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1.
The study aimed to investigate the association between MTHFR C677T, ENPP1 K121Q, and ADIPOQ 45 T/G gene polymorphisms and incidence of myocardial infarction (MI) in Egyptian patients. The study included 60 unrelated patients suffering from their first MI and 60 unrelated controls. Patients were recruited from Kasr-El Eini hospital, Cairo University. The previously mentioned polymorphisms were determined in all participants by PCR–RFLP. There was no significant difference in the distribution of genotypes and alleles of MTHFR C677T between groups. In contrast, significant difference was found in the distributions of genotypes and alleles of ENPP1 K121Q and ADIPOQ 45 T/G between MI patients and controls (P = 0.01, P = 0.004, P = 0.009, P = 0.001, respectively). Univariate analysis revealed that 121Q ENPP1 and 45 G ADIPOQ alleles were associated with the increased risk of MI (OR = 3; 95 % CI = 1.45–6.2; P = 0.004 and OR = 5.8; 95 % CI = 1.92–17.54; P = 0.001, respectively). The mutant homozygous genotypes of MTHFR, ENPP1, and ADIPOQ were more prevalent in diabetic hypertensive MI patients than it was among non-diabetic normotensive MI patients. Regarding the coagulation profile, INR (P = 0.009) and PC % (P = 0.022) were significantly different among the three genotypes of MTHFR C677T. The 677 T, 121 Q, and 45G variants were associated with MI in Egyptian patients; however, more studies are needed to determine the possible protective effect for these polymorphisms in our population.  相似文献   

2.
The present study reports thanatosis behavior in Hippocampus reidi seahorses. We observed two different types of tonic immobility during seahorse handling, both in the laboratory and in field studies. In the former, the seahorses assumed a stretched posture, and in the latter, pointed their heads towards their bellies and curled their tails in a spiral towards their abdomen. The displays lasted 124 ± 100 s (n = 3) in the laboratory and 155 ± 7.07 s (n = 5) in the field. Camouflage is the seahorses primary defense from predators and our observations suggest that thanatosis is a secondary strategy that could be more effective than retaliation or escaping predators, due to the fact that seahorses lack teeth and have limited swimming ability. The responses caused by fear occurred after manipulation, allowing for the conclusion that the seahorse H. reidi may use thanatosis as a secondary defense strategy under major stress events.  相似文献   

3.
The raccoon dog (Nyctereutes procyonoides) has a wide distribution in Europe and is a prominent example of a highly adaptable alien species. It has been recorded sporadically in Denmark since 1980 but observations since 2008 suggested that the species had established a free-ranging, self-sustaining population. To elucidate the origin and genetic patterns of Danish raccoon dogs, we studied the population genomics of 190 individuals collected in Denmark (n = 141) together with reference captive individuals from Poland (n = 21) and feral individuals from different European localities (Germany, Poland, Estonia and Finland, n = 28). We used a novel genotyping-by-sequencing approach simultaneously identifying and genotyping a large panel of single nucleotide polymorphisms (n = 4526). Overall, there was significant indication for contemporary genetic structuring of the analysed raccoon dog populations, into at least four different clusters, in spite of the existence of long distance gene flow and secondary admixture from different population sources. The Danish population was characterized by a high level of genetic admixture with neighbouring feral European ancestries and the presence of private clusters, non-retrieved in any other feral or captive populations sampled. These results suggested that the raccoon dog population in Denmark was founded by escapees from genetically unidentified Danish captive stocks, followed by a recent admixture with individuals migrating from neighbouring Germany.  相似文献   

4.
Increased advanced glycation endproducts (AGEs) and oxidation products (OPs) have been proposed as pathogenic for diabetic nephropathy (DN). We investigated the relationship between AGEs and OPs measured in different plasma and urine preparations, and progression of DN in 103 young, normoalbuminuric, normotensive participants with type 1 diabetes in the Natural History of Diabetic Nephropathy Study. The primary endpoint was electron microscopy-measured change in glomerular basement membrane (GBM) width from baseline to 5 years; change in mesangial fractional volume was a secondary endpoint. Fast progressors (FP) were defined as the upper quartile (n = 24) of rate of GBM thickening; slow progressors (SP) were the remainder (n = 79). Four AGEs [3-deoxyglucosone and methylglyoxal hydroimidazolones (DG3H1, MGH1) and carboxymethyl and ethyl lysine (CML, CEL)], and two oxidation products methionine sulfoxide and aminoadipic acid were measured by liquid chromatography, triple quadrupole mass spectrometry. Measurements were done on 10 K plasma filtrates and plasma proteolytic digests (PPD) at year 5, and at four time points over 5 years for urinary 10 K filtrates. Urinary filtrate CEL levels were significantly higher in FP, but not after adjustment for HbA1c, sex, and duration of diabetes. MGHI, CEL, and CML plasma filtrate levels were significantly higher in FP relative to SP (p < 0.05). In PPD, only MGHI showed borderline significantly higher levels in FP relative to SP (p = 0.067), while no other product showed correlation. AGE and OP measurements were not correlated with mesangial expansion. In plasma filtrates, HbA1c at year 5 accounted for 4.7 % of the variation in GBM width. The proportion of variation in GBM width was increased to 11.6 % when MGHI, CEL, and CML were added to the model (6.9 % increase).  相似文献   

