Environmental Engineering Reference
In-Depth Information
Zhang et al. 2007; Ye et al. 2011; Miller et al. 2010). Zhang et al. reported that the zinc finger
protein ZFP182 also mediated the ABA-induced antioxidant defense (Zhang et al. 2012). In
rice, ABA can significantly induce the expression and activity of OsCAT to control the
accumulation of H
2
O
2
under stress (Ye et al. 2011). Recently, ABA was discovered to induce
the production of primary and secondary metabolites, the photosynthetic capacity, the
antioxidant ability and the antioxidant enzymes (Ibrahim and Jaafar 2013).
In recent years, the phytohormone---SA was reported repeatedly to take part in salt stress
responses (Davies et al. 2005). The exogenously SA can ameliorate toxicity stress induced by
salt stress and its vital function under salt stress manifests in its enhancement on antioxidant
system. In periwinkle, non-enzymatic and enzymatic antioxidants can be induced by
exogenous SA (Idrees et al. 2011). In mungbean, SA alleviates decreases in photosynthesis by
means of enhancing antioxidant metabolism (Nazar et al. 2011). Furthermore, SA can lessen
salt stress by maintaining ion homeostasis. We all know that the ion homeostasis especially
the optimum K
+
/Na
+
ratio is crucial for plants under salt stress. Discoveries achieved by non-
invasive microelectrode ion flux estimation (MIFE) technique (Shabala et al. 1997) revealed
that SA pretreatment can enhance K
+
retention, increase H
+
-ATPase activity and reduce K
+
loss under salt stress (Jayakannan et al. 2013). Generally speaking, the potential mechanism
of SA to enhance salt tolerance lies in improving photosynthesis, enhancing antioxidant
protection, maintaining optimum K
+
/Na
+
ratio (Horváth et al. 2007; Jayakannan et al. 2013;
Nazar et al. 2011).
C
ONCLUSION
Salt stress is one of the most common abiotic stresses. Its negative influences on plants
are comprehensive. High concentrations of salt can interfere in the normal growth and
development of plants tremendously and even lead to plant death. Fortunately, plants have
acquired the abilities to ameliorate these adverse effects by physiological, molecular and
genetic regulations. Plants reduce growth rate to guarantee survive and maintain regular
photosynthesis by regulating enzyme activities under salt stress (Zhu 2001). Facing osmotic
stress produced by salt, plants accumulate compatible solutes actively to reduce cell water
potential (Munns and Tester 2008). Different channels and transporters are activated or
inhibited to regulate and maintain ion homeostasis. The clarified signaling pathways tell us
the complicated regulatory mechanisms employed by plants under salt stress. The discovery
of the SOS signaling pathway is the milestone of the signal pathway in salt stress (Liu and
Zhu 1998). The antioxidant system covering non-enzymatic and enzymatic antioxidants
system can help plants escape the harms of the salt stress (Jaleel et al. 2009). Plant hormones
are the growth regulators of plants and they are involved in the processes in every regard, and
the salt stress is no exception. ABA plays a pivotal role in the metabolomics, physiological
and signal procedures. Thus we can come to the conclusion the relationship between salt
stress and plants are the processes of influences and adaptation. Exploring and understanding
the regulatory mechanisms underlying salt stress can provide us with more methods and ideas
to improve plant resistance.
