Phloem is for “Phood”

Cercidium  sp. - Palo Verde Tree @PBG 2004apr18 LAH 003Last week’s post about xylem explained how it carries water from the roots to the rest of a plant. But there’s another transportation problem that plants have to solve. As you know, plants make food (sugars) through photosynthesis. (See my previous posts on photosynthesis.) This food factory requires both chlorophyll and sunlight, and can only take place in the green parts of a plant. Usually this means the leaves, although cacti and other xeric species (such as this Palo Verde, above right) often have chlorophyll in their stems.


Botany for Gardeners: Phloem & Xylem

Aspen_EmeraldValley-CO_LAH_4270Today’s (and next week’s) botany lessons are brought to you by “xylem” and “phloem.” You may remember these terms from a biology class, but I bet you haven’t used them lately. It’s time you did. You’ll be a better gardener as a result. Besides, I used to teach biology, and once a teacher, always a teacher. There will even be a quiz at the end.

Like all forms of life, plants have to solve a very important problem: how do you move nutrients and water from one part of your body to another? Animals (at least the more complicated ones) have a circulatory system, but what do plants do?