5.
Genetic factors play important roles in the development of tuberculosis (TB). SP110 is a promising candidate target for controlling TB infections. However, several studies associating SP110 single nucleotide polymorphisms (SNPs) with TB have yielded conflicting results. This may be partly resolved by studying other genes associated with SP110, such as MYBBP1A and RELA. Here, we genotyped 6 SP110 SNPs, 8 MYBBP1A SNPs and 5 RELA SNPs in 702 Chinese pulmonary TB patients and 425 healthy subjects using MassARRAY and SNaPshot methods. Using SNP-based analysis with Bonferroni correction, rs3809849 in MYBBP1A [Pcorrected (cor) = 0.0038] and rs9061 in SP110 (Pcor = 0.019) were found to be significantly associated with TB. Furthermore, meta-analysis of rs9061 in East Asian populations showed that the rs9061 T allele conferred significant risk for TB [P = 0.002, pooled odds ratio (OR), 1.24, 95 % confidence interval (CI) = 1.08–1.43]. The MYBBP1A GTCTTGGG haplotype and haplotypes CGACCG/TGATTG within SP110 were found to be markedly and significantly associated with TB (P = 2.00E?06, 5.00E?6 and 2.59E?4, respectively). Gene-based analysis also demonstrated that SP110 and MYBBP1A were each associated with TB (Pcor = 0.011 and 0.035, respectively). The logistic regression analysis results supported interactions between SP110 and MYBBP1A, indicating that subjects carrying a GC/CC genotype in MYBBP1A and CC genotype in SP110 possessed the high risk of developing TB (P = 1.74E?12). Our study suggests that a combination of SP110 and MYBBP1A gene polymorphisms may serve as a novel marker for identifying the risk of developing TB in the Chinese Han population.  相似文献   

6.
There is significant variation in the expression of schizophrenia across ethnically different populations, and the optimal structural and diagnostic representation of schizophrenia are contested. We contrasted both lifetime frequencies of DSM-IV criterion A (the core symptom criterion of the internationally recognized DSM classification system) symptoms and types/content of delusions and hallucinations in transethnic schizophrenia populations from Australia (n = 776), India (n = 504) and Sarawak, Malaysia (n = 259), to elucidate clinical heterogeneity. Differences in both criterion A symptom composition and symptom content were apparent. Indian individuals with schizophrenia reported negative symptoms more frequently than other sites, whereas individuals from Sarawak reported disorganized symptoms more frequently. Delusions of control and thought broadcast, insertion, or withdrawal were less frequent in Sarawak than Australia. Curiously, a subgroup of 20 Indian individuals with schizophrenia reported no lifetime delusions or hallucinations. These findings potentially challenge the long-held view in psychiatry that schizophrenia is fundamentally similar across cultural groups, with differences in only the content of psychotic symptoms, but equivalence in structural form.  相似文献   

