Brassica Study

On April 2nd, the students discovered yellow flowers and learned the formal name of these plants is Brassica.  They observed the flower carefully and M.B. noted that he “learned about the pistil.” Then the students pollinated their Brassica flowers with bee sticks. 

D.L.   learned that first “you need to pollinate your flowers and then you need to pollinate another flower.”  Most students will agree with H.S. when she says, “…even dead bees can pollinate.”  Then adds “I felt surprised that dead bees could pollinate flowers.” 

 On Monday, March 16th, the 2nd grade students planted Brassica seeds to begin their plant growth and development study.   By the end of the week, the students were surprised to see their plants sprouting.  Here is what the plants looked like a full week later.

The students discovered their plants grew each day.  By the 4th day the students were observing the heart shaped seed leaves.  Look closely and you can see them in the picture.   

Before the first week ended, the students thinned their plants.  L.C. wrote that “thinning plants means to remove extra plants to make room for other plants to grow.”  E.D. explained that “scientists need to thin their plants because the healthiest or strongest plants to survive should have no competition in what they need.”  “I felt good today in science because I thinned my plants,” said J.P. 

The height of each plant was the first difference noted, but after careful observation, other differences were noted too.  By day 8, the students discovered a new type of leave: the true leaf.  T.G. compared the two types of leaves to teeth.  In class he explained that the seed leaves were like baby teeth and soon they would not be needed because the true leaves would grow and take over the needs of the plant.

Today, May 2, was the day we finally harvested our seeds!  Each student was able to take home his/her Brassica seeds.  Even though the parent plants have been dead for quite a few days, each plant produced pods and each pod produced seeds ready to continue the Brassica life cycle.  Here is a picture of the small seeds.  J.D.’s pencil point is pointing to one seed.

 M.Q. recorded 15 seeds came from his three pods.   M.B. writes, “I harvested about 18 seeds from my two pods.”  P.H. also removed two pods from his plant and shared with us that he harvested 13 seeds.  A.C. was able to harvest 17 seeds from her two seed pods. 

Here is the dead Brassica plant with its seed pods.  The seeds are ready to be harvested.   

 Remember our orginal scientific riddle (question):  “How many seeds can you get from a single seed?”   We learned the answer is anywhere from 13 seeds from a plant that produced two pods to 80 seeds from a plant that produced 7 pods. 

The Brassica lifecycle really came to life for the children in 2K this spring all thanks to the Chatham Education Foundation!!
  

Day 42 was Monday, April 28.  This was also our first day back to school from spring break.  Our plants had been without water for 10 days.  The plants were clearly dead.  Not only did they turn brown, but the stems were very easy to break.  Today each student counted the number of seed pods on the plant he/she has been studying.  Some plants only had two pods, but others had more than 10.  Why do you think some plants produced more pods than others?  The final step is to open the pods and to count the number of seeds that were produced inside each pod.  This will be done on Friday.  We will share pictures from both Monday and Friday then.

Thursday, April 17, is the 38th day of our Brassica Plant life cycle project.  Today was about a week since the children took a close look at their plants and they still did not observe much growth.  They clearly feel that their plants are reaching the end of their life cycles.  Tomorrow, the plants will be removed from the water source.   M.P. writes that he thinks the plants must be taken off the water so that they do not rot.  J.G. also feels that taking the plants off the water will prevent the plants from rotting.  The plants will remain in school next week and here are some predictions of what the children think will happen to their plants while they are on spring break.  A.Ca. predicts that once the plants are off the water, “chorophyll will not be there and that the plant might stop growing.”  Chorophyll was a hot topic today.  A.W. also felt chorophyll was going to play a part in the next stage and predicted her plant “will turn purple after spring break because there will be no chorophyll.”  B.B. feels that his plant will droop once it is off the water source and T.L., after observing the pods carefully, thinks that the pods will open and “let out their seeds.”  Most of the children are convinced that seeds are inside the pods and that once the pods are opened, their plants will have completed the life cycle!  That brings us back to our orginal riddle from Day 1.  How many seeds can you get from a single seed?

 If you are interested in learning more about the Brassica Plants while we are away from school, check out this website.  http://www.fastplants.org/intro.lifecycle.php#menu

Day 32 did not bring much change to our Brassica plants.   We are still observing color changes in the leaves and petals, however, there is not much difference in the plants’ heights.  The petals continue to wither and fall off, but other plants have buds that are still opening to new flowers.  Pollination follows for those flowers.  Green pods are enlarging from the flowers that are losing their petals and more and more people are predicting what is inside the pods.  Now people are comparing the bumpy and wrinkly pod skin to that of an elephant’s skin or an elderly person’s skin.

