NASA - National Aeronautics and Space Administration

OpNom:

Overview | Description | Applications | Operations | Results | Publications | Imagery

Experiment Overview


Brief Summary

The Cambium investigation is one in a pair of investigations which utilizes the Advanced Biological Research System (ABRS). Cambium seeks definitive evidence that gravity has a direct effect on cambial cells (cells located under the inner bark where secondary growth occurs) in willowSalix babylonica.

Principal Investigator(s)

Rodney Savidge, Ph.D., University of New Brunswick, Fredericton, Canada

Co-Investigator(s)/Collaborator(s)

Information Pending

Developer(s)

Bionetics Corporation, Cape Canaveral, FL, United States
Kennedy Space Center, , FL, United States

Sponsoring Space Agency

Canadian Space Agency (CSA)

Sponsoring Organization

Information Pending

Research Benefits

Information Pending

ISS Expedition Duration

October 2009 - March 2010

Expeditions Assigned

21/22

Previous ISS Missions

Cambium is scheduled to arrive on the ISS during the 17A mission. Expedition 19/20 is the first mission for the Cambium investigation.

^ back to top

---

Experiment Description

Research Overview

• The Cambium payload is the first flight of the Advanced Biological Research System (ABRS) facility. The ABRS provides two independent growth volumes capable of providing illumination, thermal control, atmospheric constituent control, and relative humidity control for a variety of plants, microorganisms, or other biological specimens.



• The Cambium research is needed to help understand the fundamental processes by which plants produce cellulose and lignin, the two main structural materials found in plant matter.



• On Earth, various portions of a plant can have physically different compositions including different ratios of lignin and cellulose. One such plant material is called ?reaction wood?. It is believed that this reaction wood may develop in response to the influence of gravity.



• In the Cambium experiment, willow plants will be launched into space and then their stems will be curled into loops in an attempt to induce reaction wood formation. After some amount of additional growth in space, the plants will be preserved for analysis back on Earth to determine whether or not reaction wood was created in the absence of gravity.



• Understanding the role of cellulose and lignin production may enable researchers to control these materials in trees on Earth making those trees more suitable for paper production (more cellulose) or construction strength (more lignin).

Description

The Cambium experiment will provide an understanding of physiological processes such as gene expression, metabolism and general plant development that are affected in plant systems exposed to space flight. Cambium seeks definitive evidence that gravity has a direct effect on the cambial cells (cells located under the inner bark where secondary growth occurs) that contribute to xylogenesis (reaction wood formation) in willow plants, Salix babylonica. Tension wood fibers differentiate on the upper sides of stems when the stem is altered from its normal (vertical) growth position by looping. This reaction wood response does not occur if the orientation of the plant stem with respect to gravity is not altered. If a localized zone of tension wood should be formed in looped stems under microgravity conditions, this would be the first conclusive evidence that gravity is not required. On the other hand, if a zone of tension wood is not produced in looped stems (subjected to tension on one side, compression on the other) in microgravity, this would be the first definitive evidence that gravity has a direct effect on the cambial cells which contribute to reaction wood formation. Following return to Earth the plants will be analyzed by microscopy and chemical methods.

^ back to top

---

Applications

Space Applications

Cambium along with the ABRS hardware demonstrates the capabilities of providing the correct environment for plant growth onboard spacecraft. For future long-duration exploration, crews will need to be able to grow plants for a variety of applications.

Earth Applications

Understanding the fundamental processes by which plants produce cellulose and lignin in their tissues is of great interest in the realm of forestry and industry. Trees used for paper production are selected for maximum cellulose production and minimal lignin production. Conversely, trees used to make structural lumber are selected for maximum lignin content. However, due to the complex relationship of these two biosynthesis processes, researchers do not yet know how to genetically alter such plants to further boost their productivity.

^ back to top

---

Operations

Operational Requirements

Cambium requires a controlled environment provided by the ABRS facility which also provides images that are downlinked to the ground teams. The crew is responsible for stem looping, harvesting, reinitialization, water refill, and changing out the air filter. After harvesting, parts of the samples are chemically preserved and stored in the Minus Eighty-Degree Laboratory Freezer for ISS (MELFI).

Operational Protocols

The crew is responsible for performing the stem looping of the plants by using a looping tool that fashions a loop of reproducible size followed by application of a restraining tape to maintain the looped configuration. After the growth period the plants are harvested by cutting the looped stem and analogous unlooped stems from control plants. These stem portions are then placed into KSC fixation tubes (KFTs) containing chemical preservatives and stored at ambient conditions or frozen in MELFI.

To maintain the environment in the ABRS the crew uses a syringe to transfer approximately 60-mL of water from the ISS potable water source to each of two quick disconnect fittings associated with the two reservoirs inside the ABRS. Air filter change out is performed by opening the front hatch of the ABRS locker, loosening a Velcro restraining strap, and pulling each of the two filters off of the back side of the hatch. There are blind mate connectors on the back side of each filter.

^ back to top

---

Results/More Information

Information Pending

^ back to top

---

Related Websites

CSA - Canada's first study of how trees grow in space

^ back to top

---

Imagery

Image of the Cambium looping tool prototype. Image provided by the Canadian Space Agency.
+ View Larger Image


Looped willow plant and photogrid. Image provided by The Bionetics Corporation, Kennedy Space Center, FL
+ View Larger Image


NASA Image: ISS022E005350 - View of plants in the U.S. Laboratory. Photo was taken during Expedition 22.
+ View Larger Image


CSA Astronaut and Expedition 20/21 crew member Bob Thirsk poses with the Canadian willow trees that were used for the APEX CAMBIUM experiment. These trees have been preserved and frozen, and will return to Earth on STS 130. (Photo: NASA).
+ View Larger Image


Microscopic view of reaction wood fibers as formed on Earth. This is a cross-section of a willow stem that has been 'looped' to stimulate formation of reaction wood.. The reaction wood zone is indicated by a red line. (Photo: CSA)
+ View Larger Image


A weeping willow in St. Bruno de Montarville, Québec, 4 kilometers from the headquarters of the Canadian Space Agency. Weeping willow shoots were used in the APEX CAMBIUM experiment.(Photo: CSA)
+ View Larger Image



+ View Larger Image



+ View Larger Image