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Answered 2010-10-10 09:31:37

The xylem is responsible for the transport of water and soluble mineral nutrients from the roots throughout the plant. It is also used to replace water lost during transpiration and photosynthesis. Xylem sap consists mainly of water and inorganic ions, although it can contain a number of organic chemicals as well. This transport is not powered by energy spent by the tracheary elements themselves, which are dead by maturity and no longer have living contents. Two phenomena cause xylem sap to flow:

  • Transpirational pull: the most important cause of xylem sap flow is the evaporation of water from the surfaces of mesophyll cells to the atmosphere. This transpiration causes millions of minute menisci to form in the mesophyll cell wall. The resulting surface tension causes a negative pressure or tension in the xylem that pulls the water from the roots and soil.
  • Root pressure: If the water potential of the root cells is more negative than that of the soil, usually due to high concentrations of solute, water can move by osmosis into the root from the soil. This causes a positive pressure that forces sap up the xylem towards the leaves. In some circumstances, the sap will be forced from the leaf through a hydathode in a phenomenon known as guttation. Root pressure is highest in the morning before the stomata open and allow transpiration to begin. Different plant species can have different root pressures even in a similar environment; examples include up to 145 kPa in Vitis ripariabut around zero in Celastrus orbiculatus[2].
Anatomy of xylem
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Both phloem and xylem are complex tissues?

yes, they are collectively called vascular tissue.


Are xylem and phloem tissues?

yes, xylem and phloem are tissues in the vascular system


What fibers surround the xylem and phloem tissues?

The xylem and the phloem tissues are found in plants. Bast fibers surround the xylem and the phloem tissues in plants.


Where are xylem and phloem located?

Xylem Phloem and are complex tissues that perform transportation of food and water in a plant. Xylem occupy the center of the vascular bundle and phloem occur on outer side of the vascular bundle.


What are the 2 vascular tissues in plants called?

phloem and xylem


How are Phloem and Xylem similar?

Xylem and Phloem are both vascular tissues of a plant.


Are xylem and phloem types of tissues?

xylem and phloem aren't tissues by themselves, but together they make up vascular tissue.


Which tissues are the main transport tissues in plants?

Phloem and xylem.


Is xylem and phloem present in bryophytes?

No, bryophytes are classified as NON-vascular plants. Both xylem and phloem are vascular tissues.


What type of tissue are xylem and phloem?

Plant transport tissues. Xylem transports water, Phloem transports nutrients (such as sugar).


What are the two types of vascular tissues?

phloem and xylem


What comprises the vein?

The conducting tissues - xylem and phloem.


Do Woody stems have both xylem and phloem tissues?

Xylem and phloem are the two types of transport tissue found in vascular plants. Woody stems contain both xylem and phloem.


What are the xylem and phloem tubes called?

The xylem and phloem tube is called the Vascular Bundle.


Why are tissues present in plants?

Many types of tissues are present in plants such as - Parenchyma, sclerenchyma, chlorenchyma, collenchyma, aerenchyma and complex tissues like xylem and phloem to perform specialized functions. Such as chlorenchya in photosynthesis, sclerenchyma and collenchyma to provide strength and regidity, parenchyma for storage and xylem and phloem for conduction etc.


Why xylem and phloem called conductive tissues?

The xylem tissues, though dead, conduct water from the roots throughout the plant, especially into the leaves. The phloem conducts the finished sugars made from photosynthesis throughout the plant to wherever they are needed.


What are the two main tissues of all vascular plants?

The phloem and xylem tissues


What are xylem abd phleom and what are there functions?

Xylem and phloem are vascular tissues which help in trasportation


Facts about nonvascular plants?

Non-vascular plants do not have complex xylem & phloem tissues and these are devoid of roots. Rhizoides are present for absorption.


Do all plants have xylem and phloem?

No, not all plants (even some complex ones) have separate xylem and phloem cells.


What are vascular tissues on a plant?

There are 2 types of vascular tissue in plants: xylem & phloem. Xylem is a structurally & functionally complex tissue concerned primarily with water conduction, storage & support. Phloem tissue is also both structurally & functionally complex. Phloem is concerned with the distribution of primarily organic molecules between "sources", that is, photosynthetic or storage tissues, and "sinks", or regions of active growth & metabolism.


What contains phloem and xylem?

xylem and phloem are the vascular tissues found in the stems and trunks of woody plants. Xylem transports water upwards from roots to leaves and phloem transports sap from leaves to roots.


Why are complex tissue called so?

tissue is complex permanent tissue, which are made up of more than one type of cells. All these cells coordinate to perform a common function.Complex tissues help in transportation of organic material, water and mineral up and down the plants. That is why it is known as conducting and vascular tissue.The common types of complex permanent tissues are:• Xylem or Wood• Phloem or BastXylem and phloem together form vascular bundles.


Are phloem and xylem vascular tissues in plants?

yes they both are


Which tissues make up the vascular bundles What do they do?

Xylem and phloem.....