7.
C-reactive protein (CRP) is a heritable biomarker of systemic inflammation and a predictor of cardiovascular disease (CVD). Large-scale genetic association studies for CRP have largely focused on individuals of European descent. We sought to uncover novel genetic variants for CRP in a multiethnic sample using the ITMAT Broad-CARe (IBC) array, a custom 50,000 SNP gene-centric array having dense coverage of over 2,000 candidate CVD genes. We performed analyses on 7,570 African Americans (AA) from the Candidate gene Association Resource (CARe) study and race-combined meta-analyses that included 29,939 additional individuals of European descent from CARe, the Women’s Health Initiative (WHI) and KORA studies. We observed array-wide significance (p < 2.2 × 10?6) for four loci in AA, three of which have been reported previously in individuals of European descent (IL6R, p = 2.0 × 10?6; CRP, p = 4.2 × 10?71; APOE, p = 1.6 × 10?6). The fourth significant locus, CD36 (p = 1.6 × 10?6), was observed at a functional variant (rs3211938) that is extremely rare in individuals of European descent. We replicated the CD36 finding (p = 1.8 × 10?5) in an independent sample of 8,041 AA women from WHI; a meta-analysis combining the CARe and WHI AA results at rs3211938 reached genome-wide significance (p = 1.5 × 10?10). In the race-combined meta-analyses, 13 loci reached significance, including ten (CRP, TOMM40/APOE/APOC1, HNF1A, LEPR, GCKR, IL6R, IL1RN, NLRP3, HNF4A and BAZ1B/BCL7B) previously associated with CRP, and one (ARNTL) previously reported to be nominally associated with CRP. Two novel loci were also detected (RPS6KB1, p = 2.0 × 10?6; CD36, p = 1.4 × 10?6). These results highlight both shared and unique genetic risk factors for CRP in AA compared to populations of European descent.  相似文献   

8.
Ranya El-Bakatoushi 《Flora》2011,206(12):1045-1051
Occurrence and direction of introgressive hybridization between Plantago major taxa were tested. Plantago major plants were collected from 10 Egyptian locations. Four populations of two European taxa were used for comparison. These are ecologically and geographically separated and were identified as the subspecies Plantago major ssp. major and Plantago major ssp. intermedia. In the Egyptian populations, most individuals fall within the variation range of P. major ssp. intermedia. Only one population, from Burg El-Arab, morphologically resembled clearly P. major ssp. major and showed some ISSR fragments that characterize pure populations of this taxon. All individuals of population 2 (Alexandria) and some individuals of populations 1, 3, 5, 6 and 10 (Alexandria, Aswan) morphologically corresponded to P. major ssp. intermedia. All individuals collected from Egypt had ISSR fragments characterizing both pure P. major ssp. major and pure P. major ssp. intermedia. Most of these individuals had a higher percentage of intermedia-type fragments than major-type fragments, suggesting that P. major ssp. intermedia in Egypt shows some introgression towards P. major ssp. major. The pure populations were distinct from each other, while the Egyptian populations were intermediate according to principal coordinate analysis (PCoA) of ISSR data. In the populations collected from Egypt, major and intermedia cannot be seen as separate species. The study suggests that the dominant taxa introgressed to the minority population(s). Taxon frequency may be a key component in determining the direction of introgression.  相似文献   

9.
The Sinai primrose (Primula boveana) is one of the most endangered plant species worldwide, with less than 200 wild individuals surviving in the Sinai mountains of Egypt. There has been a decline in both the number and size of its populations in recent times, possibly caused by threats that include habitat aridification and the impact of human activities. Studying the standing genetic variation and extent of inbreeding of P. boveana is necessary for the design of appropriate conservation strategies for this species. In the present work, we used a set of seven, recently developed, polymorphic microsatellite markers to characterize the genetic variation and levels of inbreeding of the extant populations of P. boveana. We found low levels of genetic variation (H T = 0.470), high differentiation between populations (F ST = 0.737, R ST = 0.935), and very elevated levels of inbreeding (F = 0.862) due to recurrent selfing. These results may be the reflection of low levels of genetic variation and high levels of inbreeding over a long evolutionary period, suggesting that the current genetic pool of the species may enable P. boveana to persist in a habitat where water availability and pollinator services are restricted. Nevertheless, in sight of its rapidly dwindling abundance, it seems prudent to adopt swift measures, including habitat restoration and ex-situ conservation, to prevent the impending extinction of this emblematic species.  相似文献   

10.
Great apes spend half of their lives in a nightly “nest” or sleeping platform (SP), a complex object created by modifying foliage, which functions as a stable substrate on which to sleep. Of the several purported functions of SPs, one hypothesis is that they protect against parasitic infection. Here we investigate the role of SP site choice in avoiding molestation by arthropods. This study presents preliminary data on the insect-repellent properties of preferred sleeping tree species Cynometra alexandri. Insect traps were deployed in gallery forest habitats in which chimpanzees typically “nest.” We compared traps placed adjacent to SPs artificially manufactured with C. alexandri trees to an open area within the same habitat. Multiple measures of arthropod counts indicate that simulated C. alexandri SP sites have fewer arthropods than similar non-SP sites. Volatile compounds secreted by C. alexandri foliage are hypothesized to repel annoying arthropods and/or mask chimpanzee olfactory signals. Of the total insects captured (n = 6,318), n = 145 were mosquitoes. Of the total mosquitoes captured, n = 47 were identified as Anopheles (female, n = 12). The prominent malarial vector Anopheles gambiae was identified among the captured mosquito sample. These results suggest that the presence of broken branches of the tree species C. alexandri reduce the amount of insects a chimpanzee is exposed to throughout a night’s sleep. This great ape behavioral and socio-technological adaptation may have evolved, in part, to increase quality of sleep as well as decrease exposure to vectors of disease.  相似文献   

