1.
Pea
–
The pea is most commonly the small spherical seed or the seed-pod of the pod fruit Pisum sativum. Pea pods are botanically fruit, since they contain seeds and developed from the ovary of a flower, the name is also used to describe other edible seeds from the Fabaceae such as the pigeon pea, the cowpea, and the seeds from several species of Lathyrus. P. sativum is a plant, with a life cycle of one year. It is a crop grown in many parts of the world. The average pea weighs between 0.1 and 0.36 grams. The immature peas are used as a vegetable, fresh, frozen or canned and these are the basis of pease porridge and pea soup, staples of medieval cuisine, in Europe, consuming fresh immature green peas was an innovation of Early Modern cuisine. The wild pea is restricted to the Mediterranean basin and the Near East, the earliest archaeological finds of peas date from the late neolithic era of current Greece, Syria, Turkey and Jordan. In Egypt, early date from ca. 4800–4400 BC in the Nile delta area, and from ca, the pea was also present in Georgia in the 5th millennium BC. Farther east, the finds are younger, peas were present in Afghanistan ca.2000 BC, in Harappa, Pakistan, and in northwest India in 2250–1750 BC. In the second half of the 2nd millennium BC, this pulse crop appears in the Ganges Basin, a pea is a most commonly green, occasionally golden yellow, or infrequently purple pod-shaped vegetable, widely grown as a cool season vegetable crop. The seeds may be planted as soon as the temperature reaches 10 °C. They do not thrive in the heat of warmer temperate and lowland tropical climates. Many cultivars reach maturity about 60 days after planting, peas have both low-growing and vining cultivars. The vining cultivars grow thin tendrils from leaves that coil around any available support, a traditional approach to supporting climbing peas is to thrust branches pruned from trees or other woody plants upright into the soil, providing a lattice for the peas to climb. Branches used in fashion are sometimes called pea brush. Metal fences, twine, or netting supported by a frame are used for the same purpose, in dense plantings, peas give each other some measure of mutual support. In early times, peas were grown mostly for their dry seeds, from plants growing wild in the Mediterranean basin, constant selection since the Neolithic dawn of agriculture improved their yield
2.
Biological life cycle
–
In biology, a biological life cycle is a series of changes in form that an organism undergoes, returning to the starting state. The concept is related to those of the life history, development and ontogeny. Transitions of form may involve growth, asexual reproduction, and/or sexual reproduction, in some organisms, different generations of the species succeed each other during the life cycle. For plants and many algae, there are two stages, and the life cycle is referred to as alternation of generations. The term life history is used, particularly for organisms such as the red algae which have three multicellular stages, rather than two. Life cycles that include sexual reproduction involve alternating haploid and diploid stages, to return from a diploid stage to a haploid stage, meiosis must occur. In regard to changes of ploidy, there are 3 types of cycles, haplontic life cycle — the haploid stage is multicellular, diplontic life cycle — the diploid stage is multicellular and haploid gametes are formed, meiosis is gametic. Haplodiplontic life cycle — multicellular diploid and haploid stages occur, meiosis is sporic, the cycles differ in when mitosis occurs. Zygotic meiosis and gametic meiosis have one stage, mitosis occurs during the n phase in zygotic meiosis. Therefore, zygotic and gametic meiosis are collectively termed haplobiontic, sporic meiosis, on the other hand, has mitosis in two stages, both the diploid and haploid stages, termed diplobiontic. The study of reproduction and development in organisms was carried out by botanists and zoologists. Wilhelm Hofmeister demonstrated that alternation of generations is a feature that unites plants, some terms used for the description of life cycles were proposed initially for algae by Nils Svedelius, and then became used for other organisms. Other terms used in protist life cycles were introduced by Karl Gottlieb Grell, the description of the complex life cycles of various organisms contributed to the disproof of the ideas of spontaneous generation in the 1840s and 1850s. A zygotic meiosis is a meiosis of a zygote immediately after karyogamy and this way, the organism ends its diploid phase and produces several haploid cells. These cells divide mitotically to form larger, multicellular individuals. Two opposite types of gametes from these individuals or cells fuse to become a zygote, in the whole cycle, zygotes are the only diploid cell, mitosis occurs only in the haploid phase. The individuals or cells as a result of mitosis are haplonts, haplonts are, In archaeplastidans, some green algae In stramenopiles, some golden algae In alveolates, many dinoflagellates eg. Cells from the individuals then undergo meiosis to produce haploid cells or gametes
3.
