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Florigen
Florigen (or flowering hormone) is the hypothesized hormone-like molecule responsible for controlling and/or triggering flowering in plants. Florigen is produced in the leaves, and acts in the shoot apical meristem of buds and growing tips. It is known to be graft-transmissible, and even functions between species. However, despite having been sought since the 1930s, the exact nature of florigen is still disputed. Mechanism Essentially, to understand florigen, you must first understand how flowering works. For a plant to begin flowering, it must make its changes to the shoot apical meristem (SAM). However, there are factors the plant must first consider before it begins this process such as the environment but even more specifically, light. It is through "the evolution of both internal and external control systems that enables plants to precisely regulate flowering so that it occurs at the optimal time for reproductive success." The way the plant determines this optimal time is th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flowering
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanism for the union of sperm with eggs. Flowers may facilitate outcrossing (fusion of sperm and eggs from different individuals in a population) resulting from cross-pollination or allow selfing (fusion of sperm and egg from the same flower) when self-pollination occurs. There are two types of pollination: self-pollination and cross-pollination. Self-pollination occurs when the pollen from the anther is deposited on the stigma of the same flower, or another flower on the same plant. Cross-pollination is when pollen is transferred from the anther of one flower to the stigma of another flower on a different individual of the same species. Self-pollination happens in flowers where the stamen and carpel mature at the same time, and are positioned so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mikhail Chailakhyan
Mikhail Khristoforovich Chailakhyan ( hy, Միքայել Քրիստափորի Չայլախյան, russian: Михаи́л Христофо́рович Чайлахя́н) (1902–1991) was an Armenian-Soviet scientist who is widely known for proposing the existence of a universal plant hormone that is involved in flowering. He named this hormone florigen in 1936. His studies included the mechanisms of flowering, tuberization and sex expression in plants. His pioneer work included the agricultural applications of phytohormones and synthetic analogs.Aksenova, P. 2002. Problems of growth and development in the studies by M.Kh. Chailakhyan. Russian journal of Plant Physiology 49(4) 434-437. References {{DEFAULTSORT:Chailakhyan, Mikhail 1902 births 1991 deaths Full Members of the USSR Academy of Sciences Members of the German National Academy of Sciences Leopoldina Yerevan State University alumni Academic staff of Yerevan State University Soviet Armenians Armenian biologists ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photoperiodism
Photoperiodism is the physiological reaction of organisms to the length of night or a dark period. It occurs in plants and animals. Plant photoperiodism can also be defined as the developmental responses of plants to the relative lengths of light and dark periods. They are classified under three groups according to the photoperiods: short-day plants, long-day plants, and day-neutral plants. Plants Many flowering plants (angiosperms) use a photoreceptor protein, such as phytochrome or cryptochrome, to sense seasonal changes in night length, or photoperiod, which they take as signals to flower. In a further subdivision, ''obligate'' photoperiodic plants absolutely require a long or short enough night before flowering, whereas ''facultative'' photoperiodic plants are more likely to flower under one condition. Phytochrome comes in two forms: Pr and Pfr. Red light (which is present during the day) converts phytochrome to its active form (pfr). This then triggers the plant to grow. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hormone
A hormone (from the Greek participle , "setting in motion") is a class of signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and behavior. Hormones are required for the correct development of animals, plants and fungi. Due to the broad definition of a hormone (as a signaling molecule that exerts its effects far from its site of production), numerous kinds of molecules can be classified as hormones. Among the substances that can be considered hormones, are eicosanoids (e.g. prostaglandins and thromboxanes), steroids (e.g. oestrogen and brassinosteroid), amino acid derivatives (e.g. epinephrine and auxin), protein or peptides (e.g. insulin and CLE peptides), and gases (e.g. ethylene and nitric oxide). Hormones are used to communicate between organs and tissues. In vertebrates, hormones are responsible for regulating a variety of physiological processes and behavioral activities such as diges ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anton Lang (biologist)
Anton Lang (January 18, 1913 – June 24, 1996) was a Russian Empire-born American biologist and a plant physiologist. He was born in Saint Petersburg, his father was Georg Lang, a famous Russian Empire scientist and founding father of modern therapeutic therapies.Georg Lang ttps://web.archive.org/web/20100212195309/http://www.prl.msu.edu/PRL%20History/LangAwardLecturers.pdf Michigan State:The Anton Lang Memorial Awards and seminar/ref> He graduated from the University of Berlin in 1939, majoring in botany. After that, he is working as scientific assistant of Georg Melchers at the Kaiser Wilhelm Institute in Berlin-Dahlem. The cooperation between Anton Lang and Georg Melchers proved extremely fruitful and continued at the Max Planck Institute in Tübingen until 1949, when Anton, his wife Lydia, and his mother emigrated to North America. He was the recipient of a Lady Davis fellowship in the genetics department of McGill University, then a visiting professor at Texas A&M Unive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grafting
Grafting or graftage is a horticultural technique whereby tissues of plants are joined so as to continue their growth together. The upper part of the combined plant is called the scion () while the lower part is called the rootstock. The success of this joining requires that the vascular tissues grow together and such joining is called inosculation. The technique is most commonly used in asexual propagation of commercially grown plants for the horticultural and agricultural trades. In most cases, one plant is selected for its roots and this is called the stock or rootstock. The other plant is selected for its stems, leaves, flowers, or fruits and is called the scion or cion. The scion contains the desired genes to be duplicated in future production by the stock/scion plant. In stem grafting, a common grafting method, a shoot of a selected, desired plant cultivar is grafted onto the stock of another type. In another common form called bud grafting, a dormant side bud is gra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
