Plant Senescence : The Last Development Stage Of A Plant

In a plant’s life cycle, there are a few key details such as germination, growth, egg or sperm production, pollination, seed production and dispersal, and finally death. In the germination phase the seed sprouts after a certain exposure to light, temperature, and moisture (Pima Community College). In the growth stage the sprout turns into a mature plant, this is followed by the production of an egg or sperm and then pollinated by other pollen transferred by the wind or an animal. Next is the seed production when the embryo and endosperm get a seed coat to form a new seed, the dispersal of the seed occurs it is transferred from the parent by interaction with an animal. Finally death, it’s pretty obvious, death is when the plant dies.

The leaves of a plant are the main photosynthetic organs and are involved in gas exchange and water transportation throughout a plant (Evans et al, 17). A leaf typically consists of an upper and lower epidermis, the mesophyll cells, veins, guard cells and stomata. The mesophyll cells contains spongey cells which have large gaps between each cell to allow oxygen and carbon dioxide circulation. The mesophyll cells contain palisade cells, which are located beneath the upper epidermis. The palisade cells contain many chloroplasts, which are green organelles. Located in the internal layers of chloroplasts is the pigment chlorophyll which is involved in trapping the light energy in photosynthesis (Evans et al, 17).

Photosynthesis occurs each time the sun’s light reaches the lives of a plant. The chemical ingrediants for photosynthesis are carbon dioxide (CO2), a gas that passes from the air into a plant via tiny pores, and water (H20), which absorbed from the soil by the plant’s roots. Inside leaf cells, tiny structures called chloroplasts use light energy to rearrange the atoms of the ingrediants to produce sugars, most importantly glucose (C6H12O6) and other organic molecules. Chlorophyll gives the plant its green color (Simon, 02/2012, pp. 92-93). Chemical reactions transfers the sun’s light energy into the chemical bonds that hold energy-carrying molecules. The most common are

This research was conducted to see the effects of sunscreen on plants ' lifespan. The hypothesis was that the plants that had sunscreen applied to them would have a shorter lifespan than plants with no sunscreen applied to them and increasing the amount and SPF value of the sunscreen would decrease the lifespan even more. 12 Romaine Heirloom Leaf Lettuce plants were separated into 4 categories and were tested on for a period of 28 days. The 4 categories were: control or no sunscreen, 1/4 teaspoon SPF 30 sunscreen, 1/2 teaspoon SPF 30 sunscreen, and 1/4 teaspoon SPF 50 sunscreen. It was found that the original hypothesis was supported by the data. On average the control plants lived 21 days, the 1/4 teaspoon SPF 30 sunscreen lived 9 days, the 1/2 teaspoon SPF 30 lived 8 days, and the 1/4 teaspoon SPF 50 lived 5 days. This implies that sunlight is a very important factor in plant lifespan. This research could be useful to scientists trying to grow plants on other planets.

In general terms, explain how the basic plant life cycle with alternation of generations is modified in angiosperms.

Humans undergo several stages during their lifetime including growth, development, reproduction and senescence. Senescence is defined as the deteriorative biological changes that organisms experience as they age eventually leading to death. These changes include low metabolism, a weak immune system, memory loss, poor vision and loss of hearing. Senescence begins in humans during their post-reproductive years. However, gerontology research has shown that individuals who reproduce late have longer life spans compared to individuals who reproduce early. Nonetheless, it does not indicate that senescence is inevitable. All organisms experience senescence,

University Press, Cambridge, United Kingdom. E J H Corner, 2002. The Life of Plants. University of Chicago Press,

In my research paper, I will attempt to determine how the perception of light in phytochromes plays a role in the development of plants. Specifically, I will look at how phytochromes play a role in the growth and development of Arabidopsis thaliana. The paper will also look at how light perception plays a role in phototropism and the immune systems of a plant. Finally, my paper will explore how changing light conditions impact perception in phytochromes.

