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A pair (A, B) of interacting oscillators treated as a master system sending signals to its slave copy (a, b) through two communication channels A ⇒ a and B ⇒ b is considered. The effect of non-simultaneous (two-time) synchronization of the pairs (a, A) and (b, B) is demonstrated with the help of coupled Kerr oscillators producing hyperchaos. An individual pair, for example, (b, B) can also be synchronized when its communication channel B ⇒ b is turned off, provided that the second channel for the pair(a, A) is turned on. The resulted synchronization is termed induced. The efficiencies of the presented synchronization precesses are studied.. . This seems to be very impressive as multidimensional systems improve the degree of security in communication. Quite recently, a scheme of dual chaos synchronization has been proposed [25]. In the dual synchronization, signals from two noninteracting master oscillators through a single communication channel are sent to a system containing two corresponding slave oscillators. In this short paper we discuss the possibility of applying a chaos controlling method to achieve synchronization of two different pairs of oscillators. The general set up to be considered is presented in Fig. 1 The master system consists of two coupled oscillators (A, B) which interact with each other ( the symbol α denotes a parameter of interaction between A and B). If α = 0 the master system consists of two independent oscillators. The slave system (a, b) is a copy of the master system. The signals from the two master subsystems (A, B) are transmitted to the their counterparts (a, b) in the slave system by linear feedback functions. The control parameters are * Electronic address: przems@main.amu.edu.pl † Electronic address: grygielk@main.amu.edu.pl ‡ Electronic address: misiak@zon10.physd.amu.edu.pl The synchronization state is achieved if Xa(t) = XA(t) and X b (t ′ ) = XB(t ′ ). The question is whether and when t = t ′ .denoted by S 1 and S 2 , respectively. The slave and masters systems are assumed to start from different initial conditions. As a master system (A, B) let us consider two coupled Kerr oscillators governed by the following equations [26]:

Nowadays, substances stimulating the growth and development of different agricultural plant species are used in intensive farming. Some of such plant growth regulators are Asahi SL and Moddus 250-EC. So far the literature dealing with growth regulators has focused mainly on their effects on deciduous trees. Because no data are available on how those substances affect conifer trees, this paper presents description of experiments on the effects of Asahi SL and Moddus 250-EC on the increase of tree height and branch length of Picea pungens and Thuja occidentalis. The research has proved that morphological features of the plants tested in the experiment varied according to which growth regulator was used and in what month the measurements were taken. Conifer trees sprayed with Asahi SL had a bigger yearly height growth rate and bigger growth of branches than those sprayed with the stimulator Moddus 250-EC.