Importance of Xylem and Phloem Tissues Essay Example for Free

Importance of Xylem and Phloem Tissues Essay The primary xylem and primary phloem tissues are pushed inward into the] pith and outwards respectively by the continuous production of secondary tissues cut I off by the cambium ring. The primary xylem is gradually pushed inward and is found at the centre of the axis; whereas, the primary phloem, being soft in nature, gets completely crushed. These activities in the stelar region exert a great pressure outwardly. The cortex cells, the pericycle and the epidermis divide anticlinally to cope with the production of tissues in the stelar region. Formation of annual ring or growth ring The activity of the cambium ring is under the control of series of physiological and environmental factors. For example, in spring the cambium becomes more active and forms a greater number of vessels with wider cavities. In winter, the temperature is low due to which the cambium also becomes less active and forms narrow pitted vessels, tracheids and wood fibers. The xylem (wood) formed during the spring is known as spring wood or early wood and which is formed in winter is called autumn wood or late wood. The spring wood is lighter in color and exhibits low density where as the autumn (or winter) wood is darker and has higher density. These two kinds of wood appear together, in a transverse section of the stem, as a concentric ring known as the annual ring or growth ring. Successive annual rings are formed year after year by the activity of the cambium. Each annual ring corresponds to one years growth. Thus one can estimate the age of plant to some degree of accuracy by counting the total number of annual rings. Annual rings are readily seen with naked eye in the logs of a tree trunk. Heart-wood and sap-wood: In old trees, the greater part of the secondary wood is filled up with tannins resins, gums, essential oils, etc. , which make it hard and durable. It looks dark or brown. This region is known as heart-wood. The heart wood gives mechanical support to the stem. The outer region of the secondary wood is of lighter color and is known as sap-wood or alburnum. It helps in conduction of water and mineral salts from the root to the leaf. (B) Secondary growth in extra-stelar region Secondary growth in the extra stellar region occurs to cope with the addition of tissues in the stellar region. It occurs in the cortex and helps in the formation of periderm. It occurs by the formation and activities of a secondary meristem called cork cambium or phellogen. Origin and activity of the cork-cambium or phellogen Due to the addition of secondary phloem and secondary xylem elements, the outermost layer of the cortex becomes highly stretched and may crack open. During this process a few layers of meristematic tissue arise in the cortex. This is called the cork cambium or phellogen. The nature of cambium is secondary. Commonly it arises in the outer layers of the cortex i. . hypodermis. It may also arise in the epidermis itself, or in the inner layers of the cortex, or even in the pericycle. The cork combium consists of narrow, thin-walled and roughly rectangular cells. It is of few layers in thickness. The cork cambium cuts of cells on both the sides and secondary cortex on the inner. The cells of the secondary cortex are parenchymatous in nature and often contain chloroplast. Cork The new cells cut off by the cork-cambium on its outer side are rough rectangular and soon become suberized. They form the cork of the plant. Cork cells are dead, suberized, thick-walled and brown in color. They are arranged in radial rows being suberized, cork is impervious to air and water. Functions of Crock (i)It acts as a waterproof covering to the stem (ii) It also protects the plant] against the attacks of parasitic fungi, (iii) Cork cells, being dead and empty, containing air only, are bad conductors of heat. This being so, a sudden variation in outside] temperature does not affect the internal tissues of the plant; (IV) Cork is also made use of by the plant for the healing of wounds. The bottle cork is obtained from the cork] cells of Quercus suber. ) Bark In restricted sense, all the dead tissues lying outside the active cork cambium constitute the bark of the plant. It, therefore, includes the epidermis, the lenticels and cork, and sometimes also hypodermis and a portion of the cortex depending on the position of the cork-cambium. Thus the deeper the origin of the cork-cambium, the thicker would be the bark. The term bark in a wider since is used to describe all tissues outside the vascular cambium of the stem. Phellem, phelloderm and phellogen layers are collectively called periderm. Thus periderm is a protective multilayered structure of secondary origin. On the basis of function, two types of barks are distinguished- ring barks and scale bark. When the cork cambium appears in the form of a complete ring the bark that is formed comes away in a sheet; such a bark is known as the ring bark as in Betula. When the cork-combium appears in strips the resulting bark comes away in the form of scales; such a bark is known as the scale bark as in (guava) Psidium. Function of bark The bark protects the inner tissues (i) against the attack of fungi and insects (ii) against loss of water by evaporation and (iii) against variation of external temperature. Lenticels These are small aerating pores formed in the bark of stems through which gaseous exchange takes place. Externally they appear as scars or raised portions on the surface of stems. Lenticels are first formed below the stomata. A section through one of the scars shows that the lenticels consists of a loose mass of small thin walled cells called complementary cells or filling tissue.

