Physiological control of plant growth: a role for the clock?

In the cultivation of ornamental plants, and some vegetables, certain growth characteristics are considered undesirable. Excessive elongation growth decreases overall plant quality and is a major concern in (floral) horticulture.

To achieve more compact and better-shaped plants, chemical growth retardants are commonly used. However, their application is costly and environment- unfriendly. The need to find effective, environment-friendly, strategies for regulating plant height is one of the goals in future production of floricultural crops. We want to investigate the physiological basis of negative DIF and phosphate on elongation growth, since their mode of action is poorly understood. By providing insight into these processes on a fundamental level we aim to help breeders and cultivators develop more efficient methods of improving plant quality.

There are several methods to manipulate plant growth in greenhouses. In this research the focus is on the modification of temperature cycles (DIF treatment) or reducing the amount of applied phosphate fertilizer during cultivation of plants in the greenhouse. Both of these treatments result in compact plants but it is not known what the underlying mechanism is of these treatments. Understanding the mechanism could result in more fine-tuned plant growth manipulations.

Our approach:

How may differential temperature treatment lead to the control of plant elongation? Plants have an endogenous circadian clock which is entrained by light and temperature. Therefore, we have as working hypothesis that the DIF temperature treatments upset the output of the circadian clock. This is monitored using clock reporter genes and clock mutants.