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Seed germination introduction
Seed germination introduction
Seed germination introduction
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The purpose of the project was to determine whether Eucalyptus globulus had an effect on the germination of radish seeds. It was hypothesized that Eucalyptus globulus would have a negative effect on the germination of the seeds and their growth.
Before a seed can germinate it must first shed the seed coat, a protective outer layer that protects the seed from parasites, injury, and unfavorable temperatures. Inside the seed coat is the embryo which contains the root and first leaves of the plant, called cotyledons. After the seed coat has been shed the root emerges first so that it can absorb water and nutrients. After the roots have come out of the embryo the cotyledons will follow. Some seeds need certain conditions to germinate and go through a period of dormancy before they germinate. Seed dormancy ensures that the seed is protected until the conditions are right for it to germinate.
Allelopathy is the beneficial or harmful effect that one plant has on another. It occurs by the discharge of chemicals from plants by leaching, root exudation, volatilization, and residue decomposition. Allelopathy can affect the growth, occurrence, plant succession, dominance, diversity, and productivity of a plant. While allelopathy first referred to the negative effects of one plant on another, it has been broadened to include beneficial effects. Common effects of plant allelopathy are reduced seed germination and seedling growth. Although there is no common target site for allelochemicals, common sites of action are cell division, nutrient uptake, pollen germination, and photosynthesis. Allelopathy involves the interaction of phenolic compounds, flavonoids, terpenoids, alkaloids, steroids, carbohydrates, and amino acids. Sometimes mixtures of...
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...es. Leachates from stem flow and litter fall are responsible for allelopathic affects of Eucalyptus on other plants. Eucalyptus oil can be obtained by distillation of Eucalyptus leaves. The oil is used for medicinal, perfumery, and industrial purposes. Although Eucalyptus oil is used as a decongestant and treatment for bronchitis if it is taken in large dosages in pure form it is poisonous. The lethal dose of Eucalyptus oil for an adult is around .05 to .5 mL per kg of body weight. The component of Eucalyptus oil that gives it several uses is eucalyptol, also known as cineole.
Works Cited http://gardening.wsu.edu/library/vege004/vege004.htm http://edis.ifas.ufl.edu/hs186
http://www.wssp.org.pk/14,1-2,2.pdf
http://www.absoluteastronomy.com/topics/Eucalyptol
http://www.fao.org/docrep/V5350E/V5350e07.htm
http://www.jtropag.in/index.php/ojs/article/viewFile/50/45
Plant hormones are certain chemicals present in plants that control plant growth and development by affecting the division, differentiation, and elongation of cells. (Campbell, 2008) Each hormone has multiple effects depending on its site of action, its concentrations, and the developing stage of the plant. (Campbell, 2008) Auxin is a plant hormone that is synthesized within the apical meristems and young leaves of a growing plant. Auxin stimulates stem elongation when it is present is low concentrations. It promotes the formations of lateral and adventitious roots, regulates development of fruit, enhances apical dominance, functions in gravitropism and phototropism, promotes vascular differentiation, and retards leaf abscission. Gibberellic acid is one of several plant hormones that govern a plant’s growth. Gibberellins allow for stem elongation in plants. Plants without enough of this hormone tend to grow short or stunted. This chemical is high in the element potassium, which is one the main components of plant fertilizer and very important for plant growth on its own. The...
For years farmers have been adding natural fertilizers to their crops. It is a big risk though. Over fertilizing is very dangerous. It puts high concentrations of salt into the soil. It can also affect the water resources nearby. Nitrogen, Phosphate, and Potassium are the basics of fertilizer. If a certain nutrient is short in supply the fertilizer might not work as well. Calcium, iron, manganese are also nutrients that might be needed. So don’t just trust the fertilizer bag that says it has all the nutrients, test it out. (Miller and Levine 717)
These results gave us a chi-square statistic of .06787 and with a degree of freedom of 1, this .06787 is below the critical value of .05 so therefore the results do follow typical patterns of inheritance. This means that our hypothesis for the monohybrid cross was correct, the F2 generation follows Mendelian inheritance patterns. In the dihybrid cross, the observed results were 487 or 55.7 % of the plants had anthocyanin dark green leaves, 166 or 19% of the plants had anthocyanin yellowish green leaves, 136 or 15.6% of the plants had no anthocyanin dark green leaves, and 85 or 9.7% of the plants had no anthocyanin yellowish green leaves. These results gave us a chi-square statistic of 21.703 and with the degrees of freedom at 3 this is still well below the critical value of .05 and therefore the dihybrid cross does not follow typical patterns of inheritance. This means that our hypothesis for the dihybrid cross was rejected, the F2 generation of Brassica rapa did not follow Mendelian inheritance patterns. The results show that the monohybrid cross did follow Mendelian inheritance patterns, while the dihybrid
Figure 1 indicates an increasing mortality rate (positive slope) in plants as density increases; Figure 2 shows the corresponding germination rate reflecting the exact opposite trend. Mortality remains zero until 8 seeds are planted (6% mortality), then is reduced to zero at 16 seeds then increases to 14 percent (32 seeds), 32 percent (64 seeds), and more than half (57 %--128 seeds).
