|MadSci Network: Botany|
No, trees do not have a heartbeat because they have no heart or pump. The driving force for water movement upward in the tree trunk is the evaporation of water from the leaves. The water is literally pulled up the trunk because the thin water columns in the narrow diameter tubes, called xylem, are held together tightly by the strong attraction of water molecules to each other. Root cell membranes prevent dissolved mineral nutrients, or ions, from being sucked into the cells. However, roots can "suck in" mineral nutrients into the intercellular spaces of the roots outside the vascular cylinder in the center of the root. Most mineral nutrients are actively tranported across the cell membrane or plasma membrane. That enables the root to be selective in what ions it absorbs and also prevents the absorbed ions from leaking back out of the cells. References Re: I need information on the circulatory (vascular) system of plants Re: Xylem vs. phloem transport directions Transport of Water and Minerals in Plants
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