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- Author or Editor: I. Csiszár x
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Summary A class of numerical measures of informativity of observation channels or statistical experiments is defined by the aid off-divergences introduced by the author as measures of difference of two probability distributions. For observation channels with given prior probabilities, thef-informativity measures are generalizations of Shannon's mutual information and include Gallager's functionE 0(ϱQ) appearing in the derivation of error exponent for noisy channels, as well. For observation channels without prior probabilities, the suggested informativity measures have the geometric interpretation of a radius.
The aim of the present study was to investigate the effect of salicylic acid (SA) pre-treatment on the salt stress acclimation of tomato plants ( Lycopersicon esculentum Mill. L. cv. Rio Fuego). The antioxidant defence and detoxifying capacity of the tissues were analysed by measuring the accumulation of soluble, non-enzymatic antioxidants (anthocyanins) and the activities of glutathione S-transferases (GSTs) at low (10 −7 M) and high (10 −4 M) SA concentrations in plants exposed to 100 mM NaCl. GSTs are a diverse group of enzymes that catalyse the detoxification of xenobiotics and other toxic organic compounds, and anthocyanins are among the few endogenous substrates that bind to GSTs and are sequestered to the vacuole. It was found that 10 −4 M SA pre-treatment improved the acclimation of tomato to high salinity. SA pre-treatments increased the accumulation of anthocyanins both in the presence and absence of 100 mM NaCl. The extractable GST activity of tissues increased under salt stress in young leaves and roots of the control and in plants pre-treated with 10 −4 M SA, while the extractable GST activity in these organs was reduced by 10 −7 M SA. It is suggested that elevated GST activity is a prerequisite for successful acclimation to high salinity in tomato plants pre-treated with SA, but it may also be a symptom of tissue senescence.