Germination
–
Germination is the process by which a plant grows from a seed. The most common example of germination is the sprouting of a seedling from a seed of an angiosperm or gymnosperm, in addition, the growth of a sporeling from a spore, such as the spores of hyphae from fungal spores, is also germination. Thus, in a sense, germination can be thought of as anything expanding into greater being from a small existence or germ. The seed of a plant is a small package produced in a fruit or cone after the union of male and female reproductive cells. All fully developed seeds contain an embryo and, in most plant species some store of food reserves, some plants produce varying numbers of seeds that lack embryos, these are called empty seeds and never germinate. Dormant seeds are seeds that do not germinate because they are subject to external environmental conditions that prevent the initiation of metabolic processes. Under proper conditions, the seed begins to germinate and the embryonic tissues resume growth, Seed germination depends on both internal and external conditions. The most important external factors include right temperature, water, oxygen or air, various plants require different variables for successful seed germination. Often this depends on the seed variety and is closely linked to the ecological conditions of a plants natural habitat. For some seeds, their future germination response is affected by environmental conditions during seed formation, mature seeds are often extremely dry and need to take in significant amounts of water, relative to the dry weight of the seed, before cellular metabolism and growth can resume. Most seeds need enough water to moisten the seeds but not enough to soak them, the uptake of water by seeds is called imbibition, which leads to the swelling and the breaking of the seed coat. When seeds are formed, most plants store a reserve with the seed, such as starch, proteins. This food reserve provides nourishment to the growing embryo, when the seed imbibes water, hydrolytic enzymes are activated which break down these stored food resources into metabolically useful chemicals. Oxygen is required by the seed for metabolism. Oxygen is used in respiration, the main source of the seedlings energy until it grows leaves. Oxygen is a gas that is found in soil pore spaces, if a seed is buried too deeply within the soil or the soil is waterlogged. Temperature affects cellular metabolic and growth rates, Seeds from different species and even seeds from the same plant germinate over a wide range of temperatures. Seeds often have a range within which they will germinate
4.
Seed
–
A seed is an embryonic plant enclosed in a protective outer covering. The formation of the seed is part of the process of reproduction in seed plants, Seeds are the product of the ripened ovule, after fertilization by pollen and some growth within the mother plant. The embryo is developed from the zygote and the coat from the integuments of the ovule. Seed plants now dominate biological niches on land, from forests to both in hot and cold climates. The term seed also has a meaning that antedates the above—anything that can be sown, e. g. seed potatoes. In the case of sunflower and corn seeds, what is sown is the seed enclosed in a shell or husk, many structures commonly referred to as seeds are actually dry fruits. Plants producing berries are called baccate, sunflower seeds are sometimes sold commercially while still enclosed within the hard wall of the fruit, which must be split open to reach the seed. Different groups of plants have other modifications, the stone fruits have a hardened fruit layer fused to. Nuts are the one-seeded, hard-shelled fruit of plants with an indehiscent seed. Seeds are produced in several related groups of plants, and their manner of production distinguishes the angiosperms from the gymnosperms, angiosperm seeds are produced in a hard or fleshy structure called a fruit that encloses the seeds, hence the name. Some fruits have layers of hard and fleshy material. In gymnosperms, no special structure develops to enclose the seeds, however, the seeds do become covered by the cone scales as they develop in some species of conifer. Seed production in natural plant populations varies widely from year-to-year in response to weather variables, insects and diseases, over a 20-year period, for example, forests composed of loblolly pine and shortleaf pine produced from 0 to nearly 5 million sound pine seeds per hectare. Over this period, there were six bumper, five poor, and nine good seed crops, right after fertilization, the zygote is mostly inactive, but the primary endosperm divides rapidly to form the endosperm tissue. This tissue becomes the food the young plant will consume until the roots have developed after germination, after fertilization the ovules develop into the seeds. The ovule consists of a number of components, The funicle or seed stalk which attaches the ovule to the placenta and hence ovary or fruit wall, the nucellus, the remnant of the megasporangium and main region of the ovule where the megagametophyte develops. The micropyle, a pore or opening in the apex of the integument of the ovule where the pollen tube usually enters during the process of fertilization. The chalaza, the base of the ovule opposite the micropyle, the shape of the ovules as they develop often affects the final shape of the seeds
5.
