Environmental Engineering Reference
In-Depth Information
PSI and PSII under salt stress in plants may become a new interesting research issue in the
future.
Gas exchange and chlorophyll a fluorescence are the main tools for plant photosynthetic
analysis, particularly under environmental stress. A series of commercial portable open gas
exchange systems with options for controlling CO
2
, humidity, temperature, and light have
entered the markets (e.g. LI-6400, Li-Cor Inc., Lincoln, Nebraska, USA; CIRAS-II, PP,
System, Hitchin, UK). These off-the-shelf portable systems provide real-time measurements
of CO
2
uptake, transpiration, leaf conductance, and the intercellular CO
2
mole fraction.
Modulated fluorometer (Hansatech, UK; Palm, Waze) and non-modulated fluorometer
(Handy PEA, PEA Senior, M-PEA) also have been widely used for analyzing the properties
of photosynthetic apparatus, and these instruments greatly promote the photosynthetic
research. Under salt stress, gas exchange and chlorophyll a fluorescence are widely adopted
to detect the negative effects on plant photosynthesis. Chlorophyll a fluorescence transient
(O-J-I-P) is the kinetics of fast fluorescence rise process and can be measured by Handy PEA
or PEA (Figure 1). O-J-I-P transient has been accepted as a reliable and popular tool in
photosynthetic research, especially to study PSII behavior in recent years (Wen et al. 2005;
Strauss et al. 2007; Toth et al. 2007; Yang et al. 2007; Chen et al. 2008; Rapacz et al. 2008;
Yan et al. 2008; Li et al. 2009; Mehta et al. 2010; Rapacz et al. 2010; Yan et al. 2011;
Jedmowski et al. 2013). O, J, I and P are a sequence of phases in the kinetics of fast
fluorescence rise, and environmental stress often provokes the occurrence of K phase in this
transient, suggesting the damage to oxygen-evolving complex in donor side of PSII (Strasser
et al. 2004).
Figure 1. Chlorophyll a fluorescence transient measured by Handy PEA in a newly expanded leaf of
sorghum. O, J, I and P indicate the specific steps in this transient.
A method called JIP test has been developed for quantification of OJIP transient using
fluorescence intensity in these phases (Strasser et al. 2004). This test is a powerful tool for in
vivo investigation of the whole PSII function including fluxes of absorption, trapping, and