After four weeks, our plants are certainly changing.  Colors are changing and petals and leaves are falling off. “Most of my seed leaves are as yellow as a star. They’re running out of chlorophyll,” writes M.D.  J.W. says one of her seed leaves is as purple as a plum.  However,  the biggest change has been the development of pods.  A.S. writes that she observed about 18 pods today.  “The pods feel bumpy,” says J.F.  R.M. writes, “the pods on my plant look like pickels.”  J.D. describes the pods as having green bumps.  H.E. observes the pods looking like green beans and  K.S. writes the pod is like a stick. 

Here we are at the 3 week mark, Day 21, March 31, 2008.  Over the weekend we noticed the plants grew even taller.  The seed leaves are turning white/yellow and falling off. The yellow petals are starting to fall off too and green sticks are starting to grow from the flowers.  We wonder what they are.  Some of us think they are part of the plant’s stem.  Others think the flower’s pistil is growing longer and fatter, but we wonder why.

Today we learned the Brassica plant is part of the Cabbage Family.  Other well know family members are cauliflower, broccoli, turnips, cabbage and mustard seeds.

How Many Seeds Can You Get From A Single Seed?

Thanks to a grant by the Chatham Education Foundation, the second graders at MAS will solve this riddle!

On March 10, 2008 the second graders planted their Brassica seeds and began to explore the life cycle of the plant.  During the 44 day life cycle, the students will observe, measure, and tend to their plants.  The final step is to thresh and harvest the new seeds.  We hope you enjoy watching the learning unfold.  Please feel free to comment and share your thoughts with us.  So how many seeds do you think you can get from a single seed?

Here are the Brassica plants on Day 1 under the lights.  These plants belong to both 2K and 2S.

On Day 4, (March 14) the students thinned their plants so one plant could thrive in each cell.  They also had an opportunity to observe the seed leaves and the roots.  Many students still found the seed attached to the root.

Brassica plants not yet thinned.  As many as three plants per cell.

Brassica Plants after thinning process.    Just one plant per cell.               

Here is a closer look at the Brassica plants’s seed leaves and roots.

 Day 7- March 17.  Each plant is growing taller and stronger.  The seed leaves are still visible, but if you look closely, you can also see the true leaves beginning to grow.

Day 10- March 20th

This is a picture of our Brassica plants.  When we measured them and they were between 3 and 5 centimeters tall. The plants were also spreading out.   We observed the true leaves, seed leaves, little hairs attached to the true leaves and possibly even some buds.

 Here is a picture of 2K’s and 2S’s plants.  Compare this picture with the picture from Day 1.  Do you notice any changes?

 Below are three pictures from Day 14:  Monday, March 24, 2008.

 On Day 14,  after the long weekend, we noticed a great deal of growth and we were not all expecting it.  The plants grew anywhere from 7 to 11 centimeter tall.   We observed more true leaves and more buds.   On some plants there are four or more buds.   We predict that these buds will bloom soon.  By RM, AC, PH, AC, JF

On Day 14 we also made bee sticks.   Don’t worry, the bees are dead and dried.  They will not sting us.  To make the bee sticks we put glue on the toothpicks, put the bees on their backs and glued the bees to the sticks.  We observed the bees with magnifying lens and noticed they were not black and yellow, but brown and black.  We also observed that they are very hairy.  We will use these bee sticks to pollinate the flowers so we can move on with this process.  

By KS, HE, JD, MD

  On Days 17 and 18, Thursday and Friday, we pollinated our flowers with our bee sticks. The two pictures above show the pollination process.  We rubbed the bee on the flowers and the pollen stuck to the bee.  We then rubbed our bees on different flowers around the classroom.  The bees have so much hair because the pollen has to stick to their hair as they carry the pollen from one flower to another.

By MB, JW, BB, MP

Also on Days 17 and 18, March 27 and March 28, we observed the Brassica plants and specifically the flowers.  The flowers are blooming each day and are getting bigger.  The flowers have four yellow petals and four green sepals underneath the petals.    Our plants are now between 10 and 20 centimeters tall.  We predict our plants will grow even taller.  We wonder what our flowers will look like on Monday, Day 21.

 By AW, JG, TL, AS