نتایج جستجو برای: ecotypes
تعداد نتایج: 2016 فیلتر نتایج به سال:
This study was conducted to evaluate drought resistance of milk thistle (Silybum marianum L.) at seedling stage. The experiment was designed as a split plot in a randomized complete block design. Treatments were combination of drought stress levels as main plots and different milk thistle ecotypes as subplot layouts replicated 3 times and run in a hydroponic system. Root length, root volume, ch...
Studying genetic diversity is important because a decrease in genetic variability might result in a reduction of the plasticity of the crops to respond to changes in climate, pathogen populations, or agricultural practices. In this study, 72 Sardari wheat (Triticum aestivum L.) ecotypes were analyzed by AFLP markers and 17 phenotypic characters. Three pairs of EcoRI/MseI primer combinations pro...
Several saffron ecotypes (Mashhad, Torbat-Jam, Torbat-Haydarieh, Gonabad, Birjand, Ghaen) were evaluated in Urmia for stigma yield and yield components using different maternal corm weights(6, 8, 10, 12 g) in 2013 cropping year. The experiment was arranged as factorial based on randomized complete block design. Analysis of variance showed that there were significant differences among saffron ec...
Hypothesis: Seasonal variation in availability of resources maintains co-existence between different ecological types due to frequency-dependent interactions. Organism: Escherichia coli. Methods: When populations containing two ecotypes of E. coli that evolved from a common ancestor under sympatric conditions grow in batch culture on a mixture of glucose and acetate, they first use up the avail...
Specialization in plant host-symbiont-soil interactions may help mediate plant adaptation to edaphic stress. Our previous field study showed ecological evidence for host-symbiont specificity between serpentine and non-serpentine adapted ecotypes of Collinsia sparsiflora and arbuscular mycorrrhizal fungi (AMF). To test for adapted plant ecotype-AMF specificity between C. sparsiflora ecotypes and...
Killer whales (Orcinus orca) currently comprise a single, cosmopolitan species with a diverse diet. However, studies over the last 30 yr have revealed populations of sympatric "ecotypes" with discrete prey preferences, morphology, and behaviors. Although these ecotypes avoid social interactions and are not known to interbreed, genetic studies to date have found extremely low levels of diversity...
Through microscopic analysis of veins and assessment of light- and CO2-saturated rates of photosynthetic oxygen evolution, we investigated the relationship between minor loading vein anatomy and photosynthesis of mature leaves in three ecotypes of Arabidopsis thaliana grown under four different combinations of temperature and photon flux density (PFD). All three ecotypes exhibited greater numbe...
Bacteria are profoundly different from eukaryotes in their patterns of genetic exchange. Nevertheless, ecological diversity is organized in the same way across all of life: individual organisms fall into more less discrete clusters on the basis of their phenotypic, ecological, and DNA sequence characteristics. Each sequence cluster in the bacterial world appears to correspond to an "ecotype," d...
Forces driving the evolution of reproductive isolation among natural populations, as well as the mechanisms involved to maintain it, are still poorly understood. Because sympatric ¢sh ecotypes mainly di¡er in phenotypic traits associated with occupying distinct trophic niches, it is generally believed that reproductive isolation is mainly driven by ecological divergent selection, excluding geno...
Previous analysis of the PAI tryptophan biosynthetic gene family in Arabidopsis thaliana revealed that the Wassilewskija (WS) ecotype has four PAI genes at three unlinked sites: a tail-to-tail inverted repeat at one locus (PAI1-PAI4) plus singlet genes at two other loci (PAI2 and PAI3). The four WS PAI genes are densely cytosine methylated over their regions of DNA identity. In contrast, the Co...
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