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Polymorphic seeds of Atriplex triangularis were germinated at various temperatures (5–15 C, 5–25 C, 10–20 C, 20–30 C) and salinity regimes (0 to 1.5% NaCl) in order to determine their germinability and early seedling growth under these conditions. Larger seeds generally had a higher germination percentage in saline medium. The rate and percentage of germination decreased with increased salinity stress. A thermoperiod of 25 C day and 5 C night, 12 hr/12 hr, temperature enhanced germination of seeds. Early seedling growth is promoted in larger seeds at lower salinity, and at high-day and low-night temperatures. Polymorphic seeds have different physiological requirements which provide alternative situations for seed germination in natural habitats. 相似文献
23.
Background
A large number of papers have been published on analysis of microarray data with particular emphasis on normalization of data, detection of differentially expressed genes, clustering of genes and regulatory network. On other hand there are only few studies on relation between expression level and composition of nucleotide/protein sequence, using expression data. There is a need to understand why particular genes/proteins express more in particular conditions. In this study, we analyze 3468 genes of Saccharomyces cerevisiae obtained from Holstege et al., (1998) to understand the relationship between expression level and amino acid composition. 相似文献24.
The signal produced by fluorescence in situ hybridization (FISH) often is inconsistent among cells and sensitivity is low. Small DNA targets on the chromatin are difficult to detect. We report here an improved nick translation procedure for Texas red and Alexa Fluor 488 direct labeling of FISH probes. Brighter probes can be obtained by adding excess DNA polymerase I. Using such probes, a 30 kb yeast transgene, and the rp1, rp3 and zein multigene clusters were clearly detected. 相似文献
25.
Patterns of sequence conservation in presynaptic neural genes 总被引:1,自引:1,他引:0
Hadley D Murphy T Valladares O Hannenhalli S Ungar L Kim J Bućan M 《Genome biology》2006,7(11):R105-19
Background
The neuronal synapse is a fundamental functional unit in the central nervous system of animals. Because synaptic function is evolutionarily conserved, we reasoned that functional sequences of genes and related genomic elements known to play important roles in neurotransmitter release would also be conserved. 相似文献26.
27.
Atriplex prostrata was grown for one month in nutrient solutions with NaCl, KCl, Na2SO4, and K2SO4 (at osmotic potentials of 0, –0.75, –1.00, and –1.50 MPa). Plants treated with K2SO4 had less glycinebetaine at –1.0 and –1.50 MPa than those treated with Na+ salts, probably due to the inhibitory effects of K+ on glycinebetaine accumulation. 相似文献
28.
Dimorphic seeds of Atriplex prostrata were removed from cold dry storage monthly over a one year period to test for fluctuations in seed dormancy and germination
rate. For each seed type, four replicates of 25 seeds were exposed to four alternating night/day temperature regimes mimicking
seasonal fluctuations in Ohio: 5/15 °C; 5/25 °C; 15/25 °C and 20/35 °C with a corresponding 12-h photoperiod (20 μmol m−2 s−1; 400 – 700 nm). We found a significant three-way interaction of seed size, temperature and month for both percent germination
and the rate of germination. Large seeds showed the greatest germination at the 20/35 °C and 5/25 °C temperature regimes and
small seeds at the 5/25 °C regime. Large seeds had greater germination at all temperatures as compared to small seeds. Large
seeds had the fastest germination rates at 20/35 °C followed by 5/25 °C whereas small seeds had the fastest rates at 5/25
°C followed by 20/35 °C.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
29.
The influence of bracteoles on the germination response of asalt marsh annual, Atriplex prostrata, and a salt desert perennial,A. griffithii, was determined. Attached bracteoles did not inhibitgermination of A. prostrata but completely inhibited germinationof A. griffithii seeds. Germination of seeds ofA. griffithiiwas also somewhat inhibited in the presence of detached bracteoles.The osmotic potential of dissolved substances in water-saturatedbracteoles was -4.8 ± 0.05 MPa for A. griffithii and-2.4 ± 0.15 MPa for A. prostrata. Ash content of bracteoleson a dry weight basis was 28.7 ± 0.37% for A. prostrataand 30.0 ± 0.29% for A. griffithii. The presence of relativelyhigh concentrations of dissolved salts in bracteoles may explainthe reduced germination of A. griffithii. Germination of seedsof the perennial A. griffithii may also be inhibited mechanicallyby the presence of persistent bracteoles, whereas the annualA. prostrata has ephemeral bracteoles that may serve to limitgermination in the autumn but are not present during the normalspring germination period. Bracteoles could affect the dispersalof seeds by water since some fruiting structures of A. griffithiiand A. prostrata are able to float in 1.0% NaCl solutions for5 and >30 d, respectively, compared with a maximum of 4 and3 d for seeds without bracteoles. Fruiting structures of A.prostrata floated for longer over a range of salinities thandid those ofA. griffithii ; this may play a significant rolein the dispersal of this salt marsh species. Copyright 2001Annals of Botany Company Atriplex, bracteoles, dispersal, flotation, germination, salinity, temperature 相似文献
30.