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1.
2.
cDNA sequence of five mouse guanine deaminase (Gda) alleles and mapping to mouse chromosome 19. 总被引:1,自引:0,他引:1
Guanine deaminase catalyses the conversion of guanine to xanthine and ammonia, thereby irreversibly removing the guanine base from the pool of guanine-containing metabolites. We have identified five alleles at the mouse guanine deaminase locus by cDNA sequencing. These alleles were defined by single-nucleotide polymorphisms at a total of 19 positions. For each allele the representative strains are as follows: Gda(a), C57BL/6J and DBA/2J; Gda(b), A/J; Gda(c), MOLF/Ei; Gda(d), CAST/Ei; and Gda(e), SPRET-1. The only codon change resulting in an amino acid substitution was found at nucleotide 523, where GAT was replaced by AAT in Mus spretus resulting in the deduced substitution of Asp-174 by Asn. The single-nucleotide difference between the a and b alleles was also typed by allele-specific oligonucleotide amplification for 17 common strains of Mus musculus susbp. musculus. By typing the AxB and BxA recombinant inbred (RI) strain sets, Gda was mapped to mouse chromosome 19, a region syntenic with human chromosome 9q11-q22. 相似文献
3.
Genetic distance measures between the laboratory mouse strains C57BL/6J and RF/J and the wild-origin Mus musculus mouse strains CAST/Ei, MOLF/Ei, POSCH I, and CZECH II were estimated by allelic patterns revealed by RFLP analysis. These results suggest phylogenetic relationships indicating that the mouse strains related to the subspecies M.m. domesticus (RF/J, POSCH I and C57BL/6J) are more closely related to the CAST/Ei strain (derived from M.m. castaneus) than to the strains CZECH II (M.m. musculus) and MOLF/Ei (M.m. molossinus). Furthermore, the hybrid strain C57BL/6J is more closely related to POSCH I (M.m. poschiavinus) than to RF/J as calculated by the method distance measures of Cavalli-Sforza and Edwards (Evolution 21,550, 1967), Nei's minimum (Am. Natural. 106,283, 1972) and unbiased minimum (Genetics 89,583, 1978), Edwards (Biometrics 27,873, 1971; Genetic Distance, p. 41, 1974) and Rogers modified (1986). 相似文献
4.
Lambda clones of mouse DNA from BALB/c and C57BL/10, each containing an array of telomere hexamers, were localized by FISH
to a region close to the telomere of Chr 13. Amplification of mouse genomic DNA with primers flanking SSRs within the cloned
DNA showed several alleles, which were used to type eight sets of RI strains. The two lambda clones contained allelic versions
of the interstitial telomere array, Tel-rs4, which is 495 bp in C57BL/10 and which includes a variety of sequence changes from the consensus telomere hexamer.
Comparison of the segregation of the amplification products of the SSRs with the segregation of other loci in an interspecies
backcross (C57BL/6JEi × SPRET/Ei) F1× SPRET/Ei shows recombination suppression, possibly associated with ribosomal DNA sequences present on distal Chr 13 in Mus spretus, when compared with recombination in an interstrain backcross, (C57BL/6J × DBA/J) F1× C57BL/6J, and with the MIT F2 intercross. Analysis of recombination in females using a second interstrain backcross, (ICR/Ha × C57BL/6Ha) F1× C57BL/6Ha, also indicates recombination suppression when compared with recombination in males of the same strains, using
backcross C57BL/6Ha × (ICR/Ha × C57BL/6Ha) F1. Thus, more than one cause may contribute to recombination suppression in this region. The combined order of the loci typed
was D13Mit37–D13Mit30–D13Mit148–(D13Rp1, 2, 3, 4, Tel-rs4)–D13Mit53–D13Mit196–D13Mit77–(D13Mit78, 35). Data from crosses where apparently normal frequencies of recombination occur suggest that the telomere array is about 6
map units proximal to the most distal loci on Chr 13. This distance is consistent with evidence from markers identified in
two YAC clones obtained from the region.