11.
The p22phox protein subunit is essential for NADPH oxidase activity. The prevalence of C242T variants of p22phox gene was studied in 101 healthy Egyptian controls and 104 acute myocardial infarction (AMI) Egyptian patients. Contribution of oxidative stress, represented by serum oxidized-LDL (ox-LDL), in development of AMI was also examined and correlated with C242T gene variants. Genotyping and ox-LDL were assessed by PCR–RFLP and ELISA. Results showed that wild type CC genotype is prevalent in 27 % of controls; CT and TT are in 72 and 1 %. In patients, the distribution was 40.2, 59.8 and 0 % for CC, CT and TT; respectively, showing a significant difference (p = 0.0259). Serum ox-LDL levels were higher in patients than controls (p ≤ 0.0001). Subjects having CT genotype had lower levels of ox-LDL than CC genotype (p ≤ 0.005). C242T polymorphism of p22phox gene of NADPH oxidase is a novel genetic marker associated with reduced susceptibility to AMI.  相似文献   

12.
Ontogenetic niche theory predicts that individuals may undergo one or more changes in habitat or diet throughout their lifetime to maintain optimal growth rates, or to optimize trade-offs between mortality risk and growth. We combine skeletochronological and stable nitrogen isotope (δ15N) analyses of sea turtle humeri (n = 61) to characterize the growth dynamics of juvenile loggerhead sea turtles (Caretta caretta) during an oceanic-to-neritic ontogenetic shift. The primary objective of this study was to determine how ontogenetic niche theory extends to sea turtles, and to individuals with different patterns of resource use (discrete shifters, n = 23; facultative shifters n = 14; non-shifters, n = 24). Mean growth rates peaked at the start of the ontogenetic shift (based on change in δ15N values), but returned to pre-shift levels within 2 years. Turtles generally only experienced 1 year of relatively high growth, but the timing of peak growth relative to the start of an ontogenetic shift varied among individuals (before, n = 14; during, n = 12; after, n = 8). Furthermore, no reduction in growth preceded the transition, as is predicted by ontogenetic niche theory. Annual growth rates were similar between non-transitioning turtles resident in oceanic and neritic habitats and turtles displaying alternative patterns of resource use. These results suggest that factors other than maximization of size-specific growth may more strongly influence the timing of ontogenetic shifts in loggerhead sea turtles, and that alternative patterns of resource use may have limited influence on somatic growth and age at maturation in this species.  相似文献   

13.
Early menarche is associated with adverse health outcomes, including breast cancer, endometrial cancer, obesity, type 2 diabetes, and cardiovascular disease. Recently, a genomewide association study (GWAS) of age at menarche (AAM) in 104,533 individuals of European ancestry was reported by the ReproGen consortium. They identified 42 loci known and novel loci that were linked to age at menarche. Because age at menarche varies between ethnic groups, we decided to investigate if these results would be replicated in the Korean population. To this end, we examined the association of the SNPs reported in the ReproGen GWAS with AAM in 3,194 individuals from the Korean Genome and Epidemiology Study (KoGES) cohort. Genotype data for total 17 SNPs (6 genotyped SNPs and 11 imputed SNPs) were available for the association analysis using linear regression analysis for age at menarche with controlling current age, waist-to-hip ratio, and body mass index as the covariates. We found replication of the ReproGen study in two SNPs; one SNP (rs466639) in the retinoic acid receptor gamma gene (RXRG), showing a significant association with early menarche (beta = ?0.224 ± 0.065, p value = 5.2 × 10?4, Bonferroni-corrected p value = 0.009), and the other (rs10899489), in GRB2 (growth factor receptor bound protein 2)-associated binding protein 2 (GAB2), linked to late menarche (beta = 0.140 ± 0.047, p value = 2.8 × 10?3, Bonferroni-corrected p value = 0.049). This result possibly suggests that genetic factors governing AAM in the Korean population would be distinct from those in the Europeans, implying roles of modulating or interacting factors in determining AAM, including environmental factors such as nutritional status.  相似文献   

