Meristematic Tissues

Meristematic Tissues

Tissues where cells are constantly dividing are called meristems or meristematic tissues. These regions produce new cells. These new cells are generally small, six-sided boxlike structures with a number of tiny vacuoles and a large nucleus, by comparison. Sometimes there are no vacuoles at all. As the cells mature the vacuoles will grow to many different shapes and sizes, depending on the needs of the cell. It is possible that the vacuole may fill 95% or more of the cell’s total volume.

There are three types of meristems:

1. Apical Meristems
2. Lateral Meristems
3. Intercalary Meristems

Apical meristems

are located at or near the tips of roots and shoots. As new cells form in the meristems, the roots and shoots will increase in length. This vertical growth is also known as primary growth. A good example would be the growth of a tree in height. Each apical meristem will produce embryo leaves and buds as well as three types of primary meristems: protoderm, ground meristems, and procambium. These primary meristems will produce the cells that will form the primary tissues.

Lateral meristems account for secondary growth in plants. Secondary growth is generally horizontal growth. A good example would be the growth of a tree trunk in girth. There are two types of lateral meristems to be aware of in the study of plants.

The vascular cambium, the first type of lateral meristem, is sometimes just called the cambium. The cambium is a thin, branching cylinder that, except for the tips where the apical meristems are located, runs the length of the roots and stems of most perennial plants and many herbaceous annuals. The cambium is responsible for the production of cells and tissues that increase the thickness, or girth, of the plant.

The cork cambium, the second type of lateral meristem, is much like the vascular cambium in that it is also a thin cylinder that runs the length of roots and stems. The difference is that it is only found in woody plants, as it will produce the outer bark.

Both the vascular cambium and the cork cambium, if present, will begin to produce cells and tissues only after the primary tissues produced by the apical meristems have begun to mature.

Intercalary meristems are found in grasses and related plants that do not have a vascular cambium or a cork cambium, as they do not increase in girth. These plants do have apical meristems and in areas of leaf attachment, called nodes, they have the third type of meristematic tissue. This meristem will also actively produce new cells and is responsibly for increases in length. The intercalary meristem is responsible for the regrowth of cut grass.

There are other tissues in plants that do not actively produce new cells. These tissues are called nonmeristematic tissues. Nonmeristematic tissues are made of cells that are produced by the meristems and are formed to various shapes and sizes depending on their intended function in the plant. Sometimes the tissues are composed of the same type of cells throughout, or sometimes they are mixed.

Courtesy---

Dose (Biologists)

1. Louis Pasteur  was a French chemist and microbiologist best known for his remarkable breakthroughs in the causes and prevention of disease. His experiments supported the germ theory of disease, also reducing mortality from puerperal fever (childbed), and he created the first vaccine for rabies. He was best known to the general public for inventing a method to stop milk and wine from causing sickness - this process came to be called pasteurization. He is regarded as one of the three main founders of microbiology, together with Ferdinand Cohn and Robert Koch. He is also credited with dispelling the theory of spontaneous generation with his experiment employing chicken broth and a goose neck flask. He also made many discoveries in the field of chemistry, most notably the asymmetry of crystals. He is buried beneath the Institut Pasteur, an incredibly rare honor in France, where being buried in a cemetery is mandatory save for the fewer than 300 "Great Men" who are entombed in the Panthéon.
2. Norman Ernest Borlaug is an American agricultural scientist, humanitarian, Nobel laureate, and has been called the father of the Green Revolution. Borlaug is one of five people in history to have won the Nobel Peace Prize, the Presidential Medal of Freedom and the Congressional Gold Medal.
3. Alfred Russel Wallace, OM, FRS  was a British naturalist, explorer, geographer, anthropologist and biologist. He did extensive field work first in the Amazon River basin, and then in the Malay Archipelago, where he identified the Wallace line dividing the fauna of Australia from that of Asia.
4. Johann Georg Adam Forster was a German naturalist, ethnologist, travel writer, journalist, and revolutionary. At an early age, he accompanied his father on several scientific expeditions, including James Cook's second voyage to the Pacific. His report from that journey, A Voyage Round the World, contributed significantly to the ethnology of the people of Polynesia and remains a respected work among both scientists and ordinary readers. As a result of the report Forster was admitted to the Royal Society at the early age of twenty-two and came to be considered one of the founders of modern scientific travel literature.
5. Rosalind Elsie Franklin was a British physical chemist and crystallographer who made important contributions to the understanding of the fine structures of DNA, viruses, coal and graphite. Franklin is best known for her contribution to the discovery of the structure of DNA in 1953. In the years following, she led pioneering work on the tobacco mosaic and polio viruses. 
6. Barbara McClintock was a pioneering American scientist and one of the world's most distinguished cytogeneticists. 
7. Heinrich Hermann Robert Koch was a German physician. He became famous for the discovery of the anthrax bacillus (1877), the tuberculosis bacillus (1882) and the cholera bacillus (1883) and for his development of Koch's postulates. He was awarded the Nobel Prize in Physiology or Medicine for his tuberculosis findings in 1905. He is considered one of the founders of bacteriology.
8. George Ledyard Stebbins, Jr. was an American botanist and geneticist who is widely regarded as one of the leading evolutionary biologists and botanists of the 20th century.
9. Lynn Margulis is a biologist and University Professor at the University of Massachusetts Amherst. She is best-known for her theory on eukaryotic organelle genesis, the endosymbiotic theory, which is now accepted in the mainstream as the explanation for how certain organelles were formed.
10. Gregor Mendel  was an Austrian monk who is often called the "father of genetics" for his study of the inheritance of traits in pea plants. Mendel showed that there was particular inheritance of traits according to his laws of inheritance. The significance of Mendel's work was not recognized until the turn of the 20th century.