Received: 24 September 1996/Accepted: 20 January 1997 相似文献
5.
Nearly all F1 male mice with Dh/+ genotype between DDD female and DH–Dh/+ male die within a few days after birth; however, this is not observed in the reciprocal cross. The F1
Dh/+ males usually exhibit growth retardation prior to death. To identify the putative genetic locus or loci in DDD genome that
cause the abnormalities in the presence of the Dh, a linkage analysis was carried out in backcross progeny of a cross of (DDD female × DH–+/+ male) F1 female × DH–Dh/+ male. Appearance of growth retardation was examined from the day of birth, and both growth-retarded and normally weaned
Dh/+ males were genotyped for microsatellite marker loci spanning autosomes and the X Chromosome (Chr). Significant evidence
for linkage was identified on the distal edge of the X Chr, near the microsatellite marker of DXMit135. Furthermore, among mice from DDD female × reciprocal F1
Dh/+ male produced between DH–Dh/+ and progenitor strains (C57BL/6J, C3H/HeJ and BALB/cA), only the progeny from ♀DDD ×♂(♀DH–Dh/+×♂C3H/HeJ) F1
Dh/+ male did not show any lethality and/or growth retardation. Thus, the lethality in F1
Dh/+ males accompanied by growth retardation is caused by the interactions between the Dh gene, X Chr, and Y Chr. Based on the CAG repeat sequence length polymorphism among Mus musculus musculus Sry gene, C3H/HeJ was different from C57BL/6J, BALB/cA, and DH. These data suggest that there are at least two functional types
of Y Chr in Mus musculus musculus.
Received: 22 January 1999 / Accepted: 5 April 1999 相似文献
6.
Increased plasticity of genomic imprinting of Dlk1 in brain is due to genetic and epigenetic factors
Sylvie Croteau David Roquis Marie-Claude Charron Danielle Frappier Daniel Yavin J. Conceptión Loredo–Osti Thomas J. Hudson Anna K. Naumova 《Mammalian genome》2005,16(2):127-135
The expression of six imprinted genes (Dlk1, Gtl2, Igf2r, Kcnq1, Nnat, and Peg1) was examined in brains of 21 mice derived from N2 × N2 intercrosses between C57BL/6 and MOLF/Ei strains. Imprinting of Igf2r, Kcnq1, Gtl2, and Dlk1 varied among individuals. As three of these genes are implicated in cell–cell signaling or cell–environment interactions, variation in their imprinting may influence a wide range of biological processes from cell differentiation to behavior. To elucidate the mechanisms underlying the interindividual imprinting variation in the brain, we focused our effort on the paternally expressed gene Dlk1. We investigated expression of Dlk1 in the brains of animals from N9 and N10 backcrosses and found that reactivation of the normally silent maternal Dlk1 allele in the N9 and N10 mice occurred less often than in N2 × N2 animals. Our data suggest that trans-acting genetic factors of MOLF/Ei origin facilitate the reactivation of the normally silent maternal allele of Dlk1. We mapped one of these factors to the proximal part of Chr 7. The results of bisulfite sequencing methylation analysis show that reactivation of the maternal allele was also associated with hypermethylation of the intragenic differentially methylated region (IG DMR), which is the imprinting control region for the Dlk1–Gtl2 domain. Thus, the imprinting status of Dlk1 in the brain depends upon trans-acting genetic influences and correlates with the methylation status of a specific subregion of the IG DMR.The GenBank accession numbers for sequences described in this article are AY644388–644394. 相似文献
7.
