable levels from a technological and nutritional physiological point of view. Fig. 10 summarises these results. The following valuable constituents are particularly affected: dry matter, total sugar, vitamin C, essential oils and potassium, magnesium and phosphoric acid amongst the minerals. Undesirable increase of enzyme activity as well as that of free amino acid content — coupled with a decrease of biological protein value are additional consequences of excess nitrogen fertilizing. Increases of undesirable compounds refer to crude protein (e.g. brewing barley and sugar beet), nitrate nitrogen (spinach) potentially a health hazard to infants (methaemoglobinemia) in case where toxic nitrite is formed in the spinach from nitrate. The removal of watersoluble nitrate from spinach overnourished with nitrogen by prolonged blanching, suggested in some publications, is to be rejected owing to the then unavoidable in part enhanced losses of water soluble compounds of nutritive value, including vitamins and minerals. 相似文献
156.
In this study we demonstrate that the demosponge Suberites domuncula harbors a Mn(II)-oxidizing bacterium, a Bacillus strain, termed BAC-SubDo-03. Our studies showed that Mn(II) stimulates bacterial growth and induces sporulation. Moreover, we show that these bacteria immobilize manganese on their cell surface. Comparison of the 16S rDNA sequence allowed the grouping of BAC-SubDo-03 to the Mn-precipitating bacteria. Analysis of the spore cell wall revealed that it contains an Mn(II)-oxidizing enzyme. Co-incubation studies of BAC-SubDo-03 with 100 μM MnCl(2) and >1 μM of CuCl(2) showed an increase in their Mn(II)-oxidizing capacity. In order to prove that a multicopper oxidase-like enzyme(s) (MCO) exists in the cell wall of the S. domuncula-associated BAC-SubDo-03 Bacillus strain, the gene encoding this enzyme was cloned (mnxG-SubDo-03). Sequence alignment of the deduced MCO protein (MnxG-SubDo-03) revealed that the sponge bacterium clusters together with known Mn(II)-oxidizing bacteria. The expression of the mnxG-SubDo-03 gene is under strong control of extracellular Mn(II). Based on these findings, we assume that BAC-SubDo-03 might serve as a Mn reserve in the sponge providing the animal with the capacity to detoxify Mn in the environment. Applying the in vitro primmorph cell culture system we could demonstrate that sponge cells, that were co-incubated with BAC-SubDo-03 in the presence of Mn(II), show an increased proliferation potential. 相似文献
157.
Organic farming requires cultivars that are specifically adapted to this low input cropping system. Hence, organic farmers
and scientists joined in a participatory breeding approach to develop region-specific genotypes of spring faba bean for organic
conditions in Germany. A set of 49 genotypes with contrasting degrees of heterozygosity and heterogeneity was used in field
trials across five locations in Germany during 3 years 2004, 2005 and 2006. The material involved 18 inbred lines, their 18
polycross progenies, one blend of inbred lines, one blend of polycross progenies, one blend of hybrids and ten checks. Inbred
lines are uniform, thus giving the option to be specifically adapted; whereas the polycross progenies and synthetics (Syn-1;
predicted from the inbred lines and polycross progenies performance) are partly heterogeneous and heterozygous, thus giving
the option to evolve. Agronomic performance was assessed and a “personal appreciation” score of the material was assigned
to each genotype by each partner. This personal appreciation was strongly influenced by biotic and abiotic constraints faced
by the crop in each location and by the expected grain yield of the genotypes. Uniformity was apparently appreciated by organic
farmers. In all locations, the highest yielding inbred line yielded slightly better than the predicted highest yielding synthetic.
However, this slight disadvantage of the synthetic is very likely to disappear if the synthetic (Syn-1) is propagated during
successive generations. 相似文献
158.
159.
Long-term observations of Trichoniscus pusillus revealed that chemical composition and microbial activity of the leaf litter serving as food influenced the reproductive success of females and the mortality rates of juveniles as well. Of the food sources investigated, only alder litter, exhibiting high microbial activity, allowed the maintenance of a stable population with frequently reproducing females. This study concludes that the food type is a significant factor for population parameters of this parthenogenetic isopod. Our results on T. pusillus, belonging to the taxon Synocheta, are compared with data on terrestrial isopod species of the taxon Crinocheta. 相似文献
160.
Flours from nonsprouted (ns) kernels and dried sprouted (s) kernels of transgenic rye expressing HMW glutenin subunits (HMW‐GS) 1Dy10 (L10) or 1Dx5+1Dy10 (L5+10) from wheat were compared with flours from the corresponding wildtype rye (Lwt). The crude protein content of nonsprouted flours ranged from 9.2% (Lwt) to 10.4% (L5+10) and was lowered by ≈1% due to sprouting. Flour proteins were separated into albumins/globulins, prolamins, and glutelin subunits by a modified Osborne fractionation and into SDS‐soluble and insoluble fractions. Portions of the prolamin fractions were reduced in the same manner as glutelins. The different fractions were then characterized and quantified by RP‐HPLC on C8 silica gel. The proportion of albumins/globulins did not significantly differ between transgenic lines and wildtype. The proportions of alcohol‐insoluble glutelins and SDS‐insoluble proteins drastically increased in transgenic rye due to a shift of HMW and γ‐75k secalins into the polymeric fractions. Significant differences in the proportion of highly polymeric proteins between nonsprouted and sprouted flours could not be detected. The quantitative data demonstrated that the expression of HMW‐GS led to a higher degree of polymerization of storage proteins in rye flour. The HMW‐GS combination 1Dx5+1Dy10 showed stronger effects than 1Dy10 alone. The analyzed flours contained two HMW secalins (R1, R2), whose amino acid compositions were closely related to those of 1Dy10 and 1Dx5, respectively. The amounts of R1 in Lwt flours determined by RP‐HPLC were 221 mg (ns) and 186 mg (s) per 100 g and those of R2 were 344 mg (ns) and 298 mg (s), respectively. These amounts increased to 240 mg (ns)/201 mg (s) (R1) and 479 mg (ns)/432 mg (s) (R2) in L10 flours. In L5+10 flours, the amount of R1 decreased to 150 mg (ns)/132 mg (s) while R2 increased to 432 mg (ns)/338 mg (s). The amount of HMW‐GS 1Dy10 was almost the same as that of R2 in L10 flours but was strongly increased in L5+10 flour (633 mg [ns]/538 mg [s]). HMW‐GS 1Dx5 was, by far, the major subunit in L5+10 flours (987 mg 7[ns]/896 mg [s]). The summarized amounts of all HMW subunits increased from ≈0.5 g (Lwt) to ≈1.1 g (L10) and ≈2.0 g (L5+10). Thus only L10 flours were similar to wheat flours in HMW subunit content. The baking performance of L10 flour determined by a microbaking test was improved compared with Lwt flour, whereas L5x10 flour showed very poor properties obviously due to the strongly increased proportion of highly cross‐linked glutelins. The breadmaking quality of flours from 1Dy10 seeds and wildtype seeds was reduced by the same degree when flours from sprouted seeds were analyzed. 相似文献