List of Carnivorous Plants

Source--http://www.gardenguides.com/67713-list-carnivorous-plants.html

List of Carnivorous Plants

The world of carnivorous plants is far stranger and more extensive than the commonly known examples of the Venus flytrap and pitcher plant. The criteria for considering whether a plant is carnivorous include its adaptations to capture prey and the presence of digestive enzymes, helper bacteria, or another way of benefiting from the nutrients in the prey that they capture.

Aldrovanda

This plant is also known as the "waterwheel plant" and is similar to an underwater Venus flytrap. Its leaves are arranged in a wheel shape with the leafy traps on the end of its arms.

Cephalotus

The Cephalotis follicularis is also known as the Albany pitcher plant. It was named after the city of Albany, Australia in southwestern Australia and primarily grows in that area. It is pitcher shaped and covered with bristles.

Darlingtonia

This plant, also known as the cobra lily, grows along the Pacific coast in patches from Oregon to California. It relies on bacteria and animals such as flying midges and slime mites to digest its prey.

Dionaea

The Dionaea muscipula, better known as the Venus flytrap, is the most famous of the carnivorous plants. Its native range is the lowlands of North Carolina. Their habitat is threatened, but they can be seen at Carolina Beach State Park near Wilmington, North Carolina.

Drosera

Droseras are also known as sundews. There are over 180 known species of drosera growing on every continent except for Antartica. Insects that land on their leaves are caught by adhesives and digested by enzymes. The leaves do move, like those of Venus flytraps, but the motion is very slow.

Drosophyllum

Drosophyllum, or the Dewy pine, is quite large for a carnivorous plant. Its individual leaves are over a foot tall and the entire plant can be up to two feet tall. It grows in arid regions along the Portuguese coast.

Genlisea

Genlisea are also known as corkscrew plants. They grow in wet habitats and their traps are located underwater. The trap structure is formed by curved hairs which only allow their prey to progress in one direction -- until it is too late.

Heliamphora

This genus is a type of pitcher plants that grown in the South American Highlands near the borders of Brazil, Venezuela and Guyana.

Nepenthes

Nepenthes are also known as tropical pitcher plants. Although they are most definitely carnivorous, there are over 150 species of animals that are known to go inside their pitchers without becoming prey. These animals range in size from mosquito larvae to frogs.

Pinguicula

These carnivorous plants are commonly known as butterworts. They have pretty flowers that rise far above their sticky leaves so that they do not consume their own pollinators.

Sarracenia

Sarracenia is also known as North American pitcher plants and range is primarily in the southeastern U.S. Their pitchers are narrow with slick sides and bottoms filled with digestive fluids and creatures such as mosquitoes, midges and flesh flies.

Utricularia

This genus contains over 220 species. Their common name is bladderwort and this gives a clue as to the operation of their traps. Small bladders pump out water from an interior chamber, which lowers the water pressure. Prey are sucked in and slowly digested.

Scope and importance of botany

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Botany is the scientific study of plant life. As a branch of biology, it is also called plant science(s), phytology, or plant biology.


Botany covers a wide range of scientific disciplines that study plants, algae, and fungi including: structure, growth, reproduction, metabolism, development, diseases, and chemical properties and evolutionary relationships between the different groups.

The study of plants and botany began with tribal lore, used to identify edible, medicinal and poisonous plants, making botany one of the oldest sciences. From this ancient interest in plants, the scope of botany has increased to include the study of over 550,000 kinds or species of living organisms.

