Presentation is loading. Please wait.

Presentation is loading. Please wait.

By Mel, Alishia & Carla..  There are two basic patterns of root growth:  The tap-root system found, for example, in dandelions.  The fibrous system.

Similar presentations


Presentation on theme: "By Mel, Alishia & Carla..  There are two basic patterns of root growth:  The tap-root system found, for example, in dandelions.  The fibrous system."— Presentation transcript:

1 By Mel, Alishia & Carla.

2  There are two basic patterns of root growth:  The tap-root system found, for example, in dandelions.  The fibrous system found, for example, in grasses.  The tap-root system is an extension of the primary root (the young seedling). But in fibrous systems this primary root is quickly replaced by many fine roots from the base of the stem.  Very often the root is modified for storage. This helps it survive the winter. It contains food material (e.g. starch) which will be used by the developing shoots in spring. Man has made use of such stores implants like carrots, turnips, and beet. The food may be stored in the cortex or the phloem.

3  Plants absorb nutrients and water through their roots, but photosynthesis, the process by which plants create their fuel, occurs in the leaves. Therefore, plants need to get fluids and nutrients from the ground up through their stems to their parts that are above ground level.  Just as animals, plants also contain vascular tissues (xylem), which transports water and minerals up from the roots to the leaves, and phloem, which transports sugar molecules, amino acids, and hormones both up and down through the plant.  The leaves of plants also contain veins, through which nutrients and hormones travel to reach the cells throughout the leaf. Veins are easy to see some leaves but very difficult to find in others.  Sap is the mix of water and minerals that move through the xylem. Carbohydrates move through the phloem. There are several different "modes of transportation" through the xylem and phloem; their main function is to keep all cells of the plant hydrated and nourished.  Inside the cells of the root, there is a higher concentration of minerals than there is in the soil surrounding the plant. This creates root pressure, which forces water up out of the root through the xylem as more water and minerals are "pulled" into the root from the soil. This force results in guttation, which is the formation of tiny droplets on the ends of leaves or grass early in the morning.  The reason the droplets are seen in the morning is because transpiration, the loss of water from leaves doesn't occur at night, so the pressure builds until morning. Those droplets are not just water, they're sap. And, those sap droplets are proof that water and minerals get pulled up from the soil and transported through the entire plant.  Guttation may work well for small plants, but gravity works against the upward movement through larger plants, so more active processes are involved.

4  Only a few of the edible roots that humans eat include Beetroot, Carrot, Horseradish, Turnip, Garlic, Onion and Leek. Normally, roots grow downward under the influence of gravity and away from light. This reaction enables a sprouting seed to get a hold on the soil. Roots will generally grow in any direction where the correct environment of air, mineral nutrients and water exists to meet the plant's needs. Roots will not grow in dry soil. The root contains the same sort of tissues as the stem but the strengthening tissues of the root are centrally placed, reflecting the pulling strain suffered by the root as opposed to the bending strain imposed on the stem.

5

6 Photosynthesis does not happen in roots; although it plays a role. The xylem carries the water from the roots to the leaves, because the leaves need water for photosynthesis. The roots also collect minerals and valuable recourses to keep the plant alive and healthy. Where as respiration does occur in the roots as well of as every part of the plants body. Root respiration counts for approximately half of the soil respiration. Soil respiration is a key eco system process that releases carbon from the soil. However the conditions can range from 10%- 90% deepening on the different plants types and the surroundings in which they are placed. Roots respiration is the exchange of gases in and out of the atmosphere.

7  Stems support the leaves, flowers and fruits  Stems transport water, minerals and sugars to leaves and roots.  Roots provide anchorage in the soil  Roots allow absorption of water and nutrients  Roots allow transport of water and nutrients  Root hairs provide huge surface area for absorption  Root caps protect and lubricates the growing root  There is a primary root (tap) and secondary root (lateral).  Roots tend to grow downwards, away from light and towards water.  Their primary roles are anchorage, absorption and transport, however roots have adapted to fulfil a variety of other functions, including storage and support.  Leaves are a plants foot factory. They are the main site of photosynthesis, where sugars are made from water and carbon dioxide, using sunlight and energy.

8


Download ppt "By Mel, Alishia & Carla..  There are two basic patterns of root growth:  The tap-root system found, for example, in dandelions.  The fibrous system."

Similar presentations


Ads by Google