^pUniversitat;
Hannover,;
Institute;
of;
Floriculture;
and;
Wood;
Science,;
Section;
of;
Applied;
Molecular;
Physiology,;
Herrenhauser;
Strasse;
2,;
D-30419Hannover,;
Germany;
^paddress:;
Institute;
of;
Plant;
Research,;
ETH,;
Universitatstr.;
2,;
8092,;
Zurich,;
Switzerland;
^paddress:;
ZMBP,;
University;
of;
T~bingen,;
Auf;
der;
Morgenstell;
28,;
D-72076;
Tubingen,;
Germany;