Re: What are the parts of a plant?

In general, a plant needs roots to make sure that the plant isn't  blown away by the wind,
 and it needs a stem so that it can hold itself up (or if it is a tree, it has a trunk)  and this
 hold its leaves up to the sunlight so that they can use the sunlight to make food for the 
plant.  As plants need water too, the roots also draw up water from the soil, along with
 any nutrients that are dissolved in the water.

Have you noticed that lots of plants have flowers?  This group of plants is called the 
"angiosperms".  The more ancient  plants are called the "gymnosperms" and these are pine 
trees and ferns.  The difference between these groups is in how they produce and spread
  their seed. 
 
Angiosperms produce flowers which are fertilized and the resulting seeds are grown 
inside a protective covering, some coverings are hard, or like the "wings" that float down 
from maple trees in the summertime, or like the shells of  peanuts. Others are soft, like
 to parts of apples, or tomatoes that we eat.  Maple tree seeds are blown by thewind and
 before landing back on the earth, where they grow into a new maple tree.  Fruits like 
apples and tomatoes are eaten by animals, and the seed, which is more or less  undigestable
is put back into the ground in the animal manure.  

The parts of the flower include the male (anther) and the female (ovary) parts, which are
 usually found in the middle of the flower.  The ovary is actually hidden at the base of the 
flower and a tube called the stigma rises  out of the ovary to receive pollen from the 
anthers, which are connected to the flower by stalks called stamen. The petals are 
coloured to attract birds and insects to pollinate the  flower, whereas the sepals form 
a whorl around the petals protect everything inside.  
After the ovules in the female part has been fertilized, the sepals, petals,  anthers, stamen
 and stigma fall off, and the female part, the ovary swells up as the seeds are formed 
inside of her. 

Gymnosperms have their seed out in the open on things called "scales".  Take a look at a 
pine cone- it's made up of all these scales! and on each scale is a single seed, laid out as
 if it were on a plate.

We eat fruit, and we use pine cones in decorating the house at Christmas-time.  What 
about the roots?  Some plants store their food in their roots, and we humans then eat 
the roots.   Can you think of any examples?  How about the potato? Or the carrot, or a beet!

This is a very general view of what makes up a plant.
This you want more detail, and nifty pictures, check out the following web site:
http://moby.ucdavis.edu/Coursepages/PLB105/Students/Tomato/Tomhome.html