14.
Maximum number of alcoholic drinks consumed in a 24-h period (maxdrinks) is a heritable (>50 %) trait and is strongly correlated with vulnerability to excessive alcohol consumption and subsequent alcohol dependence (AD). Several genome-wide association studies (GWAS) have studied alcohol dependence, but few have concentrated on excessive alcohol consumption. We performed two GWAS using maxdrinks as an excessive alcohol consumption phenotype: one in 118 extended families (N = 2,322) selected from the Collaborative Study on the Genetics of Alcoholism (COGA), and the other in a case–control sample (N = 2,593) derived from the Study of Addiction: Genes and Environment (SAGE). The strongest association in the COGA families was detected with rs9523562 (p = 2.1 × 10?6) located in an intergenic region on chromosome 13q31.1; the strongest association in the SAGE dataset was with rs67666182 (p = 7.1 × 10?7), located in an intergenic region on chromosome 8. We also performed a meta-analysis with these two GWAS and demonstrated evidence of association in both datasets for the LMO1 (p = 7.2 × 10?7) and PLCL1 genes (p = 4.1 × 10?6) with maxdrinks. A variant in AUTS2 and variants in INADL, C15orf32 and HIP1 that were associated with measures of alcohol consumption in a meta-analysis of GWAS studies and a GWAS of alcohol consumption factor score also showed nominal association in the current meta-analysis. The present study has identified several loci that warrant further examination in independent samples. Among the top SNPs in each of the dataset (p ≤ 10?4) far more showed the same direction of effect in the other dataset than would be expected by chance (p = 2 × 10?3, 3 × 10?6), suggesting that there are true signals among these top SNPs, even though no SNP reached genome-wide levels of significance.  相似文献   

15.
Genetic polymorphisms in genes encoding glutathione S-transferases M1 (GSTM1; a member of class mu), T1 (GSTT1; a member of class theta) and O2 (GSTO2; a member of class omega) have been defined previously. Studies have revealed that there were significant differences between populations for allelic frequencies of GSTT1, GSTM1 and GSTO2 N412D polymorphisms. To get more insight into the genetic structure of Iranian populations the present study was done on Iranian Georgians living in Frydoonshahr (Isfahan province) and two Persian populations who living in Shiraz (Fars province) and Frydoonshahr. Study subjects consisted of 401 unrelated healthy individuals. From these 121 were Georgians. The remaining subjects were Persians from either Frydoonshahr (n = 34) or Shiraz (n = 246). The genetic polymorphism of GSTT1, GSTM1 and GSTO2 N412D was detected by PCR-based method. The frequency of GSTT1 null genotype in Georgian and Persians of Frydoonshahr and Shiraz was 15.7, 35.2 and 24.8%, respectively. There was significant difference between these populations for the distributions of the GSTT1 genotypes (χ2 = 7.00, df = 2, P = 0.030). No significant difference was observed between these populations for polymorphisms of GSTM12 = 1.682, df = 2, P = 0.431) and GSTO N142D2 = 4.622, df = 4, P = 0.328). The prevalence of GSTT1 null genotype in Iranian Georgians showed significant difference with Persians and other Asian countries, but it seems to be similar with the frequency which was reported from European populations.  相似文献   

16.
Non-high-density lipoprotein cholesterol(NHDL) is an independent and superior predictor of CVD risk as compared to low-density lipoprotein alone. It represents a spectrum of atherogenic lipid fractions with possibly a distinct genomic signature. We performed genome-wide association studies (GWAS) to identify loci influencing baseline NHDL and its postprandial lipemic (PPL) response. We carried out GWAS in 4,241 participants of European descent. Our discovery cohort included 928 subjects from the Genetics of Lipid-Lowering Drugs and Diet Network Study. Our replication cohorts included 3,313 subjects from the Heredity and Phenotype Intervention Heart Study and Family Heart Study. A linear mixed model using the kinship matrix was used for association tests. The best association signal was found in a tri-genic region at RHOQ-PIGF-CRIPT for baseline NHDL (lead SNP rs6544903, discovery p = 7e?7, MAF = 2 %; validation p = 6e?4 at 0.1 kb upstream neighboring SNP rs3768725, and 5e?4 at 0.7 kb downstream neighboring SNP rs6733143, MAF = 10 %). The lead and neighboring SNPs were not perfect surrogate proxies to each other (D′ = 1, r 2 = 0.003) but they seemed to be partially dependent (likelihood ration test p = 0.04). Other suggestive loci (discovery p < 1e?6) included LOC100419812 and LOC100288337 for baseline NHDL, and LOC100420502 and CDH13 for NHDL PPL response that were not replicated (p > 0.01). The current and first GWAS of NHDL yielded an interesting common variant in RHOQ-PIGF-CRIPT influencing baseline NHDL levels. Another common variant in CDH13 for NHDL response to dietary high-fat intake challenge was also suggested. Further validations for both loci from large independent studies, especially interventional studies, are warranted.  相似文献   