Scope and importance of botany

As with other life forms in biology, plant life can be studied from different perspectives, from the molecular, genetic and biochemical level through organelles, cells, tissues, organs, individuals, plant populations, and communities of plants. At each of these levels a botanist might be concerned with the classification (taxonomy), structure (anatomy and morphology), or function (physiology) of plant life.

Historically, botany covers all organisms that were not considered to be animals. Some of these "plant-like" organisms include fungi (studied in mycology), bacteria and viruses (studied in microbiology), and algae (studied in phycology). Most algae, fungi, and microbes are no longer considered to be in the plant kingdom. However, attention is still given to them by botanists, and bacteria, fungi, and algae are usually covered in introductory botany courses.

The study of plants has importance for a number of reasons. Plants are a fundamental part of life on Earth. They generate the oxygen, food, fibres, fuel and medicine that allow higher life forms to exist. Plants also absorb carbon dioxide through photosynthesis, a minor greenhouse gas that in large amounts can effect global climate. It is believed that the evolution of plants has changed the global atmosphere of the earth early in the earth's history and paleobotanists study ancient plants in the fossil record. A good understanding of plants is crucial to the future of human societies as it allows us to:

* Produce food to feed an expanding population
* Understand fundamental life processes
* Produce medicine and materials to treat diseases and other ailments
* Understand environmental changes more clearly

Botany

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Civil Services Examination Strategy For Botany

Paper I

This paper in Botany is high-scoring provided your answers are simple, diagrammatic, and focuses on evolutionary aspects of questions.
Stay simple and give diagrams with Indian-centric views. This will help you to score good marks. You should summarize tables for last minute revision.

Microbiology in Section I is important for the 200-word short notes and you should practice accordingly. Applied aspects of queries are more important. In Plant Pathology you can safely leave description of diseases but should focus on physiological aspects.

In Cryptogams, the syllabus tells you to study plant group for their structure and reproduction with evolutionary viewpoint. The question in the examination however, does not mention the word evolution explicitly but examiners expect evolutionary treatment of questions.

Phanerogams is divided into various sub-groups. The key areas are:
Gymnosperms: Emphasis on fossil types
Angiosperms: Skip the families which were asked last year. Practice floral diagrams and formulas as much as possible
Anatomy: Not a consistent portion. It can be ignored if other portions are well prepared
Embryology: Stick to prescribed topics. Draw neat diagrams. The preparation of this portion can be clubbed with Morphogenesis.

Paper II

The strategy for this paper should revolve around providing updated information, colored illustrations and focus on applications.

In Cell Biology; focus should be on molecular aspect. Any long process should be discussed only with diagrams showing all the steps. Genetics, Molecular Biology and Evolution is a high scoring area in Paper II. The focus thus should be on making notes and writing crisp answers. Students should always highlight applications in agriculture and human welfare.

During the past three years, questions from Plant Breeding, Biotechnology and Biostatistics have been asked in compulsory section of the paper. The preparation strategy should revolve around making short notes and give stepwise crosses. They should also focus on "Role of Breeding in Crop Improvement in India".

In Physiology and Biochemistry; biochemical physiology is most important. In this year's examination, photosynthesis and nitrogen metabolism are more important than respiration. Students need to cover hormones and developmental physiology in areas like flowering, seed germination and fruit ripening.

In Ecology and Plant Geography; students can do with preparing just short notes. They can however afford to skip this section if they have covered other parts well.

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Hyenas cooperate better than chimps: Study

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Chimpanzees may be smarter than spotted hyenas, but a new study has found that latter outperform the primates on cooperative problem-solving tests.

An evolutionary anthropologist says in the study published online in the October issue of 'Animal Behaviour' that captive pairs of spotted hyenas which needed to tug two ropes in unison to earn a food reward cooperated successfully and learned the maneuvers quickly with no training.

Experienced hyenas even helped inexperienced partners do the trick, he was quoted as saying by the 'Science Daily'.

On the other hand, chimpanzees and other primates many a times require extensive training while cooperation between individuals may not be easy, said Christine Drea, an evolutionary anthropologist at Duke University

.

Drea's research shows that social carnivores such as spotted hyenas may be good models for investigating cooperative problem solving and the evolution of social intelligence.

"This study shows that spotted hyenas are more adept at these sorts of cooperation and problem-solving studies in the lab than chimps are," she said.

Researchers have focused on primates for decades with an assumption that higher cognitive functioning in large-brained animals should enable organised teamwork.

But Drea's study demonstrates that social carnivores, including dogs, may be very good at cooperative problem solving, even though their brains are comparatively smaller, the Daily reported.