Maps from two interspecific backcross DNA panels available as a community genetic mapping resource 总被引:44,自引:0,他引:44
L. B. Rowe J. H. Nadeau R. Turner W. N. Frankel V. A. Letts J. T. Eppig M. S. H. Ko S. J. Thurston E. H. Birkenmeier 《Mammalian genome》1994,5(5):253-274
We established two mouse interspecific backcross DNA panels, one containing 94 N2 animals from the cross (C57BL/6J × Mus spretus)F1 × C57BL/6J, and another from 94 N2 animals from the reciprocal backcross (C57BL/6J × SPRET/Ei)F1 × SPRET/Ei. We prepared large quantities of DNA from most tissues of each animal to create a community resource of interspecific backcross DNA for use by laboratories interested in mapping loci in the mouse. Initial characterization of the genetic maps of both panels has been completed. We used MIT SSLP markers, proviral loci, and several other sequence-defined genes to anchor our maps to other published maps. The BSB panel map (from the backcross to C57BL/6J) contains 215 loci and is anchored by 45 SSLP and 32 gene sequence loci. The BSS panel map (from the backcross to SPRET/Ei) contains 451 loci and is anchored by 49 SSLP loci, 43 proviral loci, and 60 gene sequence loci. To obtain a high density of markers, we used motif-primed PCR to fingerprint the panel DNAs. We constructed two maps, each representing one of the two panels. All new loci can be located with a high degree of certainty on the maps at current marker density. Segregation patterns in these data reveal several examples of transmission ratio distortion and permit analysis of the distribution of crossovers on individual chromosomes. 相似文献
8.
9.
Details of a new model of diet-dependent polygenic obesity are presented. CAST/Ei (Mus m. castaneus) mice remain lean after 12 weeks on a high-fat (32 kcal% fat) diet, while C57BL/6J mice become obese. The genes responsible
for the obesity segregate in an F2 population derived from an intercross between CAST/Ei and C57BL/6J mice. Quantitative trait analysis, with simple sequence
length polymorphisms (SSLPs) at loci previously linked to rodent obesities, identified a quantitative trait locus (QTL) on
Chromosome (Chr) 15, accounting for approximately 9% of the variance in adiposity and 14% of the variance in mesenteric depot
size. This locus appears to be at the same location as the dietary obesity-3 (Do3) locus controlling body fat content, which was previously identified in an F2 population derived from an SWR/J × AKR/J cross. This is also at the same location as the multigenic obesity-4 (Mob4) locus found in BSB mice, which display spontaneous polygenic obesity. Suggestive linkage also was found at loci close to
the single gene mutations A
y
on Chr 2 and tub on Chr 7.
Received 15 January 1996 / Accepted 12 May 1996 相似文献
10.
Genomic imprinting is an epigenetic modification of the gamete or zygote leading to parental origin-specific differential expression of the two alleles of a gene in somatic cells of the offspring. We previously reported that the human KVLQT1 gene is imprinted and disrupted in patients with germline balanced chromosomal rearrangements and Beckwith–Wiedemann syndrome. In human, the gene is imprinted in most fetal tissues except the heart, and KVLQT1 is part of a 1-Mb cluster of imprinted genes on human chromosome 11p15.5. We sought to determine whether the mouse Kvlqt1 gene is imprinted, by performing interspecific crosses of 129/SvEv mice with CAST/Ei(Mus musculus castaneus). We identified a transcribed polymorphism that distinguishes the two parental alleles in F1offspring. Examination of embryonic, neonatal, and postnatal tissues revealed that Kvlqt1 is imprinted in mouse early embryos, in both female 129 × male CS and female CS × male 129 offspring, with preferential expression of the maternal allele, like the human homologue. Surprisingly, imprinting was developmentally relaxed, and the developmental stage and tissue specificity of relaxation of imprinting was strain-dependent. To our knowledge, this is the first example of an endogenous gene that shows strain-dependent developmental relaxation of imprinting. 相似文献
11.
12.
