Environment It is anything out an organism in

Environment: It is anything out an organism in which the organism lives. Plant ecology: it is the science deals with the interaction between the plants and all surrounding factors. The ecological factors affecting on the plant and other organisms in the biosphere are: 1. Climatic factors: as rainfall, temperature, humidity, light intensity and wind. 2. Soil (Edaphic) factors: soil composition, soil texture, soil temperature, soil water content, and soil depth. 3. Biotic factors: Include any relationship between different living organisms such as another plants, animals and human.

Climatic factors 1. Temperature In most thermometers mercury used, due to it is high sensitivity to variation in temperature and wide range from boiling point 360 ċ to freezing point -93 ċ. a. Ordinary thermometer: ﺍﻟﺰﺋﺒﻘﻲ / ﺍﻟﻠﺤﻈﻲ / ﺍﻟﺘﺮﻣﻮﻣﺘﺮ ﺍﻟﻌﺎﺩﻱ • it used to measure temperature at once. • The idea based on affecting the mercury by variation in temperature. • This instrument composed of fine capillary tube ended by bulb filled with mercury and covered with graduated glass tube. The graduate begins with 0 o. C and ended with 100 o. C (the water boiling point). • Put thermometer in definite location, mercury in bulb expands till reach to point referring the temperature of the distinct area.

B. Maximum and minimum thermometer: • Used to measure the maximum and minimum temperature in 24 hours. • The idea based on affecting the mercury and alcohol by variation in temperature. • - It is a special type of U-shaped thermometer ended by two bulbs in which one arm record the maximum and the other the minimum temperatures. The mercury fills the bottom U part above it there is alcohol in max arm left space while the min arm fill completely with alcohol. In each thermometer arm, there is a piece of an iron magnet left at the level of mercury. • - At the daytime, temperature will raise, alcohol in max arm will evaporate and mercury will expand carrying magnetic piece up in max arm indicating the maximum of temperature. • - At the nighttime, the temperature decreases, the evaporated alcohol particles at day will condensate and drop on mercury surface causing movement of mercury in min arm carrying metallic upward indicating the minimum temperature.

c. Thermograph: • This instrument continuously records temperature on a graph sheet usually for long time (one week). The recorded temperature on the graph is called thermogram. • This device consists of metallic ring attached to arm fixed from one side on pivot and another side ended with Pin with special ink adjusted to the move up and down on drum make one rotation in one week covered with graph sheet duly marked for temperature on one side and days and hours on the other. • - At the daytime, temperature will raise, metallic will expand carrying arm up to draw line on graph paper indicating the increasing of temperature. • - At the nighttime, the temperature decreases, metallic ring will contract carrying arm downward to draw line referring to the decreasing in temperature.

d. Vegetation thermometer It is ordinary thermometer carrying on motional pivot to determine the temperature at different heights through vegetation. f. Soil thermometer It is ordinary thermometer enveloped with metallic sheath at apex with pores. It is using to determine the temperature at different depth through soil