1. Dept of Plant Science, Univ. of Connecticut, Storrs, CT 06269, USA
2. Institute of Experimental Botany, The Academy of Sciences of the Czech Republic, Rozvojová 135, 165 02 Prague 6, Czech Republic
3. De Montfort Univ. Norman Borlaug Centre for Plant Science, Institute of Experimental Botany, The Academy of Sciences of the Czech Republic, Rozvojová 135, 165 02 Prague 6, Czech Republic