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61.
Control of barley root respiration 总被引:8,自引:0,他引:8
Evidence from barley [ Hordeum distichum (L.) Lam. cv. Maris Mink], and from many other species, suggests that respiration is controlled by either supply of carbohydrate or demand for ATP. The relationship between root respiration rate (measured as O2 consumption or CO2 production) and ethanol-soluble carbohydrate content altered with time following selective pruning, and the change could not be accounted for by buffering of the cytoplasmic carbohydrate concentration by sugars in the vacuole. Exogenous sucrose supplied to the roots prevented any decline of the respiration rate in shoot-pruned plants, and if supplied for 24 h stimulated the respiration rate after any treatment. Root extension responded to sucrose in a similar manner. We suggest that respiration is under fine control by adenylates, but the capacity of the respiratory system is fixed by the supply of sucrose, possibly via coarse control of the respiratory machinery, or of the processes requiring metabolic energy. 相似文献
62.
The importance of litter to nutrient and organic matter storage and the possible influence of species selection on soil fertility
in ten stands each consisting of a separate tree species were examined in this study. The plantations had been grown under
similar conditions in an arboretum in the Luquillo Experimental Forest, Puerto Rico. The species involved were: Anthocephalus chinensis, Eucalyptus × patentinervis, E. saligna, Hernandia sonora, Hibiscus elatus, Khaya nyasica, Pinus caribaea var. hondurensis, P. elliottii var. densa, Swietenia macrophylla, and Terminalia ivorensis. After 26 yr, litter mass ranged from 5 mg ha-1 in the H. sonora stand to 27.2 Mg ha-1 in the P. caribaea stand. Nutrients in the litter (N, P, K, Ca, and Mg) also varied widely, but stands were ranked in different order when ranked
by nutrients in the litter than then ranked according to accumulation of mass. Only E. saligna and A. chinensis stands were ranked similarly in accumulation of both nutrients and mass, and the stand of H. elatus was ranked higher with respect to nutrient accumulation than to accumulation of mass. The nutrient concentration in standing
leaf litter generally increased in the order of recently fallen <old intact< fragmented. Nutrient concentration of standing
leaf litter appears to increase with age and depth in the litter layer. The amount of nutrients stored in the litter compartment
of these plantations was in the same order of magnitude as the quantity of available nutrients in the top 10-cm of mineral
soil. Total litter mass was negatively correlated with the mass-weighted concentration of N, K, and Mg. The same relationship
was found for Ca in the leaf litter and N in the fine wood litter compartments. In some stands (notably P. caribaea, P. elliottii, and E. saligna), leaf litter derived from species other than the species planted in that particular stand had higher nutrient concentration
than leaf litter from the planted species. Soils of the 10 stands were classified in the same soil series and had similar
texture (clay soils). However, significantly different chemical characteristics were found. Results obtained by analysis of
covariance and by limiting comparisons to adjacent stands with similar soil texture, indicate that different species have
had different influences on the concentration of available nutrients in soil. 相似文献
63.
D. A. Belostotsky E. V. Ananiev 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1990,80(3):374-380
Summary High-molecular-weight relic DNA fraction can be electrophoretically separated from the bulk of barley DNA digested with different restriction enzymes. We have cloned and analyzed a population of relic DNA fragments. The majority of AluI-relic DNA clones contained barley simple sequence satellite DNA and other families of repetitive DNA. One of these families, designated HvRT, has been analyzed in detail. This family is composed of tandemly arranged 118-bp monomers and is present in 7 × 105 copies in the barley genome. Clones representing the HvRT family were sequenced. HvRT repeats were found to contain high levels of methylated cytosine. The HvRT family was found in the genomes of H. vulgare, H. leporinum, H. murinum, H. jubatum, but not in H. marinum, H. geniculatum, and wheat. Different barley species and cultivars show restriction fragment length polymorphism with the HvRT probe. Chromosome-specific subfamilies of HvRT were found to be present on different barley chromosomes, providing the possibility of using the HvRT probe as a chromosome specific marker. HvRT fragments up to 810 kbp in length were resolved by pulsed field gel electrophoresis. 相似文献
64.
G. Wenzel B. Foroughi-Wehr 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1990,80(3):359-365
Summary Because plant cells cultured in vitro express genetic variability and since they can be regenerated into functional plants, procedures have been designed to use this system for the production of plants with new important agronomic characteristics, particularly for disease resistance. For barley, wheat, and potato somaclones have been found that were less susceptible to a toxin of Helminthosporium, fusaric acid, Fusarium coeruleum, F. sulphureum, or Phytophthora infestans, when screened in the first in-vitro-derived generation. Here the progeny of such somaclones is evaluated after natural and artificial infection, using greenhouse-grown or field material. The progenies of the same somaclones did not express detectable differences, which indicated that no heterozygous mutations occurred. Most lines and clones differed in their level of susceptibility to the pathogen compared to the level of the starting material, but these data were in no instance significant. It is discussed here whether this lack of significance is due to a lack of genetic differences or whether the test procedures are in adequate for detecting and securing the slight, probably quantitative, alterations. 相似文献
65.
