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XI. Using the following figure make the classification of Moss Rose.


UNIT 5

Wordlist

shoot system

root system

bud

stem

tuber

rhizome

meristem ,

tissue

dermal

ground

vascular ,

waxy cuticle

I. Read the text and find out the main parts of plant.

General Plant Organization

A plant has two organ systems: 1) the shoot system, and 2) the root system. The shoot system is above ground and includes the organs such as leaves, buds, stems, flowers (if the plant has any), and fruits (if the plant has any). The root system includes those parts of the plant below ground, such as the roots, tubers, and rhizomes.

Plant cells are formed at meristems, and then develop into cell types which are grouped into tissues. Plants have only three tissue types: 1) Dermal; 2)Ground; and 3) Vascular. Dermal tissue covers the outer surface of herbaceous plants. Dermal tissue is composed of epidermal cells, closely packed cells that secrete a waxy cuticle that aids in the prevention of water loss. The ground tissue comprises the bulk of the primary plant body. Vascular tissue transports food, water, hormones and minerals within the plant.

Major organ systems of the plant body.

 

II. Using the wordlist read the text and name each paragraph.

ROOT SYSTEM

Wordlist

ascending axis

dissolve

anchor

tap-root system

diffuse

slender

parsnip

dandelion

alfalfa

ramified

tip

meristematic tissue

thrust

split

Root, in botany, the descending axis of a plant, as contrasted with the stem, the ascending axis. In most plants the root is underground. Roots function to absorb water and dissolved minerals from the soil, to transport water and nutrients, to anchor the plant, and often to store food.

There are two main types of root system: the tap-root system, in which there is a main primary root larger than the other branching roots; and the diffuse (or fibrous) root system, in which there are many slender roots with numerous smaller root branches. Tap roots are characteristic of most trees and of many other plants, including the carrot, parsnip, radish, beet, and dandelion. The grasses (e.g., corn, rye, and alfalfa) have diffuse roots; in the sweet potato some of the larger fibrous roots swell to store foodalthough these should not be confused with the tuber of the Irish potato, which is a modified underground stem.

Root systems often far exceed in mass the aboveground portions of the plant: alfalfa roots sometimes reach 40 ft (12 m) in length, and the combined length of all the roots of a mature rye plant has been measured at 612 km. These ramified root systems are important agents in preventing soil erosion. Roots grow primarily in length; only the older roots may develop a cambium layer that increases their diameter.

Protecting the constantly growing tip of the root is a cap of cells that break off as the root probes through the soil; they are replaced by new cells from a layer of meristematic tissue just behind them. Although root hairs are less than 1/3 in. (.84 cm) long, their great number enables the plant to collect enormous quantities of water, most of which is promptly lost into the air by transpiration. In spite of their slenderness and delicate structure, the spiraling forward thrust of the root tips and the pressure of their expanding cells is sufficient to split solid rock.

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