Life :: essays research papers

Sitting on the white sandy beach of Kaanapali in Maui, Hawaii a young boy approached me begging for a dollar. Seeing that he really needed and wanted the money, I gave him without any thought. I actually gave the boy two dollars more than he asked. The boy looked at me and said, â€Å"Why did you give me more than I asked,† a question I was not prepared to answer. I told him to enjoy it because live is short. The boy looked me in the face and said to me, â€Å"Sir, what is life?† Very amazed by his question, I told him I didn’t really know. The boy smiled with me and ran off to play with his friends. But what is Life? Life is the greatest unknown; it is a mysterious, unpredictable cascade of unbelievably amazing, unpremeditated experiences. Life is a true abyss, the truth may be right before your eyes or yet the truth may be so far from your eyes that trusting your eyes may be of dyer consequence. Knowing the difference between the two adds another element of di fficulty not many can sincerely claim to have dealt with victoriously. Life is never what one would wish, as life feels no guilt, contorting ones hopes, aspirations and dreams to produce a never ending array of experiences. Life is never subject to control; rather it has a sense of irony, sometimes indescribably so. Life is a teacher, an understatement that can be dismissed by no one. I myself have been time and time again a pawn in the game of life. Life has taken away so much from many of us, but for good reasons, so as to allow us to realize that we were blessed to have had so much to lose. Life has though offered us much more than we will ever know. But the greatest lesson life has taught us may be confined here in these words. We are all unique, all of our lives are unparalleled, and we are a mirror image of no one. People find it amazing how quickly children can develop into teenagers and how seemingly regressed they are at the age of adulthood. Many of us have had various good and bad experiences in life and have had to make many choices that lif e has thrown at us, but I believe it is these decisions and choices that we make in life that make us who we are.

Case Analysis – The Best-Laid Incentive Plans

This paper seeks to answer two questions from the case entitled `The Best-laid Incentive Plans` by Steve Kerr. The first one is to identify relevant metrics while the second one is to discuss the potential incentive and disincentive characteristics of your metrics. 2. Questions and Answers: 2.1. Identify relevant metrics The relevant metrics being used by Harim were efficiency and cost reduction which are focused on employees and company activities rather than on the customer. This fact is based on Harim’s plan to bring down costs which had caused the placing for savings on all the factors that could influence cost (Kerr, 2003). As proof it was commented that the company has found itself paying out bonuses but still the profitability of the company did not improve (Kerr, 2003). 2.2 Discuss the potential incentive and disincentive characteristics of your metrics. The potential incentive characteristics include the fact the employees are given out bonuses for having produced savings. Producing saving could be beneficial to the company as this will enable it to have funds for growth as well as sustaining its working capital requirements. On the other hand, the potential disincentive characteristics include the fact that the program is not fully understood by the employees as to the real purpose of the cost reduction and how it would redound to their benefits.   Another disincentive characteristic is that it is more employee-focused than customer -focused which contributes to employees not understanding why they are the targets. The program also assumes that the organization was not working hard enough while the employees know that it is not the usual case in most companies. This has the effect of affecting the self esteem of people in the organization and necessary their job morale. The program lacks a clear definition of the criteria for success. By failing to explain the cost reduction program the employees may not understand the bottom line effects of the program. This could make them think that eventually it could result to their losing their jobs since their jobs also have cost to the company. The employees not seeing the big picture will be confused and this could cause them to lose their loyalties to the company and this could be more disastrous for the company. The metrics program of Hiram focuses on the intermediary steps and assumes that such enhancements will make a positive impact on the bottom line (Kerr, 2003). By falsely assuming that short term positive impacts will result, the opposite could result because the employees cannot understand the direction that they are taking. Or although it could produce positive result in the short run, the long term success is actually being sacrificed. It may be argued that although the long term objectives or goals are broken down into short terms objective, focusing on the short objective may create more problems. To illustrate, although less employees could mean less labor cost, it could also mean less customer service and customer loyalty, which is usually built over long term but could be lost in an instant by failing to address their short term needs as customers can switch anytime. Another disincentive characteristic is its failure to link with corporate strategy of marketing. Although the quality and cost of provided services need to be controlled at manageable levels the need to have more satisfied customer are equally if not more important. By measuring only the amount of cost that will be saved without relating with amount of revenues that will be lost, the company is in a losing game from which it is clearly missing the point of any incentive program or performance metrics. 3. Conclusion: Performance should first be measured in terms of revenues before using cost reduction for the essence of going into business is using up assets and resources to generate revenues that expected to be higher that could cover up the expenses. Hiram’ program failed in this aspect. Reference: Kerr, S. â€Å"The Best-Laid incentive Plans†, Motivating People, Harvard Business Review Case Study, 2003   

Socrates And Machiavelli s Views On Violence And Violent...

Socrates and Machiavelli hold vastly different views on violence and violent actions, the former advocates strongly that it is always better to be harmed rather than to harm while the latter argues that violence is essential, when used correctly, in order to gain and maintain power. These contrasting views on violence both hold merit, yet the question of which view is more corrupting depends strongly on what corruption is defined as, and thus, which view fits this definition. Socrates is determined to be guilty of corruption by the court of Athenians, as his methods of questioning and actions regarding violence are viewed as dangerous and threatening to the Athenian democracy. However, he also acts in ways that strengthen the democracy with his view, by defending the law even when other members of the court disagree with him and violence appears imminent. Machiavelli, on the other hand, states that violence is necessary and that wickedness and improper violence corrupt more so than v iolence itself. When used properly, he believes that violence is not corrupting, but rather essential in maintaining power and creating a successful rule. In the case of examining these differing views of violence and determining which is more corrupting, corruption is to be defined as actions that are purposefully undertaken that weaken the rule of government and put the lives and property of the citizens. Based upon this definition, when violence is handled how Machiavelli suggests, his viewsShow MoreRelatedSocrates And Machiavelli2009 Words   |  9 PagesSocrates and Machiavelli are both very influential philosophers and two of the great minds of their time. However, both of these men had their own separate ideas that did not completely agree with one another. Machiavelli was born into a Renaissance time period of fragmented politics, lots of bloodshed, and angry citizens while Socrates grew up in a time of political adjustment and instability in Athens. Machiavelli constructed The Prince as a political pamphlet to his friend Lorenzo de Medici