Simultaneous measurements of chlorophyll (Chl) fluorescence and CO2 assimilation (A) in Vicia faba leaves were taken during the first weeks of growth to evaluate the protective effect of 24-epibrassinolide (EBR) against
damage caused by the application of the herbicide terbutryn (Terb) at pre-emergence. V. faba seeds were incubated for 24 h in EBR solutions (2 × 10−6 or 2 × 10−5 mM) and immediately sown. Terb was applied at recommended doses (1.47 or 1.96 kg ha−1) at pre-emergence. The highest dose of Terb strongly decreased CO2 assimilation, the maximum quantum yield of PSII photochemistry in the dark-adapted state (F
V/F
M), the nonphotochemical quenching (NPQ), and the effective quantum yield (ΔF/F′M) during the first 3–4 weeks after plant emergence. Moreover, Terb increased the basal quantum yield of nonphotochemical processes
(F
0/F
M), the degree of reaction center closure (1 − q
p), and the fraction of light absorbed in PSII antennae that was dissipated via thermal energy dissipation in the antennae
(1 − F′V/F′M). The herbicide also significantly reduced plant growth at the end of the experiment as well as plant length, dry weight,
and number of leaves. The application of EBR to V. faba seeds before sowing strongly diminished the effect of Terb on fluorescence parameters and CO2 assimilation, which recovered 13 days after plant emergence and showed values similar to those of control plants. The protective
effect of EBR on CO2 assimilation was detected at a photosynthetic photon flux density (PFD) of 650 μmol m−2 s−1 and the effect on ΔF/F′M and photosynthetic electron transport (J) was detected under actinic lightings up to 1750 μmol m−2 s−1. The highest dose of EBR also counteracted the decrease in plant growth caused by Terb, and plants registered the same growth
values as controls. 相似文献
13.
Tadao Serikawa Xavier Montagutelli Dominique Simon-Chazottes Jean-Louis Guénet 《Mammalian genome》1992,3(2):65-72
Ten single, arbitrarily designed oligodeoxynucleotide primers, with 50–70% (G+C) content, were used to amplify by polymerase chain reaction (PCR) sequences with DNA templates from several mouse species (Mus spretus, Mus musculus musculus, and Mus musculus domesticus), as well as DNA from the laboratory rat (Rattus norvegicus). Eight of these ten primers, used either individually or associated in pairs, generated a total of 13 polymorphic products which were used as genetic markers. All of these polymorphic sequences but one were mapped to a particular mouse chromosome, by use of DNA panels prepared either from interspecific backcross progeny of the type (C57BL/6 x Mus spretus)F1 x C57BL/6 or DNA samples prepared from two sets of recombinant inbred (RI) strains (AKXL and BXD). Six rat-specific DNA segments were also assigned to a particular chromosome with DNA panels prepared from 18 rat/mouse somatic cell hybrids segregating rat chromosomes. From these experiments we conclude that, under precisely standardized PCR conditions, the DNA molecules amplified with these arbitrarily designed primers are useful and reliable markers for genetic mapping in both mouse and rat. 相似文献
14.
Employing isoeletric focusing combined with enzyme-linked immunoelectrotransfer blot analysis, the fourth component of complement (C4) was analyzed in the two highly histocompatible, major histocompatibility complex homozygous groups (J and K) of Xenopus laevis. Each group had a characteristic C4 isoelectric focusing pattern, i. e., an isoelectric point range of 8.0–8.5 for J (C4
j
C4
j
) and 7.6–8.1 for K (C4
k
C4
k
). In (J x K)F1 frogs, C4 proteins were expressed in a codominant fashion (C4
j
C4
k
). In the backcrossed progeny B1 [J × (J × K)F1], those with C4
j
C4
j
rejected (J × K)F1 skins hyperacutely (< 17 days), were high responders against (J × K)F1 cells, and nonstimulators to J cells in mixed lymphocyte reaction (MLR), but they did not suffer from the graft-versus-host reaction (GVHR), even after the injection of (J x K)F1 cell-stimulated J splenocytes. On the other hand, the B1 frogs with C4
j
C4
k
acutely or chronically (> 17 days) rejected (J × K)F1 skins, were low or nonresponders against (J × K)F1 cells and high stimulators to J cells in MLR, and they suffered from GVHR after the injection of prestimulated J splenocytes. These results argue for the notion that the genes equivalent to mammalian class III map to the MHC at the phylogenetic level of the anuran amphibian. 相似文献
15.
