On a trip to the Southwest,you and a friend collect some seeds from a piñon,which is a type of pine tree.Your friend also gathers a small bagful of soil from under the piñon tree.Back home,both of you plant your seeds in commercial sterilized potting soil,but your friend adds a spoonful of the collected dirt to each of her pots.Her seedlings do better than yours.Which of the following is the likeliest reason?

Question

Quizplus · Accepted Answer

The likeliest reason that the friend's seedlings did better is that the soil from under the piñon tree probably contained fungi that were able to establish a mycorrhizal association with the seedlings' roots. Mycorrhizae are symbiotic associations between fungi and plant roots in which the fungi provide the plant with nutrients, particularly phosphorus, in exchange for carbohydrates produced by the plant. Commercial potting soil is typically sterilized, meaning that it does not contain any beneficial microorganisms like mycorrhizal fungi.

On a Trip to the Southwest,you and a Friend Collect