Plants have evolved sophisticated genetic and epigenetic regulatory systems to respond quickly to unfavorable environmental conditions such as heat, cold, drought, and pathogen infections. In particular, heat greatly affects plant growth and development, immunity and circadian rhythm, and poses a serious threat to the global food supply. According to temperatures exposing, heat can be usually classified as warm ambient temperature

Valladares, F., E. Gianoli, and J.M. Gomez. 2007. Ecological limits to plant phenotypic plasticity. New Phytologist 174:749-763.

Aging is the process of becoming older, as we age, multiple mutations occur that concern all the processes of aging well as it compromising a number of different genes. There are many theories of biological aging, such as the Cellular Aging Theory, Immunological Theory, and the Wear and Tear Theory. The Cellular Aging theory describes the process of aging in which cells slow their number of replication, thus giving each species a “biological clock that determines its maximum life span” and how quickly one 's health will deteriorate(Hooyman, 42). After a certain number of years, each cell which follows an apparent biological clock starts to replicate itself less, thus the specific individual or species slowly deteriorates. This theory gives

Photosynthesis is a very complicated process. It is not as simple as plants need a little sunlight, water, and carbon dioxide, and viola oxygen is produced. There are many steps and processes that occur during photosynthesis which make it very complicated. Now the actual word photosynthesis in Greek means photo- “light”, and –synthesis “putting together”. This is the overall basic foundation that photosynthesis stands behind. Photosynthesis can only happen in plants and some algae, due to them having an organelle called chloroplast. Chloroplast has a pigment, which is called chlorophyll. Chlorophyll is a light absorbing pigment, which allows the plant to control solar energy and use it to distribute energy and food for the plant itself. Chloroplasts are usually located in the green tissue in the interior of the leaf called the mesophyll. A usual cell has around thirty to forty chloroplast. In the inner compartment there is a thick fluid called the stroma, with a system of interconnected membranous

Biogeochemical cycles are important to the sustainability of all life. Chemical elements necessary for the growth and reproduction of all organisms have a limited quantity on earth at any one time, other than the occasional meteor that brings with it new matter. It is therefore important that the recycling of these chemical elements is efficient. Autotrophs are the basis of almost all ecosystems. The rate that autotrophs produce and transfer energy is vital to the capacity of organisms that can inhabit these ecosystems. To understand the rates in which certain species’ leaves decay and release the energy stored within them can demonstrate how quickly the energy becomes available to organisms in higher trophic levels.

All plants are subjected to a multitude of stresses throughout their life cycle. Depending on the species of plant and the source of the stress, the plant will respond in different ways. When a certain tolerance level is reached, the plant will eventually die. When the plants in question are crop plants, then a problem arises. The two major environmental factors that currently reduce plant productivity are drought and salinity (Serrano, 1999), and these stresses cause similar reactions in plants due to water stress. These environmental concerns affect plants more than is commonly thought. For example, disease and insect loss typically decrease crop yields by less than ten percent, but severe

Petiole is the support that bind the leaf blade to the stem. It is the passage between the stem and the leaf blade. Petiole ends where the blades begin. In a typical and carnivorous plant, the petiole is the channel where the products of photosynthesis are moved from individual leaves to the rest of a plant, making it an important part of photosynthesis. Lamina or blade, is the leaf tissue that encompasses mesophyll cells, which contain chloroplasts, making its primary function photosynthesis. The epidermis below or above the lamina contains stomata to facilitate gas exchange. Moreover, the lamina in a typical and carnivorous plant contains xylem and phloem that deliver water and nutrients and carry away the products of photosynthesis. Cuticle is a waxy covering in the epidermal cells. Cuticles in a typical plant help reduce water loss and effectively decrease the entry of pathogen due to their waxy secretion. The cuticle not only keep the plant surfaces from becoming wet, it also helps prevent  plants from drying out. In carnivorous plants, the cuticle allows for nutrients to go directly into the tissues. The interior pitcher walls of Sarracenia lack a cuticle which allows the nutrients from the pitcher fluids to enter the plant through its specialized gaps in the cuticle. Trichomes on typical plants are outgrowths of  the epidermis, such as hair, scale, or water vesicle and can have a variety of functions. Root hairs are trichomes that facilitate the absorption of water