Geoscience Reference
In-Depth Information
Secondary stress
Drought
Heat
Osmotic stress
Oxidative stress
Salinity
Cold
Disruption of
osmotic and ionic
homeostasis.
Deterioration of functional and
structural proteins and
membranes
Osmosensor, phospholipid cleaving
enzyme, MAP kinase, Ca ion sensors and
calcium-dependant protein kinases
Transcriptional factor
(CBF/DREB, ABF, HSF and MYC/MYB)
Chaperone function
HSP, LEA and COR
Detoxification
(SOD and PX)
Gene
activation
Osmoprotection
proline and sugar polyols
Water and ion movement
(aquaporin and ion transporter)
Re-establishment of cellular
homeostasis functional and structural
protection of proteins and membranes
Abiotic stress tolerance
FIGURe 14.2 (See colour insert.) A schematic representation
of plant response to abiotic stress.
the manipulation of genes that protect and maintain the function
and structure of cellular components, the transfer of one or sev-
eral genes involved in either signalling and regulatory pathways,
or encode enzymes present in pathways leading to the synthesis
of functional and structural protectants, such as osmolytes and
antioxidants, or encode stress-tolerance-conferring proteins.
Plant stress can be divided into two primary categories.
Abiotic stress is a physical (e.g. light, temperature) or chemical
insult that the environment may impose on a plant. Biotic stress
is a biological insult (e.g. insects, disease) to which a plant may
be exposed during its lifetime (Figure 14.3). Some plants may
be injured by a stress, which means that they exhibit one or
more metabolic dysfunctions. If the stress is moderate and short
term, the injury may be temporary and the plant may recover
when the stress is removed. If the stress is severe enough, it may
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