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The role of root apices in shoot growth regulation |
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Peter M Neumann |
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Department of
Environmental , Water & Agricultural Engineering, Civil and Environmental Engineering Faculty,
Technion-Israel Institute of Technology, Haifa 32000, Israel |
| *email:
agpetern@techunix.technion.ac.il
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Long
distance communication between roots and shoots of higher plants is essential for regulating whole plant
adaptations to environmental changes. For example, decreased availability of essential mineral nutrients or
water in the soil is often followed by a seemingly adaptive inhibition of shoot growth. Chemical, hormonal,
electrical or hydraulic signals may be used to transmit status information between plant organs. The roots
will clearly be the first to generate such signals in response to rhizosphere changes. Whether active neuronal
type changes in the root apices or simple passive changes are required in order to generate and transmit such
information to the developing shoots, is the subject of this chapter. Several examples of laboratory
experiments in which roots appear to respond actively in response to changes in nutrient or water availability
are first discussed. However, other examples indicate that shoot responses to rhizosphere changes can occur
without the active intervention of root apices. The conclusion is that while neuronal types of communication
may occur in plants, they are not always essential for early plant growth responses to environmental
changes. |
