Effect of Intraspecific Competition on the Biomass and Height of
Helianthus Annuus
Abstract: The purpose of this experiment was to study the biomass and stem length of Helianthus plants growing in an intraspecific competitive environment compared to Helianthus growing in an isolated environment. I hypothesized that increased competition would limit the amount of nutrition available to each plant and thus effect the growth potential. A total of 24 plants, 6 to each pot were grown for ten weeks under the same environmental conditions. The plants grown under competitive conditions had only 1/7 the dry biomass and 5/8 the stem length of plants experiencing no competition. The competing plants had an average dry biomass of 1.54 grams, with a standard deviation of .41. The average control had a dry biomass of 10.54 grams and a standard deviation of 3.95. Analysis revealed a p-value of .0286, considered significant. These results suggest that intraspecific plants are affected by living in close proximity to one another and I therefore except my hypothesis as correct.
Introduction: When plants reproduce, size is highly correlated with reproductive output (Samson and Werk,1986). The struggle for reproductive survival among plants is the struggle to grow in the face of competition from neighbors. So the question this experiment asks is how competition affects the growth of plants. A plant growing in a nutrient-abundant environment free from competition will exhibit maximum growth potential and seed production (Watkinson,1983). But as the plant density increases and available resources become more limited, the decision must be made between continued growth or producing viable seed. I hypothesize that as Helianthus plant proximity becomes tighter, plant size and stem length will be effected negatively. For now my null hypothesis will be that plants grown in isolation will exhibit the same size and stem length as Helianthus plants grown under intraspecific competition.
Our subject plant for this experiment is Helianthus annuus, a common sunflower plant cultivated all over the world for its seeds and seed oil. Helianthus is an annual plant that grows from 1 to 3 meters, depending on conditions. It is for this reason I chose Helianthus as our subject plant. Shorter plants have a less measurable variable. Helianthus plants, with their long straight stems, would have a much easier variable to measure. A total of 24 Helianthus plants, six to each pot, will be used in the treatment. The large number of subject plants is because of genetic variation that might sway my results if I were to use only a single treatment pot.
Reproduction and passing on genetic and behavioral traits to an offspring is a common fundamental to all the species on this planet. When studying forest ecology, it is crucial to study the proportion of individuals surviving at each stage of their growth as the lives and mortality experienced in a species population describes a characteristic of the species in question. In the case of American beech and sugar maple, their attempt to produce seeds is analogous to entering lottery, where every seedling has a potential chance of becoming a canopy but only some will survive and reach the canopy size; thus, becoming the fit ‘winners’. Our information shows that together, based on size class distribution, both the species display a ‘winner takes all’ pattern, which supports our hypothesis. The results showed a greater count for seedlings and short saplings than for tall saplings, sub-canopies and canopies. This is evident for a Type III survivorship curve. In Type III curve all individuals initially having a very low chance of survival. However, once the individuals pass their threshold age and survive, they live an advanced age. Only some individuals out the mast seeding production mature to become fully fit canopy trees. On the other hand, our hypothesis of canopy trees representing the bulk of the biomass was supported as the basal areas decreased going from growth stages of canopy to seedlings. This is evidence that once the individuals survive the bottleneck where there is high mortality of young individuals (seedlings), who are then considered as ‘losers’, will allow for the other larger size class individuals to flourish. Here, having considerable amount of dbh (diameter at breast height) accounts for greater surfac...
Many variations and species of plants can be found all around the world and in different habitats. These variations and characteristics are due to their adaptations to the natural habitat surrounding them. In three of many climatic zones, the arid, tropical and temperate zone, plants that vary greatly from each other are found in these locations. In this experiment, we’ll be observing the connection between the adaptations of the plants to their environment at the Fullerton Arboretum. The arboretum is a space containing numerous plants from different environments. The plants are carefully looked after and organized into their specific habitat. Therefore, we’ll be able to take a look at the plants within multiple
A population of Plantago lanceolata (ribwort plantain) on the path was found to have higher trampling tolerance than populations away from the path; this reflected the sharp differences in the conditions of the plant at these sites. Ribwort Plant had generally a higher tolerance to trampling than any other plants as more were found on the path, but there were less compared with other plants as distance increased from the path. These results suggest that the competition level found on the path was sufficient enough to impose a selection pressure for the evolution of tolerance in a sensitive species, but in some areas the distribution of Ribwort Plantain were the same. This provides that other conditions affect the tolerance of trampling for Ribwort Plantain.
Poorter, H, and Navas, M. 2003. Plant growth and competition at elevated CO2: on winners, losers and functional groups. New Phytologist. 157: 175-198.