P. G. Arnison P. Donaldson L. C. C. Ho W. A. Keller 《Plant Cell, Tissue and Organ Culture》1990,20(3):147-155
Embryo formation by cultured broccoli (Brassica oleracea L. var. italica) anthers was best in the pH range of 5.5 to 5.8. Manipulation of the initial medium pH showed, however, that embryos could be recovered throughout the entire pH range tested. Experiments designed to test the influence of anther density on embryo production exhibited an apparent population effect. Comparison of anthers cultured with and without filaments showed a significantly lower level of embryo formation with filaments attached. The importance of anther orientation with the adaxial surface up was also demonstrated. Detailed studies of the effect of temperature on anther response showed the importance of 35°C treatments. Other temperatures and a variety of temperature manipulations were either comparatively ineffective or inhibitory. The duration of 35°C exposure required for optimal response varied widely between 18 and 48 h. Wide variation in plant to plant response was observed despite attempts to optimize the manipulation of physical parameters. Individual plants were identified that reliably formed many thousands of embryos, whereas other plants failed to form embryos under all tested conditions. 相似文献
66.
67.
Takako S. Kaneko Mamiko Sato Masako Osumi Makoto Muroi Akira Takatsuki 《Plant cell reports》1996,15(6):409-413
Summary The effects of brefeldin A (BFA) on the secretion of acid phosphatase (APase) by tobacco protoplasts were investigated. Secretion of APase was inhibited by BFA in a dose-dependent manner, with a concomitant intracellular accumulation of the enzyme. The secreted APase was composed of two isoforms. BFA (10/ g/ml) inhibited the secretion of one of the isoforms without inhibiting that of the other, and this phenomenon explains the partial inhibition of APase secretion as a whole. The inhibition of APase secretion was accompanied by changes in the morphology of the Golgi apparatus and also by an increment in massdensity of cells.Abbreviations APase
acid phosphatase
- BFA
brefeldin A
- CHX
cycloheximide
- PAGE
polyacrylamide gel electrophoresis 相似文献
68.
星花绣线菊中的一个新二萜——绣线菊内酯B 总被引:4,自引:1,他引:3
从星花绣线菊(Spiraeajaponicavar.stellaris)根中得到1个新的Atisine型二萜,命名为绣线菊内酯B(1)。通过光谱分析测定了其结构,此外还得到了9个已知化合物,包括1个atisine型二萜-spiraminol(2)和8个二萜生物碱,spiramineA,B,C,D,F,H,P,Q。 相似文献
69.
Maria Concepción Escorial Hortensia Sixto José-Maria García-Baudin Mariá-Cristina Chueca 《Plant Cell, Tissue and Organ Culture》1996,46(3):179-186
In vitro culture of barley calluses has been used to produce plants with increased glyphosate tolerance. Calluses from immature embryos of barleyHordeum vulgare L. (Jeff) were cultured on Murashige and Skoog medium with 10-6, 10-5, 10-4, 5×10-4, 10-3, or 10-2M glyphosate for one, four or thirty months. Plants were regenerated from calluses maintained in glyphosate medium at 10-6, 10-5 or 10-4M for four months, at 10-5 or 5×10-4M for one month and at 10-5M for thirty months. The progeny of each regenerated plant was analyzed for response to glyphosate. Some progenies showed increased tolerance to glyphosate. 相似文献
70.
In order to study the influence of Arbuscular Mycorrhiza (AM) on the development of root rot infection, tomato plants were raised with or withoutGlomus mosseae and/orPhytophthora nicotianae var.parasitica in a sand culture system. All plants were fed with a nutrient solution containing one of two phosphorus (P) levels, 32µM (I P) or 96µM (II P), to test the consequence of enhanced P nutrition by the AM fungus on disease dynamics. Mycorrhizal plants had a similar development to that of control plants. Treatment withPhytophthora nicotianae var.parasitica resulted in a visible reduction in plant weight and in a widespread root necrosis in plants without mycorrhiza. The presence of the AM fungus decreased both weight reduction and root necrosis. The percentage reduction of adventitious root necrosis and of necrotic root apices ranged between 63 and 89% The enhancement of P nutrition increased plant development, but did not appreciably decrease disease spread. In our system, mycorrhiza increased plant resistance toP. nicotianae var.parasitica infection. Although a contribution of P nutrition by mycorrhiza cannot be excluded, other mechanisms appear to play a crucial role. 相似文献