Fall Seeds

My apologies to Mr. Rawitsch and the 1st grade classes at Glenmont Elementary for this late entry in my blog. Thank you, Mr. Rawitsch, for the pictures here. I hope that you and the first grade teachers and students enjoy it even though it is late – better late than never?!?

Autumn is a great time to explore seeds in the outdoor science laboratory that is a school yard. At Glenmont I had the chance to take the 1st grades outside to what they call the Big Backyard (and what I call my outdoor science laboratory) to look for and learn about seeds. An easy task, since in the fall seeds are just about everywhere.

Our exploration started with looking at the different parts of plants. One of the most obvious parts of plants are the leaves. And what do leaves do? “Green Leaves Make Food” was our chanted response to that question. The food made by the leaves is used by the plant to help all the parts of the plant to grow. Some of that food remains in the leaf and is eaten, like this grape (Vitis species) leaf we found that had been eaten by Japanese beetles (Popillia japonica). Do the leaves become the seeds? No.

We then looked at the roots of plants, in this case, crab grass (Digitaria genus). What do roots do? Well we borrowed a rhyme from Billy B (see the Billy "B" link) to help us remember – “The roots grow deep, deep into the ground, search for water, drink it when it’s found”. Do the roots become seeds? No.

Neither do the stems or branches. So what does turn into the seeds? Flower turn into seeds. That became our chant – “Flowers turn into seeds!” How do flowers turn into seeds? Well they need to be pollinated. Many flowers are pollinated by insects and other small animals. The flower colors and smell attract these creatures. It’s as if the flowers were saying, “Eat here. Eat here. Eat here.” When the insects visit for a meal of nectar and pollen they spread some of the pollen to parts of the flower that will grow into seeds. We call this pollination. We found some flower buds for bittersweet nightshade (Solanum dulcamara). Right on the same vine we found nightshade fruit. Fruits are a seed container.

Looking at the nightshade leaves, flower and fruit we could see that it looked a bit like tomatoes. That’s because nightshade is related to tomatoes and potatoes. They all belong in a group that scientist call a family. The name of this family is Solanaceae. Although they belong in the same family as tomatoes and potatoes, nightshade fruit are poisonous to people. Since nightshade is similar to tomatoes we wondered if they would have as many seeds as a tomato does. We found out by squishing open a nightshade fruit. The fruits we opened had about 20 to 30 seeds in them – lots of seeds in a fruit just like tomatoes.

Brightly colored fruits like the nightshade and grape attract animals. Their colors say to the animals “Eat me!” Here we see a grape that we’ve squished open. Inside the grape we found several seeds. While the juices and fleshy parts of the fruit are digested in the animal’s stomach the seeds would continue to travel through the animal’s digestive system. It would eventually be deposited somewhere when the animal goes to the bathroom. If the seeds end up where there is plenty of soil, water and sunlight it might grow into a plant far from the parent plant. The plant has helped out the animal by providing food. The animal helps the plant out by spreading plant seeds about the environment.

Here is a cherry (Prunus species) seed that was deposited on a wooden fence in the school yard. It probably got there by traveling in a bird’s digestive system. Not all seeds travel inside animals. What other ways might a seed be dispersed?

So much to learn about seeds, right outside the school doors, in the science laboratory that is the schoolyard!