17.
Seasonal pattern (SP) and metabolic syndrome (MetS) are major contributors to poor outcome in bipolar disorders (BD). Patients with seasonal bipolar depression present increased appetite, carbohydrate cravings, weight gain, and hypersomnia, which can increase the development of MetS. MetS also appears to be associated with seasonal mood changes in the general population. This study examines whether a SP in BD is associated with an increased risk of MetS and its sub-components. One thousand four hundred and seventy-one outpatients with BD were systematically enrolled from 2009 to 2016. Inclusion required a disease duration of at least 5 years, with 486 (33%) patients with SP (SP+) and 985 (67%) without (SP–) according to the DSM IV-TR criteria. When using continuous measures of metabolic components, SP+ patients, as compared to SP–, suffered from higher levels for systolic blood pressure (p = 0.01), low-density lipoprotein cholesterol (p = 0.009), fasting glucose (p = 0.007), triglycerides levels (p = 0.03), a larger abdominal circumference (p = 0.02), and a higher body mass index (p = 0.07). In the covariance analysis, adjusted for gender, age, and bipolar subtype, as well as the number of depressive and hypomanic episode, SP+ patients had a significantly higher level of fasting glucose and higher systolic blood pressure. The frequency of MetS did not differ between groups (21.2% in SP– versus 23.9% in SP+). When using categorical definitions for abnormal metabolic components (International Diabetes Federation criteria), there were no differences between groups, except that SP+ patients were more overweight/obese as compared to SP– patients (55.03% versus 46.7%, respectively; p = 0.002) and tended to have more frequently high fasting glucose (18.2% versus 14.3%, respectively; p = 0.07). MetS was frequent in patients with BD, however not associated with SP. Patients with SP appeared more vulnerable to overweight/obesity and presented with higher levels of MetS subcomponents although these parameters were mainly in the normal range. All patients with BD should benefit from early screening and targeted management of cardio-vascular risk factors.  相似文献   

18.
The genus Micatagla Argaman (Bradynobaenidae: Apterogyninae) is reviewed from Egypt, based on specimens collected from Wadi Allaqi (Aswan, Southern Egypt) and Kom Osheim (Fayoum) and those deposited in Egyptian insect collections as well as recorded data from the literature. A single species, Micatagla klugi (André), was previously recorded from Egypt. Micatagla allaqiensis sp. n., Micatagla ezzati sp. n. and Micatagla pseudorainerii sp. n. are described here. Micatagla antropovi Pagliano is also newly recorded from the Egyptian fauna. An illustrated key and a faunistic list comprising all Micatagla species recorded from Egypt are given.  相似文献   

19.
20.
We examined the effects of shoot position on shoot growth and morphology of Avicennia marina (Forssk.) Vierh. in the Red Sea coastal region of Egypt. To determine differences in morphological characteristics, we collected shoots from the upper and lower canopies of A. marina individuals in the wild and compared the morphological characteristics of these shoots. The study plot was established in an A. marina mangrove forest. Heights and diameters of individual trunks (n = 14) in the plot were measured at ground level. Then, five shoots with young but fully expanded leaves were collected from the upper and lower canopies of the individuals. We measured shoot length, and dry weight and also area, dry weight, thickness, and Soil Plant Analysis Development (SPAD) value of collected leaves. Our measurements showed that leaf area, dry weight, specific leaf area, and SPAD value of leaves from the upper canopy were smaller than those of lower-canopy leaves in most individuals. From the differences in traits between upper and lower leaves, we concluded that leaves in the upper canopy are typically adapted to high light levels, whereas leaves in the lower canopy exhibit adaptations to low light conditions. In addition, soil-water salinity at the study site was far higher than the optimum salinity for A. marina. Hence, it is also suggested the salinity level at this site may have influenced the reduced leaf size in the upper canopy.  相似文献   

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