Transport in Plant- Chapter 8 Flashcards
What is a xylem?
A plant tissue made up of dead, empty cells joined end to end, it transports water and mineral ions that help support the plant.
What is a phloem?
A plant tissue, made up livign tissues joined end to end, it transports substances made by the plant such as sucrose or amino acids.
What is xylem made up of?
Made up of many dallow, and dead cells joined end to end, the end walls of the cells, have dissappeared so a long open tube is formed. Xylem vessels runs from the roots of plant, right up through the stem, they branch out at ever lead. They cpntain no cytoplasm and nuclei. The walls are made up of cellulose and ligin. Lignin- a hard strog, waterporff substance that forms the walls of the xylem vessels
ow does xyle structure help with transport of water?
The cells are dead, wit no cross walls between them- this allows water to flow through easily. Lignin is very hard and tough helping the vessels stay open allowing water to flow hrough easily. The diametere of the vessel is around 15-200 micro meter depeing on the palce, this is very narrow to make sure clum of water inside them doesn’t break, and enough water can flow through
What is transpiration?
The loss of water from leaves. Water moves from the xylem vessels to mespohyll cells through osmosis. Water evapourtes from the surface of the mesophyll cell walls. The air space contain water vapor=ur. Water vpour diffuses out of the air space thorugh thhe stomata.
What is transipartion stream?
Water is contantly bein taken from the top of the xyelm vessels, to spply the cells in the leaves. This reduces the effective pressure at the top of the zylem, so the waer will flow up, this is known ast transiprtional stream.
What is transpiration pull?
What are the conditions that affect transpiration rate?
he higher the temperature, higher the kinetic energy gained, higher the evaporation of water, so transiprtion will increase.
And water vapour diffuses into and out a cell more quickly.
Water vapour diffuses out of a leaf faster on a iwndy day, then on a day when the air is still.
Humidity also increases transpiration rate. T
at are sources and sinks?
Source: part of a plant that releases sucrose or amino acids to be transported to toher parts of the plant
Sink: Part of a plant where sucrose and amion acids are bein transported to , and whre they are used and stored.
at are sources and sinks?
Source: part of a plant that releases sucrose or amino acids to be transported to toher parts of the plant
Sink: Part of a plant where sucrose and amion acids are bein transported to , and whre they are used and stored.
Explain why susbtances are transported in the phloem upwads at one time fot the year, and downwards at another time.
During summer conditions, the sources for amino acids and sucrose is leaves. As phtosynthesis occurs, so these susbstances are synthesized in the leaves. his is used by the plant to amke nectar, fruit and other essential sysbstances. The roots and flowers are the sinks. So therefore the plohem will travel downards. But during dry winre =we awZon, the plant leavs aren unable to photosynthessis, buts till requirei energy . So the sinks act as sources, transporting sucrose and amino acids to the leave and tother parts, so the ploem will travel upwards.