Brassica rapa
–
Brassica rapa L. is a plant consisting of various widely cultivated subspecies including the turnip, napa cabbage, bomdong, bok choy, and cime di rapa, and. The oil made from the seed is also called canola, which is one reason why it is sometimes confused with rapeseed oil. The oilseeds known as canola are sometimes particular varieties of Brassica rapa but usually the related species Brassica napus, in the 18th century the turnip and the oilseed-producing variants were seen as being different species by Carl Linnaeus who named them B. rapa and B. campestris. 20th-century taxonomists found that the plants were cross fertile and thus belonged to the same species, since the turnip had been named first by Linnaeus, the name Brassica rapa was adopted. Many butterflies, including the small white pollinate the B. rapa flowers, media related to Brassica rapa at Wikimedia Commons Multilingual taxonomic information. PROTA database record on Brassica rapa L. Brassica rapa, Brassica rapa L. Germplasm Resources Information Network. Agricultural Research Service, United States Department of Agriculture
6.
Fluorescent lamp
–
A fluorescent lamp or a fluorescent tube is a low pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapor which produces ultraviolet light that then causes a phosphor coating on the inside of the lamp to glow. A fluorescent lamp converts electrical energy into useful light much more efficiently than incandescent lamps, the typical luminous efficacy of fluorescent lighting systems is 50–100 lumens per watt, several times the efficacy of incandescent bulbs with comparable light output. Compact fluorescent lamps are now available in the same sizes as incandescents and are used as an energy-saving alternative in homes. Because they contain mercury, many fluorescent lamps are classified as hazardous waste, the United States Environmental Protection Agency recommends that fluorescent lamps be segregated from general waste for recycling or safe disposal, and some jurisdictions require recycling of them. Fluorescence of certain rocks and other substances had been observed for hundreds of years before its nature was understood, by the middle of the 19th century, experimenters had observed a radiant glow emanating from partially evacuated glass vessels through which an electric current passed. The explanation relied on the nature of electricity and light phenomena as developed by the British scientists Michael Faraday in the 1840s and James Clerk Maxwell in the 1860s. Little more was done with this phenomenon until 1856 when German glassblower Heinrich Geissler created a vacuum pump that evacuated a glass tube to an extent not previously possible. Geissler invented the first gas-discharge lamp, the Geissler tube, consisting of an evacuated glass tube with a metal electrode at either end. When a high voltage was applied between the electrodes, the inside of the lit up with a glow discharge. By putting different chemicals inside, the tubes could be made to produce a variety of colors, more important, however, was its contribution to scientific research. One of the first scientists to experiment with a Geissler tube was Julius Plücker who systematically described in 1858 the luminescent effects that occurred in a Geissler tube and he also made the important observation that the glow in the tube shifted position when in proximity to an electromagnetic field. Alexandre Edmond Becquerel observed in 1859 that certain substances gave off light when they were placed in a Geissler tube and he went on to apply thin coatings of luminescent materials to the surfaces of these tubes. Fluorescence occurred, but the tubes were very inefficient and had an operating life. Inquiries that began with the Geissler tube continued as even better vacuums were produced, the most famous was the evacuated tube used for scientific research by William Crookes. That tube was evacuated by the highly effective mercury vacuum pump created by Hermann Sprengel, Research conducted by Crookes and others ultimately led to the discovery of the electron in 1897 by J. J. Thomson and X-rays in 1895 by Wilhelm Roentgen. While Becquerel was interested primarily in conducting research into fluorescence. Although Edison lost interest in fluorescent lighting, one of his employees was able to create a gas-based lamp that achieved a measure of commercial success
7.