14-3-3 Protein
14-3-3 proteins are a family of conserved regulatory molecules that are expressed in all eukaryotic cells. 14-3-3 proteins have the ability to bind a multitude of functionally diverse signaling proteins, including kinases, phosphatases, and transmembrane receptors. More than 200 signaling proteins have been reported as 14-3-3 ligands. Elevated amounts of 14-3-3 proteins in cerebrospinal fluid may be a sign of Creutzfeldt–Jakob disease. Properties Seven genes encode seven distinct 14-3-3 proteins in most mammals (See ''Human genes'' below) and 13-15 genes in many higher plants, though typically in fungi they are present only in pairs. Protists have at least one. Eukaryotes can tolerate the loss of a single 14-3-3 gene if multiple genes are expressed, but deletion of all 14-3-3s (as experimentally determined in yeast) results in death. 14-3-3 proteins are structurally similar to the Tetratrico Peptide Repeat (TPR) superfamily, which generally have 9 or 10 alpha helices, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BZIP Domain
The Basic Leucine Zipper Domain (bZIP domain) is found in many DNA binding eukaryotic proteins. One part of the domain contains a region that mediates sequence specific DNA binding properties and the leucine zipper that is required to hold together (dimerize) two DNA binding regions. The DNA binding region comprises a number of basic amino acids such as arginine and lysine. Proteins containing this domain are transcription factors. bZIP transcription factors bZIP transcription factors are found in all eukaryotes and form one of the largest families of dimerizing TFs. An evolutionary study from 2008 revealed that 4 bZIP genes were encoded by the genome of the most recent common ancestor of all plants. Interactions between bZIP transcription factors are numerous and complex and play important roles in cancer development in epithelial tissues, steroid hormone synthesis by cells of endocrine tissues, factors affecting reproductive functions, and several other phenomena that aff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sequence Homology
Sequence homology is the biological homology between DNA, RNA, or protein sequences, defined in terms of shared ancestry in the evolutionary history of life. Two segments of DNA can have shared ancestry because of three phenomena: either a speciation event (orthologs), or a duplication event (paralogs), or else a horizontal (or lateral) gene transfer event (xenologs). Homology among DNA, RNA, or proteins is typically inferred from their nucleotide or amino acid sequence similarity. Significant similarity is strong evidence that two sequences are related by evolutionary changes from a common ancestral sequence. Alignments of multiple sequences are used to indicate which regions of each sequence are homologous. Identity, similarity, and conservation The term "percent homology" is often used to mean "sequence similarity”, that is the percentage of identical residues (''percent identity''), or the percentage of residues conserved with similar physicochemical properties (' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phloem
Phloem (, ) is the living biological tissue, tissue in vascular plants that transports the soluble organic compounds made during photosynthesis and known as ''photosynthates'', in particular the sugar sucrose, to the rest of the plant. This transport process is called translocation. In trees, the phloem is the innermost layer of the bark (botany), bark, hence the name, derived from the Ancient Greek word (''phloiós''), meaning "bark". The term was introduced by Carl Nägeli in 1858. Structure Phloem tissue consists of conducting Cell (biology), cells, generally called sieve elements, Ground tissue#Parenchyma, parenchyma cells, including both specialized companion cells or albuminous cells and unspecialized cells and supportive cells, such as fibres and sclereids. Conducting cells (sieve elements) Sieve elements are the type of cell that are responsible for transporting sugars throughout the plant. At maturity they lack a Cell nucleus, nucleus and have very few organelles, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Translation
Translation is the communication of the Meaning (linguistic), meaning of a #Source and target languages, source-language text by means of an Dynamic and formal equivalence, equivalent #Source and target languages, target-language text. The English language draws a terminology, terminological distinction (which does not exist in every language) between ''translating'' (a written text) and ''Language interpretation, interpreting'' (oral or Sign language, signed communication between users of different languages); under this distinction, translation can begin only after the appearance of writing within a language community. A translator always risks inadvertently introducing source-language words, grammar, or syntax into the target-language rendering. On the other hand, such "spill-overs" have sometimes imported useful source-language calques and loanwords that have enriched target languages. Translators, including early translators of sacred texts, have helped shape the very l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transcription (genetics)
Transcription is the process of copying a segment of DNA into RNA. The segments of DNA transcribed into RNA molecules that can encode proteins are said to produce messenger RNA (mRNA). Other segments of DNA are copied into RNA molecules called non-coding RNAs (ncRNAs). mRNA comprises only 1–3% of total RNA samples. Less than 2% of the human genome can be transcribed into mRNA ( Human genome#Coding vs. noncoding DNA), while at least 80% of mammalian genomic DNA can be actively transcribed (in one or more types of cells), with the majority of this 80% considered to be ncRNA. Both DNA and RNA are nucleic acids, which use base pairs of nucleotides as a complementary language. During transcription, a DNA sequence is read by an RNA polymerase, which produces a complementary, antiparallel RNA strand called a primary transcript. Transcription proceeds in the following general steps: # RNA polymerase, together with one or more general transcription factors, binds to promoter DNA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
