关键词: 番茄, 高温胁迫, 亚精胺, 叶绿素荧光

Abstract: Taking a relatively heat-sensitive tomato（Lycopersicon esculentum）cultivar‘Puhong 968’
as test material，a substrate culture experiment was conducted in growth chamber to investigate the effects
of foliar spraying spermidine（Spd）on the protection in tomato seedling leaves under high temperature
stress. The heat treatment at 38 ℃ significantly altered the shape of O-J-I-P fluorescence transient. An
increase in basal fluorescence and decrease in maximum fluorescence was observed. Higher K，J，L-band
and lower I-band were detected compared to control samples at 130 μs，300 μs，2 ms and 30 ms on the
cholorophyll fluorescence induction curve. High temperature stress significantly increased the values of
ABS/RC，TRo/RC，DIo/RC，φDo，Mo，and Fv/Fm，but decreased ETo/RC，PI(abs)，Sm，DF(abs)，Ψo，RC/CSo and φEo in leaves. However，Spd treatment reverted these changes induced by high temperature stress. Spd
resulted in a better utilization of excitation energy and a higher stability of the photosystemⅡ，causing
much enhancement of the oxygen evolving complex capacity，thermal stability of thylakoid membranes，
connectivity among PSⅡ units and electron transport activity. Meanwhile，positive effects showed up in
the photosynthetic pigment contents and growth in tomato seedling by heat treat treated with Spd.

Key words: tomato, high temperature stress, spermidine, chlorophyll fluorescence