Cereal
–
A cereal is any grass cultivated for the edible components of its grain, composed of the endosperm, germ, and bran. Cereal grains are grown in quantities and provide more food energy worldwide than any other type of crop and are therefore staple crops. Edible grains from plant families, such as buckwheat, quinoa. In their natural form, cereals are a source of vitamins, minerals, carbohydrates, fats, oils. When refined by the removal of the bran and germ, the endosperm is mostly carbohydrate. In some developing nations, grain in the form of rice, wheat, millet, in developed nations, cereal consumption is moderate and varied but still substantial. The word cereal is derived from Ceres, the Roman goddess of harvest, agriculture allowed for the support of an increased population, leading to larger societies and eventually the development of cities. It also created the need for organization of political power, as decisions had to be made regarding labor and harvest allocation and access rights to water. Agriculture bred immobility, as populations settled down for long periods of time, early Neolithic villages show evidence of the development of processing grain. The Levant is the ancient home of the ancestors of wheat, barley and peas, there is evidence of the cultivation of figs in the Jordan Valley as long as 11,300 years ago, and cereal production in Syria approximately 9,000 years ago. During the same period, farmers in China began to farm rice and millet, using man-made floods, fiber crops were domesticated as early as food crops, with China domesticating hemp, cotton being developed independently in Africa and South America, and Western Asia domesticating flax. The first cereal grains were domesticated by early primitive humans, about 8,000 years ago, they were domesticated by ancient farming communities in the Fertile Crescent region. Emmer wheat, einkorn wheat, and barley were three of the so-called Neolithic founder crops in the development of agriculture, around the same time, millets and rices were starting to become domesticated in East Asia. Sorghum and millets were also being domesticated in sub-Saharan West Africa, while each individual species has its own peculiarities, the cultivation of all cereal crops is similar. Most are annual plants, consequently one planting yields one harvest, wheat, rye, triticale, oats, barley, and spelt are the cool-season cereals. These are hardy plants grow well in moderate weather and cease to grow in hot weather. The warm-season cereals are tender and prefer hot weather, barley and rye are the hardiest cereals, able to overwinter in the subarctic and Siberia. Many cool-season cereals are grown in the tropics, however, some are only grown in cooler highlands, where it may be possible to grow multiple crops per year
8.
Perennial plant
–
A perennial plant or simply perennial is a plant that lives for more than two years. The term is used to differentiate a plant from shorter-lived annuals and biennials. The term is widely used to distinguish plants with little or no woody growth from trees and shrubs. Tomato vines, for example, live several years in their natural habitat but are grown as annuals in temperate regions because they dont survive the winter. There is also a class of evergreen, or non-herbaceous, perennials, an intermediate class of plants is known as subshrubs, which retain a vestigial woody structure in winter, e. g. Penstemon. The local climate may dictate whether plants are treated as shrubs or perennials, for instance, many varieties of Fuchsia are shrubs in warm regions, but in colder temperate climates may be cut to the ground every year as a result of winter frosts. The symbol for a plant, based on Species Plantarum by Linnaeus, is. Perennial plants can be short-lived or they can be long-lived, as are some plants like trees. They include an assortment of plant groups from ferns and liverworts to the highly diverse flowering plants like orchids. Plants that flower and fruit only once and then die are termed monocarpic or semelparous, however, most perennials are polycarpic, flowering over many seasons in their lifetime. Perennials typically grow structures that allow them to adapt to living one year to the next through a form of vegetative reproduction rather than seeding. These structures include bulbs, tubers, woody crowns, rhizomes plus others and they might have specialized stems or crowns that allow them to survive periods of dormancy over cold or dry seasons during the year. Many perennials have developed specialized features that allow them to extreme climatic. Some have adapted to hot and dry conditions or cold temperatures. Those plants tend to invest a lot of resource into their adaptations and often do not flower, Many perennials produce relatively large seeds, which can have an advantage, with larger seedlings produced after germination that can better compete with other plants. Some annuals produce many seeds per plant in one season, while some perennials are not under the same pressure to produce large numbers of seeds. In warmer and more favorable climates, perennials grow continuously, in seasonal climates, their growth is limited to the growing season. In some species, perennials retain their foliage all year round, other plants are deciduous perennials, for example, in temperate regions a perennial plant may grow and bloom during the warm part of the year, with the foliage dying back in the winter
9.
Biennial plant
–
A biennial plant is a flowering plant that takes two years to complete its biological lifecycle. In the first year, the plant grows leaves, stems, usually the stem remains very short and the leaves are low to the ground, forming a rosette. Many biennials require a treatment, or vernalization, before they will flower. During the next spring or summer, the stem of the biennial plant elongates greatly and this typically makes biennial vegetables such as spinach, fennel and lettuce unusable as food. The plant then flowers, producing fruits and seeds before it finally dies, there are far fewer biennials than either perennial plants or annual plants. Under extreme climatic conditions, a plant may complete its life cycle rapidly. This is quite common in vegetable or flower seedlings that were vernalized before they were planted in the ground and this behavior leads to many normally biennial plants being treated as annuals in some areas. From a gardeners perspective, a status as annual, biennial. Biennials grown for flowers, fruits, or seeds need to be grown for two years, biennials that are grown for edible leaves or roots are grown for just one year. Plant breeders have produced annual cultivars of several biennials that will flower the first year from seed, for example, foxglove and stock
