نتایج جستجو برای: tree species
تعداد نتایج: 692962 فیلتر نتایج به سال:
Given a gene tree and a species tree, a coalescent history is a list of the branches of the species tree on which coalescences in the gene tree take place. Each pair consisting of a gene tree topology and a species tree topology has some number of possible coalescent histories. Here we show that, for each n>or=7, there exist a species tree topology S and a gene tree topology G not equalS, both ...
Due to variances in response of different tree species in different habitats to climate changes, further studies in this field is clearly required. On the other hand, the lack of studies on chronology to evaluate the effect of solar radiation on radial growth of tree species due to lack of long term data of an important climatic variable, new approaches to determine the effect of this parameter...
introduction climate change happens due to abnormal changes of climate within the earth’s atmosphere and their consequences. one of the most significant effects of climate change is the irreversible damage to some floral species and forest ecosystems. tree species reflect the impact of climate changes on their ring width. generally, tree rings vary in size each year depending upon the environme...
Forests worldwide are currently threatened by a number of non-native tree diseases. Widespread death of a tree species will have ecological impacts on species that in some way depend on that tree species to complete their life-cycle. One measure to mitigate these impacts is to establish alternative tree species to replace the threatened tree species. These alternative tree species should be as ...
In this study, genetic differences and phylogenic relationships among six Mugilidae species (Mugil cephalus, M. capito, Liza subviridis, L. saliens, L. aurata, Valamugil buchanani) were determined using PCR-sequencing. M. cephalus, L. subviridis, and V. buchanani from the Persian Gulf and Oman Sea, and L. aurata and L. saliens from the Caspian Sea were col-lected. Samples of an imported, Egypt...
Changes in tree species distributions are a potential impact of climate change on forest ecosystems. The examination of tree species shifts in forests of the eastern United States largely has been limited to simulation activities due to a lack of consistent, long-term forest inventory datasets. The goal of this study was to compare current geographic distributions of tree seedlings (trees with ...
Maintaining genomic diversity in goat populations in different parts of Iran is essential for breeding programs, increasing production, survival, resistance to diseases, and various environmental changing conditions. The aim of the present study was to determine the sequence of HVR1 from the mitochondrial genome of Iranian native goats including Sistani, Pakistani, Black and Lorry ecotypes...
the cypress tree mealybug, planococcus vovae (nasonov) (hem., pseudococcidae) is one of the most important pests of cypress trees, especially cupressus semprevirens fastigiata l. in iran. a survey was carried out to determine the natural enemies of cypress tree mea-lybug in tehran province, during 2004-2005. as a result of this study, 17 species of preda-tors, parasitoids and hyperparasitoids b...
wood farming and especially poplar plantation is a key answer to the increasing demand of raw materials in wood and cellulosic industries. according to the diversity of wood applications, taking into account the wood quality and grading by wood farmers/buyers as well as its quantity can lead to an optimal management of production and consumption. in this regard, it is necessary to introduce and...
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