Chunhui Cao Shichun Sun Xuekui Wang Wenling Liu Ying Liang 《Journal of applied phycology》2011,23(6):1039-1043
Experimental ecology methods and chlorophyll fluorescence technology were used to study the effects of different concentrations
of manganese (10−12– 10−4 mol L−1) on the growth, photosystem II and superoxide dismutase (SOD) activity of Amphidinium sp. MACC/D31. The results showed that manganese had a significant effect on the growth rate, fluorescence parameters (maximal
photochemical efficiency of PSII (F
v
/F
m
), photochemical quenching (qP) and non-photochemical quenching (NPQ)) in the exponential stage (days 1–3) and SOD activity
of Amphidinium sp. (P < 0.05). F
v/F
m in the exponential stage in 10−12 mol L−1 manganese concentration was significantly lower whilst qP and NPQ significantly higher than those in the other concentrations.
F
v
/F
m
(days 6–9) in 10−4 mol L−1 manganese was significantly higher than those in the other concentrations. F
v
/F
m
(days 3–6) increased with increased concentration of manganese from 10−12 to 10−4 mol L−1. The values of qP and NPQ decreased with decreased concentrations of manganese, except for those in days 4–6. F
v
/F
m
under each concentration increased earlier and decreased later with culture stage whilst NPQ decreased earlier and increased
later. The SOD activity increased with increased concentration of manganese from 10−12 to 10−8 mol L−1. The SOD activity in 10−4 mol L−1 manganese was significantly higher than those in the other concentrations and in 10−12 mol L−1 manganese, it was significantly lower than those in the other concentrations. 相似文献
16.
Akira Ishikawa Eun-Hee Kim Hasbaira Bolor Md. Bazlur R. Mollah Takao Namikawa 《Mammalian genome》2007,18(4):229-239
Previous QTL studies have identified 24 QTLs for body weight and growth from 3 to 10 weeks after birth in an intersubspecific
backcross mouse population between C57BL/6J and wild Mus musculus castaneus that has 60% of the body size of C57BL/6J. The castaneus allele at the most potent QTL (Pbwg1) on proximal chromosome 2 retards growth. In this study we have developed a congenic strain with a 44.1-Mb interval containing
the castaneus allele at Pbwg1 by recurrent backcrossing to C57BL/6J. The congenic mouse developed was characterized by significantly higher body weight
gain between 1 and 3 weeks of age and lower weight of white fat pads at 10 weeks of age than C57BL/6J. However, no clear difference
in body weight at 1–10 weeks of age was observed between congenic and C57BL/6J strains. QTL analysis with 269 F2 mice between the two strains did not identify any QTLs for body weight at 1, 3, 6, and 10 weeks of age, but it discovered
eight closely linked QTLs affecting body weight gain from 1 to 3 weeks of age, lean body weight, weight of white fat pads,
and body length within the Pbwg1 region. The castaneus alleles at all fat pad QTLs reduced the phenotypes, whereas at the remaining growth and body composition QTLs, they increased
the trait values. These results illustrate that Pbwg1, which initially appeared to be a single locus, was resolved into several loci with opposite effects on the composition traits
of overall body weight. This gives a reason for the loss of the Pbwg1 effect found in the original backcross population.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
17.
