It is 3:30 p.m. on a Friday afternoon, and the man in the white lab coat in the campus greenhouse is standing next to a healthy looking tobacco plant, staring intently at the testing kit in his hand.

"We've got a positive in here," he says, meaning the plant has just tested positive for Tobacco Mosaic Virus (TMV), the scourge of the greenhouse world. So while most Cornell employees are heading home for the weekend, the greenhouse staff will instead be quarantining the greenhouse section and setting in place sophisticated monitoring, isolation and cleaning operations to contain the virus.

"TMV is the Ebola of the plant world," says Andy Leed, the newly appointed manager of the College of Agriculture and Life Sciences' greenhouse operations. "Our staff has gotten good at spotting it in the very early stages, so we can get it under control."

Virus detective is only one of the many roles Cornell's greenhouse employees fill on a daily basis. The set-up, care and maintenance of more than 200 plant projects -- from transgenic corn that grows 18-inch ears and switchgrass for biofuels research to rare species of African trees -- go well beyond the fertilizing, watering and pruning that most people associate with plant maintenance.

Each plant project has a different research, teaching or educational purpose. All require special care. Some plants must be maintained at constant temperatures, others watered at specific times, or not at all, to simulate drought conditions. Some plants in what Leed calls the "hot zone" are purposely inoculated with plant pathogens or are grown as food for certain species of insects being studied by Cornell entomologists and ecologists. Then there are popular garden plants, like the red and white geraniums, grown by the hundreds that the university uses for commencement ceremonies and other special occasions.

To streamline operations, the Cornell University Agricultural Experiment Station (CUAES) recently assumed responsibility for the greenhouses and consolidated management operations that were previously controlled by multiple departments with diverse needs and requirements.

"Cornell's greenhouses have a rich history and quality staff, supporting research and teaching and providing Cornell faculty and students and sometimes the public with greenhouse experiences and services that are unparalleled in the state," says Mike Hoffmann, director of CUAES. "We are fortunate to have such a valuable resource available to us on campus"

With 163 separate compartments -- the largest noncommercial greenhouse operation in the state -- Cornell's greenhouses are multipurpose teaching and research facilities and, in some buildings, public observatories. One such greenhouse that is open to the public is the Purple Conservatory, which is attached to the Plant Sciences Building on Tower Road. It houses more than 500 species of plants alone, each requiring a different level of care -- from the giant flowering tree from Brazil stretching to the top of the greenhouse roof to the delicate bead-on-a-string from Africa.

"There's an incredible range of teaching and research projects in the CALS greenhouses, and there are always new faces and new challenges to keep it interesting," says Leed, who took over as manager of the 155,000-square-foot facilities this past April.

In addition to the restructuring, the College of Agriculture and Life Sciences has devoted approximately $800,000 to facilities upgrades in the past two years, including just-completed construction of a new greenhouse with state-of-the-art temperature, humidity, lighting, shading and irrigation controls that will allow a whole new level of scientific research, says Hoffmann.

Lauren Chambliss is a communications specialist with the Cornell Agricultural Experiment Station in Ithaca.