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Hormonal and enzymatic factors are major elements in the control of the abscission process. In this study, the roles of indole-3-acetic acid (IAA, auxin), one of the most important hormones, and cellulase ($\beta$-1,4-glucan 4-glucanohydrolase, EC 3.2.1.4), the major enzyme involved in abscission process, were studied in coleus (Coleus Blumei Benth cv. Ball 2179 Red). An evaluation of leaf loss in greenhouse grown plants suggested that abscission occurred more at the branches located deep in the plant canopy and started from the oldest node. This pattern of abscission may be related to a decline in red light and in the ratio of red to far-red light within the canopy, resulting in a decrease in auxin synthesis in plant tissues located deep in the canopy. If light was eliminated, abscission of leaf or petiole explants was dependent on an auxin gradient across abscission zones at old nodes. Studies on auxin movement indicated that auxin transport in young tissue was faster than in old tissue. Differences in auxin transport between young and old tissue would induce differences in the auxin gradient for young and old nodes. While the abscission pattern was influenced by this gradient, tissue age was also important in the level of response to the gradient. Older nodes were more sensitive to auxin gradient than younger nodes. Leaf abscission at old nodes appeared controlled by an auxin gradient. Studies on cellulase indicated that the majority of cellulase activity from leaf abscission zones of coleus could be extracted by phosphate buffer containing no salt, suggesting a difference in the active form of the cellulase in abscission zone of coleus from the previously reported cellulase in the abscission zone of bean (Phaseolus vulgaris L. cv. Red Kidney) plants. Coleus cellulase has an isoelectric point of 4.7 and is present only in abscising tissue. A time-course study of abscission and cellulase activity indicated that an increase in cellulase activity is associated with abscission. Ethylene promoted cellulase activity whereas IAA inhibited activity in abscission zones compared with the activity in untreated controls, consistent with the effects of ethylene and IAA on abscission. By native polyacrylamide gel electrophoresis (PAGE), two cellulase isozymes were identified, both of which appeared necessary for abscission. Cellulase from abscission zones of coleus was further purified by a combination of gel filtration, and anion exchange and affinity chromatography. Both silver-stained sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and cellulase activity-stained native PAGE exhibited 2 bands of purified protein, suggesting two isozymes. The 2 proteins with molecular weights of 56 and 62 kD were apparently monomers. A test of cellulase activity indicated high levels of activity at pH 5 and pH 7.2. Cellulase activity increased with increase in reaction temperature to 50$\sp\circ$C. Purified cellulase showed no activity towards insoluble cellulose.

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The subject of landscape painting was largely overlooked for centuries in Western art. When the Renaissance artists rediscovered the beauty of natural forms, some painters expanded the bodies of their work to include the landscape. Nature was viewed very differently in China and Japan. Images from nature have special meaning to the Oriental artist, who sees in their simple, flowing rhythms the key that unlocks the Tao and brings to the surface the inner workings of tranquility. A harmony with the ebbs and flows of the forces of nature serve to inspire both the hand holding a paintbrush and the other hand writing a poem. Many landscape paintings feature the drama of the mountains or serve as a backdrop to human activity. Rare are the European or American painters who look past the majestic expanse of sky to focus their attention on the less impressive denizens of the swamp. It is in the moist, out of the way places that we come across the unassuming plant called moss. The purpose of this work is to cast a little more light on the value of moss and its habitat as a landscape subject. It is also important to consider how the qualities we observe in moss can inspire contemplation in us. An appreciation for moss may result in an increased awareness and respect for its ecological environment. I have sought to present moss as a landscape subject through the media of oil painting, etching and ceramic sculpture. Like the art pieces, the poems are personal responses to the ever moving particulars of nature and the drive for a cohesive framework that gives the particulars meaning.

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