Taking a closer look at plants

           At the end of this month, we will be having our first field trip to Jepson Prairie Reserve. During our visit, we will be conducting a pollination experiment. The goal of this experiment is to help kids fully understand the purpose of pollination, and the importance of pollinators. In order to prepare the kids for this experiment, I wanted to ensure that everyone was familiar with the structures (and functions) of a plant.
           We started by dissecting a bean (pictures below) in order to take a close look at seed structure and function. The kids were able to see the seed coat, the embryo and its food storage. After this dissection, I showed them some bean seedlings that were growing in a container that allows them to see how seedlings emerge from the soil, and how roots grow into the soil (picture below). I showed them how the food storage (cotyledons) shrinks as seedlings grow, and each kid drew a diagram of a plant, labeling each structure.
           The next step was to take a closer look at flower structure and function. Each child had a flower (Lilium) to dissect (pictures below). I asked them to take the petals out, and we discussed the function of petals. They already knew that pollinators were attracted to the color or smell of petals but they weren't sure why. The kids noticed that the next set of structures were full of pollen, but they didn't know why plants produced pollen. Most kids thought that pollen was produced for insect consumption only. I told them that the remaining structures on their flowers were for reproduction, and told them that plants also use sperm and egg for sexual reproduction. I then asked them to take a closer look at the structures (stamen and pistil) and speculate which structure was responsible for producing each of the gametes. We then talked about how a seed is produced  - the pollen is transferred to another flower, after pollination the pollen grain produces a tube that travels down the female structure of the flower (style) until it reaches the ovary, where the ovules are located. At this point, the nucleus of the pollen tube produces a sperm cell that fertilizes the ovule leading to the production of a seed.
           Our last activity was centered around the botanical definitions of fruits and vegetables. After showing them how seeds are produced, I told them that the definition of a fruit is a mature ovary. This means that all fruits have seeds inside (unless they are genetically altered not to produce seeds). So what is a vegetable? Well, a vegetable is any other part of a plant that is not an ovary. A vegetable can be a root, a stem, leaves, or an inflorescence. We then played a game to help everyone see the difference between fruits and vegetables. I brought a few fruits and vegetables to the classroom, and showed them to the kids one at time asking them whether it was a fruit or a vegetable. If they guessed fruit, we had to find the seeds, and if they guessed vegetable, we had to identify what part of the plant that vegetable was.