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Lacy Leaves

based on 9 ratings
Author: Jane Healey
Topics: Sixth Grade, Botany

Grade Level: 6th; Type: Botany

Objective:

The goal of this project is to reveal the vein structure or venation of leaves. The process of dissolving the soft plant tissue from leaves is a means of removing flesh, cleanly exposing vein patterns. Since subclasses of plants have distinct patterns, students can determine the class of the sample based on the visible venation.

Research Questions:

  • What are the characteristics of monocot and dicot venation patterns?
  • What may account for the differences?

Scientists classify plants as either monocots or dicots. Monocot plants are the older of the two classes and have parallel venation patterns. Dicots evolved later and have a more sophisticated branched venation. The skeletons of the samples will demonstrate the difference between monocots and dicots. 

This project teaches students the process of skeletonizing plant samples and comparing characteristics to classify plants.

Materials:

  • Several broad leaf-samples (ivy, oak, maple, etc.)
  • Several narrow-leaf samples (spider plant, lily, etc.)
  • Shallow pan
  • Baking soda
  • Measuring cup
  • Paper towels
  • Shallow bowl
  • Bleach
  • Tweezers
  • Wax paper
  • Heavy book
  • Washer
  • Black construction paper
  • Spray varnish
  • Logbook

Experimental Procedure:

  1. In a shallow pan mix 1 teaspoon of baking soda with 2 cups of warm water.
  2.  Add samples of broad and narrow leaves, making sure that the leaves sink to the bottom of the pan. Place a washer on any leaf that floats.
  3. Place the pan in a sunny location and observe everyday for approx. 2 weeks. (Do not disturb the pan during observations.)
  4. Record observations in a log.
  5. When the flesh of the leaves fully dissolves, use tweezers to carefully remove the samples.
  6. Rinse each sample in a bowl of clean water and place on a paper towel to dry.
  7. When the samples are dry, place them on a sheet of wax paper. Cover the samples with another sheet of wax paper and place a heavy book or other weight on top.
  8. After several days, remove the weight and wax paper.
  9. Pour ½ cup of bleach into a shallow bowl and add 2 cups of water.
  10. Carefully submerge the samples in the bowl of bleach until they whiten. Remove the samples and place on paper towels to dry.
  11. Place the skeleton of the sample on black construction paper to view the veins.
  12. Under supervision, gently spray the skeletons with a thin coat of varnish to preserve and display them.

The logbook of daily observations and photographs can serve as a chronicle of the projects process:

 
Day
Observation
1
 

No noticeable alterations.

2
 

A feint loss of color around the edges of the broad-leaf samples. No noticeable changes to the narrow leaves.

 
3
 

Discoloration creeping internally on the broad-leaf samples gradually bleaching the green to white. The edges of the narrow-leaf samples beginning to lose color, too.

 
Etc.
 
 
 

Terms: Dicot (dicotyledons); Monocot (monocotyledons); Venation

References:

 

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