BSC 196 Lecture Notes - Lecture 22: Gynoecium, Stamen, Zygote

• School: ISU
• Department: Biological Sciences
• Course: BSC 196
• Professor: sakaluk

Document Summary

Apical meristems are located at the tips of roots and shoots: apical meristems elongate shoots and roots, a process called primary growth. Lateral meristems add thickness to woody plants, a process called secondary growth. There are two lateral meristems: the vascular cambium and the cork cambium. The vascular cambium adds layers of vascular tissue called secondary xylem (wood) and secondary phloem. The cork cambium replaces the epidermis with periderm, which is thicker and tougher. The innermost layer of the cortex is called the endodermis. The endodermis regulates passage of substances from the soil into the vascular cylinder. In most eudicots, the vascular tissue consists of vascular bundles arranged in a ring. In most monocot stems, the vascular bundles are scattered throughout the ground tissue, rather than forming a ring. Leaves contain specialized pores called stomata: allow gas exchange between plant and environment, major site for water loss (evaporation) Guard cells regulate opening and closing of stomata.