| 【Ojective】The objective was to study the diurnal variation of chlorophyll fluorescence of different
Coffea varieties and its correlation with environmental factors, and to explore the adaptability of Coffea to the environment
for providing a basis for the cultivation of Coffea varieties adapted to local climate. Study the adaptation of Coffea to their
environment in order to provided references for breed varieties. 【Method】The chlorophyll fluorescence parameters and
SPAD of four Coffea cultivars(Coffea liberica, Coffea robusta, Coffea arabica Catimor 2 and Catimor 3) were measured by
modulated chlorophyll fluorescence fluorometer (pulse-amplitude-modulation FMS-2) and hand-held chlorophyll analyzer respectively. 【Results】The diurnal variation of Fo of Coffea liberica and Coffea arabica Catimor 2 is in “M” shape, the
diurnal variation of Fo of Coffea liberica and Coffea arabica Catimor 2 is in “M” shape, while that of Coffea robusta and
Coffea arabica Catimor 3 is in “V” shape . At 15:00, Fo of Coffea liberica decreased significantly, with the minimum value
183.20, and that of Coffea robusta reached the maximum value of 262.60. At 17:00, Fo of Coffea arabica Catimor 3 reached
the maximum value of 199.44. Fo of Coffea arabica Catimor 2 was lower than that of the other three Coffea varieties for most of
the day session. The diurnal variation of Fv/Fm of four Coffea varieties is in “V” type curve. Except that the lowest point of
Coffea robusta was 0.65 at 13:00, the other varieties were 0.60, 0.66 and 0.65 at 15:00 respectively. The correlation analysis
showed that, Coffea robusta and Coffea arabica Catimor 3 have correlation with environmental factors such as temperature,
relatively humidity and solar radiation intensity while Coffea liberica has a significant negative correlation with relative humidity
and Coffea arabica Catimor 2 has a significant positive correlation with relative humidity. The correlation between SPAD and
four varieties is not significant. 【Conclusion】In the day, under strong solar radiation, high temperature and low air humidity
conditions, Coffea liberica protect itself mainly by increasing thermal dissipation, Coffea robusta, Coffea arabica Catimor 2 and
Catimor 3 mainly take the reversible inactivation and damage of PSII reaction center as the protection mechanism. And Fv/Fm
of four Coffea varieties decreases first and then increases, showing the reversible inactivation of PS Ⅱ reaction centre of Coffea
arabica Catimor 2, Catimor 3 and Coffea robusta. Fo of Coffea arabica Catimor 2 is lower than that of the other three varieties for
most of the day and its Fv/Fm is higher, so more energy is used for photoreaction. |
