Issue: March 2, 1998


Growing an avacodo bush

Question:

Can you help me on how to go about growing an avocado bush?

Answer:

You didn't state where you wish to grow avocadoes. It is not hardy outside in any part of New Mexico. The avocado is a large tropical tree. It can, however, be grown indoors as an ornamental in a greenhouse or well-lighted atrium. It will be difficult to get large enough to produce fruit, and as you described may be best grown pruned as a shrub.

I have grown avocado seeds by planting them in good potting soil and waiting. I used a sandy soil that did not hold too much water and therefore would not stay soggy. To keep from forgetting to water the seeds, I planted some flowers in the pot. By keeping the flowers well watered, I didn't let the avocado seed dry. In one case it took over three months for the seed to germinate and grow. In other cases the seed germinates much more rapidly. I have also stuck tooth picks into the side of the avocado near the broad end and placed the toothpicks across the top of a narrow drinking glass filled with water so that the narrow end of the seed was in the water. In this case I could watch the root begin to grow and plant the seed in soil when the root appeared. Finally, I have just placed the seed into a small plastic drinking cup with just a small amount of water. I closed the top of the drinking cup with plastic wrap held with a rubber band around the top. When the root appeared, I planted the seed. In every case I have had some failures and some successes. It depends upon the maturity of the seed and keeping the seed from rotting while waiting for it to begin to grow.


Flower colors

Question:

My daughter is doing a science project on "Where do flowers get their color?" I was hoping that someone could provide a brief explanation. Anything would be greatly appreciated.

Answer:

While I could write a long explanation, let me start with a brief one. You didn't say what grade she is in, so I don't want to start off over her head. I also apologize if I offend by being too basic.

One of the organelles (or parts of a plant cell) is the vacuole. This is essentially the "storage site" of the cell. Unneeded materials are stored in the vacuole. Some of these are used later as needed, but in many cases they are just stored. Some of the chemicals stored in the vacuole are the pigments (colored chemicals of the plant). Anthocyanin gives red and purple colors to a plant, xanthophylls and caroteniods give orange and yellows, other pigments give other colors. In many cases these pigments reside in the vacuole. In leaves, these colors are hidden by chlorophyll (green) which masks the other colors; however, the shade of green often betrays the presence of the other pigments in the leaves and suggests the colors of the flowers when flowers develop.

Most flowers do not contain chlorophyll, so the chemical pigments in the vacuole are revealed immediately, not having to wait for frost to degrade the chlorophyll as in leaves.

I don't know if you are interested in the following information, but you may find it interesting. The yellow pigments are very useful in shielding plants from excess sunlight and even in passing solar energy to the chlorophyll molecules which use the sun's energy to turn carbon dioxide and water into carbohydrates, food for the plants and for us.