Many fundamental aspects of leaf development and pattern formation in plants are poorly understood. This research will use a species of aquatic plants to study the development of two specific tissue types - stomata and lateral veins (i.e. vascular tissue) - in leaves. This plant possesses unique advantages for this research because the two tissue types are normally absent on submerged plant leaves, but they can be induced to differentiate on plants exposed to the plant growth regulator abscisic acid (ABA). Thus, this system presents an opportunity to study alternative modes of development against a uniform genetic background. The proposed research will examine the relationship between microtubule orientation and ABA-induced stomatal development using a combination of immunofluorescence microscopy and microtubule- disrupting drugs. ABA-induced vascular development will be studied through a combination of experiments. Finally, a fundamental study will be a made of the relationship of ABA to cell division rates in developing Hippuris leaves. Results obtained from this research will increase understanding of stomatal and vascular development both in Hippuris vulgaris specifically and in plants in general. Z^//
