The role of plasticity in the acclimation of desert plants to their environment
To
date, very little is known about the molecular mechanisms underlying
the acclimation of plants to their habitat. This knowledge is crucial
because in nature, unlike the controlled conditions used in the
laboratory, a large number of different parameters may affect the plant
simultaneously. To study the response of plants to changes in
environmental conditions within their ecosystem we study the evergreen
C3 desert legume Retama raetam. We use plants that grow naturally
within an arid dune ecosystem (located along the Israeli-Egyptian
border in Nizzana; see, http://aerc.es.huji.ac.il/), and we correlate
all of our findings to environmental parameters recorded at the
research site by data loggers. Our analysis includes physiological
measurements of plants in the field and molecular analysis of samples
collected from the field in the lab. Our studies revealed that the R.
raetam uses an acclimation strategy of partial plant dormancy to
acclimate to its ecosystem. We cloned different genes associated with
dormancy in this plant, and we are in the process of studying whether
the plasticity observed in the cycles of dormancy and growth in this
plant are crucial for its survival within the harsh desert habitat.
Mittler,
R., Merquiol, E., Hallak-Herr, E., Kaplan, A., and Cohen, M. (2001) Living under a "dormant" canopy: a molecular
acclimation mechanism of the desert plant Retama raetam. Plant J. 25, 407-416.
Pnueli,
L., Hallak-Herr, E., Rozenberg, M., Cohen, M., Goloubinoff, P., Kaplan,
A. and Mittler, R. (2002) Molecular and biochemical mechanisms associated with dormancy and drought tolerance in the desert legume Retama raetam. Plant J. 31, 319-330.
Mittler, R., Merquiol, E., Hallak-Herr, E., Kaplan, A., and Cohen, M. (2002) Seasonal and diurnal variations in gene expression in the desert legume Retama raetam. Plant Cell & Environment. 25, 1627-1638.