Agriculture Reference
In-Depth Information
of these low molecular weight HSPs in chloroplast membranes suggest
that these proteins preserve the PSII from improper impacts of heat stress
and have a major function in transport of photosynthetic electron (Barua
et al., 2003).
10.5
DEVELOPMENT OF HEAT-STRESS TOLERANCE
Heat tolerance is generally defined as the ability of the plant to grow and
produce economic yield under high temperatures. However, while some
researchers believe that night temperatures are major limiting factors,
while others have argued that day and night temperatures do not affect
the plant independently and that the diurnal mean temperature is a better
predictor of plant response to high temperature and day temperature plays
a secondary role (Peet and Willits, 1998).
In general, the negative impacts of abiotic stresses on agricultural pro-
ductivity can be reduced by a combination of genetic improvement and
cultural practices. Genetic improvement entails development of cultivars,
which can tolerate environmental stresses and produce economic yield.
However, adjustment/modifications in cultural practices, such as plant-
ing time, plant density, and soil and irrigation managements, can mini-
mize stress effects. The aim should be to synchronize the stress sensitive
stage of the plant with the most favorable time period of the season. In
recent times, exogenous applications of protectants in the form of osmo-
protectants (proline, Pro; glycine betaine, GB; trehalose, Tre, etc.), phy-
tohormones (abscisic acid, ABA; gibberellic acids, GA; jasmonic acids,
JA; brassinosteroids, BR; salicylic acid, SA, etc.), signaling molecules
(e.g., nitric oxide, NO), polyamines (putrescine, Put; spermidine, Spd and
spermine, Spm), trace elements (selenium, Se; silicon, Si, etc.) and nutri-
ents (nitrogen, N; phosphorus, P; potassium, K, calcium, Ca, etc.) have
been found effective in mitigating high temperature stress induced dam-
age in plants (Barnabás, 2008; Hasanuzzaman et al., 2010b, 2012b, 2012c,
2013b, 2013c; Waraich et al., 2012).
Agricultural productivity can be improved under stress environment by
employing both genetic improvement and adjustment in cultural practices
simultaneously. Agriculturists have long been aware of desirable cultural
practices to minimize adverse effects of environmental stresses on crop
production. However, genetic improvement of crops for stress tolerance