The germinating seeds consumed almost no oxygen throughout the experiment in the 10-degree C water bath. I think that this is because when an organism cools down, all of its cellular functions slow down.
Each plant species has a unique pattern of resource allocation that is genetically determined but not fixed. Plants can adjust there allocation pattern when they experience different environments and the presence of other species. Phenotypic plasticity goes hand in hand with resource allocation as well. When a plant has to adjust itʻs resource allocation, sometimes it uses itʻs resources to help the plant grow different characteristic so that the plant can have a greater chance of living in the environment. For example, if a plant from an environment that does not experience wind on the regular basis enters a new environment that has a lot of wind the plant may change itʻs resource allocation and spend more of itʻs resources growing deeper
Planting a wicked seed will grow onto become a tree and as the growth progresses, so does the
Schumann, Gail L., and Cleora J. D'Arcy. Hungry Planet: Stories of Plant Diseases. St. Paul: American Phytopathological Society, 2012. Print.
This gave rise to nonvascular plants like, mosses, liverworts, and hornworts. The second period of plant evolution began 425 million years ago was the diversification of plants with vascular tissue allowing plants to grow much taller and rise above the ground. The next period of plant evolution is the origin of seeds, about 360 million years ago. Seeds are embryos packed along with food in a protective covering. Last is flowering plants about 140 million years ago, which is seeds within protective chambers called ovaries. Animal evolution begins when an animals egg and sperm fuse, producing a zygote. The zygote splits by mitosis and forms an blastula, which usually is a hollow ball of cells. One side of the blastula folds in forming a gastrula, which develops into an embryo with a two-layered wall and an opening on one end. After the gastrula stage animals develop into
It scattered on the hard footpaths where it had no chance to take root, on the thin soil above the limestone rock, in the soil with the thorny roots, and some in the rich soil, which was free from such. The birds ate the seeds that lie exposed on the hard footpaths. (B, 285; C, 74; D, 672; H, 165) " Here the soil had different capacities, but each yielded a good harvest according to its ability." (Hobbs, 165) "
Plant defences are those mechanisms employed by plants in response to herbivory and parasitism. According to Hanley et al. (2007), “the tissues of virtually all terrestrial, freshwater, and marine plants have qualities that to some degree reduce herbivory, including low nitrogen concentration, low moisture content, toxins or digestibility-reducing compounds”. The type of chemical defence may be species specific (Scott 2008). The defences that plants possess may be in the form of chemical production or in the form of physical defences such as thorns or spikes and even through reinforced, rigid leaves. “The compounds that are produced in response to herbivory can either have a direct effect on the attacker itself (e.g. toxins or digestibility reducers), or serve as indirect defenses by attracting the natural enemies of the herbivores” (Bezemer & van Dam 2005). This essay will focus on chemical plant defences and in particular the effects of terpenes, phenolics, nitrogen-based defences as well as allelopathy in plants.
Insect pollination as we all know, is the process that enables reproduction and fertilization by the transfer of pollen performed by insects. Insects are some of the oldest pollinators of plants. Pollinating insects date back to 140 million years ago. Since then, due to how effective insect pollinators are, these flowering plants have become the major group of terrestrial vascular plants. Flowering plants, also known as angiosperms, have imperative roles within our ecosystems, both natural and agricultural. For instance, insects provide food, fiber and shelter for wildlife and humankind alike (2007). It is commonly know that in humans, high levels of fruit and vegetable consumption are associated with decreased risk of chronic disease (Calderone 2012). Aside from these important roles, plants have also been considered as a viable option for fuel sources (Calderone 2012). There are around 300,00 species of flowering plants in the world and without pollination, the reproductive process would be very difficult since pollination causes the production of seeds (Calderone 2012). Of the 300,000 plant species worldwide, a little over 3,000 of these plants have been used as a source of food. Close to 300 of these species are grown around the world today and only 12 of these plants make up about 90 percent of the food sources in our world. These 12 include the grains...
Seed dispersal is the transport or movement of seeds away from the parent plant in order to help prevent the overcrowding (if this happens plants would not have enough food and light to survive in the area) and help to create new colonies. Thus giving the seed the best chance to germinate in a new location away from the parent plant and hopefully start new colonies. Due to the fact plants have limited mobility they rely on a variety of dispersal vectors to transport their seeds via abiotic (non-living) and biotic (living) vectors. There are five main methods of seed dispersal, animals, gravity, wind, ballistic and water (1). Fire is also another way for seeds to be dispersed but is not as common as the other methods.
This lesson is designed to review and reinforce a few important concepts about plants (e.g. Needs, parts, sequence of planting) and to also guide the students through applying a few scientific inquiry (e.g. Making observations, experimentation, discussion, reflection, reporting results etc.). The students have previously planted corn and bean seeds and today’s lesson has provided the students a chance to see the results of the planted corn and bean seeds. Additionally, seeds have been planted under and growing under the following conditions: without water, and without soil. The students see the results of these seeds planted under these conditions for the past week. Two plants in particular have already been grown their growth has been