Oryza rufipogon Griff. is the ancestor of Asian cultivated rice (O. sativa L.) and possesses valuable genes for rice breeding. Pollen abortion is one of the major causes of indica–japonica hybrid sterility in rice and it happens due to allelic interaction at the pollen sterility gene loci. A total of six loci
(Sa, Sb, Sc, Sd, Se, and Sf) have been found to be associated with F1 pollen sterility between indica and japonica rice, and five of them (all except Sf) have been mapped. Neutral alleles (S
n
) at each locus have the potential to overcome the pollen sterility associated with the respective locus. Therefore, exploitation
and utilization of neutral alleles have significant importance in overcoming indica–japonica hybrid sterility. In this study, an accession (IRW28) of O. rufipogon, native to China, was selected as paternal to cross with typical japonica (Taichung 65) and indica (Guanglu’ai 4) tester lines, and two F2 populations were developed. The simple sequence repeat markers tightly linked to five pollen sterility loci were applied
for genotyping the F2 populations. Chi-squared tests were applied to examine the normal segregation/distortion at each locus. The expected and
observed pollen sterility for each locus were estimated. As a result, the genotypes at five pollen sterility gene loci for
IRW28 were identified as: Sa
i−1/Sa
i−1, Sb
n
/Sb
n
, Sc
i−2/Sc
i−2, Sd
n
/Sd
n
and Se
n
/Se
n
. Our results suggest that IRW28 (O. rufipogon) has the neutral alleles for pollen fertility at the Sb, Sd and Se loci, and these alleles have a good affinity with indica and japonica rice. These neutral alleles provide valuable gene resources to overcome the inter-subspecific hybrid pollen sterility in
rice. 相似文献
18.
Niyogi S Wood CM 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2004,174(3):243-253
We evaluated the differential nature of interactions between waterborne Ca and Cd transport in the gills of yellow perch (Perca flavescens) and rainbow trout (Oncorhynchus mykiss), two species with a more than 400-fold difference in acute waterborne Cd tolerance. The Jmax (maximum rate of uptake) and Km (inverse of affinity) for Ca uptake, in the absence of Cd, were significantly lower in yellow perch (120.48 nM g–1 wet wt h–1 and 92.17 M, respectively) relative to rainbow trout (188.68 nM g–1 wet wt h–1 and 243.90 M, respectively). Similarly, the Jmax for Cd uptake, at the lowest waterborne Ca level (100 M) tested, was significantly lower in yellow perch (0.27 nM g–1 wet wt h–1) relative to rainbow trout (0.40 nM g–1 wet wt h–1), but no significant difference was observed in the Km values between the two species (yellow perch: 32.47 nM; rainbow trout: 31.27 nM). Waterborne Cd (0–890 nM) as well as waterborne Ca (100–1,000 M) competitively inhibited branchial uptake of each other in both species. However, analyses of inhibitor constants for branchial Ca uptake by waterborne Cd (
) revealed that the inhibition was about 1.8 times more potent in rainbow trout compared to yellow perch. In contrast, analyses of inhibitor constants for branchial Cd uptake by waterborne Ca (
) indicated that the inhibition was more than three fold more potent in yellow perch than in rainbow trout. Higher branchial Ca uptake and more potent inhibition by Cd as well as higher branchial Cd uptake and less potent inhibition by Ca were also reflected in whole-body measurements of Ca and Cd influx in trout relative to perch. Overall, whole-body effects were in accord with the branchial kinetic analyses. These results further strengthen the conclusion that branchial influxes of Ca and Cd occur through common pathways. Moreover, interspecific differences in acute waterborne Cd sensitivity can be explained, at least in part, by the differential nature of interactions between waterborne Ca and Cd transport in fish gills.Abbreviations
FAAS
flame atomic absorption spectrophotometer
-
GFAAS
graphite furnace atomic absorption spectrophotometer
-
J
max
maximum rate of uptake
-
K
i
inhibitor constant
-
K
m
substrate concentration at which the rate of uptake is half of the Jmax
-
96 h LC50
concentration at which 50% mortality occurs after 96 h
Communicated by L.C.-H. WangThis revised version was published online in February 2004 with corrections to the abbreviation
. 相似文献
19.