As a result of these factors, the flora has adapted to these conditions in a variety of ways including their shape, leaf type, root system, and color. One of the most prominent adapt...
The communities of various native plants have been significantly minimized as a result of ...
Comparing the Growth of Pea Plants Grown in the Light and in the Dark Aim: To compare the vertical growth and weight gain of pea plants grown in the light and in the dark. Background Knowledge: Photosynthesis forms the basis for this experiment. This is the process by which a plant makes food for itself from the raw materials around it. The energy needed for photosynthesis comes from sunlight, which is the variable for this experiment.
Lauffer, H. B., Williams, P., & Lauffer, D. (2012). Wisconsin Fast Plants® Program. Retrieved February 26, 2014, from http://www.fastplants.org
Rising Carbon Dioxide is Great For Plants. (1992, December). Consumer's Research Magazine, 75 (12), p. 25. [Online]. Available: http://insite.palni.edu/WebZ/Authorize:sessionid=0.
Two members of the group were instructed to visit the laboratory each day of the experiment to water and measure the plants (Handout 1). The measurements that were preformed were to be precise and accurate by the group by organizing a standardized way to measure the plants. The plants were measured from the level of the soil, which was flat throughout all the cups, to the tip of the apical meristems. The leaves were not considered. The watering of the plants took place nearly everyday, except for the times the lab was closed. Respective of cup label, the appropriate drop of solution was added to the plant, at the very tip of the apical meristems.
Sanders, G.E., Clark A.G., Colls, J.J. (1991) The influence of open-top chambers on the growth and development of field bean. New Phytol 117:439–447
The “Fast Plant” experiment is an observation of a plants growth over the span of twenty-eight days. The objective is to observe how plants grow and use their resources throughout the span of their life. In our lab we observed the Brassica rapa, a herbaceous plant in the mustard family which has a short cycle which makes it a perfect plant to observe in this experiment. Like other plants the Brassica rapa must use the resources in the environment to create energy to complete itʻs life cycle and reproduce. By observing the plant it is easy to see in what organ or function the plant is using itʻs energy and resources and if overtime the resources switch to other part of the plants. By conducting this experiment we are able to observe where and how plants allocate their resources throughout their life by harvesting plants at different points in their life.
Plants have two different ways to reproduce. The first one is vegetative reproduction. With this type all the plants that have the same parent have the same genetic make-up. This also lets plants pass adaptations on that they have abtained over the years. Plants with good genetic make-up usually spread quickly and take over an area. An example of this would be the dandelion. These plants can sprout from any part of the plant. An example of this is the potato, farmers will pick the potatoes and cut them into small pieces and then plant them again so they may grow again. Scientists have also placed a branch from one tree and place it on another one; it is now possible to buy an apple tree with six different branches and six different types of apples. The more common way to reproduce is sexual reproduction. In order for this to happen gametes must be produced and fertilized. Seeds, fruits, and embryos must also be developed. The two main advantages of reproducing this way are new genetic combinations and seeds spread over a large area. The following are the reproductive parts in this process. The first part is the flower, which has four types of modified leaves. The first one is the sepal, which protects the other parts of the plant. The second is the petal, which is located inside the sepal. These are normally bright in color to attract animal pollinators. The third is the stamen, which is the male or pollen producing substance. The stamen contains anthers, which is were poll...
The sunflower got its name from its flower, which resembles the sun. The large flower is actually a mature flower head, composed a bunch of tiny flowers clumped together (Duncan 1975). The sunflower is an annual, erect, broadleaf plant. It has a tough, strong stem and rough simple leaves. The leaves on the immature buds are phototropic and follow the sun’s rays, one of the properties that increase light interception. The sunflower is not prone to many diseases, which make it appealing to producers (Duncan 1975). The plant grows rapidly and very large in the right location. They thrive in northern areas. One of the beneficial properties is the plants ability for phtytoremediation. It’s able to r...
Asexual propagation is the process through which reproduction without passage through the seed cycle occurs. The advantages of asexual propagation are that it preserves genetic makeup, propagates seedless plants, disease control, rapid production, the plants are identical, cheaper, faster and easier reducing or avoiding juvenility. The disadvantages of asexual propagation are that it increases disease and insect susceptibility, plants are bulky, and the mother plants could become contaminated. The goal of this experiment was to determine the development of adventitious roots and shoots, and observe these plants over a period of five weeks. Due to auxin being produced in the tip, tip cuttings should root faster than any other cuttings. Auxin is a plant hormone that is responsible for cell elongation and enlargement, root formation, and growth. There are two forms of auxins; phototropism, which is produced in the tip and moves downward on the side away from the light and gravitropism, which is where plant roots grow downward and plant shoots grow upward.(Plant Auxin 201...