Sala CA Bulos M Altieri E Weston B 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2012,124(2):385-396
Imisun and CLPlus are two imidazolinone (IMI) tolerance traits in sunflower (Helianthus annuus L.) determined by the expression of different alleles at the same locus, Ahasl1-1 and Ahasl1-3, respectively. This paper reports the level of tolerance expressed by plants containing both alleles in a homozygous, heterozygous
and in a heterozygous stacked state to increasing doses of IMI at the enzyme and whole plant levels. Six genotypes of the
Ahasl1 gene were compared with each other in three different genetic backgrounds. These materials were treated at the V2–V4 stage
with increasing doses of imazapyr (from 0 to 480 g a.i. ha–1) followed by an assessment of the aboveground biomass and herbicide phytotoxicity. The estimated dose of imazapyr required
to reduce biomass accumulation by 50% (GR50) differed statistically for the six genotypes of the Ahasl1 gene. Homozygous CLPlus (Ahasl1-3/Ahasl1-3) genotypes and materials containing a combination of both tolerant alleles (Imisun/CLPlus heterozygous stack, Ahasl1-1/Ahasl1-3) showed the highest values of GR50, 300 times higher than the susceptible genotypes and more than 2.5 times higher than homozygous Imisun materials (Ahasl1-1/Ahasl1-1). In vitro AHAS enzyme activity assays using increasing doses of herbicide (from 0 to 100 μM) showed similar trends, where
homozygous CLPlus materials and those containing heterozygous stacks of Imisun/CLPlus were statistically similar and showed
the least level of inhibition of enzyme activity to increasing doses of herbicide. The degree of dominance for the accumulation
of biomass after herbicide application calculated for the Ahasl1-1 allele indicated that it is co-dominant to recessive depending on the imazapyr dose used. By the contrary, the Ahasl1-3 allele showed dominance to semi dominance according to the applied dose. This last allele is dominant over Ahasl1-1 over the entire range of herbicide rates tested. At the level of enzymatic activity, however, both alleles showed recessivity
to semi-recessivity with respect to the wild-type allele, even though the Ahasl1-3 allele is dominant over Ahasl1-1 at all the herbicides rates used. 相似文献
20.
Kun-dong Bai De-bao Liao De-bing Jiang Kun-fang Cao 《Trees - Structure and Function》2008,22(4):449-462
Photosynthetic induction times and photoinhibition in relation to simulated sunflecks (sudden increase of irradiance from
20 to 1,500 μmol m−2 s−1) were examined in leaves of co-occurring Fagus lucida (a deciduous tree) and Castanopsis lamontii (an evergreen tree) saplings grown either in a beech forest understory or in an adjacent open site during a late rainy season.
Two hypotheses were tested: (1) understory leaves would display faster photosynthetic induction times and greater photoinhibition
than open-grown leaves; and (2) evergreen species would have slower photosynthetic induction times and lighter photoinhibition
than deciduous species. Times to reach 90% of maximal CO2 assimilation rate (t
90%A
) and stomatal conductance
did not differ between species, but showed faster by 3–5 min in open-grown leaves than understory leaves due to higher initial
stomatal conductance (g
s
initial) and induction state 1 min into simulated sunflecks (IS1min) in the former. Our analysis across the published data on photosynthetic induction of 48 broad-leaved woody species again
revealed the negative correlations between t
90%A
and either g
s initial or IS1min, and the similarity of t
90%A
and between evergreen and deciduous species. Measurements of maximum PSII photochemical efficiency (F
v/F
m) indicated that photoinhibition occurred in saplings in any of the growth habitats during sunfleck-induced photosynthetic
induction. Despite no interspecific differences in the degree of photoinhibition, understory leaves of both species suffered
heavier photoinhibition than open-grown leaves, as indicated by a stronger decrease of F
v/F
m in the former. Dynamic changes in the quantum yields of PSII photochemistry and ΔpH- and xanthophyll-regulated thermal dissipation
and adjustments in the partitioning of electron flow between assimilative and non-assimilative processes were functional to
resist photoinhibition. However, such photoinhibition, together with stomatal and biochemical limitations, would decrease
carbon gain during simulated sunflecks, particularly in understory leaves. 相似文献